Experimental and simulation analysis of the effect of GNPs on the mechanical and interfacial properties of CF/PEEK-Ti fiber metal laminates

In this study, graphene nanoplatelets (GNPs) were used to improve the interfacial and mechanical properties of carbon fibre-reinforced polyetheretherketone-based titanium alloy laminates (CF/PEEK-Ti) and molecular dy-namics (MD) simulations were used to investigate the mechanism by which GNPs improve CF/PEEK-Ti, collectively known as fibre reinforced metal laminates (FMLs). In addition, surface anodising of titanium (Ti) sheets was used further to enhance the interfacial bonding properties of the FMLs. The experimental results showed that the flexural and shear strengths of the anodised FMLs were increased by 77.7% and 29.5%, respectively, compared with those of the Ti plates without surface anodisation. Based on this, different levels (0-1.5 wt.%) of GNPs were added to the FMLs matrix, and test results showed that FMLs containing 0.5 wt.% GNPs had the best flexural and shear strengths, 108.9% and 130.8% higher than untreated FMLs without GNPs. In addition, an in-depth microscopic analysis was carried out to understand the enhancement mechanism of GNPs on FMLs. Finally, MD simulations were used to analyze the role and mechanism of GNPs in this system. The results show that the addition of GNPs can increase the interfacial energy of FMLs. In other words, the interfacial mechanical properties of FMLs are improved. The effect of the dispersion of GNPs on the interfacial properties of FMLs was also investigated. The polyetheretherketone (PEEK) matrix could be significantly improved by well-dispersed GNPs. These findings provide insight into designing high-performing composites for various engi-neering applications.