Remarkable improvement of recovery stress of Fe–Mn–Si shape memory alloy fabricated by equal channel angular pressing

Effects of equal channel angular pressing and subsequent annealing temperature on the recovery stress of Fe–19.04Mn–4.98Si–8.50Cr–4.59Ni alloy were studied. The results show the maximum recovery stress σm and the room recovery stress σr of the as-pressed specimen increase firstly and then decrease with increase of annealing temperature. σm and σr of the as-pressed specimens annealed at optimal temperature 873 K are 260 MPa and 261 MPa higher than that of the as-quenched ones, respectively. The reason is that as-pressed alloys have higher yield strength and lower Ms temperature, suppressing the plastic deformation and the γ → ɛ phase transformation induced by the recovery stress in cooling.