Effect of carbon content on shape memory effect of Fe-Mn-Si-Cr-Ni-based alloys at different deformation temperatures

To clarify the effect of C addition on shape memory effect (SME) in Fe-Mn-Si-based alloys, the SME and microstructures of two Fe-Mn-Si-Cr-Ni alloys with different C contents had been studied after deformed between 293 K and 77 K. The results showed that the SME in the Fe-Mn-Si-based alloys can be significantly enhanced by the addition of more C when deformed at a proper temperature. A comparable recovery strain of 4.2% to that in the Fe-Mn-Si-based alloys subjected to special treatments was obtained in a solution treated Fe-16.99Mn-5.59Si-9.28Cr-5.67Ni-0.12 C alloy when deformed at 77 K. This significant improvement can be ascribed to the remarkably increased difference between the critical stress for the permanent slip and that for the stress-induced ε martensitic transformation due to the addition of more C.