Recrystallization in severely deformed Ag, Au, and Fe studied by positron-annihilation and XRD methods

摘要

Positron-annihilation studies of severely deformed samples of pure Ag, Au, and Fe are reported. The observed changes of the positron-annihilation parameters during isochronal annealing are linked to the recrystallization process confirmed by measurements of the XRD patterns and pole figures. The latter, being sensitive to the crystallographic texture, change significantly during the recrystallization process for all three metals. The measured annihilation line-shape parameter dependencies are described by a model that takes into account the boundary migration of the new defect-free grains and positron diffusion inside these grains. The model fairly well describes the observed dependencies and allows us to determine the activation energy for grain-boundary migration. The usefulness of the positron-annihilation studies for determination of the recrystallization temperature in deformed metals and alloys is discussed.(C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim