Matrix Microstructure and Its Micro-Analysis of Constituent Phases in As-Cast Fe-Cr-C-V Alloys

Abstract

The as-cast matrix microstructure in 19 mass%Cr-2.8 mass%C white cast iron with up to 4.7 mass% V additions has been studied. Type and degree of the austenite transformation in the course of cooling after solidification in Fe-Cr-C-V alloys appeared to be dependent on the content of carbon and other alloying elements. Results obtained by EDS analysis of the phases in the tested Fe-Cr-C-V alloys indicated that vanadium is present in both matrix and carbide. Increasing the vanadium content in the alloy, its concentration increases in the matrix, whereas the concentration of carbon decreases. The precipitation kinetic of carbides in austenite was found dependent on the vanadium content. The volume fraction of M23C6 carbides was larger when the vanadium content was higher. TEM analysis revealed that both twinned and dislocation type martensites were present around secondary carbides. The transformation of austenite into martensite in the Fe-C-Cr-V alloys seems to be closely related to the precipitation of secondary carbides. [doi:10.2320/matertrans.M2009002]