Transformation lines in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy

Transformation lines, the martensitelaustenite start and finish conditions in the stress-temperature plane, are determined in an Fe-Cr-Ni-Mn-Si polycrystalline shape memory alloy with two different experimental procedures. The transformation lines are shown to be almost linear with nearly the same slope. The martensitic transformation zone and the reverse transformation zone do not coincide, and the reverse transformation zone is very wide; T Af -T As ≃ 180 K. The strong dependence on the preloading of the transformation lines, especially of the reverse transformation lines, is examined