Influence of isothermal ageing on mechanical behaviour in Ni-rich Ti–Zr–Ni shape memory alloy

The effect of isothermal ageing on compression cycling, martensitic transformation temperatures and microstructure was investigated for a Ti–6 mol.%Zr–53 mol.%Ni alloy. The ageing behaviour of the microstructures was a two-stage process, i.e., an enhancement of diffuse scattering in electron diffraction pattern, most likely related to development of short-range order (SRO) structure, and then fine coherent precipitation followed by coarsening. Microstructures with fine coherent precipitates or well-developed SRO offer the best superelastic properties.