Formulation of an appropriate equation of state to predict the melting temperature of metallic solids

Abstract

The aim of this work is to derive an equation for the melting curve of metals through distinct isothermal equations of state, namely the equations of state proposed by Singh and Kao, Murnaghan, and Kholiya. The developed models define the relation among the pressure, bulk modulus, melting temperature, volume, and pressure derivative of bulk modulus at zero pressure. These models are applied for the metals Pd, Au, Zn, Cu and Pt to determine the melting curves over the wide range of pressure to 30 GPa. The outcome of the Singh and Kao equation of state gives a too large increment in the melting temperature due to the large increment in bulk modulus. The outcome of Kholiya equation of state is the one that best fit experimental results. The results of Murnaghan equation of state tends to underestimate the melting temperature. The study provides insights into the fundamental understanding of quantitative effect of pressure on melting temperature of different solids. The obtained models can be used to extrapolate melting temperatures to higher pressures.