The Influence of the Defect Rate of Graphene on Its Reinforcing Capability Within High-Entropy Alloys

Graphene, a remarkable two-dimensional material, enhances the mechanical properties of high entropy alloys as a reinforcing phase. This study uses molecular dynamics to explore the influence of vacant defects in graphene on mechanical properties of alloys. By incorporating graphene with varying vacancy defects into FeNiCrCoCu high entropy alloys containing initial dislocations, tensile and compressive simulations were conducted. Simulation results indicate that graphene, serving as the reinforcing phase in high-entropy alloy (FeNiCrCoCu), experiences a reduction in strength and load-bearing capacity due to its vacancy defects. These defects result in premature failure during the initial stages of strain and diminish the elastic strengthening effect. However, even with defects, graphene retains the ability to enhance the flow stress post-yield. A small number of defects can effectively impede dislocation motion, thereby strengthening the alloy. Conversely, an excessive number of defects allows dislocations to penetrate through the graphene, weakening the strengthening effect. Research has revealed that a defect structure characterized by a homogeneous loss of up to 5% of carbon atoms can enhance both the toughness of graphene and the yield strain of the alloy. Beyond this critical threshold, however, structural stability diminishes, leading to a significant reduction in the strengthening effect.