2013 年 54 巻 9 号 p. 1597-1604
We applied first-principles calculations to study the relationship between the grain boundary energy (GBE) and grain boundary excess free volume (BFV) at the tilt grain boundaries in aluminum. GBE increased linearly as the grain BFV increased and the value of the proportionality constant between them, α, was 13.8 GPa for aluminum. The grain boundary elastic energies calculated on the basis of first principles using a dummy boundary as well as the classical elasticity theory were close to the grain boundary energies. We examined the free volume in nanocrystalline and ultrafine-grained materials and proposed a method for estimating GBE using the density of nanocrystalline and ultrafine-grained materials with the proportionality constant α. The GBE of nanocrystalline aluminum fabricated by ball milling and subsequent consolidation was estimated to be comparable to or lesser than that in coarse-grained aluminum.
