Body Diagonal Diffusion Couple Method for Estimation of Tracer Diffusion Coefficients in a Multi-Principal Element Alloy

TL;DR

This paper introduces a novel method to estimate tracer diffusion coefficients in multicomponent alloys using only two diffusion profiles, significantly simplifying the process and enabling comprehensive diffusion coefficient analysis.

Contribution

The study presents a new approach based on the body diagonal diffusion couple method that reduces the number of required diffusion profiles to estimate all diffusion coefficients in multicomponent systems.

Findings

Successfully estimated tracer diffusion coefficients from two profiles.

Compared new estimates with radiotracer data showing good agreement.

Method extends to systems where radiotracer techniques are infeasible.

Abstract

The estimation of (n-1)2 interdiffusion coefficients in an n component system requires (n-1) diffusion paths to intersect or pass closely in the (n-1) dimensional space according to the body diagonal diffusion couple method. These interdiffusion coefficients are related to n(n-1) intrinsic (or n tracer diffusion coefficients), which cannot be estimated easily following the Kirkendall marker experiment in a multicomponent system despite their importance for understanding the atomic mechanism of diffusion and the physico-mechanical properties of materials. In this study, the estimation of tracer diffusion coefficients from only two diffusion profiles following the concept of the body diagonal diffusion couple method in a multicomponent system is demonstrated. Subsequently, one can estimate the intrinsic and interdiffusion coefficients. This reduces the overall effort up to a great extent since it needs only two instead of (n-1) diffusion profiles irrespective of the number of components, with an additional benefit of enabling the estimation of all types of diffusion coefficients. The available tracer diffusion coefficients estimated following the radiotracer method are compared to the data estimated in this study following this method. This method can also be extended to the systems in which the radiotracer method is not feasible.