# The Interfacial Structure and Bonding Properties of the Al(111)/CrB2(0001) Interface: Insights for Advanced Al-Based Composites

## TL;DR

This study explores how aluminum and CrB2 materials bond at the atomic level to improve the strength of aluminum composites.

## Contribution

The study reveals how doping elements affect the bonding strength and stability of the Al(111)/CrB2(0001) interface.

## Key findings

- Cr-terminated HCP stacking at the interface provides maximum adhesion and minimal energy due to strong covalent bonding.
- Fe, Mg, and Mn doping improve adhesion and reduce interfacial energy, while Cu, Zn, and Si have the opposite effect.
- Binding energy trends show Fe > Mn > Mg > Si > Zn > Cu in enhancing interfacial performance.

## Abstract

This research focuses on the structural and bonding characteristics of the Al(111)/CrB2(0001) interface, aiming to clarify the adhesion mechanisms of CrB2 coatings on aluminum composites. Utilizing first-principles calculations grounded in density functional theory (DFT), we systematically examined the interfacial properties of both clean and doped Al(111)/CrB2(0001) systems. And key aspects such as binding energy, electron density distribution, and chemical bonding types were thoroughly evaluated. The results demonstrate that the Cr-terminated HCP stacking arrangement at the Al(111)/CrB2(0001) interface achieves the maximum adhesion work and minimal interfacial energy. This is primarily due to the strong covalent interactions between Al-p and Cr-p orbitals, which contribute to exceptional interfacial strength and stability. Furthermore, the incorporation of Fe, Mg, and Mn at the interface not only markedly improves working adhesion but also effectively lowers the interfacial energy for the Cr-terminated HCP stacking configuration. This phenomenon significantly enhances the overall bonding performance of the Al/CrB2 system. Conversely, the addition of Cu, Zn, and Si leads to an increase in interfacial energy, negatively impacting the bonding quality. Analysis of binding energies at the doped interface revealed a consistent trend among the elements: Fe > Mn > Mg > Si > Zn > Cu. These findings offer valuable guidance for the design and optimization of Al-based surface coatings with improved performance.