Effect of molar volume of diffusing elements and cross terms of Onsager formalism (vacancy wind effect) on estimated diffusion coefficients in ternary and multicomponent solid solutions

TL;DR

This paper investigates how molar volume variations and vacancy wind effects influence the accuracy of diffusion coefficient estimates in complex solid solutions, highlighting significant errors when these factors are neglected.

Contribution

It introduces a comprehensive analysis of the impact of molar volume and vacancy wind effects on diffusion coefficients in multicomponent systems, challenging previous assumptions of constant molar volume.

Findings

Neglecting molar volume differences causes significant errors in diffusion estimates.

Including vacancy wind effects improves the accuracy of diffusion modeling.

Results suggest a need to revise diffusion analysis methods for multicomponent systems.

Abstract

The correlation between intrinsic and tracer diffusion coefficients considering the molar volume of the diffusing elements and cross phenomenological constants of Onsager contributing to the vacancy wind effect in ternary and multicomponent systems. Manning established this correlation assuming constant molar volume. The difference in data calculated considering a constant molar volume and neglecting the vacancy wind effect, which is mainly practised until today, is compared with the data considering the molar volume of diffusing elements and vacancy wind effect in NiCoFeCr and an imaginary quaternary multi-principal element system. This indicates a significant error in estimated data when considering a constant molar volume if the molar volumes of the diffusing elements are reasonably different. Therefore, the outcome of this study is expected to bring a significant change in diffusion analysis in ternary and multicomponent systems.