On grain boundary wetting during deformation

We use numerical experiments to analyze the kinetics of grain boundary wetting in polycrystalline aggregates under the influence of an external applied shear stress. Grain boundary wetting is driven by the stress concentration at the tip of the fluid front. The extent of wetting of favorably oriented grain boundaries depends on the fluid mobility number b, which is defined as the ratio of the rate of stress relaxation by grain boundary wetting to the rate of stress relaxation by grain boundary diffusion. The applied stress can be relaxed by grain boundary diffusion, by grain boundary wetting or by a combination of both. In the wetting regime, an anisotropic grain boundary fluid network will develop due to the external shear stress. 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.