Ab-initio simulation of elastic constants for some ceramic materials

摘要

Athermal elasticity for some ceramic materials (alpha-Al2O3, SiC (alpha and beta phases), TiO2 (rutile and anatase), hexagonal AlN and TiB2, cubic BN and CaF2, and monoclinic ZrO2) have been investigated via density functional theory. Energy-volume equation-of-state computations to obtain the zero pressure equilibrium volume and bulk modulus as well as computations of the full elastic constant tensor of these ceramics at the experimental zero pressure volume have been performed. The present results for the single crystal elasticity are in good agreement with experiments both for the aggregate properties (bulk and shear modulus) and the elastic anisotropy. In contrast, a considerable discrepancy for the zero pressure bulk modulus of some ceramics evaluated from the energy-volume fit to the computational zero pressure volume has been observed.