The vacancy formation thermodynamics in six FCC metals A& Au, Cu, Ni, Pd and Pf are determined from atomistic simulations as a function of temperature. This investigation is performed using the embedded atom method interatomic potentials and the finite temperature propenies are determined within the local harmonic and the quasiharmonic frameworks. The temperature dependence of the vacancy formation free energy, entropy. enthalpy and vacancy formation volume are determined. We find that the temperature dependence of the vacancy formation energy can make a significant wnlribution to the vacancy c o n c e n~o n at high temperatures. An additional goal of the present study is to evaluate the accuracy of the local harmonic method under circumstances in which the excess entropy associated with the fomation of a defect is very small. Ow data demonstrate that while the ermrs associated with determining the vacancy formation entropy in the local harmonic model are large, a simple extension to the local harmonic method yields thermodynamic properties mmparable to that obtained in the quasiharmonic model, but with much higher wmpurational efficiency. MI 48109, USA Recently, Gillan [I] has studied vacancy formation energies by applying the pseudopotential method and local-density approximation for exchange and correlation in a periodically repeating supercell geometq. While this is a first-principle approach, it is limited to zero Kelvin. Finite-temperature studies, based upon empirical descriptions of atomic bonding and the molecular dynamics [21 and Monte Carlo [3.4] methods, have been able to overcome these limitations. In the present study, we employ embedded atom method (EAM) potentials [5] to describe atomic interactions, classical lattice dynamics methods ana a novel finite temperature simulation approach to examine vacancy formation thermodynamics in six face centred cubic (Zc) metals as a function of temperature.

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