The effects of pre-strain, recovery temperature, and bending deformation on shape memory effect in an Fe–Mn–Si–Cr–Ni alloy

In this study, effects of pre-strain, recovery temperature, and number of bending test cycles on the microstructure and shape memory behavior of Fe-12.5%Mn-5.5%Si-9%Cr-3.5%Ni alloy have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction method, and bending test. Experiments show that the shape memory effect of the alloy can be enhanced by convenient recovery temperature and pre-strain rate. The shape recovery ratio increases with increasing pre-strain and recovery temperature, while it decreases with an increase in the number of bending test cycles. The changes in the shape memory are attributed to the variation of amount of ɛ martensite and crystal defects. The amount of ɛ martensite increases with increasing the pre-stain ratio. Crystal defects decrease with an increase in the recovery temperature, while they increase with increasing the number of the bending test cycles.