Indian Journal of Science and Technology

Abstract

A statistically mechanical-based equation of state has been employed to calculate the liquid density of refractory metals over a wide range of temperatures and pressures. There are three temperature-dependent quantities that are required to use the EOS: the second virial coefficients B2, an effective van der Waals co-volume, b and a correction factor, . The second virial coefficients are calculated from a two-parameter corresponding states correlation, which is constructed with two constants as scaling parameters, i.e., melting temperature Tm and molar density in melting point m. Our calculations on the liquid density of tantalum, rhenium, molybdenum, titanium, zirconium, hafnium, and niobium from undercooled temperatures up to several hundred degrees above the boiling point (1650 K-7400 K) and pressures ranging from 0 up to 200 MPa reproduces very accurately the experimental PVT data. In order to evaluate the proposed correlation equation for the second virial coefficient, we have compared our results for these systems with those obtained earlier. Our results are in favor of the preference of the TM EOS over two other equation of state. Keywords: Refractory Metals, Density, Equation of state, Tao- Mason EOS.