The influence of external stresses on the transformation behaviour in a Fe-Mn-Si alloy

Abstract

The influence of external stresses on the transformation behavior has been studied for a polycrystalline Fe-31Mn-SSi alloy exhibiting the γ→ε martensitic transformation. Samples have been loaded at temperatures above the M3 temperature, cooled with a constant external load to a temperature below the M3 temperature and subsequently heated without load to temperature above the A3temperature of the alloy. Stress, strain and temperature have been continuously meassured and transformation temperatures and strains have been determined from the change on strain during the transformation. It has been found the the M3 temperature during cooling with load is not influenced by 0.3-2% plastic pre-deformation of the austenite whereas there is a substantial increase in the transformation strain, i.e. variants with a favorable orientation are enhanced by pre-strain of austenite.