INVESTIGATION OF GRAIN-BOUNDARY SELF-DIFFUSION AT LOW-TEMPERATURES IN POLYCRYSTALLINE ALUMINUM BY MEANS OF THE DISLOCATION SPREADING METHOD

The dislocation spreading method was used to study grain boundary (GB) self-diffusion in polycrystalline aluminium. This made it possible to obtain information on GB self-diffusion in aluminium at temperatures as low as 0.31-0.43 T(m). The distributions of GB diffusivity were determined at temperatures: 293, 343, 373 and 403 K. On the basis of these results the distributions of Arrhenius parameters (activation energy of GB self-diffusion and pre-exponential factor) were obtained. Both distributions of GB diffusivity and distributions of Arrhenius parameters depend on the history of the material. The obtained values of GB self-diffusion activation energy are consistent with results obtained by other methods. Higher diffusional properties of GBs and greater uniformity of GB diffusivity in polycrystalline aluminium were observed in the case of a higher recrystallization temperature.