Two-way shape memory effect and its stability in a Ti-Ni-Nb wide hysteresis shape memory alloy

The effect of training strain, deformation temperature and number of training cycles on the two-way shape memory effect (TWSME) and its stability have been investigated systematically in a Ti_46.3Ni _44.7Nb₉ (at%) wide hysteresis shape memory alloy (SMA). The experimental results indicate that two-way shape memory strain increases with increasing the training strain up to 14.5% and then decreases with further increasing the training strain. When the training strain is less than 12%, the two-way shape memory strain increases with the increase of number of training cycles in the Ti_46.3Ni_44.7Nb₉ alloy deformed at the room temperature. Compared with TiNi binary alloy, the TWSME is smaller and the training strain to get the maximum TWSME is larger in the Ti-Ni-Nb alloy due to the deformation of β-Nb soft particles during training. However, the Ti-Ni-Nb alloy exhibits excellent stability of TWSME during the thermal cycling.