Structure Evolution of Fe-Mn Based Alloys under a Near-Rapid Solidification Process

Abstract

A series of near-rapid solidification experiments were performed to investigate the structure evolution in Fe-(6, 11, 13, 17, 21) wt.% Mn and Fe-11wt.%Mn-(0.1, 0.5,1.4) wt.% C strips. The α’-martensite of body-centered cubic structures were observed in all Fe-Mn alloy strips. The ε-martensite phase appeared when the manganese content was up to 13wt.% and its amount gradually increased with the increasing of manganese content. The austenitic phase began to appear in Fe-21wt.%Mnstrip. As for the solidified structure analysis, the Fe-13wt.%Mn strip had a quite large equiaxed grain zone, while other Fe-Mn strips mainly consisted of columnar grains grew from the surfaces. The addition of 0.1wt.%C was helpful for the formation of ε-martensite in Fe-11wt.%Mn strip, but the addition of 0.5 and 1.4wt.%C promoted the transformation of ε-martensite to austenite phase. And addition of 0.5wt.% carbon could increase the area ratio of equiaxed grains formation.