Kinetic mechanisms of phenomena to be induced by the diffusion on the grain
boundaries in polycrystalline and nanostructured (NS) materials have been
analyzed. By way of example of nickel and copper nanostructured (grain size
100+300 nm) it was shown that the effect of diffusion induced loss of stre
ngth by creep was much observed at temperatures low than 400 K in compariso
n with polycrystalline condition with grain size 20 mu m. It was supposed t
hat the physical reason for the decrease in the temperature for the effect
to manifest itself is much higher value of diffusion coefficients of impuri
ties in nanostructures. (C) 1999 Acta Metallurgica Inc.