Martensitic transformation of Ni64Al34Re2 shape memory alloy

As-rolled and annealed Ni64Al34Re2 shape memory alloy (SMA) exhibits B2 → L10 (3R) martensitic transformation with Ms temperature up to about 210 °C. Experimental results indicate that the annealing temperature is the major factor that affects the Ms temperature. It is found that adding 2 at.% Re to replace Al in Ni64Al36 binary SMA can significantly refine the alloy's grain size and enhance the softening behavior during transformation. Meanwhile, Re has the same trend as Ni to affect the Ms temperature, but it has a less effect than Ni. The lattice constants and microstructures of NiAl-B2 phase, NiAl-L10 (3R) martensite and Ni3Al-L12 phase are almost similar to those of Ni-Al binary SMAs.