Effect of Heating Rate on the Kinetics of Martensitic Transformation of Ni-Ti-Hf alloys using Differential Scanning Calorimetry (DSC)

The transformation martensite-austenite and Kinetics in Ni-Ti-Hf shape memory alloys (SMAs) were calculated for the first time. The Johnson- Mehl – Avrami- Komogorov (JMAK) equation was used to simulate the transformation Martensite- Austenite, which exhibited the same trends as the DSC test results. DSC studies were conducted using four different heating rates to study the kinetics of the thermally induced transformation process and the dependence of the kinetic parameters and the heating rate. It was clarified that the heating rate adjusts the enthalpies of transformation, indicating that the heating rate can be used to adjust the phase change parameter. The Arrhenius method was used to calculate the activation energies, and it was observed from its use that the activation energies increase as there is an increase in the ternary element in the composition. Moreover, using the same heating is a valuable means of comparing activation energies for the same alloy system. This study provides a reference for designing and calculating the kinetics of Ni- Ti- Hf high-temperature shape memory alloys.

Keywords:
Shape Memory Alloys; Kinetic Transformation; Differential Scanning Calorimetry; High-Temperature Shape Memory Alloys