First-principle calculations for the diffusion of 3d transition metal solutes in Ni demonstrated the existence of a higher diffusion energy barrier for solutes with smaller atomic sizes. The calculations revealed that smaller transition metal atoms are, actually, among the least compressible due to the formation of incompressible solute-host directional bonds. Magnetism was shown to have a profound effect on the solute diffusion trends across the 3d transition metal series: the existence of a local minimum in the diffusion energy barrier was accompanied by the occurrence of a maximum in the magnetic moment. The calculated diffusion rates disprove the traditional view that the diffusion of solutes was least rapid when the size misfit with the host was the greatest.
Diffusion Rates of 3d Transition Metal Solutes in Nickel by First-Principles Calculations. M.Krčmar, C.L.Fu, A.Janotti, R.C.Reed: Acta Materialia, 2005, 53, 2369-76