Stress relaxation caused by the combination of interfacial sliding and diffusion around spherical inclusions

Sliding and diffusion on matrix-inclusion interfaces change stress states o f dispersion-hardened materials. Stress relaxation due to the combined acti on of the interfacial sliding and diffusion is examined for elastically def ormed dispersion-hardened materials containing spherical inclusions. The oc currence of the interfacial sliding and diffusion is treated as the generat ion of Somigliana's dislocations on the matrix-inclusion interfaces. Essent ial roles of the interfacial sliding in diffusional relaxation are shown by formulating the kinetics of the combined relaxation process. By letting th e volume fraction of inclusions approach unity, results obtained for the di spersion-hardened materials are applied to the discussion of the Coble cree p of polycrystals modeled as an aggregate of spherical grains. Stress state s in grains during the diffusional creep are also shown. (C) 1999 Elsevier Science Ltd. All rights reserved.