Martensitic nucleation - revisited

Abstract

Some recent findings concerning heterogeneous martensitic nucleation are highlighted in this memorial tribute to Professor Zenji Nishiyama. It is now possible, with appropriate experimental observations, to express the distributions of nucleation-defect potencies (or equivalently, the activation energies) of both preexisting and autocatalytically-generated defects. Based on this treatment, the full course of a martensitic transformation on cooling or on isothermal holding can be derived. On the other hand, it is shown that homogeneous martensitic nucleation can function in a defect-free parent phase provided the transformational driving force is sufficiently large.