Investigation of the Contribution of R-phase Transformation on the Two-way Shape Memory Effect

Electrical resistance measurement and elongation-temperature measurement were used to study the contribution of R-phase and martensitic phase transformation to the two-way shape memory effect. And the effect of thermo-mechanical training on the transformation characteristics was also studied. The results showed that thermo-mechanical training results in the occurrence of R-phase transformation. The R-phase transformation yields a large part of the TWSME. The transformation temperatures of inverse martensitic, martensitic and R-phase transformation temperatures decreased with increasing thermo-mechanical training cycles, which was attributed to the dislocations introduced into the TiNi Shape memory alloys.