Transformation temperature of Ti-Ni-Cu Shape Memory Alloy Subjected to Thermo-mechanical Cycle and Superelastic Cycle

In this study, we proposed a new parameter in order to estimate the change of various transformation temperatures of which the alloy was subjected to either of the superelastic cycle and thermo mechanical cycle. The accumulated strain energy was defined as the recovery strain energy decreased up to an arbitrary cycle in Ti-Ni-Cu shape memory alloy. This study for a new parameter made it possible to estimate with unification the changes of the transformation temperature, which were greatly influenced by the stress field around the dislocation increased by cold working in the alloy. Therefore, it was found that the accumulated strain energy was possible to become a unified parameter expressing the change of the internal energy condition due to the cyclic deformation and transformation. We discussed about the results of analysis together with considering the effect of the cold work and shape memory treatment on the transformation temperature.