The coupling effects of external mechanical stress and chemical stress upon diffusion were studied. A self-consistent diffusion equation, including the chemical stress and external mechanical stress gradient, was developed within the framework of thermodynamic theory and Fick’s law. For a thin plate subjected to unidirectional tensile stress fields, the external stress coupled diffusion equation was solved numerically using the finite difference method for one-sided and two-sided charging processes. The results showed that, for two such types of charging process, the external stress gradient would accelerate the diffusion process and thus increase the concentration value while reducing the magnitude of the chemical stress when the diffusion direction was identical to that of the stress gradient: M•D = 1. On the other hand, when the diffusion direction was opposite to that of the

stress gradient, M•D = -1, the external stress gradient obstructed the process of solute penetration by decreasing the concentration value and increasing the magnitude of the chemical stress. For two-side charging, as compared with that without the coupling effect of external stress, an asymmetrical distribution of concentration was produced due to the asymmetrical mechanical stress field feedback to the diffusion.

Coupling Effects of Chemical Stresses and External Mechanical Stresses on Diffusion. F.Z.Xuan, S.S.Shao, Z.Wang, S.T.Tu: Journal of Physics D, 2009, 42[1], 015401