Assessment of the aluminum-rich corner of the Al–Cu–Mg–(Ag) phase diagram

The thermodynamic expressions for the phases found in the aluminum-rich corner of the Al–Cu–Mg–(Ag) system were evaluated and refined to develop a self-consistent database. Microstructural characterization and thermal analysis aided in revising published thermodynamic data for the Al–Cu–Mg and Al–Cu–Mg–Ag systems. To represent the presence of silver an additional interaction energy term was formulated for the S phase, which was completed with the help of ab initio calculations that predicted silver substitution for aluminum within the phase.