Effect of Si and Al additions on the low temperature toughness and fracture mode of Fe-27Mn alloys.

Abstract

The effect of Si and Al additions on the low temperature toughness and fracture mode of Fe-27Mn(in mass'/) alloys was investigated in terms of the microstructure, heterogeneous deformation and stacking fault energy. The Fe-27Mn binary a[loy has two constituent phases at 77 K; Epsilon martensite(E) and metastable austenite (Y) It undergoes a ductile-to-brittle transition because of an intergranular fracture associated with heterogeneous deformation. The intergranular fracture is caused by stress concentration at grain boundaries on which large 8 plates impinge. Silicon addition to the Fe-27Mn binary alloy is effective for refining g plates and changesthe fracture modefrom intergranular to transgranular.