The effect of low-temperature heat treatment on the superelasticity in Ti–50.6 at.% Ni single crystals

As a result of low-temperature aging at 573 K for 1.5 h of Ti–50.6 at % Ni [001]-oriented single crystals quenched from 1253 K, a high-strength state is obtained due to the precipitation of Ti$_{3}$Ni$_{4}$ nanoscale particles ($d<$ 10 nm). The aging leads to the development of the $B$ 2– $B$ 19' martensitic transformation through an intermediate $R$ phase, a reduction in the $B$ 19' martensite formation temperatures by 40–60 K, an increase in the strength properties of the $B$ 2 phase from 730 to 2100 MPa, and an extension of the superelasticity interval $\Delta T_{\mathrm{SE}}$ in compression from $\Delta T_{\mathrm{SE}}$ = 60 to 170 K (compared to quenched crystals).