First-principles insights into solute partition among various nano-phases in Al-Cu-Li-Mg alloys
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Yantai Nanshan University, Yantai 265713, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
2. School of Materials Science and Engineering, Yantai Nanshan University, Yantai 265713, China;
3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)
Abstract: First-principles energetics calculations were performed over a group of 25 candidate elements, to investigate their partition energies and behaviors among major nano-phases (δ？-Al3Li, θ？-Al2Cu, T1-Al6Cu4Li3 and S-Al2CuMg) in most commercial Al-Cu-Li-Mg alloys. It was revealed that principal alloying element Li cannot directly affect θ？ and S, Cu cannot directly affect δ？, Mg cannot directly affect θ？ and δ？ but can weakly partition into T1. As for micro-alloying elements, Si is the only element that can partition into all the four nano-phases. Au can partition into δ？, θ？ and S. Cd can partition into δ？, T1 and S. Zr can partition into δ？ and T1. Ni substitution can weakly partition into θ？ and S. Ti, V, Zn, Ag and Mo can partition into δ？ only. Cr, Mn, Fe and Co cannot directly affect any of the four nano-phases. Almost all RE-elements can strongly partition into T1, δ？ and S, but would be expelled by θ？. Only Sc is somehow particular to S, showing no partition preference in S. The newly obtained fundamental results could constitute a simple prototype database in support for the accelerated design of Al-Li based alloys and other related Al alloys.
Key words: Al-Cu-Li-Mg alloy; nano-phase; micro-alloying; solute partition; first-principles