COMPUTER-SIMULATION OF REVERSIBLE MARTENSITIC TRANSFORMATIONS

This article reports the results of computer simulation studies of rev ersible, athermal martensitic transformations in idealized, two-dimens ional crystals. The transformation is accomplished by sequentially tra nsforming elementary cells. The model accounts for the elastic strain developed during the transformation, assuming homogeneous elastic cons tants, negligible interfacial tension, and no external stress. The eff ects of frictional resistance to the transformation and plastic relaxa tion of the elastic strain are included in a simple way. The model is used to study the sources of hysteresis in the temperature-transformat ion (TT) curve and in the microstructural transformation path when the transformation is reversed. The central result is that some hysteresi s is inevitable in a transformation of the type studied here. Even in the absence of friction and plastic relaxation, the transformation fol lows a path in which sequential elements of martensite relax the elast ic strain of those that have previously formed. This causes the marten site to form in bursts and has the consequence that the reverse transf ormation does not reverse the path of the forward transformation. Fric tion and plastic relaxation increase hysteresis.