Mechanical performance and deformation mechanisms of AlCrFeCuNi high-entropy alloy/graphene nanocomposites

• Published in: Composites communications 2025-01, Vol.53, p.102211, Article 102211
• Main Authors: Doan, Dinh-Quan, Pham, Anh-Vu, Vu, Ngoc-Chien, Nguyen, Trong-Linh, Vu, Huu-Chuyen, Chu, Van-Tuan
• Format: Article
• Language: English
• Subjects: Composite; Graphene; High-entropy alloy; Interface; MD simulation
• ISSN: 2452-2139
• DOI: 10.1016/j.coco.2024.102211

Molecular dynamics (MD) simulations provide insights into the mechanical properties and deformation mechanisms of AlCrFeCuNi high-entropy alloy (HEA)/graphene (GR) composites under uniaxial tensile testing. The HEA/GR composite exhibits improved strength compared to pure HEA, primarily through the strain hardening effect imparted by the graphene layer. The HEA/GR interface acts as a nucleation site for shear strain and dislocations while also impeding dislocation propagation, thus enhancing strain hardening and mechanical performance. Deformation analysis reveals structural changes in the graphene layer, including wrinkle formation, which impact the tensile behavior of the composite. Key findings reveal that the mechanical characteristics of HEA/GR composites are notably influenced by graphene layer spacing. A reduction in graphene layer spacing correlates with enhanced yield strength, ultimate strength, and Young's modulus, in accordance with the Hall-Petch relationship. The increased resistance to deformation and tensile strength is attributed to the higher density of graphene layers in the HEA substrate, which intensify atomic shear strain. At the HEA/GR interfaces, dislocation nucleation triggers transitions in atomic configurations and defect structures. Additionally, HEA/GR composites exhibit greater strength and Young's modulus in the Y direction compared to the X direction, reflecting the significant impact of graphene orientation and crystallographic effects on mechanical properties. These findings demonstrate the crucial role of graphene layer spacing and orientation in determining the performance of HEA/GR composites. •HEA/Gr composites show improved strength due to graphene's strain hardening effect.•The HEA/Gr interface nucleates dislocations while simultaneously annihilating them.•Graphene layer deformation, including wrinkles, impacts the tensile behavior of composites.•Reduced graphene layer spacing enhances yield strength, ultimate strength, and Young's modulus.•HEA/Gr composites exhibit greater strength and Young's modulus in Y direction than X.