Abstract
Shape memory alloys (SMAs) are unique class of metal alloys that after a large deformation can, on heating, recover their original shape. Its non-linear behavior and thermal dependence attracted many researchers, engineers, and designers to choose the right material for proper applications in many fields of industry. The most commonly used material is Nitinol (NiTi). Nitinol has been increasingly utilized in a variety of medical devices, biomedical, aerospace, actuators, robotic industries, and nuclear engineering applications. Nitinol, during service in nuclear reactors, is exposed to many types of radiations which may affect its properties and structure. In this article, a comprehensive review on irradiating Nitinol to energetic protons is very useful to people working in this field. Amorphization occurs during proton irradiation. After proton irradiation, the austenite transformation temperatures were raised, the hysteresis, the size and amount of vacancy clusters were increased. Proton irradiation has considerable effect on the transformation temperatures in NiTi SMAs: the martensitic transformation temperature of Nitinol alloy decreased when the proton beam energy exceeded 1.875 MeV. The induced defects by proton irradiation are temporary, and the alloy can retain the parent condition by aging the sample at room temperature for about 76 days or annealing it at 520 K for about 30 min. Nano crystalline materials can exhibit enhanced irradiation resistance.