In-situ measurement of plastic strain in martensite matrix induced by austenite-to-martensite transformation

Abstract

Employing in-situ tensile test under scanning electron microscope and micro-scale digital image correlation, the present work, for the first time, measures quantitatively the plastic strain in the martensite matrix that is induced by the martensitic transformation of retained austenite. The plastic strain is rationalized as a consequence of the large internal stresses triggered by the volume change associated with the martensitic transformation. The in-situ experimental evidence indicates that the energy barrier or the free energy change associated with martensitic transformation may need modifications to explicitly consider the associated plastic strain energy in the martensite matrix.