First-principles insights into solute partition among various nano-phases in Al−Cu−Li−Mg alloys
Zhengqing Liu, Yong Jiang, Yiren Wang, Jian-Gang Yao
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 (δʹ-Al3Li, θʹ-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 θʹ and S, Cu cannot directly affect δʹ, Mg cannot directly affect θʹ and δʹ 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 δʹ, θʹ and S. Cd can partition into δʹ, T1 and S. Zr can partition into δʹ and T1. Ni substitution can weakly partition into θʹ and S. Ti, V, Zn, Ag and Mo can partition into δʹ only. Cr, Mn, Fe and Co cannot directly affect any of the four nano-phases. Almost all RE-elements can strongly partition into T1, δʹ and S, but would be expelled by θʹ. 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.