TY  - CONF
AU  - Mihajlović, Dragana R.
AU  - Rakin, Marko P.
AU  - Međo, Bojan I.
AU  - Đokić, Veljko R.
PY  - 2024
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7382
PB  - Vancouver : Peers Alley Media
C3  - 6th edition of Advanced Materials Science World Congress, Adv. Materials Science 2024, March 21-22, 2024
T1  - Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application
EP  - 40
SP  - 39
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7382
ER  - 

@conference{
author = "Mihajlović, Dragana R. and Rakin, Marko P. and Međo, Bojan I. and Đokić, Veljko R.",
year = "2024",
publisher = "Vancouver : Peers Alley Media",
journal = "6th edition of Advanced Materials Science World Congress, Adv. Materials Science 2024, March 21-22, 2024",
title = "Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application",
pages = "40-39",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7382"
}

Mihajlović, D. R., Rakin, M. P., Međo, B. I.,& Đokić, V. R.. (2024). Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application. in 6th edition of Advanced Materials Science World Congress, Adv. Materials Science 2024, March 21-22, 2024
Vancouver : Peers Alley Media., 39-40.
https://hdl.handle.net/21.15107/rcub_technorep_7382

Mihajlović DR, Rakin MP, Međo BI, Đokić VR. Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application. in 6th edition of Advanced Materials Science World Congress, Adv. Materials Science 2024, March 21-22, 2024. 2024;:39-40.
https://hdl.handle.net/21.15107/rcub_technorep_7382 .

Mihajlović, Dragana R., Rakin, Marko P., Međo, Bojan I., Đokić, Veljko R., "Microstructure, mechanical and corrosion properties of anodized ultrafine-grained titanium based materials for medical application" in 6th edition of Advanced Materials Science World Congress, Adv. Materials Science 2024, March 21-22, 2024 (2024):39-40,
https://hdl.handle.net/21.15107/rcub_technorep_7382 .

TY  - CONF
AU  - Rakin, Marko
AU  - Mihajlović, Dragana
AU  - Međo, Bojan
AU  - Đokić, Veljko
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6294
AB  - The Ti-13Nb-13Zr alloy made by conventional methods (coarse-grained, CG) was examined, as well as the alloy and commercially pure titanium (cpTi) after the high pressure torsion (HPT) process (ultrafine-grained, UFG) performed at room temperature. All materials were subjected to nanostructured surface modification. Nanostructured surface modification was done in 1M H3PO4 + 0.5 wt. % NaF electrolyte during 60 and 90 minutes, for the desired potential of 25V with a scan rate of 100 mVs-1. As the result of the nanostructured surface modification nanotubular titanium based oxide layer was obtained.
Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the homogeneity of nanotubular titanium based oxide layer and dimensions of the formed nanotubes. In order to define the chemical structure of oxide layer, energy dispersive spectroscopy (EDS) was used. The obtained results indicate that the duration of the nanostructured surface modification significantly affects on the homogeneity of the nanotubular titanium based oxide layer morphology, as well as on the dimensions of the nanotubes (diameter and wall thickness of the nanotubes). Also, the effect of the HPT process on the homogeneity and thickness of the nanotubular oxide layer (length of the nanotubes) are shown and discussed.
The mechanical behavior of nanotubular titanium based oxide layer was examined by nanoindentation test. The control of nanoindentation test was done by total displacement. The displacements were 2000 nm for non-modified surface and 10% of the thickness of nanotubular titanium based oxide layer for modified surface. The test was performed on a nanoindenter using as an indenter the Berkovich-type diamond tip. As results, loading-displacement curves and the mean value of ten measurements of the surface modulus of elasticity and nanohardness were obtained. Also, in order to characterize deformation of the oxide layer after nanoindentation SEM was done. Having in mind that nanotubular oxide thin layer can affect tensile properties of metallic materials, tensile testing was performed.
PB  - InovSciTech No. 302, Uttarahalli, Bangalore-560061, India
C3  - 6th Global Webinar on Materials Science & Engineering (GWMSE-2023), The International Research Conference
T1  - Structural and mechanical behavior of titanium based oxide thin layer for biomedical application
EP  - 15
SP  - 14
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6294
ER  - 

@conference{
author = "Rakin, Marko and Mihajlović, Dragana and Međo, Bojan and Đokić, Veljko",
year = "2023",
abstract = "The Ti-13Nb-13Zr alloy made by conventional methods (coarse-grained, CG) was examined, as well as the alloy and commercially pure titanium (cpTi) after the high pressure torsion (HPT) process (ultrafine-grained, UFG) performed at room temperature. All materials were subjected to nanostructured surface modification. Nanostructured surface modification was done in 1M H3PO4 + 0.5 wt. % NaF electrolyte during 60 and 90 minutes, for the desired potential of 25V with a scan rate of 100 mVs-1. As the result of the nanostructured surface modification nanotubular titanium based oxide layer was obtained.
Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the homogeneity of nanotubular titanium based oxide layer and dimensions of the formed nanotubes. In order to define the chemical structure of oxide layer, energy dispersive spectroscopy (EDS) was used. The obtained results indicate that the duration of the nanostructured surface modification significantly affects on the homogeneity of the nanotubular titanium based oxide layer morphology, as well as on the dimensions of the nanotubes (diameter and wall thickness of the nanotubes). Also, the effect of the HPT process on the homogeneity and thickness of the nanotubular oxide layer (length of the nanotubes) are shown and discussed.
The mechanical behavior of nanotubular titanium based oxide layer was examined by nanoindentation test. The control of nanoindentation test was done by total displacement. The displacements were 2000 nm for non-modified surface and 10% of the thickness of nanotubular titanium based oxide layer for modified surface. The test was performed on a nanoindenter using as an indenter the Berkovich-type diamond tip. As results, loading-displacement curves and the mean value of ten measurements of the surface modulus of elasticity and nanohardness were obtained. Also, in order to characterize deformation of the oxide layer after nanoindentation SEM was done. Having in mind that nanotubular oxide thin layer can affect tensile properties of metallic materials, tensile testing was performed.",
publisher = "InovSciTech No. 302, Uttarahalli, Bangalore-560061, India",
journal = "6th Global Webinar on Materials Science & Engineering (GWMSE-2023), The International Research Conference",
title = "Structural and mechanical behavior of titanium based oxide thin layer for biomedical application",
pages = "15-14",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6294"
}

Rakin, M., Mihajlović, D., Međo, B.,& Đokić, V.. (2023). Structural and mechanical behavior of titanium based oxide thin layer for biomedical application. in 6th Global Webinar on Materials Science & Engineering (GWMSE-2023), The International Research Conference
InovSciTech No. 302, Uttarahalli, Bangalore-560061, India., 14-15.
https://hdl.handle.net/21.15107/rcub_technorep_6294

Rakin M, Mihajlović D, Međo B, Đokić V. Structural and mechanical behavior of titanium based oxide thin layer for biomedical application. in 6th Global Webinar on Materials Science & Engineering (GWMSE-2023), The International Research Conference. 2023;:14-15.
https://hdl.handle.net/21.15107/rcub_technorep_6294 .

Rakin, Marko, Mihajlović, Dragana, Međo, Bojan, Đokić, Veljko, "Structural and mechanical behavior of titanium based oxide thin layer for biomedical application" in 6th Global Webinar on Materials Science & Engineering (GWMSE-2023), The International Research Conference (2023):14-15,
https://hdl.handle.net/21.15107/rcub_technorep_6294 .

TY  - CONF
AU  - Mihajlović, Dragana
AU  - Rakin, Marko
AU  - Veljović, Đorđe
AU  - Međo, Bojan
AU  - Đokić, Veljko
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7011
AB  - The coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloy (TNZ) were used as tested materials in this
study. UFG alloy was obtained using a high-pressure torsion process (HPT) at room temperature, with 5 rotations, and
with 4.1 GPa pressure. After that, the surface was modified using electrochemical anodization in the 1M H3PO4 + NaF
electrolyte, for 60 and 90 minutes.
Scanning electron microscopy (SEM) was used to characterize the morphology of the modified surface after
electrochemical anodization. In order to determine whether the electrochemical anodization leads to obtaining the
surface modulus of elasticity values close to the values characteristic of the human bones, a nanoindentation test was
done. The nanoindentation test was performed on the device called nanoindenter G200, Agilent Technologies, where
a diamond tip of the Berkovich type shaped as a three-sided pyramid was used as an indenter. Control of
the nanoindentation test was done by nanoindentation depth, where for non-anodized materials a depth of 2000 nm was
used, while for anodized materials a minimum value of 10% of the thickness of the formed nanostructured oxide layer
was used. Biocompatibility of the tested titanium alloy was estimated by the tetrazolium salt colorimetric test
(MTT test) using mouse fibroblasts (L-929) and human lung fibroblasts (MRC-5). The cell adhesion on the alloy
surface was analyzed using SEM.
Electrochemical anodization has led to the formation of the nanostructured oxide layer on the titanium alloy surface.
The obtained results show the existence of the influence of anodizing time on the nanostructured oxide layer
morphology. Characterization of the titanium alloy surface using nanoindentation showed a decrease in the values
of modulus of elasticity for an alloy with a nanostructured oxide layer, which is close to the values of bone tissue in
the human body. The results of the MTT test showed that the titanium alloys before and after electrochemical
anodization were not cytotoxic. After electrochemical anodization, a uniform nanostructured surface, with nanotubes,
was formed which led to better cell viability and adhesion of L-929 and MRC-5 cells in contact with the test alloys than
of cells in contact with the control material.
PB  - Belgrade : Association of Metallurgical Engineers of Serbia (AMES)
C3  - Book of Abstracts / 5th Metallurgical & Materials Engineering Congress of SouthEast Europe MME SEE Congress 2023, Trebinje, Bosnia and Herzegovina 7-10th June 2023
T1  - Advancement of biocompatibility and mechanical surface characteristics of the Ti-13Nb-13Zr alloy using electrochemical anodization
SP  - 56
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7011
ER  - 

@conference{
author = "Mihajlović, Dragana and Rakin, Marko and Veljović, Đorđe and Međo, Bojan and Đokić, Veljko",
year = "2023",
abstract = "The coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloy (TNZ) were used as tested materials in this
study. UFG alloy was obtained using a high-pressure torsion process (HPT) at room temperature, with 5 rotations, and
with 4.1 GPa pressure. After that, the surface was modified using electrochemical anodization in the 1M H3PO4 + NaF
electrolyte, for 60 and 90 minutes.
Scanning electron microscopy (SEM) was used to characterize the morphology of the modified surface after
electrochemical anodization. In order to determine whether the electrochemical anodization leads to obtaining the
surface modulus of elasticity values close to the values characteristic of the human bones, a nanoindentation test was
done. The nanoindentation test was performed on the device called nanoindenter G200, Agilent Technologies, where
a diamond tip of the Berkovich type shaped as a three-sided pyramid was used as an indenter. Control of
the nanoindentation test was done by nanoindentation depth, where for non-anodized materials a depth of 2000 nm was
used, while for anodized materials a minimum value of 10% of the thickness of the formed nanostructured oxide layer
was used. Biocompatibility of the tested titanium alloy was estimated by the tetrazolium salt colorimetric test
(MTT test) using mouse fibroblasts (L-929) and human lung fibroblasts (MRC-5). The cell adhesion on the alloy
surface was analyzed using SEM.
Electrochemical anodization has led to the formation of the nanostructured oxide layer on the titanium alloy surface.
The obtained results show the existence of the influence of anodizing time on the nanostructured oxide layer
morphology. Characterization of the titanium alloy surface using nanoindentation showed a decrease in the values
of modulus of elasticity for an alloy with a nanostructured oxide layer, which is close to the values of bone tissue in
the human body. The results of the MTT test showed that the titanium alloys before and after electrochemical
anodization were not cytotoxic. After electrochemical anodization, a uniform nanostructured surface, with nanotubes,
was formed which led to better cell viability and adhesion of L-929 and MRC-5 cells in contact with the test alloys than
of cells in contact with the control material.",
publisher = "Belgrade : Association of Metallurgical Engineers of Serbia (AMES)",
journal = "Book of Abstracts / 5th Metallurgical & Materials Engineering Congress of SouthEast Europe MME SEE Congress 2023, Trebinje, Bosnia and Herzegovina 7-10th June 2023",
title = "Advancement of biocompatibility and mechanical surface characteristics of the Ti-13Nb-13Zr alloy using electrochemical anodization",
pages = "56",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7011"
}

Mihajlović, D., Rakin, M., Veljović, Đ., Međo, B.,& Đokić, V.. (2023). Advancement of biocompatibility and mechanical surface characteristics of the Ti-13Nb-13Zr alloy using electrochemical anodization. in Book of Abstracts / 5th Metallurgical & Materials Engineering Congress of SouthEast Europe MME SEE Congress 2023, Trebinje, Bosnia and Herzegovina 7-10th June 2023
Belgrade : Association of Metallurgical Engineers of Serbia (AMES)., 56.
https://hdl.handle.net/21.15107/rcub_technorep_7011

Mihajlović D, Rakin M, Veljović Đ, Međo B, Đokić V. Advancement of biocompatibility and mechanical surface characteristics of the Ti-13Nb-13Zr alloy using electrochemical anodization. in Book of Abstracts / 5th Metallurgical & Materials Engineering Congress of SouthEast Europe MME SEE Congress 2023, Trebinje, Bosnia and Herzegovina 7-10th June 2023. 2023;:56.
https://hdl.handle.net/21.15107/rcub_technorep_7011 .

Mihajlović, Dragana, Rakin, Marko, Veljović, Đorđe, Međo, Bojan, Đokić, Veljko, "Advancement of biocompatibility and mechanical surface characteristics of the Ti-13Nb-13Zr alloy using electrochemical anodization" in Book of Abstracts / 5th Metallurgical & Materials Engineering Congress of SouthEast Europe MME SEE Congress 2023, Trebinje, Bosnia and Herzegovina 7-10th June 2023 (2023):56,
https://hdl.handle.net/21.15107/rcub_technorep_7011 .

TY  - CONF
AU  - Mihajlović, Dragana R.
AU  - Rakin, Marko P.
AU  - Bajat, Jelena B.
AU  - Međo, Bojan I.
AU  - Đokić, Veljko R.
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6974
AB  - Titanium-based nanotubelayer was formed through the electrochemical anodization technique on
coarse-grained and ultrafine-grained Ti-13Nb-13Zr (wt.%) alloy, in 1M H3PO4 + NaF electrolyte
for 90 minutes. The nanotube layer morphology was analyzed using the scanning electron
microscopy (SEM) and the X-ray diffraction (XRD). The electrochemical impedance spectroscopy (EIS) technique was used to determine the corrosion resistance of the alloy before and after
electrochemical anodization. These materials were exposed to a solution simulating conditions in
the human body (Ringer'
s solution) with pH of 5.5 at a temperature of 37 ºC. In order to investigate
the titanium-based nanotube layer adhesion on alloy surface a scratch test was done. The scratch
test was performedon nanoindenter G200, Agilent Technologies, using an indenter Berkovichtype diamond tip with applying an increasing load up to 40 mN. It was established that electrochemical anodization led to the formation of the nanotube oxide layer on the surface of titaniumbased materials. Influence of the ultrafine-grained material structure on the homogeneity of the
nanotube layer obtained by electrochemical anodization has been noticed. Both coarse-grained
and ultrafine-grained alloy showed excellent corrosion resistance in Ringer’s solution. Moreover,
electrochemical anodization led to a decrease or an increase of the corrosion resistance of these
materials, depending on the nanotube layer morphology. The scratch test showed that plastic
deformation was present in the nanotube layer. The scratch resistance for the nanotube layer
failure was on the higher load, pointing to the good adhesion for the titanium-based nanotube layer
formed using electrochemical anodization.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Twenty-fourth Annual Conference YUCOMAT 2023, Herceg Novi, Montenegro, September 4 - 8, 2023
T1  - Corrosion and scratch resistance of the nanotube layer formed on the titanium-based materials
SP  - 171
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6974
ER  - 

@conference{
author = "Mihajlović, Dragana R. and Rakin, Marko P. and Bajat, Jelena B. and Međo, Bojan I. and Đokić, Veljko R.",
year = "2023",
abstract = "Titanium-based nanotubelayer was formed through the electrochemical anodization technique on
coarse-grained and ultrafine-grained Ti-13Nb-13Zr (wt.%) alloy, in 1M H3PO4 + NaF electrolyte
for 90 minutes. The nanotube layer morphology was analyzed using the scanning electron
microscopy (SEM) and the X-ray diffraction (XRD). The electrochemical impedance spectroscopy (EIS) technique was used to determine the corrosion resistance of the alloy before and after
electrochemical anodization. These materials were exposed to a solution simulating conditions in
the human body (Ringer'
s solution) with pH of 5.5 at a temperature of 37 ºC. In order to investigate
the titanium-based nanotube layer adhesion on alloy surface a scratch test was done. The scratch
test was performedon nanoindenter G200, Agilent Technologies, using an indenter Berkovichtype diamond tip with applying an increasing load up to 40 mN. It was established that electrochemical anodization led to the formation of the nanotube oxide layer on the surface of titaniumbased materials. Influence of the ultrafine-grained material structure on the homogeneity of the
nanotube layer obtained by electrochemical anodization has been noticed. Both coarse-grained
and ultrafine-grained alloy showed excellent corrosion resistance in Ringer’s solution. Moreover,
electrochemical anodization led to a decrease or an increase of the corrosion resistance of these
materials, depending on the nanotube layer morphology. The scratch test showed that plastic
deformation was present in the nanotube layer. The scratch resistance for the nanotube layer
failure was on the higher load, pointing to the good adhesion for the titanium-based nanotube layer
formed using electrochemical anodization.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Twenty-fourth Annual Conference YUCOMAT 2023, Herceg Novi, Montenegro, September 4 - 8, 2023",
title = "Corrosion and scratch resistance of the nanotube layer formed on the titanium-based materials",
pages = "171",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6974"
}

Mihajlović, D. R., Rakin, M. P., Bajat, J. B., Međo, B. I.,& Đokić, V. R.. (2023). Corrosion and scratch resistance of the nanotube layer formed on the titanium-based materials. in Programme and The Book of Abstracts / Twenty-fourth Annual Conference YUCOMAT 2023, Herceg Novi, Montenegro, September 4 - 8, 2023
Belgrade : Materials Research Society of Serbia., 171.
https://hdl.handle.net/21.15107/rcub_technorep_6974

Mihajlović DR, Rakin MP, Bajat JB, Međo BI, Đokić VR. Corrosion and scratch resistance of the nanotube layer formed on the titanium-based materials. in Programme and The Book of Abstracts / Twenty-fourth Annual Conference YUCOMAT 2023, Herceg Novi, Montenegro, September 4 - 8, 2023. 2023;:171.
https://hdl.handle.net/21.15107/rcub_technorep_6974 .

Mihajlović, Dragana R., Rakin, Marko P., Bajat, Jelena B., Međo, Bojan I., Đokić, Veljko R., "Corrosion and scratch resistance of the nanotube layer formed on the titanium-based materials" in Programme and The Book of Abstracts / Twenty-fourth Annual Conference YUCOMAT 2023, Herceg Novi, Montenegro, September 4 - 8, 2023 (2023):171,
https://hdl.handle.net/21.15107/rcub_technorep_6974 .

TY  - CONF
AU  - Mihajlović, Dragana
AU  - Međo, Bojan
AU  - Đokić, Veljko
AU  - Bajat, Jelena
AU  - Rakin, Marko
AU  - Putić, Slaviša
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/7172
AB  - Intenzivno plastično deformisanje (IPD, eng. Severe Plastic Deformation, SPD)  jesu različiti savremeni postupci čiji je osnovni cilj dobijanje sitnozrne strukture (eng. ultrafine-grained, UFG) metalnih materijala. Sitnozrni metalni materijali najčešće pokazuju poboljšana mehanička svojstva u odnosu na metalne materijale dobijene konvencionalnim postupcima izrade, dok je koroziona otpornost ovih materijala još uvek nedovoljno ispitana. Jedna od metoda intenzivnog plastičnog deformisanja je i metoda uvijanja pod visokim pritiskom (UVP, eng. High Pressure Torsion, HPT). U cilju ispitivanja uticaja nanostrukturne modifikacije površine na svojstva sitnozrnog komercijalnog čistog titana (korozionu postojanost, površinski modul elastičnosti i tvrdoću) u radu je urađena elektrohemijska anodizacija. Karakterizacija površinske modifikovane strukture kod sitnozrnog komercijalnog čistog titana urađena je primenom skenirajuće elektronske mikroskopije (eng. Scanning Electron Microscopy, SEM). Homogenost materijala nakon UVP postupka procenjen je merenjem mikrotvrdoće duž prečnika uzoraka primenom metode po Vikersu (eng. Vickers). Otpornost prema koroziji sitnozrnog komercijalnog čistog titana pre i posle elektrohemijske andizacije ispitana je primenom potenciodinamičke metode, pri čemu je pokazano povećanje korozione otpornosti u simuliranom rastvoru ljudskog organizma. Karakterizacija površine sitnozrnog komercijalnog čistog titana primenom nanoindentacije pokazala je smanjenje vrednosti površinskog modula elastičnosti i tvrdoće kod materijala sa nanostrukturnim oksidnim slojem, koje su bliže vrednostima koštanog tkiva u ljudskom organizmu.
AB  - Severe Plastic Deformation (SPD) are modern procedures whose main goal is to obtain an
ultrafine-grained structure of metallic materials. Ultrafine-grained metallic materials show
improved mechanical properties compared to metallic materials obtained by conventional
manufacturing methods, while the corrosion resistance of these materials is still insufficiently
tested. One of the methods of Severe Plastic Deformation is the method of High Pressure
Torsion (HPT). In order to examine the influence of nanostructural surface modification on
the properties of ultrafine-grained commercially pure titanium (corrosion resistance, surface
modulus of elasticity and hardness), electrochemical anodization was performed. The
characterization of the surface modified structure of ultrafine-grained commercially pure
titanium was performed using Scanning Electron Microscopy (SEM). The homogeneity of
the material after the HPT procedure was assessed by measuring the microhardness along the
diameter of the samples using the Vickers method. Corrosion resistance of ultrafine-grained
commercially pure titanium before and after electrochemical andization was tested using the
potentiodynamic method, where an increase corrosion resistance in a simulated solution of
the human organism was demonstrated. The characterization of the surface of the comercially
pure titanium using nanoindentation showed a decrease in the values of the surface modulus
of elasticity and hardness for titanium with a nanostructured oxide layer, which are closer to
the values of bone tissue in the human body.
PB  - Požarevac : Savez društava inženjera i tehničara grada Požarevca
PB  - Požarevac : Društvo hemičara, tehnologa i metalurga
C3  - Zbornik radova / Savetovanje "Novi materijali i mogućnosti njihove primene", Požarevac, 2023 godine
T1  - Uticaj nanostrukturne modifikacije površine na svojstva komercijalno čistog titana za primenu u medicini
T1  - The influence of nanostructure surface modification on the properties of commercially pure titanium for application in medicine
EP  - 60
SP  - 51
UR  - https://hdl.handle.net/21.15107/rcub_technorep_7172
ER  - 

@conference{
author = "Mihajlović, Dragana and Međo, Bojan and Đokić, Veljko and Bajat, Jelena and Rakin, Marko and Putić, Slaviša",
year = "2023",
abstract = "Intenzivno plastično deformisanje (IPD, eng. Severe Plastic Deformation, SPD)  jesu različiti savremeni postupci čiji je osnovni cilj dobijanje sitnozrne strukture (eng. ultrafine-grained, UFG) metalnih materijala. Sitnozrni metalni materijali najčešće pokazuju poboljšana mehanička svojstva u odnosu na metalne materijale dobijene konvencionalnim postupcima izrade, dok je koroziona otpornost ovih materijala još uvek nedovoljno ispitana. Jedna od metoda intenzivnog plastičnog deformisanja je i metoda uvijanja pod visokim pritiskom (UVP, eng. High Pressure Torsion, HPT). U cilju ispitivanja uticaja nanostrukturne modifikacije površine na svojstva sitnozrnog komercijalnog čistog titana (korozionu postojanost, površinski modul elastičnosti i tvrdoću) u radu je urađena elektrohemijska anodizacija. Karakterizacija površinske modifikovane strukture kod sitnozrnog komercijalnog čistog titana urađena je primenom skenirajuće elektronske mikroskopije (eng. Scanning Electron Microscopy, SEM). Homogenost materijala nakon UVP postupka procenjen je merenjem mikrotvrdoće duž prečnika uzoraka primenom metode po Vikersu (eng. Vickers). Otpornost prema koroziji sitnozrnog komercijalnog čistog titana pre i posle elektrohemijske andizacije ispitana je primenom potenciodinamičke metode, pri čemu je pokazano povećanje korozione otpornosti u simuliranom rastvoru ljudskog organizma. Karakterizacija površine sitnozrnog komercijalnog čistog titana primenom nanoindentacije pokazala je smanjenje vrednosti površinskog modula elastičnosti i tvrdoće kod materijala sa nanostrukturnim oksidnim slojem, koje su bliže vrednostima koštanog tkiva u ljudskom organizmu., Severe Plastic Deformation (SPD) are modern procedures whose main goal is to obtain an
ultrafine-grained structure of metallic materials. Ultrafine-grained metallic materials show
improved mechanical properties compared to metallic materials obtained by conventional
manufacturing methods, while the corrosion resistance of these materials is still insufficiently
tested. One of the methods of Severe Plastic Deformation is the method of High Pressure
Torsion (HPT). In order to examine the influence of nanostructural surface modification on
the properties of ultrafine-grained commercially pure titanium (corrosion resistance, surface
modulus of elasticity and hardness), electrochemical anodization was performed. The
characterization of the surface modified structure of ultrafine-grained commercially pure
titanium was performed using Scanning Electron Microscopy (SEM). The homogeneity of
the material after the HPT procedure was assessed by measuring the microhardness along the
diameter of the samples using the Vickers method. Corrosion resistance of ultrafine-grained
commercially pure titanium before and after electrochemical andization was tested using the
potentiodynamic method, where an increase corrosion resistance in a simulated solution of
the human organism was demonstrated. The characterization of the surface of the comercially
pure titanium using nanoindentation showed a decrease in the values of the surface modulus
of elasticity and hardness for titanium with a nanostructured oxide layer, which are closer to
the values of bone tissue in the human body.",
publisher = "Požarevac : Savez društava inženjera i tehničara grada Požarevca, Požarevac : Društvo hemičara, tehnologa i metalurga",
journal = "Zbornik radova / Savetovanje "Novi materijali i mogućnosti njihove primene", Požarevac, 2023 godine",
title = "Uticaj nanostrukturne modifikacije površine na svojstva komercijalno čistog titana za primenu u medicini, The influence of nanostructure surface modification on the properties of commercially pure titanium for application in medicine",
pages = "60-51",
url = "https://hdl.handle.net/21.15107/rcub_technorep_7172"
}

Mihajlović, D., Međo, B., Đokić, V., Bajat, J., Rakin, M.,& Putić, S.. (2023). Uticaj nanostrukturne modifikacije površine na svojstva komercijalno čistog titana za primenu u medicini. in Zbornik radova / Savetovanje "Novi materijali i mogućnosti njihove primene", Požarevac, 2023 godine
Požarevac : Savez društava inženjera i tehničara grada Požarevca., 51-60.
https://hdl.handle.net/21.15107/rcub_technorep_7172

Mihajlović D, Međo B, Đokić V, Bajat J, Rakin M, Putić S. Uticaj nanostrukturne modifikacije površine na svojstva komercijalno čistog titana za primenu u medicini. in Zbornik radova / Savetovanje "Novi materijali i mogućnosti njihove primene", Požarevac, 2023 godine. 2023;:51-60.
https://hdl.handle.net/21.15107/rcub_technorep_7172 .

Mihajlović, Dragana, Međo, Bojan, Đokić, Veljko, Bajat, Jelena, Rakin, Marko, Putić, Slaviša, "Uticaj nanostrukturne modifikacije površine na svojstva komercijalno čistog titana za primenu u medicini" in Zbornik radova / Savetovanje "Novi materijali i mogućnosti njihove primene", Požarevac, 2023 godine (2023):51-60,
https://hdl.handle.net/21.15107/rcub_technorep_7172 .

TY  - JOUR
AU  - Veljić, Darko
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Radović, Nenad
AU  - Međo, Bojan
AU  - Mrdak, Mihailo
AU  - Bajić, Darko
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6008
AB  - This paper deals with analysis and comparison of the equivalent plastic strain and temperature fields in the aluminium alloy 2024 T3 welded joint, with macro/microstructure appearance and hardness profile. In the alloys hardened by heat treatment, grain size and particle size of the precipitate are functions of equivalent plastic strain, strain rate and temperature. By analyzing the equivalent plastic strain fields and temperature fields it is possible, to some extent, to capture the effect of welding parameters and thermo-mechanical conditions on grain structure, and therefore hardness and strength in the welded joint. A coupled thermo-mechanical model is applied to study the material behaviour during the linear welding stage of friction stir welding (FSW). Three-dimensional finite element (FE) model has been created in ABAQUS/Explicit software using the Johnson-Cook material law. The values of thermo-mechanical quantities during the welding stage are obtained from the numerical model and shown as distributions across the joint. The obtained values of these quantities are related to the microstructure of the joint zones and hardness distribution, and this relation is discussed.
PB  - VINČA Institute of Nuclear Sciences
T2  - Thermal Science
T1  - Influence of temperature and plastic deformation on AA2024 T3 friction stir welded joint microstructure
EP  - 320
IS  - 1A
SP  - 311
VL  - 27
DO  - 10.2298/TSCI210216186V
ER  - 

@article{
author = "Veljić, Darko and Rakin, Marko and Sedmak, Aleksandar and Radović, Nenad and Međo, Bojan and Mrdak, Mihailo and Bajić, Darko",
year = "2023",
abstract = "This paper deals with analysis and comparison of the equivalent plastic strain and temperature fields in the aluminium alloy 2024 T3 welded joint, with macro/microstructure appearance and hardness profile. In the alloys hardened by heat treatment, grain size and particle size of the precipitate are functions of equivalent plastic strain, strain rate and temperature. By analyzing the equivalent plastic strain fields and temperature fields it is possible, to some extent, to capture the effect of welding parameters and thermo-mechanical conditions on grain structure, and therefore hardness and strength in the welded joint. A coupled thermo-mechanical model is applied to study the material behaviour during the linear welding stage of friction stir welding (FSW). Three-dimensional finite element (FE) model has been created in ABAQUS/Explicit software using the Johnson-Cook material law. The values of thermo-mechanical quantities during the welding stage are obtained from the numerical model and shown as distributions across the joint. The obtained values of these quantities are related to the microstructure of the joint zones and hardness distribution, and this relation is discussed.",
publisher = "VINČA Institute of Nuclear Sciences",
journal = "Thermal Science",
title = "Influence of temperature and plastic deformation on AA2024 T3 friction stir welded joint microstructure",
pages = "320-311",
number = "1A",
volume = "27",
doi = "10.2298/TSCI210216186V"
}

Veljić, D., Rakin, M., Sedmak, A., Radović, N., Međo, B., Mrdak, M.,& Bajić, D.. (2023). Influence of temperature and plastic deformation on AA2024 T3 friction stir welded joint microstructure. in Thermal Science
VINČA Institute of Nuclear Sciences., 27(1A), 311-320.
https://doi.org/10.2298/TSCI210216186V

Veljić D, Rakin M, Sedmak A, Radović N, Međo B, Mrdak M, Bajić D. Influence of temperature and plastic deformation on AA2024 T3 friction stir welded joint microstructure. in Thermal Science. 2023;27(1A):311-320.
doi:10.2298/TSCI210216186V .

Veljić, Darko, Rakin, Marko, Sedmak, Aleksandar, Radović, Nenad, Međo, Bojan, Mrdak, Mihailo, Bajić, Darko, "Influence of temperature and plastic deformation on AA2024 T3 friction stir welded joint microstructure" in Thermal Science, 27, no. 1A (2023):311-320,
https://doi.org/10.2298/TSCI210216186V . .

TY  - CONF
AU  - Barjaktarević, Dragana R.
AU  - Rakin, Marko P.
AU  - Međo, Bojan I.
AU  - Radosavljević, Zoran M.
AU  - Đokić, Veljko R.
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6018
AB  - Titanium alloys are metal materials widely used in medicine owing to their suitable characteristics such as low density, good corrosion resistance and biocompatibillity. High biocompatibility of the titanium alloy results from the creation of a spontaneous oxide layer with good adhesion and homogeneous morphology. In order to improve characteristics of the metallic materials for application in medicine, electrochemical methods that enable surface nanostructured modification are extensively used, and one of these methods is electrochemical anodization which makes it possible to obtain a nanostructured oxide layer composed of nanotubes on the surface of the metal material. The tested material was ultrafine-grained Ti-13Nb-13Zr (UFG TNZ) alloy obtained by the severe plastic deformation (SPD) processing using the high pressure torsion (HPT) process. Nanostructured oxide layer on the titanium alloy was formed by electrochemical anodization during the time period from 30 to 120 minutes. Characterization of the surface morphology obtained during different times of electrochemical anodization was done using scanning electron microscopy (SEM), while the topography and surface roughness of the titanium alloy before and after electrochemical anodization was determined using atomic force microscopy (AFM). Scratch test was used to determine the cross profile of the surface topography and critical load during scratching. Electrochemical anodization led to the formation of a nanostructured oxide layer on the surface of the titanium alloy. The obtained results indicated strong influence of the electrochemical anodization time on the oxide layer morphology - with its increase the diameter of the nanotubes increases too, while the wall thickness of nanotubes decreases. Also, electrochemical anodization led to an increase in the surface roughness.
PB  - Novi Sad : Faculty of Technology
C3  - Proceedings of the 2nd International Conference on Advanced Production and Processing ICAPP 2022, Novi Sad
T1  - THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY
EP  - 114
SP  - 105
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6018
ER  - 

@conference{
author = "Barjaktarević, Dragana R. and Rakin, Marko P. and Međo, Bojan I. and Radosavljević, Zoran M. and Đokić, Veljko R.",
year = "2023",
abstract = "Titanium alloys are metal materials widely used in medicine owing to their suitable characteristics such as low density, good corrosion resistance and biocompatibillity. High biocompatibility of the titanium alloy results from the creation of a spontaneous oxide layer with good adhesion and homogeneous morphology. In order to improve characteristics of the metallic materials for application in medicine, electrochemical methods that enable surface nanostructured modification are extensively used, and one of these methods is electrochemical anodization which makes it possible to obtain a nanostructured oxide layer composed of nanotubes on the surface of the metal material. The tested material was ultrafine-grained Ti-13Nb-13Zr (UFG TNZ) alloy obtained by the severe plastic deformation (SPD) processing using the high pressure torsion (HPT) process. Nanostructured oxide layer on the titanium alloy was formed by electrochemical anodization during the time period from 30 to 120 minutes. Characterization of the surface morphology obtained during different times of electrochemical anodization was done using scanning electron microscopy (SEM), while the topography and surface roughness of the titanium alloy before and after electrochemical anodization was determined using atomic force microscopy (AFM). Scratch test was used to determine the cross profile of the surface topography and critical load during scratching. Electrochemical anodization led to the formation of a nanostructured oxide layer on the surface of the titanium alloy. The obtained results indicated strong influence of the electrochemical anodization time on the oxide layer morphology - with its increase the diameter of the nanotubes increases too, while the wall thickness of nanotubes decreases. Also, electrochemical anodization led to an increase in the surface roughness.",
publisher = "Novi Sad : Faculty of Technology",
journal = "Proceedings of the 2nd International Conference on Advanced Production and Processing ICAPP 2022, Novi Sad",
title = "THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY",
pages = "114-105",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6018"
}

Barjaktarević, D. R., Rakin, M. P., Međo, B. I., Radosavljević, Z. M.,& Đokić, V. R.. (2023). THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY. in Proceedings of the 2nd International Conference on Advanced Production and Processing ICAPP 2022, Novi Sad
Novi Sad : Faculty of Technology., 105-114.
https://hdl.handle.net/21.15107/rcub_technorep_6018

Barjaktarević DR, Rakin MP, Međo BI, Radosavljević ZM, Đokić VR. THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY. in Proceedings of the 2nd International Conference on Advanced Production and Processing ICAPP 2022, Novi Sad. 2023;:105-114.
https://hdl.handle.net/21.15107/rcub_technorep_6018 .

Barjaktarević, Dragana R., Rakin, Marko P., Međo, Bojan I., Radosavljević, Zoran M., Đokić, Veljko R., "THE SURFACE CHARACTERIZATION OF THE ANODIZED ULTRAFINE-GRAINED Ti-13Nb-13Zr ALLOY" in Proceedings of the 2nd International Conference on Advanced Production and Processing ICAPP 2022, Novi Sad (2023):105-114,
https://hdl.handle.net/21.15107/rcub_technorep_6018 .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Doncheva, Elisaveta
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Milošević, Nenad
AU  - Radu, Dorin
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6584
AB  - Crack size and undermatching effects on fracture behavior of undermatched welded joints are presented and analyzed. Experimental and numerical analysis of the fracture behavior of high-strength low-alloyed (HSLA) steel welded joints with so-called small and large crack in undermatched weld metal and the base metal was performed, as a part of more extensive research previously conducted. J integral was determined by direct measurement using special instrumentation including strain gauges and a CMOD measuring device. Numerical analysis was performed by 3D finite element method (FEM) with different tensile properties in BM and WM. Results of J-CMOD curves evaluation for SUMITEN SM 80P HSLA steel and its weld metal (WM) are presented and analyzed for small and large cracks in tensile panels. This paper is focused on some new numerical results and observations on crack tip fields and constraint effects of undermatching and crack size keeping in mind previously performed experiments on the full-scale prototype. In this way, a unique combined approach of experimental investigation on the full-scale proto-type and tensile panels, as well as numerical investigation on mismatching and crack size effects, is achieved.
PB  - MDPI
T2  - Materials
T1  - Crack Size and Undermatching Effects on Fracture Behavior of a Welded Joint
IS  - 13
SP  - 4858
VL  - 16
DO  - 10.3390/ma16134858
ER  - 

@article{
author = "Sedmak, Aleksandar and Doncheva, Elisaveta and Međo, Bojan and Rakin, Marko and Milošević, Nenad and Radu, Dorin",
year = "2023",
abstract = "Crack size and undermatching effects on fracture behavior of undermatched welded joints are presented and analyzed. Experimental and numerical analysis of the fracture behavior of high-strength low-alloyed (HSLA) steel welded joints with so-called small and large crack in undermatched weld metal and the base metal was performed, as a part of more extensive research previously conducted. J integral was determined by direct measurement using special instrumentation including strain gauges and a CMOD measuring device. Numerical analysis was performed by 3D finite element method (FEM) with different tensile properties in BM and WM. Results of J-CMOD curves evaluation for SUMITEN SM 80P HSLA steel and its weld metal (WM) are presented and analyzed for small and large cracks in tensile panels. This paper is focused on some new numerical results and observations on crack tip fields and constraint effects of undermatching and crack size keeping in mind previously performed experiments on the full-scale prototype. In this way, a unique combined approach of experimental investigation on the full-scale proto-type and tensile panels, as well as numerical investigation on mismatching and crack size effects, is achieved.",
publisher = "MDPI",
journal = "Materials",
title = "Crack Size and Undermatching Effects on Fracture Behavior of a Welded Joint",
number = "13",
pages = "4858",
volume = "16",
doi = "10.3390/ma16134858"
}

Sedmak, A., Doncheva, E., Međo, B., Rakin, M., Milošević, N.,& Radu, D.. (2023). Crack Size and Undermatching Effects on Fracture Behavior of a Welded Joint. in Materials
MDPI., 16(13), 4858.
https://doi.org/10.3390/ma16134858

Sedmak A, Doncheva E, Međo B, Rakin M, Milošević N, Radu D. Crack Size and Undermatching Effects on Fracture Behavior of a Welded Joint. in Materials. 2023;16(13):4858.
doi:10.3390/ma16134858 .

Sedmak, Aleksandar, Doncheva, Elisaveta, Međo, Bojan, Rakin, Marko, Milošević, Nenad, Radu, Dorin, "Crack Size and Undermatching Effects on Fracture Behavior of a Welded Joint" in Materials, 16, no. 13 (2023):4858,
https://doi.org/10.3390/ma16134858 . .

TY  - JOUR
AU  - Musrati, Walid
AU  - Međo, Bojan
AU  - Cvijović-Alagić, Ivana
AU  - Gubeljak, Nenad
AU  - Štefane, Primož
AU  - Radosavljević, Zoran
AU  - Rakin, Marko
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6607
AB  - Steel pipelines in industrial plants consist of different elements, including seamless and/or welded (seam) pipes. Properties of welded pipes, including their fracture behaviour, depend on the characteristics of both, the base metal, and the weld metal. In this work, two seam pipes are considered having different diameters and manufactured of P235TR1 steel. Hardness and microstructure were examined on the samples which contained the seam zone, to capture the influence of heterogeneity. Fracture resistance of the pipeline material, i.e. of both base metals and both seams, was determined by experimental examination of the recently proposed Pipe ring notch bending specimens with sharp stress concentrators. Differences between the two tested pipes, including the influence of the heterogeneity caused by the welded joint, were determined by comparison of the crack growth resistance curves. Effects of the initial stress concentrator shape, sharp machined notch or fatigue precrack are discussed.
AB  - Čelični cevovodi u industrijskim postrojenjima se sastoje od različitih elemenata, uključujući bešavne i/ili
zavarene (šavne) cevi. Osobine šavnih cevi, uključujući ponašanje materijala cevi pri lomu, zavise i od
osnovnog metala i od metala šava. U ovom radu razmatrane su dve šavne cevi različitih prečnika,
izrađene od čelika P235TR1. Tvrdoća i mikrostruktura su analizirane na uzorcima isečenim iz cevi u zoni
šava, da bi se odredio uticaj heterogenosti. Otpornost prema lomu materijala cevovoda, tj. oba osnovna
metala i oba šava, je određena na osnovu ispitivanja epruveta oblika prstena sa oštrim koncentratorima
napona, predloženih u prethodnim studijama. Poređenjem krivih otpornosti prema rastu prsline
određene su razlike između dve ispitivane cevi, kao i uticaj heterogenosti izazvan postojanjem zavarenog
spoja. Razmotren je uticaj oblika početnog koncentratora napona, oštrog žleba odnosno zamorne
početne prsline.
PB  - Association of the Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Microstructure, hardness and fracture resistance of P235TR1 seam steel pipes of different diameters
T1  - Otpornost prema lomu, tvrdoća i mikrostruktura šavnih cevi različitog prečnika izrađenih od čelika P235TR1
EP  - 165
IS  - 2
SP  - 155
VL  - 77
DO  - 10.2298/HEMIND230222016M
ER  - 

@article{
author = "Musrati, Walid and Međo, Bojan and Cvijović-Alagić, Ivana and Gubeljak, Nenad and Štefane, Primož and Radosavljević, Zoran and Rakin, Marko",
year = "2023",
abstract = "Steel pipelines in industrial plants consist of different elements, including seamless and/or welded (seam) pipes. Properties of welded pipes, including their fracture behaviour, depend on the characteristics of both, the base metal, and the weld metal. In this work, two seam pipes are considered having different diameters and manufactured of P235TR1 steel. Hardness and microstructure were examined on the samples which contained the seam zone, to capture the influence of heterogeneity. Fracture resistance of the pipeline material, i.e. of both base metals and both seams, was determined by experimental examination of the recently proposed Pipe ring notch bending specimens with sharp stress concentrators. Differences between the two tested pipes, including the influence of the heterogeneity caused by the welded joint, were determined by comparison of the crack growth resistance curves. Effects of the initial stress concentrator shape, sharp machined notch or fatigue precrack are discussed., Čelični cevovodi u industrijskim postrojenjima se sastoje od različitih elemenata, uključujući bešavne i/ili
zavarene (šavne) cevi. Osobine šavnih cevi, uključujući ponašanje materijala cevi pri lomu, zavise i od
osnovnog metala i od metala šava. U ovom radu razmatrane su dve šavne cevi različitih prečnika,
izrađene od čelika P235TR1. Tvrdoća i mikrostruktura su analizirane na uzorcima isečenim iz cevi u zoni
šava, da bi se odredio uticaj heterogenosti. Otpornost prema lomu materijala cevovoda, tj. oba osnovna
metala i oba šava, je određena na osnovu ispitivanja epruveta oblika prstena sa oštrim koncentratorima
napona, predloženih u prethodnim studijama. Poređenjem krivih otpornosti prema rastu prsline
određene su razlike između dve ispitivane cevi, kao i uticaj heterogenosti izazvan postojanjem zavarenog
spoja. Razmotren je uticaj oblika početnog koncentratora napona, oštrog žleba odnosno zamorne
početne prsline.",
publisher = "Association of the Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Microstructure, hardness and fracture resistance of P235TR1 seam steel pipes of different diameters, Otpornost prema lomu, tvrdoća i mikrostruktura šavnih cevi različitog prečnika izrađenih od čelika P235TR1",
pages = "165-155",
number = "2",
volume = "77",
doi = "10.2298/HEMIND230222016M"
}

Musrati, W., Međo, B., Cvijović-Alagić, I., Gubeljak, N., Štefane, P., Radosavljević, Z.,& Rakin, M.. (2023). Microstructure, hardness and fracture resistance of P235TR1 seam steel pipes of different diameters. in Hemijska industrija
Association of the Chemical Engineers of Serbia., 77(2), 155-165.
https://doi.org/10.2298/HEMIND230222016M

Musrati W, Međo B, Cvijović-Alagić I, Gubeljak N, Štefane P, Radosavljević Z, Rakin M. Microstructure, hardness and fracture resistance of P235TR1 seam steel pipes of different diameters. in Hemijska industrija. 2023;77(2):155-165.
doi:10.2298/HEMIND230222016M .

Musrati, Walid, Međo, Bojan, Cvijović-Alagić, Ivana, Gubeljak, Nenad, Štefane, Primož, Radosavljević, Zoran, Rakin, Marko, "Microstructure, hardness and fracture resistance of P235TR1 seam steel pipes of different diameters" in Hemijska industrija, 77, no. 2 (2023):155-165,
https://doi.org/10.2298/HEMIND230222016M . .

TY  - JOUR
AU  - Trajković, Isaak
AU  - Rakin, Marko
AU  - Milošević, Miloš
AU  - Mitrović, Nenad
AU  - Travica, Milan
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6649
AB  - In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.
PB  - Elsevier Ltd.
T2  - Engineering Fracture Mechanics
T1  - Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials
SP  - 109573
VL  - 292
DO  - 10.1016/j.engfracmech.2023.109573
ER  - 

@article{
author = "Trajković, Isaak and Rakin, Marko and Milošević, Miloš and Mitrović, Nenad and Travica, Milan and Sedmak, Aleksandar and Međo, Bojan",
year = "2023",
abstract = "In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.",
publisher = "Elsevier Ltd.",
journal = "Engineering Fracture Mechanics",
title = "Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials",
pages = "109573",
volume = "292",
doi = "10.1016/j.engfracmech.2023.109573"
}

Trajković, I., Rakin, M., Milošević, M., Mitrović, N., Travica, M., Sedmak, A.,& Međo, B.. (2023). Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials. in Engineering Fracture Mechanics
Elsevier Ltd.., 292, 109573.
https://doi.org/10.1016/j.engfracmech.2023.109573

Trajković I, Rakin M, Milošević M, Mitrović N, Travica M, Sedmak A, Međo B. Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials. in Engineering Fracture Mechanics. 2023;292:109573.
doi:10.1016/j.engfracmech.2023.109573 .

Trajković, Isaak, Rakin, Marko, Milošević, Miloš, Mitrović, Nenad, Travica, Milan, Sedmak, Aleksandar, Međo, Bojan, "Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials" in Engineering Fracture Mechanics, 292 (2023):109573,
https://doi.org/10.1016/j.engfracmech.2023.109573 . .

TY  - PAT
AU  - Veljić, Darko
AU  - Rakin, Marko
AU  - Međo, Bojan
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6922
AB  - Prikazani pronalazak, modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna kao predmet pronalaska, odnosi se na konstrukciono rešenje alata za zavarivanje u čvrstom stanju legura obojenih metala. Alat se satoji od: tela (1) alata, trna (2) i steznog vijka (3). Gornji deo tela (1) alata služi za stezanje u mašini, a donji deo tela (1) alata poseduje bočni otvor (5) sa navojem za fiksiranje trna (2). Sa donje strane tela (1) alata se nalazi čelo (7) alata sa urezanom levom zavojnicom. Telo (1) alata ima otvor (4) celom dužinom za smeštaj trna (2). Trn (2) ima konusni vrh sa narezanim levim navojem. Moguće je podešavati dužinu trna (2), odnosno rastojanje od vrha trna (2) do čela (7) alata u zavisnosti od vrste spoja i debljine materijala koji se zavaruje. Stezni vijak (3) služi za fiksiranje trna (2) alata na željenu poziciju.
T2  - Zavod za intelektualnu svojinu
T1  - Modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna
IS  - MP-2023/0001
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6922
ER  - 

@misc{
author = "Veljić, Darko and Rakin, Marko and Međo, Bojan",
year = "2023",
abstract = "Prikazani pronalazak, modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna kao predmet pronalaska, odnosi se na konstrukciono rešenje alata za zavarivanje u čvrstom stanju legura obojenih metala. Alat se satoji od: tela (1) alata, trna (2) i steznog vijka (3). Gornji deo tela (1) alata služi za stezanje u mašini, a donji deo tela (1) alata poseduje bočni otvor (5) sa navojem za fiksiranje trna (2). Sa donje strane tela (1) alata se nalazi čelo (7) alata sa urezanom levom zavojnicom. Telo (1) alata ima otvor (4) celom dužinom za smeštaj trna (2). Trn (2) ima konusni vrh sa narezanim levim navojem. Moguće je podešavati dužinu trna (2), odnosno rastojanje od vrha trna (2) do čela (7) alata u zavisnosti od vrste spoja i debljine materijala koji se zavaruje. Stezni vijak (3) služi za fiksiranje trna (2) alata na željenu poziciju.",
journal = "Zavod za intelektualnu svojinu",
title = "Modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna",
number = "MP-2023/0001",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6922"
}

Veljić, D., Rakin, M.,& Međo, B.. (2023). Modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna. in Zavod za intelektualnu svojinu(MP-2023/0001).
https://hdl.handle.net/21.15107/rcub_technorep_6922

Veljić D, Rakin M, Međo B. Modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna. in Zavod za intelektualnu svojinu. 2023;(MP-2023/0001).
https://hdl.handle.net/21.15107/rcub_technorep_6922 .

Veljić, Darko, Rakin, Marko, Međo, Bojan, "Modularni alat za zavarivanje trenjem mešanjem sa podesivom dužinom trna" in Zavod za intelektualnu svojinu, no. MP-2023/0001 (2023),
https://hdl.handle.net/21.15107/rcub_technorep_6922 .

TY  - JOUR
AU  - Jovanović, Gvozden
AU  - Glišić, Dragomir
AU  - Dikić, Stefan
AU  - Međo, Bojan
AU  - Marković, Branislav
AU  - Vuković, Nikola
AU  - Radović, Nenad
PY  - 2023
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6938
AB  - Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at −196 °C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite, bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith’s equation are 1970 MPa and 1791 MPa, respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm−2 to 86 Jm−2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm−2 to 82 Jm−2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.
PB  - MDPI
T2  - Materials
T1  - Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels
IS  - 22
SP  - 7192
VL  - 16
DO  - 10.3390/ma16227192
ER  - 

@article{
author = "Jovanović, Gvozden and Glišić, Dragomir and Dikić, Stefan and Međo, Bojan and Marković, Branislav and Vuković, Nikola and Radović, Nenad",
year = "2023",
abstract = "Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at −196 °C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite, bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith’s equation are 1970 MPa and 1791 MPa, respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm−2 to 86 Jm−2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm−2 to 82 Jm−2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.",
publisher = "MDPI",
journal = "Materials",
title = "Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels",
number = "22",
pages = "7192",
volume = "16",
doi = "10.3390/ma16227192"
}

Jovanović, G., Glišić, D., Dikić, S., Međo, B., Marković, B., Vuković, N.,& Radović, N.. (2023). Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels. in Materials
MDPI., 16(22), 7192.
https://doi.org/10.3390/ma16227192

Jovanović G, Glišić D, Dikić S, Međo B, Marković B, Vuković N, Radović N. Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels. in Materials. 2023;16(22):7192.
doi:10.3390/ma16227192 .

Jovanović, Gvozden, Glišić, Dragomir, Dikić, Stefan, Međo, Bojan, Marković, Branislav, Vuković, Nikola, Radović, Nenad, "Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels" in Materials, 16, no. 22 (2023):7192,
https://doi.org/10.3390/ma16227192 . .

TY  - JOUR
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Mladenović, Goran
AU  - Kudrjavceva, Ljudmila
AU  - Međo, Bojan
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5348
AB  - This paper presents a part of development of a non-standard method for testing of cylindrical test specimens for measurement of fracture properties of pipeline materials. This method for testing of cylindrical structures working under pressure is based on determining of fracture mechanics parameters on SENT (Single Edge Notched Tension) specimens and new PRNT (Pipe Ring Notched Tension) specimens. In this work, both types of specimens required for this testing were manufactured from polyamide PA12 by using SLS (selective laser sintering) additive manufacturing method. Testing of the specimens is performed on the universal device for testing of mechanical properties of materials Shimadzu, AGS-X 100 kN. The tensile testing is accompanied by GOM Aramis 2M system, used for digital image correlation. By using these two systems, test results are obtained for ring-shaped and SENT specimens, including forces, displacements and fracture mechanics parameters CMOD (Crack Mouth Opening Displacement) and CTOD-δ5 (Crack Tip Opening Displacement obtained by δ5 technique), as well as crack growth. Repeatability of this process, along with valid result consistency, represent the basis for further development of the new method, including the determining of energy-based fracture mechanics parameters: J integral and stress intensity factor.
PB  - International Institute for the Science of Sintering (IISS)
T2  - Science of Sintering
T1  - Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens
EP  - 386
IS  - 3
SP  - 373
VL  - 54
DO  - 10.2298/SOS2203373T
ER  - 

@article{
author = "Trajković, Isaak and Milošević, Miloš and Travica, Milan and Rakin, Marko and Mladenović, Goran and Kudrjavceva, Ljudmila and Međo, Bojan",
year = "2022",
abstract = "This paper presents a part of development of a non-standard method for testing of cylindrical test specimens for measurement of fracture properties of pipeline materials. This method for testing of cylindrical structures working under pressure is based on determining of fracture mechanics parameters on SENT (Single Edge Notched Tension) specimens and new PRNT (Pipe Ring Notched Tension) specimens. In this work, both types of specimens required for this testing were manufactured from polyamide PA12 by using SLS (selective laser sintering) additive manufacturing method. Testing of the specimens is performed on the universal device for testing of mechanical properties of materials Shimadzu, AGS-X 100 kN. The tensile testing is accompanied by GOM Aramis 2M system, used for digital image correlation. By using these two systems, test results are obtained for ring-shaped and SENT specimens, including forces, displacements and fracture mechanics parameters CMOD (Crack Mouth Opening Displacement) and CTOD-δ5 (Crack Tip Opening Displacement obtained by δ5 technique), as well as crack growth. Repeatability of this process, along with valid result consistency, represent the basis for further development of the new method, including the determining of energy-based fracture mechanics parameters: J integral and stress intensity factor.",
publisher = "International Institute for the Science of Sintering (IISS)",
journal = "Science of Sintering",
title = "Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens",
pages = "386-373",
number = "3",
volume = "54",
doi = "10.2298/SOS2203373T"
}

Trajković, I., Milošević, M., Travica, M., Rakin, M., Mladenović, G., Kudrjavceva, L.,& Međo, B.. (2022). Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens. in Science of Sintering
International Institute for the Science of Sintering (IISS)., 54(3), 373-386.
https://doi.org/10.2298/SOS2203373T

Trajković I, Milošević M, Travica M, Rakin M, Mladenović G, Kudrjavceva L, Međo B. Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens. in Science of Sintering. 2022;54(3):373-386.
doi:10.2298/SOS2203373T .

Trajković, Isaak, Milošević, Miloš, Travica, Milan, Rakin, Marko, Mladenović, Goran, Kudrjavceva, Ljudmila, Međo, Bojan, "Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens" in Science of Sintering, 54, no. 3 (2022):373-386,
https://doi.org/10.2298/SOS2203373T . .

TY  - CONF
AU  - Rakin, Marko
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Đokić, Veljko
AU  - Gubeljak, Nenad
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6012
AB  - The intent of the study was to modify virgin biomedical Ti-13Nb-13Zr alloy in aim to realize whether applied modifications could improve mechanical properties. Two groups of modifications were applied to the prepared samples: structural modification achieved by severe plastic deformation (SPD) and modification of alloy surface obtained by electrochemical method. Structural modification was performed by using high pressure torsion (HPT) as one of the SPD methods. Pressure of 4.1 GPa was applied and up to 5 rotations were made at room temperature. After HPT treatment an ultrafine-grained (UFG) structure was obtained. The homogeneity of the UFG alloy was checked by using Vickers microhardness tester. Electrochemical anodization was done in the 1M H3PO4 + NaF electrolyte during 90 minutes, resulting in formation of an oxide layer on the alloy surface. Surface roughness was determined using an atomic force microscope. Tensile properties of the alloy before and after electrochemical anodization and HPT processing were determined. The scanning electron microscopy was used to characterize both morphology of anodized surfaces and the fracture surfaces after the tensile tests. 
The HPT treated alloy has higher values of tensile strength and modulus of elasticity and lower value of plasticity than the virgin alloy. Surface modification of virgin alloy leads to a decrease of these values compared to non-treated samples and practically has no influence on tensile properties on the UFG alloy. Mechanical properties of the surface – modulus of elasticity and nanohardness were determined using a nanoindentation test. The surfaces of anodized alloys (both virgin and HPT treated) have lower modulus of elasticity than surfaces of non-anodized ones.
C3  - 4th Virtual Congress on Materials Science & Engineering
T1  - Mechanical characterization of surface modified Ti-based alloy before and after severe plastic deformation
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6012
ER  - 

@conference{
author = "Rakin, Marko and Barjaktarević, Dragana and Međo, Bojan and Đokić, Veljko and Gubeljak, Nenad",
year = "2022",
abstract = "The intent of the study was to modify virgin biomedical Ti-13Nb-13Zr alloy in aim to realize whether applied modifications could improve mechanical properties. Two groups of modifications were applied to the prepared samples: structural modification achieved by severe plastic deformation (SPD) and modification of alloy surface obtained by electrochemical method. Structural modification was performed by using high pressure torsion (HPT) as one of the SPD methods. Pressure of 4.1 GPa was applied and up to 5 rotations were made at room temperature. After HPT treatment an ultrafine-grained (UFG) structure was obtained. The homogeneity of the UFG alloy was checked by using Vickers microhardness tester. Electrochemical anodization was done in the 1M H3PO4 + NaF electrolyte during 90 minutes, resulting in formation of an oxide layer on the alloy surface. Surface roughness was determined using an atomic force microscope. Tensile properties of the alloy before and after electrochemical anodization and HPT processing were determined. The scanning electron microscopy was used to characterize both morphology of anodized surfaces and the fracture surfaces after the tensile tests. 
The HPT treated alloy has higher values of tensile strength and modulus of elasticity and lower value of plasticity than the virgin alloy. Surface modification of virgin alloy leads to a decrease of these values compared to non-treated samples and practically has no influence on tensile properties on the UFG alloy. Mechanical properties of the surface – modulus of elasticity and nanohardness were determined using a nanoindentation test. The surfaces of anodized alloys (both virgin and HPT treated) have lower modulus of elasticity than surfaces of non-anodized ones.",
journal = "4th Virtual Congress on Materials Science & Engineering",
title = "Mechanical characterization of surface modified Ti-based alloy before and after severe plastic deformation",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6012"
}

Rakin, M., Barjaktarević, D., Međo, B., Đokić, V.,& Gubeljak, N.. (2022). Mechanical characterization of surface modified Ti-based alloy before and after severe plastic deformation. in 4th Virtual Congress on Materials Science & Engineering.
https://hdl.handle.net/21.15107/rcub_technorep_6012

Rakin M, Barjaktarević D, Međo B, Đokić V, Gubeljak N. Mechanical characterization of surface modified Ti-based alloy before and after severe plastic deformation. in 4th Virtual Congress on Materials Science & Engineering. 2022;.
https://hdl.handle.net/21.15107/rcub_technorep_6012 .

Rakin, Marko, Barjaktarević, Dragana, Međo, Bojan, Đokić, Veljko, Gubeljak, Nenad, "Mechanical characterization of surface modified Ti-based alloy before and after severe plastic deformation" in 4th Virtual Congress on Materials Science & Engineering (2022),
https://hdl.handle.net/21.15107/rcub_technorep_6012 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Jevtić, Ivana
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6010
AB  - This work presents the fabrication and tensile testing of polyamide specimens fabricated by
selective laser sintering (SLS). Two geometries are considered: SENT (Single Edge Notched
Tension) and PRNT (Pipe Ring Notched Tension) specimens. Experimental testing of these
specimens is a step in development of a new method for testing of properties of the pipeline
materials. The samples were produced by SLS (Selective Laser Sintering) additive production
technique. The samples were made from polyamide PA12 on EOS Formiga P100 machine
(fabrication parameters: laser power 30 W, print layer height 0.1 mm, scanning speed 1.6-5
m/s, operating temperature 170⁰C). Testing was performed in the displacement control on a
universal tensile testing machine Shimadzu AGS - X. On this machine, the values of force as
well as the values of stress and strain were obtained directly from the Trapezium X software.
Special attention in this work is devoted to two important aspects: fixing of the ring specimen
for testing and influence of friction between the specimen and the tool. The results obtained
on the examined specimens indicate that this study is a valuable contribution for further
development and verification of the new fracture resistance testing procedure for different
pipeline materials.
PB  - Serbian Academy of Sciences and Arts
C3  - Serbian Ceramic Society Conference ADVANCED CERAMICS AND APPLICATION X New Frontiers in Multifunctional Material Science and Processing
T1  - Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries
SP  - 80
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6010
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Travica, Milan and Rakin, Marko and Jevtić, Ivana and Sedmak, Aleksandar and Međo, Bojan",
year = "2022",
abstract = "This work presents the fabrication and tensile testing of polyamide specimens fabricated by
selective laser sintering (SLS). Two geometries are considered: SENT (Single Edge Notched
Tension) and PRNT (Pipe Ring Notched Tension) specimens. Experimental testing of these
specimens is a step in development of a new method for testing of properties of the pipeline
materials. The samples were produced by SLS (Selective Laser Sintering) additive production
technique. The samples were made from polyamide PA12 on EOS Formiga P100 machine
(fabrication parameters: laser power 30 W, print layer height 0.1 mm, scanning speed 1.6-5
m/s, operating temperature 170⁰C). Testing was performed in the displacement control on a
universal tensile testing machine Shimadzu AGS - X. On this machine, the values of force as
well as the values of stress and strain were obtained directly from the Trapezium X software.
Special attention in this work is devoted to two important aspects: fixing of the ring specimen
for testing and influence of friction between the specimen and the tool. The results obtained
on the examined specimens indicate that this study is a valuable contribution for further
development and verification of the new fracture resistance testing procedure for different
pipeline materials.",
publisher = "Serbian Academy of Sciences and Arts",
journal = "Serbian Ceramic Society Conference ADVANCED CERAMICS AND APPLICATION X New Frontiers in Multifunctional Material Science and Processing",
title = "Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries",
pages = "80",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6010"
}

Trajković, I., Milošević, M., Travica, M., Rakin, M., Jevtić, I., Sedmak, A.,& Međo, B.. (2022). Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries. in Serbian Ceramic Society Conference ADVANCED CERAMICS AND APPLICATION X New Frontiers in Multifunctional Material Science and Processing
Serbian Academy of Sciences and Arts., 80.
https://hdl.handle.net/21.15107/rcub_technorep_6010

Trajković I, Milošević M, Travica M, Rakin M, Jevtić I, Sedmak A, Međo B. Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries. in Serbian Ceramic Society Conference ADVANCED CERAMICS AND APPLICATION X New Frontiers in Multifunctional Material Science and Processing. 2022;:80.
https://hdl.handle.net/21.15107/rcub_technorep_6010 .

Trajković, Isaak, Milošević, Miloš, Travica, Milan, Rakin, Marko, Jevtić, Ivana, Sedmak, Aleksandar, Međo, Bojan, "Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries" in Serbian Ceramic Society Conference ADVANCED CERAMICS AND APPLICATION X New Frontiers in Multifunctional Material Science and Processing (2022):80,
https://hdl.handle.net/21.15107/rcub_technorep_6010 .

TY  - CONF
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Musrati, Walid
AU  - Gubeljak, Nenad
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6179
AB  - In recent years, several attempts have been made by research groups worldwide to propose and verify new laboratory specimens
for measurement of pipeline materials fracture resistance. The main reason for these efforts is the requirement of standard
fracture mechanics procedures for relatively large specimen thickness, i.e. plane strain conditions. It is almost impossible,
and also too conservative, to apply such an approach to the thin-walled pipes, which form the majority of industrial pipelines.
Failure resistance of pipeline steel is examined by testing the recently proposed Pipe Ring Notched Bend (PRNB) specimens
with different dimensions. The seam, i.e. longitudinal weld, is analysed as a source of material heterogeneity;
however, seamless pipes are also examined. The results are repeatable, and the dependence on the specimen geometry is
not significant (it is even lower than it could be expected from standard thick fracture mechanics specimens). The seam
materials (weld metals) have shown different fracture behaviour for different batches/sizes of the pipes; they have either
lower or similar fracture resistance in comparison with the base material. Briefly, it can be said that fracture testing of a
relatively small amount of specimens revealed a lot of important data about the resistance of the pipes to ductile failure.
Fracture is modelled by application of the micromechanical approach in software package Abaqus, in particular the
Complete Gurson model. Additionally, the model is used for prediction of fracture resistance in plane strain conditions.
This can be useful for comparison of the examined pipe materials and others with known plane strain fracture properties.
Currently, the authors are working on a new geometry: pipe rings with a sharp notch exposed to tensile loading. This
will form a comprehensive approach to pipeline testing, where two geometries and two loading regimes (bending and
tension) will be available in the framework of a unified testing procedure.
C3  - 3rd Global Webinar on Materials Science and Engineering
T1  - Failure assessment of steel pipes using non-standard ring specimens.
SP  - 11
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6179
ER  - 

@conference{
author = "Rakin, Marko and Međo, Bojan and Musrati, Walid and Gubeljak, Nenad",
year = "2022",
abstract = "In recent years, several attempts have been made by research groups worldwide to propose and verify new laboratory specimens
for measurement of pipeline materials fracture resistance. The main reason for these efforts is the requirement of standard
fracture mechanics procedures for relatively large specimen thickness, i.e. plane strain conditions. It is almost impossible,
and also too conservative, to apply such an approach to the thin-walled pipes, which form the majority of industrial pipelines.
Failure resistance of pipeline steel is examined by testing the recently proposed Pipe Ring Notched Bend (PRNB) specimens
with different dimensions. The seam, i.e. longitudinal weld, is analysed as a source of material heterogeneity;
however, seamless pipes are also examined. The results are repeatable, and the dependence on the specimen geometry is
not significant (it is even lower than it could be expected from standard thick fracture mechanics specimens). The seam
materials (weld metals) have shown different fracture behaviour for different batches/sizes of the pipes; they have either
lower or similar fracture resistance in comparison with the base material. Briefly, it can be said that fracture testing of a
relatively small amount of specimens revealed a lot of important data about the resistance of the pipes to ductile failure.
Fracture is modelled by application of the micromechanical approach in software package Abaqus, in particular the
Complete Gurson model. Additionally, the model is used for prediction of fracture resistance in plane strain conditions.
This can be useful for comparison of the examined pipe materials and others with known plane strain fracture properties.
Currently, the authors are working on a new geometry: pipe rings with a sharp notch exposed to tensile loading. This
will form a comprehensive approach to pipeline testing, where two geometries and two loading regimes (bending and
tension) will be available in the framework of a unified testing procedure.",
journal = "3rd Global Webinar on Materials Science and Engineering",
title = "Failure assessment of steel pipes using non-standard ring specimens.",
pages = "11",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6179"
}

Rakin, M., Međo, B., Musrati, W.,& Gubeljak, N.. (2022). Failure assessment of steel pipes using non-standard ring specimens.. in 3rd Global Webinar on Materials Science and Engineering, 11.
https://hdl.handle.net/21.15107/rcub_technorep_6179

Rakin M, Međo B, Musrati W, Gubeljak N. Failure assessment of steel pipes using non-standard ring specimens.. in 3rd Global Webinar on Materials Science and Engineering. 2022;:11.
https://hdl.handle.net/21.15107/rcub_technorep_6179 .

Rakin, Marko, Međo, Bojan, Musrati, Walid, Gubeljak, Nenad, "Failure assessment of steel pipes using non-standard ring specimens." in 3rd Global Webinar on Materials Science and Engineering (2022):11,
https://hdl.handle.net/21.15107/rcub_technorep_6179 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6421
AB  - In order to define a procedure for integrity assessment of pipelines and determining the fracture mechanics parameters, a new type of specimen with a sharp notch, Pipe Ring Notched Tension (PRNT) specimen, is tested. The aim of the study is to determine the influence of the specimen geometry (cylindrical shape, as well as number and length of stress concentrators) on parameters such as force, Crack Mouth Opening Displacement CMOD, Crack Tip Opening Displacement CTOD and J integral. The specimens were fabricated by an additive production method - selective laser sintering (SLS). EOS Formiga P100 machine is used, and the material is polyamide PA12. In addition to Pipe Ring Notched Tension specimens, Single Edge Notched Tension (SENT) specimens with identical cross section were also considered. All specimens were tested on a universal tensile testing machine. A tool specially designed to apply contact pressure to the inner walls in the tension direction was used, simulating the internal pressure. For determining the field of displacement and strain on the surface of the tested samples that occur during the loading, Aramis GOM 2M optical measurement system was used. Aramis is applied for determination of geometry fracture mechanics parameters: CMOD and CTOD (based on δ5 concept). In addition to the examination of fracture properties of additively manufactured PA12, the main topic of this work is the development of the non-standard testing procedure, which will be subsequently applied to the specimens cut from metallic or non-metallic pipes. As an important part of this procedure, the calculation of fracture parameters will be conducted based on the results presented here.
PB  - Elsevier B.V.
C3  - Procedia Structural Integrity
T1  - Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry
EP  - 1319
SP  - 1314
VL  - 42
DO  - 10.1016/j.prostr.2022.12.167
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Rakin, Marko and Sedmak, Aleksandar and Međo, Bojan",
year = "2022",
abstract = "In order to define a procedure for integrity assessment of pipelines and determining the fracture mechanics parameters, a new type of specimen with a sharp notch, Pipe Ring Notched Tension (PRNT) specimen, is tested. The aim of the study is to determine the influence of the specimen geometry (cylindrical shape, as well as number and length of stress concentrators) on parameters such as force, Crack Mouth Opening Displacement CMOD, Crack Tip Opening Displacement CTOD and J integral. The specimens were fabricated by an additive production method - selective laser sintering (SLS). EOS Formiga P100 machine is used, and the material is polyamide PA12. In addition to Pipe Ring Notched Tension specimens, Single Edge Notched Tension (SENT) specimens with identical cross section were also considered. All specimens were tested on a universal tensile testing machine. A tool specially designed to apply contact pressure to the inner walls in the tension direction was used, simulating the internal pressure. For determining the field of displacement and strain on the surface of the tested samples that occur during the loading, Aramis GOM 2M optical measurement system was used. Aramis is applied for determination of geometry fracture mechanics parameters: CMOD and CTOD (based on δ5 concept). In addition to the examination of fracture properties of additively manufactured PA12, the main topic of this work is the development of the non-standard testing procedure, which will be subsequently applied to the specimens cut from metallic or non-metallic pipes. As an important part of this procedure, the calculation of fracture parameters will be conducted based on the results presented here.",
publisher = "Elsevier B.V.",
journal = "Procedia Structural Integrity",
title = "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry",
pages = "1319-1314",
volume = "42",
doi = "10.1016/j.prostr.2022.12.167"
}

Trajković, I., Milošević, M., Rakin, M., Sedmak, A.,& Međo, B.. (2022). Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity
Elsevier B.V.., 42, 1314-1319.
https://doi.org/10.1016/j.prostr.2022.12.167

Trajković I, Milošević M, Rakin M, Sedmak A, Međo B. Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity. 2022;42:1314-1319.
doi:10.1016/j.prostr.2022.12.167 .

Trajković, Isaak, Milošević, Miloš, Rakin, Marko, Sedmak, Aleksandar, Međo, Bojan, "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry" in Procedia Structural Integrity, 42 (2022):1314-1319,
https://doi.org/10.1016/j.prostr.2022.12.167 . .

TY  - CONF
AU  - Barjaktarević, Dragana
AU  - Rakin, Marko
AU  - Veljović, Đorđe
AU  - Međo, Bojan
AU  - Đokić, Veljko
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5258
AB  - Nanostructured surface of Ti-13Nb-13Zr alloy (coarse-grained (CG), and ultrafine-grained (UFG), obtained by high pressure torsion - HPT) was formed using electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 30, 60, 90 and 120 minutes. The scanning electron microscopy (SEM) was used to characterise the morphology of the surface, while chemical characterization of the obtained nanostructured surface was performed using energy dispersive spectroscopy (EDS). The surface modulus of elasticity and hardness before and after the surface nanostructure modification, was examined using the nanoindentation test, while the analysis of deformation and damage of the nanostructured surface after nanoindentation was performed using SEM. Cytotoxicity of the tested alloys and cell culture viability were assessed using the tetrazolium salt colorimetric test (MTT test) using mouse fibroblasts (L-929) and human lung fibroblasts (MRC-5) in liquid medium. Morphology and adhesion of cells on the surface were analysed using SEM. The obtained results indicate the strong influence of time, as a parameter of anodization, on the surface morphology. Influence of the HPT processing on the homogeneity of the nanostructured surface obtained by electrochemical anodization has also been shown. The alloys before and after the surface nanostructure modification are adequate in their biocompatibility for use in the implantology. Characterization of the titanium-based materials surface using nanoindentation showed a decrease in the values of modulus of elasticity and hardness for materials with nanostructured surface, which are close to the values of bone tissue in the human body.
PB  - Materials Research Society of Srebia
C3  - Twenty-third Annual Conference YUCOMAT 2022 &
Twelfth World Round Table Conference on Sintering XII WRTCS
T1  - Nanostructured surface modification and characterization of titanium based materials for medical application
SP  - 154
UR  - https://hdl.handle.net/21.15107/rcub_technorep_5258
ER  - 

@conference{
author = "Barjaktarević, Dragana and Rakin, Marko and Veljović, Đorđe and Međo, Bojan and Đokić, Veljko",
year = "2022",
abstract = "Nanostructured surface of Ti-13Nb-13Zr alloy (coarse-grained (CG), and ultrafine-grained (UFG), obtained by high pressure torsion - HPT) was formed using electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 30, 60, 90 and 120 minutes. The scanning electron microscopy (SEM) was used to characterise the morphology of the surface, while chemical characterization of the obtained nanostructured surface was performed using energy dispersive spectroscopy (EDS). The surface modulus of elasticity and hardness before and after the surface nanostructure modification, was examined using the nanoindentation test, while the analysis of deformation and damage of the nanostructured surface after nanoindentation was performed using SEM. Cytotoxicity of the tested alloys and cell culture viability were assessed using the tetrazolium salt colorimetric test (MTT test) using mouse fibroblasts (L-929) and human lung fibroblasts (MRC-5) in liquid medium. Morphology and adhesion of cells on the surface were analysed using SEM. The obtained results indicate the strong influence of time, as a parameter of anodization, on the surface morphology. Influence of the HPT processing on the homogeneity of the nanostructured surface obtained by electrochemical anodization has also been shown. The alloys before and after the surface nanostructure modification are adequate in their biocompatibility for use in the implantology. Characterization of the titanium-based materials surface using nanoindentation showed a decrease in the values of modulus of elasticity and hardness for materials with nanostructured surface, which are close to the values of bone tissue in the human body.",
publisher = "Materials Research Society of Srebia",
journal = "Twenty-third Annual Conference YUCOMAT 2022 &
Twelfth World Round Table Conference on Sintering XII WRTCS",
title = "Nanostructured surface modification and characterization of titanium based materials for medical application",
pages = "154",
url = "https://hdl.handle.net/21.15107/rcub_technorep_5258"
}

Barjaktarević, D., Rakin, M., Veljović, Đ., Međo, B.,& Đokić, V.. (2022). Nanostructured surface modification and characterization of titanium based materials for medical application. in Twenty-third Annual Conference YUCOMAT 2022 &
Twelfth World Round Table Conference on Sintering XII WRTCS
Materials Research Society of Srebia., 154.
https://hdl.handle.net/21.15107/rcub_technorep_5258

Barjaktarević D, Rakin M, Veljović Đ, Međo B, Đokić V. Nanostructured surface modification and characterization of titanium based materials for medical application. in Twenty-third Annual Conference YUCOMAT 2022 &
Twelfth World Round Table Conference on Sintering XII WRTCS. 2022;:154.
https://hdl.handle.net/21.15107/rcub_technorep_5258 .

Barjaktarević, Dragana, Rakin, Marko, Veljović, Đorđe, Međo, Bojan, Đokić, Veljko, "Nanostructured surface modification and characterization of titanium based materials for medical application" in Twenty-third Annual Conference YUCOMAT 2022 &
Twelfth World Round Table Conference on Sintering XII WRTCS (2022):154,
https://hdl.handle.net/21.15107/rcub_technorep_5258 .

TY  - JOUR
AU  - Veljić, Darko M.
AU  - Rakin, Marko P.
AU  - Sedmak, Aleksandar S.
AU  - Radović, Nenad A.
AU  - Međo, Bojan I.
AU  - Mrdak, Mihailo R.
AU  - Bajić, Darko R.
PY  - 2022
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5152
AB  - The influence of friction stir welding parameters on thermo-mechanical behavior of the material during welding is analyzed. An aluminum alloy is considered (Al 2024 T351), and different rotating and welding speeds are applied. The finite element model consists of the working plate (Al alloy), backing plate and welding tool. The influence of the welding conditions on material behavior is taken into account the application of the Johnson-Cook material model. The rotation speed of the tool affects the results. If increased, it contributes to an increase of friction-generated heat intensity. The other component of the generated heat, which stems from the plastic deformation of the material, is negligibly changed. When the welding speed, i.e. tool translation speed, is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming is becoming more pronounced. Summed, this leads to rather small change of the total generation. The changes of the heat generation influence both the temperature field and reaction force. Also, the inadequate selection of welding parameters resulted in occurrence of the defects (pores) in the model.
PB  - VINČA Institute of Nuclear Sciences
T2  - Thermal Science
T1  - Thermo-mechanical analysis of linear welding stage in friction stir welding Influence of Welding Parameters
EP  - 2134
IS  - 3A
SP  - 2125
VL  - 26
DO  - 10.2298/TSCI210216186V
ER  - 

@article{
author = "Veljić, Darko M. and Rakin, Marko P. and Sedmak, Aleksandar S. and Radović, Nenad A. and Međo, Bojan I. and Mrdak, Mihailo R. and Bajić, Darko R.",
year = "2022",
abstract = "The influence of friction stir welding parameters on thermo-mechanical behavior of the material during welding is analyzed. An aluminum alloy is considered (Al 2024 T351), and different rotating and welding speeds are applied. The finite element model consists of the working plate (Al alloy), backing plate and welding tool. The influence of the welding conditions on material behavior is taken into account the application of the Johnson-Cook material model. The rotation speed of the tool affects the results. If increased, it contributes to an increase of friction-generated heat intensity. The other component of the generated heat, which stems from the plastic deformation of the material, is negligibly changed. When the welding speed, i.e. tool translation speed, is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming is becoming more pronounced. Summed, this leads to rather small change of the total generation. The changes of the heat generation influence both the temperature field and reaction force. Also, the inadequate selection of welding parameters resulted in occurrence of the defects (pores) in the model.",
publisher = "VINČA Institute of Nuclear Sciences",
journal = "Thermal Science",
title = "Thermo-mechanical analysis of linear welding stage in friction stir welding Influence of Welding Parameters",
pages = "2134-2125",
number = "3A",
volume = "26",
doi = "10.2298/TSCI210216186V"
}

Veljić, D. M., Rakin, M. P., Sedmak, A. S., Radović, N. A., Međo, B. I., Mrdak, M. R.,& Bajić, D. R.. (2022). Thermo-mechanical analysis of linear welding stage in friction stir welding Influence of Welding Parameters. in Thermal Science
VINČA Institute of Nuclear Sciences., 26(3A), 2125-2134.
https://doi.org/10.2298/TSCI210216186V

Veljić DM, Rakin MP, Sedmak AS, Radović NA, Međo BI, Mrdak MR, Bajić DR. Thermo-mechanical analysis of linear welding stage in friction stir welding Influence of Welding Parameters. in Thermal Science. 2022;26(3A):2125-2134.
doi:10.2298/TSCI210216186V .

Veljić, Darko M., Rakin, Marko P., Sedmak, Aleksandar S., Radović, Nenad A., Međo, Bojan I., Mrdak, Mihailo R., Bajić, Darko R., "Thermo-mechanical analysis of linear welding stage in friction stir welding Influence of Welding Parameters" in Thermal Science, 26, no. 3A (2022):2125-2134,
https://doi.org/10.2298/TSCI210216186V . .

TY  - CHAP
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Đokić, Veljko
AU  - Rakin, Marko
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5252
AB  - Lower value of modulus of elasticity, closer to that of a bone, is one of the crucial surface properties in accepting the implant material from the surrounding tissue, and reduces the possibility of slow disappearance of bone in contact with the implant. In the present study, ultrafine-grained (UFG) Ti-13Nb-13Zr alloy was obtained using high pressure torsion process (HPT) under a pressure of 4.1 GPa with a rotational speed of 0.2 rpm up to 5 rotations at room temperature. Nanostructured surface on coarse-grained (CG) and UFG Ti-13Nb-13Zr alloy was formed using electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 60 and 90 minutes. Scanning electron microscopy (SEM) was used to characterise the morphology of the surface, while nanomechanical properties of the surface, modulus of elasticity and nanohardness were determined using the nanoindentation test. Also, in order to characterise deformation of the nanotubes after nanoindentation test, SEM was done. It was shown that the nanotubular oxide layer was formed as result of the electrochemical anodization process during both anodizing times. The surface of anodized alloys has lower modulus of elasticity than surface of non-anodized ones. Anodized UFG alloy had the lowest modulus of elasticity of the surface when compared to other tested samples, which makes it more acceptable for biomedical usage.
PB  - Springer
T2  - Proceedings of the International Conference
of Experimental and Numerical Investigations
and New Technologies
T1  - Morphology and nanomechanical properties of the ultrafine-grained Ti-13Nb-13Zr alloy surface obtained using electrochemical anodization
EP  - 141
SP  - 123
VL  - 323
DO  - 10.1007/978-3-030-86009-7_7
ER  - 

@inbook{
author = "Barjaktarević, Dragana and Međo, Bojan and Đokić, Veljko and Rakin, Marko",
year = "2021",
abstract = "Lower value of modulus of elasticity, closer to that of a bone, is one of the crucial surface properties in accepting the implant material from the surrounding tissue, and reduces the possibility of slow disappearance of bone in contact with the implant. In the present study, ultrafine-grained (UFG) Ti-13Nb-13Zr alloy was obtained using high pressure torsion process (HPT) under a pressure of 4.1 GPa with a rotational speed of 0.2 rpm up to 5 rotations at room temperature. Nanostructured surface on coarse-grained (CG) and UFG Ti-13Nb-13Zr alloy was formed using electrochemical anodization in the 1M H3PO4 + NaF electrolyte, during 60 and 90 minutes. Scanning electron microscopy (SEM) was used to characterise the morphology of the surface, while nanomechanical properties of the surface, modulus of elasticity and nanohardness were determined using the nanoindentation test. Also, in order to characterise deformation of the nanotubes after nanoindentation test, SEM was done. It was shown that the nanotubular oxide layer was formed as result of the electrochemical anodization process during both anodizing times. The surface of anodized alloys has lower modulus of elasticity than surface of non-anodized ones. Anodized UFG alloy had the lowest modulus of elasticity of the surface when compared to other tested samples, which makes it more acceptable for biomedical usage.",
publisher = "Springer",
journal = "Proceedings of the International Conference
of Experimental and Numerical Investigations
and New Technologies",
booktitle = "Morphology and nanomechanical properties of the ultrafine-grained Ti-13Nb-13Zr alloy surface obtained using electrochemical anodization",
pages = "141-123",
volume = "323",
doi = "10.1007/978-3-030-86009-7_7"
}

Barjaktarević, D., Međo, B., Đokić, V.,& Rakin, M.. (2021). Morphology and nanomechanical properties of the ultrafine-grained Ti-13Nb-13Zr alloy surface obtained using electrochemical anodization. in Proceedings of the International Conference
of Experimental and Numerical Investigations
and New Technologies
Springer., 323, 123-141.
https://doi.org/10.1007/978-3-030-86009-7_7

Barjaktarević D, Međo B, Đokić V, Rakin M. Morphology and nanomechanical properties of the ultrafine-grained Ti-13Nb-13Zr alloy surface obtained using electrochemical anodization. in Proceedings of the International Conference
of Experimental and Numerical Investigations
and New Technologies. 2021;323:123-141.
doi:10.1007/978-3-030-86009-7_7 .

Barjaktarević, Dragana, Međo, Bojan, Đokić, Veljko, Rakin, Marko, "Morphology and nanomechanical properties of the ultrafine-grained Ti-13Nb-13Zr alloy surface obtained using electrochemical anodization" in Proceedings of the International Conference
of Experimental and Numerical Investigations
and New Technologies, 323 (2021):123-141,
https://doi.org/10.1007/978-3-030-86009-7_7 . .

TY  - CONF
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Đokić, Veljko
AU  - Rakin, Marko
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5259
AB  - Anodized surface on coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloy was obtained using electrochemical surface modification in the 1M H3PO4 + NaF electrolyte. Scanning electron microscopy (SEM) was used to characterise the microstructure of anodized surface, while mechanical surface properties were determined from the nanoindentation test. Numerical analysis of deformation of oxide film exposed to nanoindentation is performed on simplified 2D finite element models, with the main aim to determine the influence of the dimensions of the nanotubes on resistance to external loading. Software package Simulia Abaqus is used. It was shown that the homogeneous oxide film was formed at longer time period, while inhomogeneous oxide film was formed at shorter time period, for both materials. The oxide film was composed of nanotubes, whose deformation after the nanoindentation test is characterized by SEM. The surface of anodized alloys has lower mechanical surface properties (modulus of elasticity and nanohardness) than surface of non-anodized ones, which make them more acceptable for biomedical usage. Numerical calculations revealed the influence of morphology of the anodized surface layer on its load carrying capacity
PB  - Innovation Center of Faculty of Mechanical Engineering, Belgrade
C3  - International Conference of Exsperimental and Numerical Investigations and New Technologies
T1  - Microstructure and mechanical properties of anodized surface of ultrafine-grained Ti-13Nb-13Zr alloy for biomedical application
SP  - 36
UR  - https://hdl.handle.net/21.15107/rcub_technorep_5259
ER  - 

@conference{
author = "Barjaktarević, Dragana and Međo, Bojan and Đokić, Veljko and Rakin, Marko",
year = "2021",
abstract = "Anodized surface on coarse-grained (CG) and ultrafine-grained (UFG) Ti-13Nb-13Zr alloy was obtained using electrochemical surface modification in the 1M H3PO4 + NaF electrolyte. Scanning electron microscopy (SEM) was used to characterise the microstructure of anodized surface, while mechanical surface properties were determined from the nanoindentation test. Numerical analysis of deformation of oxide film exposed to nanoindentation is performed on simplified 2D finite element models, with the main aim to determine the influence of the dimensions of the nanotubes on resistance to external loading. Software package Simulia Abaqus is used. It was shown that the homogeneous oxide film was formed at longer time period, while inhomogeneous oxide film was formed at shorter time period, for both materials. The oxide film was composed of nanotubes, whose deformation after the nanoindentation test is characterized by SEM. The surface of anodized alloys has lower mechanical surface properties (modulus of elasticity and nanohardness) than surface of non-anodized ones, which make them more acceptable for biomedical usage. Numerical calculations revealed the influence of morphology of the anodized surface layer on its load carrying capacity",
publisher = "Innovation Center of Faculty of Mechanical Engineering, Belgrade",
journal = "International Conference of Exsperimental and Numerical Investigations and New Technologies",
title = "Microstructure and mechanical properties of anodized surface of ultrafine-grained Ti-13Nb-13Zr alloy for biomedical application",
pages = "36",
url = "https://hdl.handle.net/21.15107/rcub_technorep_5259"
}

Barjaktarević, D., Međo, B., Đokić, V.,& Rakin, M.. (2021). Microstructure and mechanical properties of anodized surface of ultrafine-grained Ti-13Nb-13Zr alloy for biomedical application. in International Conference of Exsperimental and Numerical Investigations and New Technologies
Innovation Center of Faculty of Mechanical Engineering, Belgrade., 36.
https://hdl.handle.net/21.15107/rcub_technorep_5259

Barjaktarević D, Međo B, Đokić V, Rakin M. Microstructure and mechanical properties of anodized surface of ultrafine-grained Ti-13Nb-13Zr alloy for biomedical application. in International Conference of Exsperimental and Numerical Investigations and New Technologies. 2021;:36.
https://hdl.handle.net/21.15107/rcub_technorep_5259 .

Barjaktarević, Dragana, Međo, Bojan, Đokić, Veljko, Rakin, Marko, "Microstructure and mechanical properties of anodized surface of ultrafine-grained Ti-13Nb-13Zr alloy for biomedical application" in International Conference of Exsperimental and Numerical Investigations and New Technologies (2021):36,
https://hdl.handle.net/21.15107/rcub_technorep_5259 .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Arsić, Miodrag
AU  - Damnjanović, Ivana
AU  - Stefanović, Ana
AU  - Grabulov, Vencislav
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6016
AB  - The defects in pipe elbows can, depending on their size and position, affect the integrity and safe service, as well as deformation ability of the piping systems in exploitation. Incompletely filled groove, which is the type of defect examined here, was observed by ultrasonic measurement on the pipeline in the regulation system of the hydro power plant Djerdap. Three-dimensional finite element analysis is performed using Simulia Abaqus software package. First, the models with dimensions of the defects observed by non-destructive examination are formed. Stress and strain fields for different loading types are shown and commented. The influence of the defect dimensions on the pipe elbow load-carrying capacity is determined through plastic collapse loads, which are obtained from bending moment - rotation angle diagrams. Twice elastic slope (TES) technique is applied. Additionally, some more severe defects are considered, in the form of sharp pre-cracks at the bottom of the defect; plastic collapse loads are also determined for these geometries. Both opening and closing bending moments are taken into consideration and the results are discussed and compared to two closed-form solutions from the literature. The influence of the boundary conditions applied for examination of the pipe elbows is
commented.
PB  - Faculty of Technology Zvornik, University of East Sarajevo
T2  - Journal of Engineering & Processing Management
T1  - Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment
EP  - 28
IS  - 1
SP  - 19
VL  - 13
DO  - 10.7251/JEPM2101019M
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Arsić, Miodrag and Damnjanović, Ivana and Stefanović, Ana and Grabulov, Vencislav",
year = "2021",
abstract = "The defects in pipe elbows can, depending on their size and position, affect the integrity and safe service, as well as deformation ability of the piping systems in exploitation. Incompletely filled groove, which is the type of defect examined here, was observed by ultrasonic measurement on the pipeline in the regulation system of the hydro power plant Djerdap. Three-dimensional finite element analysis is performed using Simulia Abaqus software package. First, the models with dimensions of the defects observed by non-destructive examination are formed. Stress and strain fields for different loading types are shown and commented. The influence of the defect dimensions on the pipe elbow load-carrying capacity is determined through plastic collapse loads, which are obtained from bending moment - rotation angle diagrams. Twice elastic slope (TES) technique is applied. Additionally, some more severe defects are considered, in the form of sharp pre-cracks at the bottom of the defect; plastic collapse loads are also determined for these geometries. Both opening and closing bending moments are taken into consideration and the results are discussed and compared to two closed-form solutions from the literature. The influence of the boundary conditions applied for examination of the pipe elbows is
commented.",
publisher = "Faculty of Technology Zvornik, University of East Sarajevo",
journal = "Journal of Engineering & Processing Management",
title = "Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment",
pages = "28-19",
number = "1",
volume = "13",
doi = "10.7251/JEPM2101019M"
}

Međo, B., Rakin, M., Arsić, M., Damnjanović, I., Stefanović, A.,& Grabulov, V.. (2021). Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment. in Journal of Engineering & Processing Management
Faculty of Technology Zvornik, University of East Sarajevo., 13(1), 19-28.
https://doi.org/10.7251/JEPM2101019M

Međo B, Rakin M, Arsić M, Damnjanović I, Stefanović A, Grabulov V. Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment. in Journal of Engineering & Processing Management. 2021;13(1):19-28.
doi:10.7251/JEPM2101019M .

Međo, Bojan, Rakin, Marko, Arsić, Miodrag, Damnjanović, Ivana, Stefanović, Ana, Grabulov, Vencislav, "Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment" in Journal of Engineering & Processing Management, 13, no. 1 (2021):19-28,
https://doi.org/10.7251/JEPM2101019M . .

TY  - JOUR
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Stefane, Primoz
AU  - Gubeljak, Nenad
AU  - Cvijović-Alagić, Ivana
AU  - Đokić, Veljko
AU  - Rakin, Marko
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/11
AB  - Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the high-pressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti-13Nb-13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti-13Nb-13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of alpha ' and beta phases in the CG TNZ alloy microstructure, while the additional omega phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer's solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.
PB  - Korean Inst Metals Materials, Seoul
T2  - Metals and Materials International
T1  - Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion
EP  - 3341
IS  - 9
SP  - 3325
VL  - 27
DO  - 10.1007/s12540-020-00837-z
ER  - 

@article{
author = "Barjaktarević, Dragana and Međo, Bojan and Stefane, Primoz and Gubeljak, Nenad and Cvijović-Alagić, Ivana and Đokić, Veljko and Rakin, Marko",
year = "2021",
abstract = "Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the high-pressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti-13Nb-13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti-13Nb-13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of alpha ' and beta phases in the CG TNZ alloy microstructure, while the additional omega phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer's solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.",
publisher = "Korean Inst Metals Materials, Seoul",
journal = "Metals and Materials International",
title = "Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion",
pages = "3341-3325",
number = "9",
volume = "27",
doi = "10.1007/s12540-020-00837-z"
}

Barjaktarević, D., Međo, B., Stefane, P., Gubeljak, N., Cvijović-Alagić, I., Đokić, V.,& Rakin, M.. (2021). Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion. in Metals and Materials International
Korean Inst Metals Materials, Seoul., 27(9), 3325-3341.
https://doi.org/10.1007/s12540-020-00837-z

Barjaktarević D, Međo B, Stefane P, Gubeljak N, Cvijović-Alagić I, Đokić V, Rakin M. Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion. in Metals and Materials International. 2021;27(9):3325-3341.
doi:10.1007/s12540-020-00837-z .

Barjaktarević, Dragana, Međo, Bojan, Stefane, Primoz, Gubeljak, Nenad, Cvijović-Alagić, Ivana, Đokić, Veljko, Rakin, Marko, "Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion" in Metals and Materials International, 27, no. 9 (2021):3325-3341,
https://doi.org/10.1007/s12540-020-00837-z . .

TY  - CONF
AU  - Međo, Bojan
AU  - Arsić, Miodrag
AU  - Damnjanović, Ivana
AU  - Stefanović, Ana
AU  - Grabulov, Vencislav
AU  - Rakin, Marko
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/6296
AB  - Imajući u vidu da greške u zavarenim spojevima ugrožavaju nosivost i sigurnost rada
cevovoda, ispitan je uticaj unutrašnjeg pritiska i momenta savijanja na cevi i cevne
lukove sa inicijalnim oštećenjima. Razmatrane su dimenzije obimnog oštećenja
(neprovara) prethodno otkrivene ultrazvučnim ispitivanjem na unutrašnjoj površini
zavarenih spojeva cevnih lukova cevovoda u hidroelektrani “Đerdap I”, ladovo.
Takođe, analizirani su i slučajevi kada na mestu neprovara postoji početna prslina;
dimenzije i položaj prsline su varirani. Za procenu sigurnosti opreme pod pritiskom u
eksploataciji koriste se eksperimentalne, analitičke i numeričke metode. U ovom radu,
urađena je analiza metodom konačnih elemenata (M E , koja spada u grupu
numeričkih metoda. Trodimenzionalna analiza MKE je urađena korišćenjem
programskog paketa Abaqus. Na osnovu dobijenih rezultata, zaključeno je da greške
koje su otkrivene ultrazvučnim merenjem ne ugrožavaju sigurnost rada cevovoda pri
dejstvu unutrašnjeg pritiska i momenta savijanja. Pri tome, oblik konačnog elementa nije
imao značajnog uticaja na rezultate; korišćeni su elementi oblika tetraedra sa 10
čvorova i heksaedra sa dvadeset čvorova. Nosivost cevovoda u odnosu na unutrašnji
pritisak se značajno smanjuje samo ukoliko postoji obimno oštećenje tipa prsline čija
dubina i dužina su znatno veće od maksimalnih vrednosti uočenih primenom ispitivanja bez razaranja. Slični rezulteti dobijeni su i razmatranjem uticaja momenta savijanja;
znatno veća nosivost dobijena je za “otvaranje” kolena, u poređenju sa “zatvaranjem”.
PB  - Централни институт за конзервацију
C3  - Zbornik rezimea „Bezbednost, kulturno nasleđe i nove tehnologije
T1  - Uticaj grešaka u zavarenim spojevima cevnih lukova na sigurnost rada cevovoda.
EP  - 34
SP  - 33
UR  - https://hdl.handle.net/21.15107/rcub_technorep_6296
ER  - 

@conference{
author = "Međo, Bojan and Arsić, Miodrag and Damnjanović, Ivana and Stefanović, Ana and Grabulov, Vencislav and Rakin, Marko",
year = "2020",
abstract = "Imajući u vidu da greške u zavarenim spojevima ugrožavaju nosivost i sigurnost rada
cevovoda, ispitan je uticaj unutrašnjeg pritiska i momenta savijanja na cevi i cevne
lukove sa inicijalnim oštećenjima. Razmatrane su dimenzije obimnog oštećenja
(neprovara) prethodno otkrivene ultrazvučnim ispitivanjem na unutrašnjoj površini
zavarenih spojeva cevnih lukova cevovoda u hidroelektrani “Đerdap I”, ladovo.
Takođe, analizirani su i slučajevi kada na mestu neprovara postoji početna prslina;
dimenzije i položaj prsline su varirani. Za procenu sigurnosti opreme pod pritiskom u
eksploataciji koriste se eksperimentalne, analitičke i numeričke metode. U ovom radu,
urađena je analiza metodom konačnih elemenata (M E , koja spada u grupu
numeričkih metoda. Trodimenzionalna analiza MKE je urađena korišćenjem
programskog paketa Abaqus. Na osnovu dobijenih rezultata, zaključeno je da greške
koje su otkrivene ultrazvučnim merenjem ne ugrožavaju sigurnost rada cevovoda pri
dejstvu unutrašnjeg pritiska i momenta savijanja. Pri tome, oblik konačnog elementa nije
imao značajnog uticaja na rezultate; korišćeni su elementi oblika tetraedra sa 10
čvorova i heksaedra sa dvadeset čvorova. Nosivost cevovoda u odnosu na unutrašnji
pritisak se značajno smanjuje samo ukoliko postoji obimno oštećenje tipa prsline čija
dubina i dužina su znatno veće od maksimalnih vrednosti uočenih primenom ispitivanja bez razaranja. Slični rezulteti dobijeni su i razmatranjem uticaja momenta savijanja;
znatno veća nosivost dobijena je za “otvaranje” kolena, u poređenju sa “zatvaranjem”.",
publisher = "Централни институт за конзервацију",
journal = "Zbornik rezimea „Bezbednost, kulturno nasleđe i nove tehnologije",
title = "Uticaj grešaka u zavarenim spojevima cevnih lukova na sigurnost rada cevovoda.",
pages = "34-33",
url = "https://hdl.handle.net/21.15107/rcub_technorep_6296"
}

Međo, B., Arsić, M., Damnjanović, I., Stefanović, A., Grabulov, V.,& Rakin, M.. (2020). Uticaj grešaka u zavarenim spojevima cevnih lukova na sigurnost rada cevovoda.. in Zbornik rezimea „Bezbednost, kulturno nasleđe i nove tehnologije
Централни институт за конзервацију., 33-34.
https://hdl.handle.net/21.15107/rcub_technorep_6296

Međo B, Arsić M, Damnjanović I, Stefanović A, Grabulov V, Rakin M. Uticaj grešaka u zavarenim spojevima cevnih lukova na sigurnost rada cevovoda.. in Zbornik rezimea „Bezbednost, kulturno nasleđe i nove tehnologije. 2020;:33-34.
https://hdl.handle.net/21.15107/rcub_technorep_6296 .

Međo, Bojan, Arsić, Miodrag, Damnjanović, Ivana, Stefanović, Ana, Grabulov, Vencislav, Rakin, Marko, "Uticaj grešaka u zavarenim spojevima cevnih lukova na sigurnost rada cevovoda." in Zbornik rezimea „Bezbednost, kulturno nasleđe i nove tehnologije (2020):33-34,
https://hdl.handle.net/21.15107/rcub_technorep_6296 .

TY  - JOUR
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Sedmak, Aleksandar
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4389
AB  - Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.
PB  - Srpsko društvo za mehaniku, Beograd
T2  - Theoretical and Applied Mechanics
T1  - An overview of application of micromechanical models in ductile fracture analysis of welded joints
EP  - 62
IS  - 1
SP  - 33
VL  - 47
DO  - 10.2298/TAM200117004R
ER  - 

@article{
author = "Rakin, Marko and Međo, Bojan and Gubeljak, Nenad and Sedmak, Aleksandar",
year = "2020",
abstract = "Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.",
publisher = "Srpsko društvo za mehaniku, Beograd",
journal = "Theoretical and Applied Mechanics",
title = "An overview of application of micromechanical models in ductile fracture analysis of welded joints",
pages = "62-33",
number = "1",
volume = "47",
doi = "10.2298/TAM200117004R"
}

Rakin, M., Međo, B., Gubeljak, N.,& Sedmak, A.. (2020). An overview of application of micromechanical models in ductile fracture analysis of welded joints. in Theoretical and Applied Mechanics
Srpsko društvo za mehaniku, Beograd., 47(1), 33-62.
https://doi.org/10.2298/TAM200117004R

Rakin M, Međo B, Gubeljak N, Sedmak A. An overview of application of micromechanical models in ductile fracture analysis of welded joints. in Theoretical and Applied Mechanics. 2020;47(1):33-62.
doi:10.2298/TAM200117004R .

Rakin, Marko, Međo, Bojan, Gubeljak, Nenad, Sedmak, Aleksandar, "An overview of application of micromechanical models in ductile fracture analysis of welded joints" in Theoretical and Applied Mechanics, 47, no. 1 (2020):33-62,
https://doi.org/10.2298/TAM200117004R . .