Measurement of tracer diffusion coefficients in an interdiffusion context for multicomponent alloys

A recently developed novel approach of simultaneous analysis of isotope and interdiffusion profiles in binary alloy systems is significantly advanced in order to apply to the case of multicomponent alloy systems. The resulting relations for the tracer or self-diffusion coefficients allow for the avoiding of the explicit solution of the interdiffusion equations. This remarkable result means that in the experimental implementation of this new technique there is no need for multiple diffusion couples. Only two profiles of the same component are necessary for the complete analysis. These can be two different isotopes or just two spatially different parts of the same atomic species. Descriptions of three possible experimental implementations of the novel technique combined with the Sauer-Freise method are discussed. Therefore, the new development is ready to be applied experimentally and can provide valuable insight into otherwise very difficult diffusion investigations into multicomponent alloys including high-entropy alloys.