Intrinsic kinetic effects during martensitic transformations

In this paper, we present a study by AC calorimetry on the thermoelastic martensitic transformation in a Cu-Al-Ni shape memory alloy, both under quasi-isothermal conditions and by using a dynamical method. Whereas internal friction measurements have shown that the martensitic transformation behaviour exhibits a strong dependence on the rate of change of temperature in both cooling and heating, calorimetric measurements using DSC do not usually show this dependence. Therefore, it is usually argued that the internal friction results are linked to the measurement technique and not to the martensitic transformation itself. However, our AC calorimetry measurements also suggest that the martensitic transformation exhibits some intrinsic kinetic effects dependent on the rate of change of temperature