Mechanical stabilisation of bainite

Abstract

Compression experiments in which plastically deformed austenite is allowed to transform to bainite have revealed that bainite, like martensite, is susceptible to mechanical stabilisation. The overall transformation kinetics becomes slower and the maximum attainable fraction of bainite decreases in deformed austenite. This is because the motion of the transformation interface is hindered by the accumulated debris of dislocations in the austenite. The number density of nucleation sites is increased in deformed austenite, resulting in a more refined microstructure. Severe deformation eventually leads to a recovery in the maximum attainable fraction of bainite because of the corresponding increase in nucleation site density.MST/3148