Effect of vacancy on the sliding of an iron grain boundary

We perform a first-principles calculation to investigate the effect of a vacancy on the sliding of an iron (Fe) Sigma 5 (310) [001] tilt grain boundary (GB). We calculate vacancy formation energies in order to determine the site preference of the vacancy at the Fe GB. We show that vacancies can easily segregate to the GB region, which is attributed to special atomic configurations of the GB. We demonstrate that the maximal sliding energy barrier of the GB with a monovacancy is 2.78 J/m(2), 15% lower than that of the vacancy-free GB, suggesting that the presence of vacancy at the GB increases the GB mobility. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3593182]