Temperature‐dependent elastic and thermodynamic properties of Fe3Ga (DO3, L12, and DO19) alloys from first‐principles calculations

Abstract

For the first time, the influence of temperature on the elastic and thermodynamic properties of magnetostrictive material iron–gallium with cubic DO3, L12, and hexagonal DO19 structure was investigated by using the first‐principles calculations combined with the quasi‐harmonic approximation approach. Equilibrium volume as a function of temperature from phonon calculations were calculated to obtain temperature‐dependent elastic and thermodynamic properties. The obtained lattice parameters and thermal expansion coefficient are in good accordance with available experimental data. In terms of calculated elastic properties, the adiabatic elastic constants and polycrystalline elastic modulus decrease with the increasing temperature. In addition, the three types Fe3Ga are mechanically stable at room temperature and maintain ductility nature with increasing temperature. However, it should be noted that the DO3 type Fe3Ga is more sensitive to temperature, while the elastic properties of L12 and DO19 type Fe3Ga exhibit a very gentle changing trend with increasing temperature. This indicates that L12 and DO19 type Fe3Ga can keep their mechanical properties through wide temperature range and have good temperature stability. In contrast, for Fe3Ga in DO3 structure, the elastic properties are not as stable as the L12 and DO19 structures when temperature is higher than 475 K.