Theoretical study of some thermodynamical properties for solid under high pressure using finite-strain EOS

Abstract

This work involves the influence of high pressure on some thermodynamical properties of solid aluminum (Al) using a 3rd and 4th order Birch–Murnaghan equation of state based on the finite Eulerian strain theory. The comparison results for relative compression volume in the range of 1–0.65 versus applied high pressure for the 3rd and 4th order B–M EOS and experimental data indicated that up to 20 GPa are in good agreement. But beyond this and up to 100 GPa, the results for the 3rd order B–M EOS do diverge from the 4th order B–M EOS as well as from the experimental data. The isothermal bulk modulus (KT) has been worked out by using the 3rd and 4th order B–M EOS. Results were not found in good agreement above 20 GPa. However, the data for first pressure derivative (K0 T) for both 3rd and 4th order B–M EOS show a big divergence starting from 20 GPa. Finally, the effect of high pressure on (Al) melting temperature has been studied. The Mie– Gruneison–Debye equation (based upon the 3rd and 4th order B–M EOS) and Lindemann and Kumar’s equations were investigated. Comparison results for melting temperature as a function of melting pressure by using the above mentioned equations and the experimental data have been found to be in good agreement.