A positron study of hysteresis temperature in Ti-Ni alloy

For Ti-Ni alloy, it is exceedingly difficult; to prepare an element that has a desired and defined hysteresis temperature for its preparing process is not perfect at present. Because the mechanism of transformation in Ti-Ni has not been fully clarified, it is far more exceedingly difficult to explain the hysteresis temperature only by using the traditional metal physics techniques. But position annihilation seems to be a suitable method for it. The positron annihilation measurements show that the hysteresis temperature may be controlled mainly by the relative fraction of the defects contained in a two-way shape memory element.