Structural properties and relative stability of (meta)stable ordered, partially ordered, and disordered Al-Li alloy phases

Abstract

We resolve issues that have plagued reliable prediction of relative phase stability for solid-solutions and compounds. Due to its commercially important phase diagram, we showcase Al-Li system because historically density-functional theory (DFT) results show large scatter and limited success in predicting the structural properties and stability of solid-solutions relative to ordered compounds. Using recent advances in an optimal basis-set representation of the topology of electronic charge density (and, hence, atomic size), we present DFT results that agree reasonably well with all known experimental data for the structural properties and formation energies of ordered, off-stoichiometric partially-ordered and disordered alloys, opening the way for reliable study in complex alloys.

Design of high-strength refractory complex solid-solution alloys

“…A variational potential zero v0 was used to yield kinetic energies nearing those of full-potential methods. 55 For self-consistent densities, complexenergy contour integration 56 used 20-point Gauss-Legendre semicircular contour.…”

Atomic short-range order and incipient long-range order in high-entropy alloys

“…Scalar-relativistic effects are included, but spin orbit is ignored. Because the potential zero v 0 , i.e., muffin-tin zero, can dramatically affect stability prediction for spherical potentials, we use a variational definition [32] that yields kinetic energies that approach those of full-potential methods [32,33].…”

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

“…From alloy chemical design aspect, one potential way to improve the ductility of the alloys is to introduce metallic alloying elements into the materials [14,15]. The transition metals have been used to modify the thermodynamic and mechanical properties of δ'-Al 3 Li phase according to previous investigations [16][17][18][19][20][21][22][23][24][25]. However, in order to identify the effect of alloying elements on the improvement of the thermodynamic and mechanical properties of Al 3 Li, knowing of the solute elements site occupancy behaviour in ordered L1 2 Al 3 Li is of great importance.…”

“…However, in order to identify the effect of alloying elements on the improvement of the thermodynamic and mechanical properties of Al 3 Li, knowing of the solute elements site occupancy behaviour in ordered L1 2 Al 3 Li is of great importance. Despite the fact that the mechanical and thermodynamic properties [16][17][18][19][20][21][22][23][24][25] as well as the site preference behaviour [26] of a list of elements in L1 2 -Al 3 Li have been investigated previously in the literature, there is no systematic calculation of alloying elements site occupancy behaviour for the whole transition metals in L1 2 -Al 3 Li phase. Particularly, Tian et al [26] have studied the site preference of a list of alloying elements (8 elements) in L1 2 Al 3 Li by using first-principles calculations, they have used the enthalpy of formation of alloyed L1 2 Al 3 Li to predict the 0K site preference of solute.…”