Physical properties controlling shape memory effect in FeMnSi alloys

The variation of magnetic susceptibility with martensitic and magnetic phase changes is examined in FeMnSi shape memory alloys using a Faraday type magnetic balance. The ca ratio of stress induced e martensites is determined for each e plate under a high voltage electron microscope. It is found that the magnetic properties and the ca ratios deduced from these measurements are well correlated with the complete and incomplete shape memory effect obtained in these alloys through the analyses of thermally activated dislocation motion. The optimum conditions to obtain a complete shape memory effect are discussed on the basis of these findings, which were obtained over a wide temperature range (4.2–400 K).