Ti-Ni-Cu Shape Memory Alloy Preparation by Powder Metallurgy and Hot Forging

Ti-Ni-Cu shape memory alloys (SMAs), produced through an optimized preparation route including thermo-mechanical deformation, present a promising alternative to traditional Ti-Ni alloys, offering certain advantages. In this study, two Ti-Ni-Cu SMAs were fabricated using powder metallurgy. Fine micron-sized powders were mixed elementally, followed by spark plasma sintering, hot forging, and heat treatment comprising homogenization, solution treatment, aging, and low-temperature quenching. Microstructural evolution across processing stages was examined, and the transformation behavior of heat-treated alloys was characterized by differential scanning calorimetry. Corrosion resistance and hardness were also evaluated. Results revealed relatively high transformation temperatures (60–75°C) with reduced hysteresis. Hot forging significantly enhanced alloy performance by refining microstructure and improving elemental bonding and diffusion. Corrosion resistance improved notably compared to Ti-Ni alloys, while Ti50-Ni30-Cu20 exhibited a 28% hardness increase. Overall, Ti-Ni-Cu SMAs demonstrate improved functional and structural properties, making them strong candidates for advanced shape memory applications.