Ab-initio simulation of elastic constants for some ceramic materials
Fraunhofer Institut – Silicatforschung (ISC), 97082 Wuerzburg, Germany
2 Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany
Revised: 15 June 2007
Published online: 1 August 2007
Athermal elasticity for some ceramic materials (α-Al2O3, SiC (α and β 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.
PACS: 31.15.Ar – Ab-initio calculations / 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections / 62.20.Dc – Elasticity, elastic constants
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007