Homogenization effect on microstructure Al-Mg-Si alloy containing low-melting point elements

Abstract

The subject of this study has been an investigation of the homogenization temperature effect on the microstructure of Al-Mg-Si alloy containing low-melting point Pb and Bi elements. The results of the characterization show that homogenization at temperatures lower than 500 °C requires extraordinary long in order to initiate ß-AlFeSi -> α-AlFe(Mn)Si transformation, necessary for good extrdability of the alloy ransformation, necessary for good extrudability of the alloy. In addition, precipitation of ß-Mg2Si phase takes place, decreasing the alloy's aging potential during the further processing. High-temperature homogenization not only results in complete ß-AlFeSi -> α-AlFe(Mn)Si transformation and dissolution of ß-Mg2Si phase but expected Pb and Bi escape to the specimen surface does not occur.

Predmet ovog rada je bilo ispitivanje i karakterizacija uslova homogenizacionog žarenja na mikrostruktu Al-Mg-Si legure legirane nisko-topivim metalima Pb i Bi. Rezultati pokazuju da homogenizacija na temperaturama nižim od 500 °C zahteva izuzetno duga vremena žarenja da bi došlo do ß-AlFeSi -> α-AlFe(Mn)Si transformacije, neophodne za sposobnost legure za presovanje. Dodatno, dolazi do izdvajanja ß-Mg2Si faze, čime se smanjuje sposobnost legure za starenje u daljoj preradi. Visoko-temperaturna homogenizacija ne samo da rezultuje u potpunoj ß-AlFeSi -> α-AlFe(Mn)Si transformaciji i rastvaranju ß-Mg2Si faze, već i ne dolazi do očekivanog gubitka Pb i Bi usled izdvajanja na površini uzoraka.