Defect Generation and Diffusion Mechanisms in Al and Al-Cu

Abstract

AbstractWe describe a newly-developed defect generation mechanism, namely the grain boundary Frenkel pair (GBFP) model, and corresponding diffusion mechanisms during electromigration developed using atomic molecular statics (MS), Monte Carlo (MC), and molecular dynamics (MD) simulation techniques in Al and Al-Cu. We contend that large numbers of interstitials and vacancies exist at grain boundaries and both contribute to mass transport. Cu preferentially segregates to the interstitial sites at grain boundaries via a Frenkel pair generation process and reduces the overall grain boundary diffusivity due to the strong binding in the Al-Cu dimer. Predictions from our models are in excellent agreement with available experimental data and observations.