Self-diffusion in high-density nanocrystalline Fe

In order to gain insight into the characteristic behavior of grain boundari es in nanocrystalline (n-) materials, high-density n-Fe specimens are prepa red by compaction of gas-condensed nanocrystallites at elevated temperature s and the self-diffusion coefficients are measured by radiotracer technique s. The self-diffusion coefficients of n-Fe (relative density higher than 91 %) determined by assuming a type-C kinetics are similar to those extrapola ted from high temperature data of conventional grain boundaries, suggesting that the grain boundaries in the high-density n-Fe are similar to those in conventional polycrystalline Fe. (C) 1999 Acta Metallurgica Inc.