Stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy

Abstract

The paper presents the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy, namely the alloy causes positive/reverse ε martensitic transformation and accompanied by deformation in order to adapt the variation of the outside macroscopical stress and deformation. From XRD analysis, it is found that the stress-induced γ↔ε martensitic transformation and its reverse transformation would occur in Fe-Mn-Si shape memory alloy under the tension-compression stress and also validated the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy. In cycles of tension and compression deformation, the stress self-accommodation characteristic of Fe-Mn-Si shape memory alloy can increase fatigue life of the alloy by reducing stress concentration, restraining plastics gliding deformation and delaying the formation and growing of microcracks. The fatigue fracture in Fe-Mn-Si alloy shows quasi-cleavage brittle rupture type.