It was noted that 57Co probe atoms, which were introduced by diffusion into polycrystalline samples, enriched grain boundaries in Cr and W, depleted the boundaries in Ta and did not segregate at boundaries in Pd, Pt or Au. The isomer shift and width of 2 components of the nuclear γ-resonance spectra were used to investigate the segregation of residual interstitial impurities in the grain-boundary core (type-1 segregation) and outside of the grain-boundary core (type-2 segregation). In the case of type-2 segregation, residual interstitial impurities did not have cubic symmetry and caused the formation of similar complexes of point defects. In W, interstitial impurities possessed cubic symmetry in the case of type-1 segregation. The change in the isomer shift and width of the components of the nuclear γ-resonance spectra of Ta, Cr, W, Pd, Pt and Au depended upon the difference in valence of 57Co and the matrix.

Segregation of Atomic Probes and Interstitial Impurities in the Grain Boundary Core and Outside Grain Boundaries in 3d, 4d and 5d Metals. V.N.Kaigorodov, S.M.Klotsman, M.I.Kurkin, V.V.Dyakin: Materials Science Forum, 1999, 294-296, 431-4