An investigation of grain-boundary phase in Fe–30Mn–6Si–5Cr shape memory alloy

The formation of the grain-boundary phase in the Fe–30Mn–6Si–5Cr shape memory alloy and how it affected the shape memory effect were investigated. The grain-boundary phase in the Fe–30Mn–6Si–5Cr shape memory alloy formed during annealing at temperatures ranging from 600 to 750°C, especially at 700°C. Conversely, the grain-boundary phase was not observed at annealing temperatures exceeding 800°C or lower than 550°C. The grain-boundary phase exhibited an ordered BCC structure with a lattice parameter of about 8.798 Å, and had a similar chemical composition as that of the matrix. The shape memory effect and tensile property of the Fe–30Mn–6Si–5Cr alloy monotonously degraded with increasing density of the grain-boundary phase.