Micromechanics-based understanding of the stability of film-like austenite in steels

Abstract

Based on the carbon content and processing technique, the austenite morphology in steels can be either film-like or blocky. Experiments have shown that a film-like morphology of austenite shows a higher resistance to strain-induced martensitic transformation than its blocky counterpart. In the present work, using aspect ratio to distinguish austenite morphology, a micromechanical model is developed to show that the presence of an unfavourable stress field discourages the austenite to martensite transformation in film-like morphology, thereby lending its stable nature compared to the blocky version.