Multicomponent Diffusion at Zero-Flux Planes

摘要

Multicomponent diffusion gives rise to zero flux planes, ZFP's, where the flux of a component vanishes. The conditions for developing ZFP's in multicomponent alloys are now well understood through the works of Morral and co-workers. In this presentation we analyze the kinetics of multicomponent diffusion near stationary ZFP's. In contrast to the normal global component mixing that occurs in binary diffusion couples, the average equilibrium composition is achieved in the presence of a stationary ZFP by release of a pair of coupled diffusion waves. Curiously, each wave unilaterally establishes the average concentration of the ZFP component on each side of the Matano interface. A stationary ZFP always prevents net transport of the component across the diffusion zone, which has practically interesting implications for both the design and lifetime of multicomponent films, coatings, and claddings that resist loss of a component into the substrate. Flux behavior is discussed for a number of combinations of single-phase Cr-Al-Ni ternary alloys near the composition 10[at.%]-Cr, 10[at.%]-Al, 80[at.%]-Ni.