Melting of Cu under hydrostatic and shock wave loading to high pressures

Molecular dynamics simulations are performed to investigate hydrostatic melting and shock-induced melting of single crystal Cu described by an embedded-atom method potential. The thermodynamic (equilibrium) melting curve obtained from our simulations agrees with static experiments and independent simulations. The planar solid-liquid interfacial energy is found to increase with pressure. The amount of maximum superheating or supercooling is independent of pressure, and is 1.24 +/- 0.01 and 0.68 +/- 0.01 at a heating or cooling rate of 1 K ps(-1), respectively. We explore shock loading along three main crystallographic directions: < 100 >, < 110 > and < 111 >. Melting along the < 100 > principal Hugoniot differs considerably from < 110 > and < 111 >, possibly due to different extents of solid state disordering. Along < 100 >, the solid is superheated by about 20%, before it melts with a pronounced temperature drop. In contrast, melting along < 110 > and < 111 > is quasi-continuous, and premelting (similar to 7%) is observed.