Mechanical and thermodynamic behaviors of AlSi2Sc2 under uniaxial tensile loading: A first-principles study

Abstract

This study investigates the structural, mechanical, and thermodynamic behaviors of AlSi2Sc2 under uniaxial tensile loading by performing first-principles calculations based on density functional theory. The parameters of the lattice a and c were found to depend on the Al–Si and the Sc–Si bonds, respectively. Tensile stress–strain curves were used to obtain ideal tensile strengths of 16.1 GPa and 21.2 GPa along the a- and c-axes, respectively. The criteria for stability showed that the AlSi2Sc2 compound became mechanically unstable when the strain exceeded 0.1 and 0.3 along the a- and the c-axes, respectively. The polycrystalline elastic constants of AlSi2Sc2 decreased with increasing strain along both axes as well, as did its Debye temperature and minimum thermal conductivity. An analysis of its electronic structure indicated that the Al–Si bonds mainly originated from the hybridization of the Al-3p and the Si-3p states, whereas the Sc–Si bonds originated from the Sc-3d and Si-3p states.