Stacking fault energy of face-centered cubic metals: thermodynamic and ab initio approaches

TL;DR

This paper investigates the stacking fault energy in fcc metals using thermodynamic and ab initio methods, differentiating between actual and pseudo-interfacial energies, and provides detailed calculations for several metals and alloys.

Contribution

It introduces a clear distinction between interfacial and pseudo-interfacial energies and computes these for multiple metals and alloys using first-principles calculations.

Findings

Interfacial and pseudo-interfacial energies differ significantly.

Strong chemistry dependence of interfacial energies observed.

Pseudo-interfacial energies for Fe-Cr-Ni alloys match literature data.

Abstract

The formation energy of the interface between face-centered cubic (fcc) and hexagonal close packed (hcp) structures is a key parameter in determining the stacking fault energy (SFE) of fcc metals and alloys using thermodynamic calculations. Often the contribution of the planar fault energy to the SFE has the same order of magnitude as the bulk part, and thus the lack of a precise information about it can become the limiting factor in thermodynamic predictions. Here, we differentiate between the actual interfacial energy for the coherent fcc(111)/hcp(0001) interface and the "pseudo-interfacial energy" that enters the thermodynamic expression for the SFE. Using first-principles calculations, we determine the coherent and pseudo- interfacial energies for six elemental metals (Al, Ni, Cu, Ag, Pt, and Au) and for three paramagnetic Fe-Cr-Ni alloys. Our results show that the two interfacial energies significantly differ from each other. We observe a strong chemistry dependence of both interfacial energies. The calculated pseudo-interfacial energies for the Fe-Cr-Ni steels agree well with the available literature data.