A CALPHAD Helmholtz energy approach to calculate thermodynamic and thermophysical properties of fcc Cu

Abstract

A CALPHAD Helmholtz energy approach, based on the Debye–Grüneisen model, is proposed to study thermodynamic and thermophysical properties of fcc Cu. With several parameters that have physical meanings, this approach allows a consistent description of both thermodynamic properties, e.g. heat capacity and Gibbs energy, and thermophysical properties, e.g. volume, thermal expansion, bulk modulus and Poisson's ratio. This method is intrinsically applicable to a large temperature and pressure ranges from 0 K upwards and from atmospheric pressure to extremely high pressures without resulting in any abnormal behavior of any properties. By taking advantage of PARROT, an optimization module in Thermo-Calc, experimental thermodynamic and thermophysical data can be assessed simultaneously so that inconsistencies among different kinds of measured properties can be detected and an optimum set of parameters can be obtained to accurately reproduce most of the experimental data. In addition, this approach leads to a straightforward way to couple CALPHAD assessments with ab initio calculations.

Keywords:

• CALPHAD
• Helmholtz energy
• Debye–Grüneisen model
• thermodynamics
• thermophysical property
• Cu