Shock Hugoniot and Mie-Grüneisen EOS of TiAl alloy: A molecular dynamics approach

Abstract

Molecular dynamics (MD) simulations coupling multi-scale shock technique (MSST) are performed to study the shock Hugoniot and Mie-Grüneisen equation of state (EOS) for TiAl alloy. The accuracy of the EAM potential for TiAl is examined by both melting temperature at a free pressure and Hugoniot curve. The material composition seriously affects the linear relation of shock wave velocity and particle velocity, Hugoniot curve, and internal energy. The Born-Mayer potential and Morse potential both can describe the cold curve at lower compressions, while the cold curve described via the Born-Mayer potential is larger than that of Morse potential at higher compressions. The shock melting temperature (Tm) is totally determined by Grüneisen coefficient γ, which shows an opposite trend as compared with the increasing Tm at the whole compressions. Mie-Grüneisen EOS presents a concave surface in pressure – specific volume – internal energy (P-V-E) space, which is independent of the reference curves utilized the cold curve and Hugoniot curve.