Study of thermoelastic and surface properties of tantalum at various temperatures and pressures

An analytical method (i.e., no computer simulation) has been developed to calculate the thermoelastic and surface properties of tantalum (Ta) at any (corresponding to the solid phase) temperature T and pressure P. This method takes into account the contribution of both lattice and electronic metal subsystems. This method calculated the equation of state of Ta, as well as the baric and temperature dependence for the Debye temperature, Grüneisen parameter, isothermal elastic modulus, thermal expansion coefficient, and isobaric heat capacity. It was shown that the calculated dependences are in good agreement with the data obtained both experimentally and using computer simulation. For the first time, the surface properties of Ta were calculated: the specific surface energy, as well as its derivatives in temperature and pressure. Both the baric dependences of these functions along isotherms 300 and 3000 K and the temperature dependences along isobars 0 and 100 GPa were obtained. This made it possible both to study the properties of Ta under P–T conditions that were difficult to access experimentally and to find out in which area of the P–T arguments the electronic contribution to these properties is noticeable, and in which area its influence on the properties of Ta can be neglected.