The formation of grain structures and grain-boundary microstructures in polycrystalline Mo, produced by thermomechanical processing of cylindrical single crystals with initial surface normal orientations of <110>, <111> or <112>, were investigated with the object of controlling grain-boundary microstructures. The polycrystalline specimens exhibited differing microstructures; depending upon the initial orientation of the single crystal and the deformed microstructure. The recrystallized microstructure comprised some oriented-grain clusters, in which grains which possessed a similar orientation were assembled. The frequency of low-angle boundaries was very high in the oriented-grain clusters. A close relationship also existed between the grain boundary character distribution and the triple-junction distribution. The grain-boundary microstructures were compared for body-centred cubic Mo, and face-centred cubic polycrystalline materials, with reference to path-dependent percolation resistance.

Control of Grain Boundary Microstructures in Molybdenum Polycrystals by Thermomechanical Processing of Single Crystals. S.Kobayashi, S.Tsurekawa, T.Watanabe, A.Kobylanski: Philosophical Magazine, 2008, 88[4], 489-506