FEM Calculation of the Micromechanics of a Diffusional Transformation

Abstract

We have performed FEM calculations on a ’unit cell’ of a material, modelled by a 3D FEM mesh, through which a successive phase transformation passes. An external stress is applied to the cell. The example chosen is the isothermal pearlitic transformation of a steel. Two different descriptions of the transformation progress have been used : spherical growth and random transformation order. We study the evolution of the transformation plastic strain versus the progress of the transformation. On one hand it is shown that, in the case of spherical growth, the size of the transformation step has a great effect on the range of transformation plastic strain. On the other hand, we conclude that the random transformation model is the best in order to simulate the behaviour of a specimen when comparing the calculated results with the experimental ones.