Change in the lattice properties and melting temperature of a face-centered cubic iron under compression

Abstract

All four parameters of the Mie–Lennard-Jones pair interatomic potential have been determined, and the state equation (P) and baric dependences of the lattice properties of an fcc iron are calculated using a previously proposed method. The dependences have been studied for the following properties: Debye temperature; the first, second, and third Gruneisen parameters; isothermal bulk modulus B_T and B′(P); isochoric specific heat C_v and C_v′(P); isobaric specific heat C_p; coefficient of thermal expansion α_p and α_p′(P); specific surface energy σ and σ′(P). Calculations performed along two isotherms (1500 and 3000 K) have shown good agreement with the experimental data. Analytical approximations of the baric dependences for B′(P), α_p(P), C_p(P), and σ′(P) have been obtained, and it is shown that at P → ∞ the functions B_T(P) and σ(P) change linearly, while the functions α_p′(P) and C_p′(P) tend to zero. The calculated baric dependence of the melting temperature shows good agreement with the experimental data.