A perturbed hard-sphere equation of state for refractory metals

A perturbed hard-sphere equation of state developed previously for liquid alkali metals has been employed to calculate the liquid density of refractory metals over a wide range of temperatures and pressures. Two temperature-dependent parameters appear in the equation of state, which are universal functions of the reduced temperature, i.e., two scale parameters are sufficient to calculate the temperature-dependent parameters, and hence, to predict the equation of state. It is shown that the scale constants correlate with the normal boiling point parameters of metals. 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 and pressures ranging from 0 up to 200 MPa reproduces very accurately the experimental PVT data.