Deformation Behavior, Structure and Properties of an Equiatomic Ti–Ni Shape Memory Alloy Compressed in a Wide Temperature Range

In the present work, flow curves of an equiatomic Ti–Ni shape memory alloy after deformation by compression in the temperature range from 100 to 900 °C at a strain rate of 1 s−1 and up to a true strain (e) of 0.9 were obtained. The phase composition, mechanical and functional properties after compression to e = 0.5 were studied. The boundaries of the temperature ranges of the development of dynamic softening processes were determined, as follows: dynamic recovery in 100–300 °C range; dynamic polygonization in 300–500 °C range and dynamic recrystallization above 500 °C. An optimum deformation temperature range in terms of accumulation of high strains and achieving improved functional properties is 300–500 °C. It has also been found that post-deformation annealing at temperatures above the deformation temperature leads to the decrease in the B2-austenite lattice defectness and to a significant increase in shape recovery characteristics.