Crystal Chemistry and Electronic Properties of the Al-Rich Compounds, Al₂Cu, ω-Al₇Cu₂Fe and θ-Al₁₃Fe₄ with Cu Solution

Abstract

In this work, we investigate Cu solution in θ-Al13Fe4 and related Al-rich ω-Al7Cu2Fe and Al2Cu phases in the Al-Cu-Fe system using the first-principles density functional theory (DFT) with on-site Coulomb interaction correction. The results show preference of Cu at Al7, forming a ternary θ-Al76Cu2Fe24 at ambient conditions, and both Al7 and Al9 sites (in Grin’s note), forming θ-(Al76−xCu2+x)Fe24 at a high temperature. The relative stability of the Al-rich compounds and their crystal and electronic properties are investigated. We show the importance of the Hubbard U correction to the standard DFT functionals for Cu-containing metallic materials. This study helps characterize the intermetallic compounds in Cu-containing Al alloys, and helps further control Fe-containing intermetallic compounds in the solidification of Al-based alloys.

Keywords

• Cu solution in θ-Al₁₃Fe₄
• Cu-containing compounds
• crystal chemistry
• on-site coulomb correction
• density functional theory