MOLECULAR-DYNAMICS STUDIES OF THE THERMAL-PROPERTIES OF THE SOLID AND LIQUID FCC METALS AG, AU, CU, AND NI USING MANY-BODY INTERACTIONS

Molecular-dynamics (MD) simulations of pure Ag, Au, Cu, and Ni are reported. The NPT (isobaric-isothermal) MD method is used in order to reveal the behavior of these metals at various temperatures in the solid as well as in the liquid state. According to the embedded-atom method [M. S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)] the interactions in metals are assumed to be composed of the pair component (caused by cores overlapping) and the cohesive many-body term (gluing term). The scheme for the empirical N-body potentials derivation proposed by Ackland et al. [G. J. Ackland, G. Tichy, V. Vitek, and M. W. Finnis, Philos. Mag A 56, 735 (1987)] is used. The potential parameters have been derived exclusively on the basis of the room-temperature properties (the equilibrium lattice constant, elastic constants, the cohesive energy, the stacking-fault energy, the unrelaxed vacancy-formation energy, and the volume-pressure dependency). The various quantities describing the temperature-dependent behavior of the simulated systems (thermal-expansion coefficients of solids and liquids, specific heats of solids and liquids, the volume change on melting, and the enthalpy of melting) as well as the radial distribution functions at various temperatures are derived. Generally, satisfactory agreement with the experimental data is achieved. © 1990 The American Physical Society.