MICROMECHANICAL MODELING OF MARTENSITIC-TRANSFORMATION IN RANDOM MICROSTRUCTURES

A thermodynamic transformation criterion is used to describe the strai n induced martensitic transformation (SIMT) in two different materials , namely in a dilute Cu-Fe alloy and in a low alloyed TRIP-steel. A fi nite element calculation makes it possible to evaluate the local stres s and strain fields and to monitor the kinetics of the martensitic tra nsformation. The degree of randomness of the austenite's crystallograp hic lattice orientation with respect to an external load direction str ongly influences the stability of the austenite against SIMT. The effe ct of the austenite grain size on its stability against SIMT and on th e microstructure of the martensite is investigated. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.