Effect of ageing on the phase transformation temperatures and shape memory effect of a NiAl-Fe alloy

Effect of ageing at temperatures of 200–600°C on the phase transformation temperatures and shape memory effect of a NiAl-Fe alloy were investigated. It was found that the martensitic transformation temperature and the reverse temperature of Ni-24.1 at% Al–18.2 at% Fe specimens decreased gradually as the ageing temperature increased from 200 to 400°C, and then increased as the ageing temperature increased higher than 400°C. The amount of one-way, without load, shape recovery of Ni-24.1 at%Al–18.2 at% Fe specimens, aged, increased as the ageing temperature increased from 200 to 400°C for 1 h, and decreased dramatically as the ageing temperature increased to 600°C.