Efficient Calculation Methods for the Diffusion Coefficient of Interstitial Solutes in Dilute Alloys

Area of Science:

• Materials Science
• Computational Materials Science
• Physical Chemistry

Background:

• Understanding solute diffusion in alloys is crucial for predicting material properties.
• Ferritic iron alloys are widely used, making their diffusion characteristics important.
• Previous methods for calculating diffusion coefficients were computationally intensive.

Purpose of the Study:

• To develop a more efficient method for calculating diffusion coefficients in dilute ferritic iron alloys.
• To separate diffusion contributions and utilize analytical expressions and simulations.
• To generalize the method for other interstitial diffusion systems.

Main Methods:

• Separating diffusion coefficient calculation into interaction region and pure Fe components.
• Using Density-Functional-Theory (DFT) for binding energies and migration barriers.
• Employing atomistic kinetic Monte Carlo (AKMC) simulations for interaction region diffusion.

Main Results:

• Developed analytical expressions for diffusion times using DFT binding energies.
• AKMC simulations require data for only one solute concentration, efficiently yielding results for others.
• Significant reduction in computational effort compared to previous approaches.

Conclusions:

• The presented method offers a computationally efficient approach to calculating diffusion coefficients.
• The methodology can be generalized to other interstitial diffusion in alloys with substitutional solutes.
• The approach allows for analytical solutions under specific conditions, further minimizing computational needs.