Matrix Green'S Function Analysis Of Multicomponent Diffusion In Multilayered Assemblies

In order to describe interdiffusion in layered structures in multicomponent systems, matrix Green's functions may be employed in seeking solutions to multicomponent diffusion equations. A transfer matrix method employing a matrix notation is utilized for this analysis. For single-phase multilayered assemblies set up with thin alloy layers of different compositions between thick terminal alloy disks, expressions for the temporal and spatial evolution of the concentration profiles are developed on the basis of a set of constant interdiffusion coefficients. The theory is developed in general for multilayered diffusion assemblies containing any number of finite layers. It is applied to an experimental ternary diffusion assembly containing one layer sandwiched between two thick terminal alloys in the Cu-Ni-Zn system. The Cu-Ni-Zn layered diffusion assembly was assembled with three alpha (fcc) Cu-Ni-Zn alloys of different compositions and annealed at 775 degrees C for 4 days. The agreement between the experimentally observed concentration profiles and the predicted concentration profiles is found to be quite satisfactory.