A study was made of symmetrical and asymmetrical grain-boundary faceting, using molecular dynamics simulations and two embedded atom method potentials. Facet formation, coarsening and the reversible phase transition of a Σ3 {110} boundary into a Σ3 {112} twin, were demonstrated. The results were consistent with previous experimental studies and theoretical models. The Σ11 {002}1/{667}2 boundary exhibited faceting into {225}1/{441}2 and {667}1/{001}2 boundaries, and coarsened at a lower rate as compared with Σ3 {112} facets. However, the facets formed by {111}1/{112}2 and {001}1/{110}2 boundaries from a {116}1/{662}2 boundary, were stable to finite-temperature annealing. In the above faceted boundary, the elastic strain energy introduced by the atomic mismatch across the boundary created barriers to facet coarsening. The grain-boundary tension was too small to stabilize the finite-length faceting in both Σ3 {112} twin and asymmetrical {111}1/{112}2 and {001}1/{110}2 facets. The observed finite facet sizes were dictated by facet coarsening kinetics which could be strongly retarded by deep local energy minima; associated with atomic matching across the boundary.

Grain Boundary Finite Length Faceting. Z.X.Wu, Y.W.Zhang, D.J.Srolovitz: Acta Materialia, 2009, 57[14], 4278-87