Quaternary diffusion in the Cu−Ni−Zn−Mn system at 775°C

Abstract

Quaternary diffusion was investigated in the α (fcc) region of the Cu−Ni−Zn−Mn system at 775°C with solid-solid diffusion couples assembled with alloys characterized by similar concentrations of one of the components. The concentration profiles of the quaternary couples were examined on the basis of a relative concentration variable for each component; the profiles for any given couple exhibited a common cross-over composition. The interdiffusion fluxes of the components were calculated directly from the concentration profiles. Interdiffusion of each component up its own concentration gradient was observed in several couples, while the zero-flux planes for the individual components were identified in selected couples. The common cross-over composition reflected the relative diffusion depths in the terminal alloys of the single-phase quaternary diffusion couples. The quaternary diffusion paths were presented on the basis of relative concentration variables for the individual components.