Li Lujuan, Cao Qianqian, Hu Xin, Ma Yongze
College of Information Science and Engineering, Jiaxing University, Jiaxing 314001, P. R. China.
College of Mechanical Engineering, Jiaxing University, Jiaxing 314001, P. R. China.
Langmuir. 2025 Feb 18;41(6):3812-3821. doi: 10.1021/acs.langmuir.4c03746. Epub 2025 Feb 3.
The fracture mechanism and mechanical response of Ni/graphene nanocomposites under nanoindentation are investigated by molecular dynamics simulations. We analyze the effect of the overlapping area on the microstructural transition, HCP atomic fraction, dislocation density, load-displacement relationship, and stress distribution. It was found that the maximum indentation depth of embedded graphene has a nonlinear dependence relation with the overlapping area, and it becomes smaller at the overlapping width comparable to the indenter diameter. The graphene layer is able to hinder the expansion of the dislocation into the interior of the Ni matrix in the initial stage. The densities of HCP atoms and dislocations in the composite gradually increase with increasing indentation depth. The stress concentration tends to cause nucleation of dislocations below the indentation surface. When the graphene is ruptured, the elastic recovery to some extent occurs in the deformed substrate. This work sheds light on modifying the mechanical properties of metal/graphene composites by tuning the overlapping boundary of graphene.
通过分子动力学模拟研究了镍/石墨烯纳米复合材料在纳米压痕下的断裂机制和力学响应。我们分析了重叠面积对微观结构转变、六方密堆积（HCP）原子分数、位错密度、载荷-位移关系和应力分布的影响。结果发现，嵌入石墨烯的最大压痕深度与重叠面积呈非线性依赖关系，并且在与压头直径相当的重叠宽度处会变小。在初始阶段，石墨烯层能够阻碍位错向镍基体内部扩展。随着压痕深度的增加，复合材料中HCP原子和位错的密度逐渐增大。应力集中倾向于在压痕表面下方引起位错形核。当石墨烯破裂时，变形的基体在一定程度上会发生弹性恢复。这项工作为通过调整石墨烯的重叠边界来改善金属/石墨烯复合材料的力学性能提供了思路。
