My diffusion research program in multicomponent systems includes both theoretical and experimental studies of intrinsic diffusion and interdiffusion in metallic alloys, intermetallic phases and silicides, investigations of diffusion structures and diffusion paths in multiphase systems for interface stability and microstructural evolution, and analysis and development of zero-flux planes and flux reversals for kinetic and thermodynamic interactions among the diffusing species.

Experimental studies have been carried out in several Cu-base, Ni-base and Fe-base ternary alloys, Fe-Ni aluminides, Ni-base high temperature alloys, MCrAlY coatings, U-Pu-Zr fuels, and stainless steel claddings. Diffusion studies in silicides of Mo, W, Ta, Nb and Re have been carried out for the determination of intrinsic and interdiffusion coefficients and energies of activation for diffusion of the individual components. Diffusion studies in the Fe-Ni-Al system with ordered and disordered phases have identified the development of unusual diffusion paths including double serpentine diffusion paths. Interdiffusion of Al in Mo-Si-Al system has been examined by diffusion Al in columnar grained MoSi2 for the assessment of flux contributions from bulk and grain boundary diffusion. Also, a study of diffusion of silver in tricrystals of Cu is currently under way in order to assess diffusion along triple junctions.