First-principles study of mechanical and thermodynamic properties of Ti-Ga intermetallic compounds

A systematically investigation of Ti-Ga intermetallic compounds was performed to explore their mechanical and thermodynamic properties using density functional theory (DFT). Based on the experimental and theoretical reported data, a series of Ti-Ga alloys are chosen to study in this work. By assessing the elastic property of Ti-Ga alloys including bulk modulus, shear modulus, Young's modulus and Poisson's ratio, the results indicate that these Ti-Ga alloys are mechanically stable. The Pugh's ratio B/G is calculated to reveal that these Ti-Ga alloys display ductile character, except for Ga3Ti and Ga3Ti2. Meanwhile, the anisotropy factor A and Vickers hardness HV are studied, and the hardness is found in the order: Ga3Ti>Ga3Ti2>Ga3Ti5>GaTi2>GaTi>GaTi3. Furthermore, the thermodynamic property is predicted by means of different empirical formulae, the results reveal that the alloys exhibit more high melting point and thermal conductivity. By the evaluation of the heat capacity with temperature 0-80 K, indicating that the electron excitations plays a main role below 17 K, while the phonon excitations mainly contribute to the heat capacity in the range of 31-80 K.