Low temperature isothermal ageing in shape memory CuAlNi single crystals

Some CuAlNi alloys can undergo martensitic transformations by cooling or by applying stress from a metastable β body-centred cubic (bcc) phase. These martensitic transformations are responsible for the shape memory and pseudoelastic effects that these alloys present. Low temperature isothermal ageing of this metastable β phase can favor the culmination of an ordering process and the decomposition into stable phases. These two processes can generate changes in both thermally and stress-induced martensitic transformations, modifying the characteristic martensitic transformation temperatures, the type of induced martensitic phases, the critical stress and the hysteresis width of the martensitic transformations.