Effect of thermomechanical treatment and microstructure on pseudo-elastic behavior of Fe-Mn-Si-Cr-Ni-(V, C) shape memory alloy

This study systematically investigated the effects of heat and thermomechanical treatments on the pseudo-elastic behavior of an Fe-based shape-memory alloy (Fe???17Mn???5Si???10Cr???4Ni-1(V, C) %wt.). First, samples were solution-annealed at 1000 ???C for 2 h and aged at 760 ???C for 6 h. A thermomechanical treatment was then applied to the heat-treated samples. The microstructure and mechanical properties (i.e., 0.1% yield stress and pseudo-elasticity) were characterized using X-ray diffraction, scanning and transmission electron microscopy, and uni-axial tensile tests. The results showed that decreasing the grain size and precipitation of VCs resulted in an improved pseudo-elasticity. The thermomechanical treatment decreased the number of thermal twins and developed a [111] texture in the austenite phase, which reduced the critical stress for inducing martensite. The presence of VC precipitates and texture formation in the thermomechanical-treated samples increased the pseudo-elastic strain more than twofold from 0.4 to 0.98%. Superscript/Subscript Available