Development and characterization of Nickel-Titanium-Zirconium shape memory alloy for engineering applications

Shape Memory Alloys (SMA) are unique class of alloys which possess various engineering applications. One such SMA is Nickel-Titanium (Nitinol) shape memory alloy. The problem, however with Nickel is that the metal may leach out in form of toxic Ni2+ ions. The latter may prove costly when used in various applications. To increase the corrosion resistant properties of Nitinol and to evaluate its shape memory properties, small amount of Zirconium i.e. 5 and 10 at % are added into the existing Nitinol system. Buttons of Nitinol and Nickel-Titanium with Zirconium additions are made using the button arc furnace. For the characterization of the alloys, various techniques including Energy Dispersive Spectroscopy (EDS), Back Scattering Electron (BSE) imaging, Differential Scanning Calorimetry (DSC) have been performed. The work conducted reveals that addition of Zirconium in Nitinol has marked influence on microstructure, shape memory properties, transformation temperature, hardness values, and corrosion properties of the alloy.