The thermal generation kinetics of vacancies from octahedral voids in aluminium has been studied by the measurement of residual resistance due to vacancies generated during pulse heating of the specimen for short time, and also by electron microscopic observation of the voids. The vacancy generation curves saturated at the levels of 3.2 Delta rho (o) and 2.3 Delta rho (o) for the voids with edge length l = 6 nm at 543 K and 573 K, respectively, where Delta rho (o) is the resistivity due to the thermal equilibrium concentration of vacancies. For the voids with edge length l = 17 nm the generation curves saturated at the levels of (1.02-1.05)Delta rho (o) for both temperatures. These results are consistent with a newly proposed model that takes account of diffusion limited vacancy generation from the edge and the surface parts of the voids, with the respective promotive energies of vacancy formation DeltaE and epsilon. The new model yielded the best rt value sets DeltaE = 0.16 +/- 0.01) eV and epsilon = 0 for the voids with l = 6 nm, and DeltaE = (0.04 +/- 0.01) eV and epsilon = 0 for l = 17 nm voids. These results indicate that the contribution from the surface part to the vacancy generation curves is dominant in the large voids, while the contribution from the edge part becomes significant in the small voids. [References: 11]
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