The influence of alloying on the stacking fault energy of gold from density functional theory calculations

TL;DR

This study uses density functional theory to analyze how various alloying elements affect the stacking fault energy of gold, revealing significant influences on its deformation properties.

Contribution

It provides a detailed computational analysis of how different alloying elements modify gold's stacking fault energy and deformation behavior.

Findings

Alloying decreases the intrinsic SFE of gold.

SFE varies with alloying element type and concentration.

Misfit strain significantly influences SFE changes.

Abstract

The generalized stacking fault (SFE) energy curves of pure gold (Au) and its binary alloys with transition metals are determined from density functional theory (DFT). Alloy elements Ag, Al, Cu, Ni, Ti, Zr, Zn, In, Ga, Sn, Mn, Cd, Sn, Ta and Cr are substituted into Au at concentrations up to 4%. A comparison of various proposed methodologies to calculate SFEs is given. The intrinsic SFE decreases for all alloying elements from its value for pure Au, but SFE energies (both stable and unstable) vary strongly with the distance of the alloying element from the stacking fault region, and with alloy concentration. The compositional dependence of the SFE on the volume change associated with alloying element is determined. This work demonstrates that the SFE is strongly influenced by misfit strain caused by the alloying elements. Moreover, the computed generalized SFE curves provide information valuable to developing an understanding of the deformation behavior of Au and Au-alloys.