This study investigates the effect of graphene network configuration and interface orientation on the mechanical behavior of graphene-reinforced nickel (Gr/Ni) composites under tensile and compressive loadings, using molecular dynamics simulations. Two graphene configurations, a single sheet ($\text{NiGr}[-]$, 0.66 vol%) embedded within the Ni matrix and a cross-shaped network ($\text{NiGr}[\times ]$, 1.0 vol%), were assessed across three interface orientations: Gr/Ni(100), Gr/Ni(110), and Gr/Ni(111). The obtained results show that graphene reinforcement significantly enhances the composites' strength, stiffness, and ductility across all crystallographic orientations. Notably, Gr/Ni composites exhibit superior tensile strength and Young's modulus, especially in the Gr/Ni(110) and Gr/Ni(111) orientations, with the $\text{NiGr}[\times ]$ configuration showing the highest performance. Under compression, the composites demonstrate remarkable increases in compressive strength, with the $\text{NiGr}[\times ]$ configuration again outperforming others. Dislocation density analysis reveals that while graphene effectively hinders dislocation motion under tension, its impact is reduced under compression due to sheet buckling and rippling. Additionally, the study highlights significant ductility enhancements in Gr/Ni composites, especially in the Gr/Ni(111) orientation, where the $\text{NiGr}[\times ]$ configuration sustains over five times the strain of pure Ni before failure. These findings underscore the potential of optimizing Gr/Ni composites for applications requiring exceptional mechanical performance and provide valuable insights for advanced material design.

中文翻译：

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石墨烯网络增强和界面取向对镍复合材料力学行为的影响：分子动力学研究


本研究使用分子动力学模拟研究了石墨烯网络构型和界面取向对石墨烯增强镍 （Gr/Ni） 复合材料在拉伸和压缩载荷下力学行为的影响。在三个界面方向上评估了两种石墨烯构型，即嵌入 Ni 基体中的单片 （ $\text{NiGr}[-]$ ， 0.66 vol%） 和十字形网络 （ $\text{NiGr}[\times ]$ ， 1.0 vol%）：Gr/Ni（100）、Gr/Ni（110） 和 Gr/Ni（111）。获得的结果表明，石墨烯增强显著提高了复合材料在所有晶体学方向上的强度、刚度和延展性。值得注意的是，Gr/Ni 复合材料表现出优异的拉伸强度和杨氏模量，尤其是在 Gr/Ni（110） 和 Gr/Ni（111） 取向， $\text{NiGr}[\times ]$ 其配置显示出最高性能。在压缩下，复合材料的抗压强度显著提高，该 $\text{NiGr}[\times ]$ 配置的性能再次优于其他配置。位错密度分析表明，虽然石墨烯在拉伸下有效地阻碍了位错运动，但在压缩下由于板材屈曲和波纹，其影响会减小。此外，该研究强调了 Gr/Ni 复合材料的显著延展性增强，尤其是在 Gr/Ni（111） 取向，其中 $\text{NiGr}[\times ]$ 配置在失效前承受的应变是纯 Ni 的五倍以上。这些发现强调了优化 Gr/Ni 复合材料在需要卓越机械性能的应用中的潜力，并为高级材料设计提供了有价值的见解。