EFFECT OF PRE-STRAIN ON THE KINETICS OF ISOTHERMAL MARTENSITIC-TRANSFORMATION

A detailed study of the effect of pre-strain on the isothermal martensitic transformation kinetics in an Fe-23.2wt% Ni-2.8wt% Mn is reported. The activation energy for isothermal martensitic nucleation in pre-strained samples is derived by analysing the nucleation and overall transformation kinetics data in terms of a phenomenological model. A critical analysis of the literature data on the activation energy for martensitic nucleation in solid-solution-strengthened alloys at subzero temperatures, enables us to estimate the contribution of Mn and Ni to the thermal component of the interfacial frictional work. With knowledge of the athermal and thermal contributions to the interfacial frictional work due to these solute atoms, it is possible to make a quantitative estimate of the interfacial friction owing to dislocation forest hardening.