Cyclic mechanical properties of copper-based shape memory alloys: The effect of strain accommodation at grain boundaries

Fatigue behavior of shape memory alloys depends on deformation mechanisms (e.g., martensitic transformation, variant conversion, slip, and elastic deformation) and how they interact with microstructure. In this paper, we examine fatigue properties of Cu-based shape memory alloys, focusing on the effect of strain accommodation at grain boundaries on fatigue life and fracture mode under various deformation mechanisms in polycrystals. Comparisons with single crystals and static test results are also made. As lack of plastic accommodation at grain boundaries often leads to brittle intergranular fracture, incorporation of a ductile intergranular phase is promising for providing strain accommodation for transformation nearby and improving superelastic fatigue life.