Superelasticity of single crystalline Fe-30.8 at.Pd alloy

摘要

We have investigated superelastic behavior of an Fe-30.8 at.%Pd alloy. This alloy transforms from a FCC parent phase to a FCT martensite phase at 255 K with a latent heat of 38 J/mol. When a compressive stress is applied in the [001] direction above the transformation temperature, the specimen exhibits a large elastic-like strain of more than 3% under relatively small stress of 100 MPa. The large elastic-like strain mainly comes from the elastic strain of the parent and martensite phases. The transformation strain also contributes to the strain, but it decreases linearly with increasing temperature and stress. The transformation strain |Δε| is extrapolated to be about 1.4 % under zero stress, and 0 % under 100 MPa. Probably a critical point, at which first order nature of the transformation disappears, exists for the FCC to FCT transformation in Fe-Pd alloys.