Evolution of a grain-boundary ensemble of submicrocrystalline molybdenum annealed under nickel diffusion along grain boundaries

The effect of annealing, including that performed under impurity diffusion from an external medium (coating), on an evolution of the structure and grain-boundary ensemble of submicrocrystalline molybdenum produced by severe plastic deformation is investigated. The distribution of grain boundaries over misorientations is shown to depend on the degree of strain experienced by the material during severe plastic deformation. Grainboundary diffusion fluxes of nickel atoms from the surface of the specimen are found to increase the fraction of special grain boundaries in the grain-boundary ensemble of submicrocrystalline molybdenum. Presumably, this is related to nucleation of new grains induced by the grain-boundary diffusion fluxes of nickel.