A first-principles study on the site occupancy behavior of transition metals in L12-Al3Li phase

Abstract

The main strengthening mechanism in Al-Li alloys is generally achieved by the existence of a high volume fraction of the L1 _2 -Al _3 Li precipitation from Al matrix. In this work, we do density functional theory (DFT) total energy calculations on the site occupancy behaviour of transition metals in L1 _2 -Al _3 Li compound. The ground state properties of L1 _2 -Al _3 Li, fcc-Al, and bcc-Li are determined and compared to the available literature data. The formation energies of intrinsic point defects in L1 _2 -Al _3 Li phase as well as Al _3 LiX alloy formation energy are calculated and identified. We show that the Li antisite is preferential to from in the L1 _2 -Al _3 Li phase. Finally, the site occupancy behaviour of transition metals in L1 _2 -Al _3 Li as well as the solute atomic volume effect on the solute site preference and lattice expansion of the L1 _2 -Al _3 Li have been studied, the later results can be used for an indirect estimation of the site substitution behaviour of the alloying elements in L1 _2 -Al _3 Li phase.

Keywords

• L12-Al3Li phase
• Intrinsic defect
• Transition metals
• Al-Li alloy
• Site occupancy behavior