Tuned Vacancy Diffusion by Mn via Anomalous Friedel Oscillations in NiCoFeCrMn High Entropy Alloys

TL;DR

This paper demonstrates how Mn in NiCoFeCrMn high entropy alloys influences vacancy diffusion through anomalous Friedel Oscillations, revealing a novel mechanism for defect control in advanced materials.

Contribution

It uncovers a new atomic diffusion mechanism involving Mn-induced Friedel Oscillations that modulate vacancy behavior in high entropy alloys.

Findings

Mn presence lowers vacancy diffusion barrier energy.

Enhanced vacancy and interstitial defect recombination.

Suppression of vacancy clusters under irradiation.

Abstract

Vacancy is known to play a critical role in solid state diffusion and determine many properties of the materials. We report a proof-of-principle result on Mn in the role of tuning vacancy diffusion by an anomalous Friedel Oscillations effect in an equivalent NiCoFeCrMn high entropy alloy. The vacancy induced Friedel Oscillations is destroyed by the presence of the first nearest neighboring Mn, opening a channel for long-range influence on the surrounding atoms from the vacancy, resulting in a lower vacancy diffusion barrier energy, despite of the atom type. The effects lead to a remarkable diffusion overlaps of the two type defects, vacancy and interstitial, enhancing their recombination, which can explain well for the experimental results with suppression of vacancy clusters under irradiation. This finding presents new understanding on the atomic diffusion mechanism and thus suggests novel concepts for tuning defect properties in the design of advanced materials with outstanding properties, in a broad field.