The diffusivity of vacancies was deduced from the shrinkage rate of voids during annealing. The observation of voids was carried out by means of transmission electron microscopy, below the order-disorder transition, at temperatures ranging from 453 to 653K. The suppression of the diffusion of vacancies which had been emitted from voids was detected at temperatures above 493K.

I.Hashimoto, K.Yamagata, Y.Oketani, H.Yamaguchi: Physica Status Solidi B, 1996, 195[1], 55-60