Distribution of Formation and migration energies of point defects in concentrated solid-solution alloys: Ni_{0.5}Co_{0.5}, Ni_{0.5}Fe_{0.5}, Ni_{0.8}Fe_{0.2} and Ni_{0.8}Cr_{0.2}

TL;DR

This study uses ab initio calculations to analyze defect formation and migration energies in Ni-based concentrated solid-solution alloys, revealing elemental effects and energy overlaps that influence defect recombination.

Contribution

It introduces a new efficient method to determine chemical potentials considering composition and short-range order in alloy defect studies.

Findings

Fe has the largest effect on alloy defect energies among the studied elements.

Distribution overlap of vacancy and interstitial migration energies suggests enhanced defect recombination.

Method accounts for global composition and local order in defect energy calculations.

Abstract

Using ab initio calculations and special quasirandom structures, we have characterized the distribution of defect formation energy and migration barrier in Ni-based solid-solution alloys: Ni_{0.5}Co_{0.5}, Ni_{0.5}Fe_{0.5}, Ni_{0.8}Fe_{0.2} and Ni_{0.8}Cr_{0.2}. As defect formation energies depend sensitively on elemental chemical potential, we have developed a computationally efficient method for determining it which takes into account the global composition and local short-range order. We find that Fe has the biggest alloy effects for Ni among these four elements. Our results show that the distribution of migration energies for vacancies and interstitial have a region of overlap, which will facilitate the recombination between them.