Effects of Gradient Energy and Stress Terms in Diffusional Intermixing of Multilayers

摘要

Results of simulations, carried out on the basis of our general continuum equations for the atomic currents (which allow simulations for simultaneous action of stress accumulation and relaxation as well as spinodal decomposition in diffusion intermixing) and in a deterministic discrete (Martin's) model, are presented for metallic model multilayer systems. It is shown that the results of both models for the stress-free limit are qualitatively the same and indicate that, if there is an initially wide interface, the spinodal decomposition can lead to a metastable "wave" formation in the interface. This process is asymmetrical if the diffusion coefficient has strong concentration dependence. Taking into account stress effects in the continuum model (it is not possible to do so in the discrete one) we have shown in an ideal system that - depending on the direction of the net volume transport - the stress accumulation and relaxation can enhance or diminish the curvature on the ln(I/I_o) versus t curves (I/I_o is the relative intensity of the first order small angle Bragg peak) caused originally by the concentration dependent diffusivities.