NANOSTRUCTURAL PREDICTION OF SHAPE MEMORY ALLOYS RESISTANCE ASYMMETRY

摘要

It is known that polycrystalline shape memory alloys (SMAs) showing isotropic behavior are often asymmetric resistant materials. Their loading diagrams in the modes of martensitic inelasticity, superelasticity or of accumulation of direct transformation strains expressed in terms of stress and strain intensities are significantly dependent on the stress state type. One of the reasons for such behavior of SMAs is the crystallographic features of the thermoelastic phase transformations occurring in these materials, in particular, the multivariance of the direct phase transition. The paper presents a method for estimating the SMAs resistance asymmetry based on data on the geometry of the corresponding crystal cells and the processes of their intertransitions.