The superelasticity of TiPdNi high temperature shape memory alloy

In the high temperature shape memory alloy (HTSMA) Ti51Pd30Ni19, superelasticity is found for the first time and the superelasticity is quite different from that of NiTi or CuZnAl. The recoverable superelastic strain is 7% without failure of the specimen. Shape memory effect (SME) at room temperature is evaluated as 7.2% with the recovery rate of 100%. The phase transformation temperatures were determined using differential scanning calorimeter (DSC). It has been found that the temperatures are changed during the process of alloy preparation. XRD analyses indicate that the macro- residual stress is eliminated and precipitation occurred after recovery treatment. The characteristics of both mechanical and transformation behavior are associated with the changes in the recovery process. Accordingly, an effective way to obtain the superelasticity is pointed out.