Molecular-Level Insights into Reinforcement Effects and Interface Chemistry in Graphene/Nickel Nanocomposites under Tension—A Molecular Dynamics Study

This study presents a comprehensive investigation of the uniaxial tensile behavior of graphene-reinforced nickel nanocomposites (Gr/Ni) using molecular dynamics (MD) simulations. Two distinct reinforcement architectures were examined: (1) a monolayer graphene sheet embedded within the nickel matrix (denoted NiGr[−], ~0.66 vol%) and (2) a cross-shaped graphene network (denoted NiGr[×], ~1.0 vol%). The mechanical response was evaluated under uniaxial tensile loading along the z-axis, considering three crystallographic interface orientations between graphene and nickel: (100), (110), and (111).

The incorporation of graphene significantly enhances the mechanical performance of the nickel matrix, particularly in terms of stiffness, strength, and ductility. Specifically, the Young’s modulus increased by approximately 123% in the NiGr[−] configuration, while the NiGr[×] network further improved stiffness by 135%, 154%, and 143% for the (100), (110), and (111) orientations, respectively. Similarly, the ultimate tensile strength (UTS) increased by 0.47 GPa, 3.61 GPa, and 4.97 GPa in the NiGr[−] system and by 1.84 GPa, 6.24 GPa, and 10.62 GPa in the NiGr[×] system for the same orientations.

The analysis revealed that the NiGr[×] configuration, particularly in the (110) and (111) orientations, exhibits the most pronounced reinforcement effects. Dislocation density mapping during deformation demonstrated that graphene acts as an effective barrier to dislocation propagation. Remarkably, the NiGr[×] structure enabled the composite to sustain a strain level exceeding that of pure nickel by more than five times before failure.

These findings highlight the superior load-bearing capacity and enhanced structural integrity of Gr/Ni nanocomposites, with the cross-shaped graphene network offering exceptional mechanical advantages. The results suggest significant potential for such architectures in advanced engineering applications, particularly in industries requiring high-performance structural materials.