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.