Temperature dependence of the mechanical properties of Heusler [formula omitted] and [formula omitted] using the Quasi-Harmonic Approximation

Abstract

The study of electronic properties of Fe2TiSi and Fe2TiSn using two functionals GGA and meta-GGA confirms the semiconductor nature of these alloys. This result enables us to compute elastic constants within Quasi-Harmonic Approximation without considering the electronic contribution. These elastic parameters decreased as the temperature increased with respect to the mechanical stability criteria of Born. Poisson’s and Pugh’s ratios indicate that both alloys have ionic bonding and are brittle. From the Vicker’s Hardness values, both alloys are found to be hard. Finally, we found that the mechanical properties of Fe2TiSi are more sensitive to temperature changes than those of Fe2TiSn; however, the former is harder than the latter over the temperature range of 0K to 1000K. The good mechanical properties make Fe2TiSi and Fe2TiSn a good solution for use as thermoelectric generators and waste heat recovery.