Edge dislocation core structures in FCC metals determined from ab initio calculations combined with the improved Peierls-Nabarro equation

TL;DR

This study combines ab initio density functional theory with an improved Peierls-Nabarro model to accurately analyze edge dislocation core structures in FCC metals, providing insights into dissociation behavior and partial dislocation formation.

Contribution

It introduces a novel approach integrating first-principles calculations with the Peierls-Nabarro equation to study dislocation cores in FCC metals.

Findings

Accurate core width and dissociation distances matching experimental data.

Preference for partial dislocation formation in Cu.

Full dislocations more observable in Al, Ir, Pd, Pt.

Abstract

We have employed the improved Peierls-Nabarro (P-N) equation to study the properties of 1/2<110> edge dislocation in {111} plane in FCC metals Al, Cu, Ir, Pd, and Pt. The generalized-stacking-fault energy (GSFE) surface entering the equation is calculated by using first-principles density functional theory (DFT). The accuracy of the method has been tested by calculating values for various stacking fault energies which favorably compare with the previous theoretical and experimental results. The core structures, including the core widths both of the edge and screw components, dissociation behavior for edge dislocations have been investigated. The dissociated distance between two partials for Al in our calculation agrees well with the values obtained from the numeric simulation with DFT and molecular dynamics simulation, as well as experiment. Our calculations show that it is preferred to create partial dislocation in Cu, and to be easily observed full dislocation in Al, Ir, Pd, and especially Pt.