Study of Thermal Scanning Rate On Transformations of Ti-19Nb-9Zr (at.%) by Means of Differential Scanning Calorimetry (DSC) Analysis

Differential scanning calorimetry (DSC) thermal analysis is a well accepted technique used to measure transformation temperature intervals and its elastic strain energies. In this study, both forward and reverse transformation temperatures of a nickel-free Ti-19Nb-9Zr (at.%) shape memory alloy (SMA) were investigated using this technique with different cooling and heating scanning rates. The results showed that the transformation temperature intervals are subjective to the thermal scanning rates. It is found to decrease continuously with decreasing cooling and heating rates. The experimental temperature intervals of forward and reverse martensitic transformations in the Ti-19Nb-9Zr (at.%) SMA were found to be ~140°C and 115°C, respectively, with using the smallest thermal scanning rates (5°C/min). Also, based on these measurements, the elastic strain energies store between the forward and reverse transformations were estimated to be ~7.3J/g and ~15.9J/g, respectively. The appropriate selection of scanning rate for SMA analysis was discussed.