Quantitative data on δ' growth kinetics on dislocations demonstrated that, at homologous temperatures greater than 0.5, volume diffusion was the predominant mechanism. However, a small contribution of about 1 atom in 300, was made by pipe diffusion through the dislocation. This could be established by careful analysis of the dislocation climb which was associated with precipitate growth. An analysis which was based upon δ' growth kinetics, and the diffusion equation, yielded an activation energy of 0.56eV for Li pipe diffusion. At homologous temperatures of less than 0.5, the δ' precipitate growth was faster when associated with dislocations. Pipe diffusion was necessary here in order of account for the observed kinetics.

Growth of δ' on Dislocations in a Dilute Al-Li Alloy Z.M.Wang, G.J.Shiflet: Metallurgical and Materials Transactions A, 1998, 29[8], 2073-80