Ma Zhonglei, Wang Hongding, Zhao Yanlong, Li Zhengning, Liu Hong, Yang Yizhao, Zhao Zigeng
School of Mechanical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
Materials (Basel). 2024 Sep 16;17(18):4552. doi: 10.3390/ma17184552.
This study explores the mechanical properties of graphene/aluminum (Gr/Al) nanocomposites through nanoindentation testing performed via molecular dynamics simulations in a large-scale atomic/molecular massively parallel simulator (LAMMPS). The simulation model was initially subjected to energy minimization at 300 K, followed by relaxation for 50 ps under the NPT ensemble, wherein the number of atoms (N), simulation temperature (T), and pressure (P) were conserved. After the model was fully relaxed, loading and unloading simulations were performed. This study focused on the effects of the Gr arrangement with a brick-and-mortar structure and incorporation of high-entropy alloy (HEA) coatings on mechanical properties. The findings revealed that Gr sheets (GSs) significantly impeded dislocation propagation, preventing the dislocation network from penetrating the Gr layer within the plastic zone. However, interactions between dislocations and GSs in the Gr/Al nanocomposites resulted in reduced hardness compared with that of pure aluminum. After modifying the arrangement of GSs and introducing HEA (FeNiCrCoAl) coatings, the elastic modulus and hardness of the Gr/Al nanocomposites were 83 and 9.5 GPa, respectively, representing increases of 21.5% and 17.3% compared with those of pure aluminum. This study demonstrates that vertically oriented GSs in combination with HEA coatings at a mass fraction of 3.4% significantly enhance the mechanical properties of the Gr/Al nanocomposites.
本研究通过在大规模原子/分子大规模并行模拟器（LAMMPS）中进行分子动力学模拟的纳米压痕测试，探索了石墨烯/铝（Gr/Al）纳米复合材料的力学性能。模拟模型最初在300 K下进行能量最小化，然后在NPT系综下弛豫50 ps，其中原子数（N）、模拟温度（T）和压力（P）保持不变。在模型完全弛豫后，进行加载和卸载模拟。本研究重点关注了具有砖-灰浆结构的Gr排列以及高熵合金（HEA）涂层的加入对力学性能的影响。研究结果表明，Gr片层（GSs）显著阻碍了位错传播，阻止了位错网络在塑性区内穿透Gr层。然而，与纯铝相比，Gr/Al纳米复合材料中位错与GSs之间的相互作用导致硬度降低。在改变GSs的排列并引入HEA（FeNiCrCoAl）涂层后，Gr/Al纳米复合材料的弹性模量和硬度分别为83 GPa和9.5 GPa，与纯铝相比分别提高了21.5%和17.3%。本研究表明，质量分数为3.4%的垂直取向GSs与HEA涂层相结合可显著提高Gr/Al纳米复合材料的力学性能。
