Phase change behavior of nitinol Shape Memory Alloys: Influence of heat and thermomechanical treatments

Among other special characteristics Shape Memory Alloys (SMAs) have the ability to return to a predetermined shape when heated. In fact, the phase change of an existing element can strongly be influenced by thermal and thermo-mechanical treatments. Up to now, SMEs have been discovered in various materials, which can generally be classified into noble-metal based, Cu-based, Fe-based, Ni-Ti-based alloy systems and non-metallic SMAs. In this paper a general overview of the Ni-Ti system and a detailed review over the Ni-Ti-Cu system will be given with special regard to the influence of heat treatments upon the phase change behavior.