Stress-strain characteristics in Ni-Ga-Fe ferromagnetic shape memory alloys

Tensile and compressive stress-strain characteristics for Ni-Ga-Fe ferromagnetic shape memory alloys were investigated. The crystal structure of the martensite phase obtained by tensile-stress-induced martensitic transformation was calculated from the degree of the transformation strain. It was shown that the parent phase with L2₁ transforms into the stress induced martensite phase with 14M by tensile stress and by applying further stress, the 14M stress induced martensitically transforms into L1₀. It was found that variant rearrangement occurred by very low compressive stress less than 3 MPa.