Prediction on structural, mechanical and thermal properties of Al4SiC4, Al4C3 and 4H-SiC under high pressure by first-principles calculation

Abstract

A theoretical study is conducted by first-principles theory to study the structural, electronic, elastic and thermal properties of Al4SiC4, Al4C3 and 4H-SiC phases under pressure. The calculated results indicated that the volumetric shrinkage of Al4SiC4 declines to 16% compared with 4H-SiC for 12% and its length of lattice parameter along c-axis decreases faster than that of along other axes in cell structures. The mechanical properties of Al4SiC4 like elastic constants and elastic moduli increase continuously under pressure. The thermal expansion coefficient of three compounds under pressure are studied first. When temperature is lower than 500 K, the coefficient increases rapidly first then gradually tends to a linear accession at higher temperature and the propensity of increment becomes moderate. The [Formula: see text] data decreases slightly with pressure but increases dramatically with temperature for all compounds.