Prediction of the Diffusion Behavior of Interstitial Nonmetallic B and N Atoms Diffusing in FCC_CoNiV Multi-Principal Element Alloy Based on Sublattice Preference: A Comparative Study

Abstract

The general predictive approach established in our previous work Qiao et al., Materials Genome Engineering Advances. 2025;3(3):e70021. was employed to study the diffusion behavior of interstitial B and N atoms in FCC_CoNiV multi-principal element alloy (MPEA) based on sublattice preference, with comparative C data from prior work, to enrich the diffusion genome database of lightweight interstitial elements. Furthermore, we employed the Kabsch algorithm to describe the lattice distortion of the octahedra containing interstitial atoms quantitatively. The results show that the number of V atoms in the local octahedral environment exerts a different regulatory effect on the diffusion behavior of interstitial atoms B and N; that is, B and C exhibit a higher diffusion barrier when migrating into V-rich sites, whereas N exhibits such higher barrier when leaving these sites. Electron localization function (ELF) analysis shows the difference is due to the diverse bonding strengths between V atoms and interstitial atoms B, N, and C. Nonperiodic diffusion barrier waves and diffusion parameters were quantitatively predicted in detail. The fundamental understanding of interstitial diffusion mechanisms and quantitative characterization of the diffusion parameters of B, N, and C in FCC_CoNiV MPEA provide a benchmark and critical insights for tailoring alloy properties through interstitial engineering.