Place: 15th International Conference on Diffusion in Solids and Liquids, Athens, Greece
Diffusion in multi-principal element alloys such as High Entropy Alloys (HEA) or Compositionally Complex Alloys (CCA) is far from being well understood, though of central importance in processing of these alloys. In particular a consistent understanding of the relation between chemical mobilities in models for interdiffusion and tracer mobilities in selfdiffusion is missing to date. The presentation will pinpoint the main difficulties which arise when dilute solution models are extrapolated into the center of the composition space in multi-principal element alloys. The “Pair-Diffusion Model” (PDM) will be introduces as a generalization of conventional multi-component diffusion models. It is shown how measured self-diffusion coefficients can be consistently incorporated into kinetic databases for interdiffusion. The potential of the approach is demonstrated by application to diffusion couple experiments in the system of a Cantor type HEA.