Influence of heat treatment on the mechanical and electrical characteristics of Ni0.5Ti0.5 alloy prepared by electron-beam melting

Nickel titanium alloys (Ni0.5Ti0.5) were successfully produced from elemental Ni/Ti powders by electron-beam melting method and then subjected to annealing and aging treatment. Microstructure of the alloys was examined by XRD and SEM. The mechanical properties of the alloyed surface were examined. The microhardness was studied as a function of annealing temperature and time. It was found that the microhardness decreases with increasing annealing temperature until 660 °C after which the microhardness increases. Electrical resistance measurements were carried out in order to study the transformation behavior. The electrical measurements point out the importance of temperature dependence of Ni0.5Ti0.5 electrical resistance for the identification of particular transformation. The influence of aging on the development of electrical resistivity was also investigated.