Influence of precipitates on the thermal hysteresis of Ti–Ni–Pd shape memory thin films

Ti–Ni–Pd thin film samples were investigated by analytical transmission electron microscopy. For Ti50+xNi35-xPd15 (x < 9) alloys the amount of Ti2Ni and Ti2Pd precipitates increases with increasing Ti content. The width of the thermal hysteresis was determined to be independent of the amount of Ti2Pd due to an orientation relationship between Ti2Pd precipitates and the matrix. Precipitation of Ti2Ni was found to be the dominating factor responsible for the linear increase of the thermal hysteresis with increasing Ti content.