Sluggish, chemical bias and percolation phenomena in atomic transport by vacancy and interstitial diffusion in Ni–Fe alloys

Abstract

In this article, we report the results of extended atomistic modeling of intrinsic mobility of point defects and associated atomic transport in Ni–Fe model binary alloys. We consider the effects of composition and temperature and present evidence of the sluggish and chemically biased diffusion, and percolation effects occurring in atomic transport via the vacancy and interstitial migration mechanisms. The results are analyzed and discussed in the light of previous studies and some experimental observations. It is demonstrated that the sluggish diffusion, the chemically biased diffusion, and the percolation are interlinked phenomena that are defined by the chemical complexity of particular alloys. Methods for predicting these phenomena in multicomponent alloys are discussed. We report a fundamental understanding of sluggish diffusion, chemically-biased diffusion, as well as percolation phenomena, in Ni–Fe random alloys for vacancy and interstitial atom migration mechanisms.