Reversibility of shape deformation in the reverse martensitic transformation in Fe-Ni alloys

Abstract

The reversibility of shape deformations of individual martensite plates in the austenite (γ) ← martensite (α′) ← austenite (γ) transformation in Fe-Ni alloys has been studied. It was found that the shape change of each martensite plate produced in the γ ← α′ transformation is reversible, though partially, in the reverse transformation (α′ ← γ), despite the fact that the reverse transformation proceeds not by the backward movement of the existing γ/α′ interface, but by the nucleation of small γ platelets in each martensite plate. It is suggested that the driving force for such a reversible shape change may be residual internal stresses that have not been completely relieved by the formation of self-accommodating martensite variants.