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

In this work, we investigate Cu solution in theta-Al13Fe4 and related Al-rich omega-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 Al-7, forming a ternary theta-Al76Cu2Fe24 at ambient conditions, and both Al-7 and Al-9 sites (in Grin's note), forming theta-(Al-76-Cu2Fe24 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.