Reinforcing role of graphene in high entropy alloy matrix composites

This study explores the mechanical and interfacial properties of Graphene (Gr)-reinforced FeNiCrCoCu high-entropy alloy (HEA) composites. Tensile stress-strain analyses reveal that increasing Gr volume fractions significantly enhances elastic modulus and Yield stress of the composite, with peak tensile strength reaching ~ 30 GPa in the zigzag direction at 18.11% Gr volume fraction. Molecular dynamics simulations indicate robust interfacial shear strength (ISS) of ~ 294.7 MPa, demonstrating strong Gr-metal interaction. The zigzag orientation of Gr offers superior mechanical performance compared to armchair and out-of-plane directions due to the alignment of its covalent bonds with the loading axis. Enhanced dislocation confinement at the Gr-metal interface contributes to increased strength and strain hardening, particularly through the formation of immobile dislocations. However, out-of-plane loading results in reduced strength due to weaker van der Waals interactions and potential delamination. This study also indicates the presence of 1% vacancy defects can significantly reduce tensile strength by 23.92% and elastic modulus by 26.02%, highlighting the sensitivity of mechanical properties to defect concentrations. The present study highlights the tunable anisotropic properties of these composites and the critical role of Gr orientation and volume fraction in optimizing mechanical performance. These findings underscore the potential of Gr-HEA composites for advanced structural applications, with opportunities for further research into interfaces and new alloy systems.