Grain coalescence by grain rotation in nano-ceramics

Grain rotation is an effective energy dissipating mechanism, the rate of which inversely depends on the fourth power of the grain size. The propensity of the nano-grain rotation to preserve the nano-structure in a metastable state depends on the nano-structure evolution. The relative rotation probability of the nano-grains was considered during coalescence to form low-energy, low-angle grain boundaries, vs. rotation step, temperature, and grain size. Nano-grain rotation is suppressed within the first two steps, resulting in bi- and tri-grain clusters. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.