Structural, electronic, elastic and thermodynamic properties of CaAl2Zn2 compound under different pressures

Information on the CaAl2Zn2 compound is important for the development of Ca added Mg–Al–Zn alloys. In this paper, the dependences of the structural, electronic, elastic and thermodynamic properties of CaAl2Zn2 compound on pressure were investigated for the first time by means of the first-principles method based on the density functional theory with generalized gradient approximation and local density approximation. It was found that the pressure has significant effects on the equilibrium volume, elastic properties and electronic properties. Our calculated structural data are in good agreement with the previous experimental data results at zero pressure. The calculated anisotropy factors AG and AE and linear compressibility coefficients kc/ka are used to estimate anisotropic elasticity. The isotropic bulk modulus B, shear modulus G, Young’s modulus E, and Poisson’s ratio ν of polycrystalline CaAl2Zn2 compound were determined using the Voigt–Reuss–Hill averaging scheme. The B/G and microhardness parameter H are also calculated. The band structure and density of states are discussed from theoretical viewpoint. The Debye temperature can be obtained from the knowledge of the elastic constants and the sound velocities. The calculated elastic constants indicated that this compound is ductile at different pressures.

► Theoretical prediction was conducted on CaAl2Zn2 compound.
► The calculated results agree well with the experimental data.
► CaAl2Zn2 exhibits weakly anisotropic elasticity.
► The CaAl2Zn2 compound exhibit metallic properties.
► This compound remains ductile up to 50 GPa.