Thermophysical properties of undercooled liquid Au-Cu alloys from molecular dynamics simulations

摘要

The density and the specific heat of liquid Au-Cu alloy above and below the melting temperature are investigated in a wide composition range via constant temperature and constant pressure molecular dynamics simulations. The atomic interaction of the alloy is described with the embedded-atom method (EAM). The equilibrium melting temperature is evaluated from the change in the growth direction of a crystal-liquid sandwich structure under annealing. The simulated density of the Au-Cu alloy increases linearly with decrease of the temperature, whereas the specific heat remains constant over the entire temperature range of 900-1900 K. The excess volume is calculated according to the predicted density of Au-Cu alloy. The negative value of the excess volume and the exponential concentration dependence of the specific heat indicate that the Neumann-Kopp rule does not apply to the Au-Cu binary alloy system. [References: 24]