Molecular Dynamics Simulations of the Thermal Evolution of Voids in Cu Bulk and Grain Boundaries

Abstract

The formation of voids in fcc metals is thought to result from the accumulation of vacancies, although the exact mechanisms underlying their formation, stabilization, and evolution remain unknown. Due to the stabilizing effect of H on voids, H embrittlement is regarded as a primary cause of self-induced voiding (SIV). In the present study, we looked into how voids evolve/decay in the bulk and at grain boundaries of Cu during thermal annealing molecular dynamics simulations up to 800 K. At temperatures above 500 K, voids of up to 100 vacancies were found to totally dissolve. H was shown to have a stabilizing effect in the voids, with voids withstanding temperatures close to 750 K without dissociating. This was observed both in the bulk and at grain boundaries.