Shape memory alloys (SMAs) are metallic alloys that can undergo martensitic phase transformations as a result of applied thermomechanical loads and are capable of recovering permanent strains when heated above a certain temperature. The key characteristic of all SMAs is the occurrence of a martensitic phase transformation between the austenitic phase and the different variants of the lowtemperature, lowsymmetry martensitic phase [1].In near equiatomic Ti–Ni alloys, the shape memory effect and superelasticity occur in association with the thermoelastic martensitic transformation from the parent phase (β) with a B2 structure to the phase with a monoclinic B19’ structure, or more often in association with the two-step transformation from β to a trigonal phase (so called R-phase) and then to the B19’ phase [2]. In this work, the effect of cooling temperature on the mechanical behaviour of the NiTi shape memory alloy has been studied.
