Computer Simulation of Martensitic Transformation Under Stress

Abstract
This paper reports a computer simulation of martensitic transformation in both Cu-Zn-Al and Fe-Ni-C alloys by a 2-dimensional model. The influence of the imposed stress on the mechanical behaviour, the transformation kinetics, and the microstructure are illustrated for Cu-Zn-Al alloy. The study of transformation kinetics shows the following features : (1) in case of stress-free transformation, both alloys transform in burst, the transformation will go directly to near completion once a band can overcome the energy barrier. (2) the transformation temperature range spreads monotonically as the load is increased from 0 to 500 MPa. (3) M_f is nearly the same for the different tested loading conditions. Even if the assumption of elastic accommodation is not realistic for Fe-Ni-C alloy, we can analyse the influence of the volume change associated with the transformation on the local stress level and on the behaviour of the alloy. This volume change has no notable influence at the earlier stage of the transformation. It becomes larger as the transformed fraction increases.