Mechanical, electronic and dynamical properties of T2-Al2MgC2 under pressure

Abstract

The presence of T2-Al2MgC2 compound has significant influence on the mechanical properties of magnesium alloys. The mechanical, electronic and dynamical properties of T2-Al2MgC2 under high pressure are investigated by plane wave pseudopotential method based on the first-principles calculation. The results show that T2-Al2MgC2 is mechanically stable under high pressure, the elastic constants except [Formula: see text] increase with the increase of pressure. This compound presents brittleness and the brittleness decreases with increasing pressure when [Formula: see text][Formula: see text]GPa, but it displays ductility when [Formula: see text][Formula: see text]GPa. T2-Al2MgC2 has strong anisotropy, and the anisotropy decreases with increasing pressure. T2-Al2MgC2 is an indirect bandgap semiconductor material. Our calculated bandgap is 1.893[Formula: see text]eV at ambient pressure, the bandgap first increases and then decreases with increasing pressure. The phonon band structure as well as the total and partial phonon density of the state under different pressures had been analyzed. The constant volume heat capacity [Formula: see text] and entropy S of T2-Al2MgC2 increase with increasing pressure.