Molecular dynamics simulations of shock melting in single crystal Al and Cu along the principle Hugoniot

• Published in: Materials today communications Vol. 26; p. 101990
• Main Authors: Pu, Chuanjin, Yang, Xin, Xiao, Dingjun, Cheng, Jianlong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2021
• Subjects: Clausius-Clapeyron relation; GRAY EOS; Latent heat; Liquid fraction; Melting curve; Molecular dynamics simulations; Latent heat; Melting curve; Clausius-Clapeyron relation; Molecular dynamics simulations; Liquid fraction; GRAY EOS
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2020.101990

Shock melting in single crystal Al and Cu along the principle Hugoniot was investigated through molecular dynamics simulations. First, the GRAY equation of state (EOS) was employed to reproduce the melting curve, which aimed at obtaining the Simon melting equation. The accuracy and validity of Simon melting curve are evaluated by the first-order derivative of melting temperature with respect to pressure at zero pressure, initial and complete melting temperatures and pressures, which are in good agreement with the available data. Next, the specific melting volume and latent heat calculated by the Clausius-Clapeyron equation present a descending and ascending trend as pressure increases, respectively. Then it is assumed that the liquid fraction is a power law function of pressure, whose nonlinear increasing is featured by the symmetry. More importantly, the expression of second-order derivative of melting temperature with respect to pressure is deduced by the Clausius-Clapeyron relation and Simon melting equation, respectively. Specifically for the Clausius-Clapeyron relation, its application to solid-liquid phase transformation for Al and Cu is quite effective and the result of the second-order derivative at zero pressure is reasonably compatible with that calculated from the Simon melting equation, which manifests that this two methods can be verified mutually. Moreover, it further discusses that the change characteristics of Simon melting equation by virtue of its first- and second-order derivatives.