Deformation Behavior, Structure, and Properties of an Aging Ti-Ni Shape Memory Alloy after Compression Deformation in a Wide Temperature Range

The deformation behavior, microstructure, phase composition, and mechanical and functional properties of Ti-50.9 at.%Ni shape memory alloy during uniaxial compression in the temperature range from 25°C to 1000°C have been analyzed and are discussed herein. It was found that the deformation temperature of 300°C marked a boundary for the transition from the low- to high-temperature type of flow curves; achievement of the steady-state deformation stage was observed across a wide range of deformation temperatures. Following comprehensive analysis of the obtained data, the temperature ranges of the dynamic processes of recovery, polygonization, and recrystallization of the Ti-50.9 at.%Ni alloy were determined. Deformation in the range of dynamic polygonization is accompanied by not only the formation of B2-austenite and R-phase, but also the precipitation of fine Ti3Ni4 particles during deformational aging. The highest shape recovery characteristics were obtained after deformation of the Ti-50.9 at.%Ni alloy in the temperature range from 300°C to 600°C.