Microstructure and tensile properties of Cu-Al-Ni-Ti-Nb shape memory alloy

Microstructure and tensile properties of Cu-Al-Ni-Ti-Nb shape memory alloy

This study investigates the effects of adding of Ti and Nb elements into the Cu-Al-Ni base system to enhance the microstructural and mechanical properties of CuAlNi shape memory alloys. The newly developed Cu-13.2Al-4.2Ni-0.7Ti-0.5Nb (wt%) alloy exhibits a significantly reduced grain size, down to approximately 188 µm, and a distinctive 18R martensite microstructure with the presence of Nb-rich and Ti-rich phases. X-ray diffraction patterns confirm the presence of the 18R martensite structure and secondary phases. Tensile testing at room temperature demonstrates a remarkable increase in fracture stress to 1583 MPa and improved ductility (8.1%) due to the Ti and Nb additions.