CALPHAD-based modeling of pressure-dependent Al, Cu and Li unary systems

Abstract

The study presents a pressure-dependent CALPHAD-based model for assessment of the Al, Cu and Li unary systems, focusing on phase changes under varying pressures. By incorporating the Murnaghan equation of state and ab initio phonon calculations, the thermal properties for stable and metastable phases are accurately predicted. To ensure a comprehensive representation of the system's response to pressure changes; compressibility, volumetric thermal expansion coefficient as a function of temperature, the derivative of bulk modulus with pressure, and molar volume for the condensed phases are integrated in the framework. The model provides essential insights into pressure-induced transformation, aiding in the understanding of solid-state processing, such as high-pressure torsion and extrusion. The results from this work are in excellent agreement with the experimental literature and can be utilized to enhance phase predictions under non-equilibrium conditions.