Microstructures and mechanical properties of Ti-45 at.%Ni-5 at.%Cu alloy ribbons containing Ti_2Ni particles

摘要

Microstructures, shape memory characteristics and the superelasticity of Ti-45Ni-5Cu (at.%) alloy ribbons were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Coherent Ti_2Ni particles less than 13 nm in diameter are formed when the melt spinning temperature is higher than 1773 K. The ribbons with coherent Ti_2Ni particles do not show a residual elongation, which may be ascribed to the increase due to the coherent Ti_2Ni particles of the critical stress for slip deformation by the coherent Ti_2Ni particles. Almost perfect superelastic recovery is found in the ribbons containing coherent Ti_2Ni particles, while only partial superelastic recovery is observed in Ti_2Ni particle-free ribbons.