The depth-concentration profiles of nickel upon diffusion in sub-microcrystalline molybdenum processed by severe plastic deformation were studied using Auger electron spectroscopy. The coefficients, Db, and activation energies of the grain-boundary diffusion of nickel in sub-microcrystalline molybdenum were determined at 973 to 1123K. The results indicated that a difference between the Db-values in sub-microcrystalline and coarse-grained molybdenum was related to a non-equilibrium state of grain boundaries in the severe plastic deformation-processed metal.

Grain-Boundary Diffusion of Nickel in Submicrocrystalline Molybdenum Processed by Severe Plastic Deformation. G.P.Grabovetskaya, I.P.Mishin, I.V.Ratochka, S.G.Psakhie, Y.R.Kolobov: Technical Physics Letters, 2008, 34[2], 136-8