Effect of graphene on the interfacial and mechanical properties of hybrid glass/Kevlar fiber metal laminates

Abstract

The remarkable resurgence of fiber metal laminates (FMLs) is certainly attributed to the hybrid properties inherent to light metals and fibers reinforced polymer (FRP). There are few reports on the role of nano-size reinforcements in these composites. In this study, the effect of graphene nanoplatelets (GNPs) on the flexural and Charpy impact properties of FMLs of aluminum (Al) 2024 reinforced with hybrid glass/Kevlar fibers-epoxy was investigated. Different wt.% of GNPs (0.0, 0.1, 0.25 and 0.5) and hand lay-up method were used to fabricate nano-FMLs followed by evaluating them in three-point bend and Charpy impact tests. Before making the FMLs, the surfaces of Al sheets were modified to generate surface pores/nano-pores in order to improve the interfacial bonding within the FMLs layers. The FMLs containing 0.1 wt.% GNPs exhibited 10%, 9% and 11% improvement in flexural strength and modulus and impact strength, respectively, compared to the FMLs containing 0.0 wt.% GNPs. Increase of the GNPs to 0.25 wt.% caused a reduction of the flexural strength and modulus and impact strength values; 13.7%, 3% and 25.5% compared to the samples without GNPs. Also increase of the GNPs to 0.5 wt.% decreased these properties to 31.3%, 8.8% and 29.5%. Scanning electron microscopy (SEM) observations of their fracture surfaces showed better adhesion at both polymer/fibers (within the FRP) and Al/FRP interfaces. However, at higher wt.% of GNPs, the FMLs became weaker and more brittle. Agglomerated GNPs at the Al/FRP interface penetrated/filled the surface pores/nano-pores on the Al surfaces. Therefore prevent the polymer penetration in pores, resulting in weak interfacial bond and thus overall weaker and less ductile FMLs. As a result, the Charpy impact values for the 0.25 and 0.5 wt.% GNPs samples were respectively 33 and 37 percent smaller than that for the 0.1 wt.% GNPs sample.

Experimental investigation of quasi-static behavior of composite and fiber metal laminate panels modified by graphene nanoplatelets

“…28 The GNPs, as one of the most widely used nanoplatelets, have been able to enhance the properties and strength of composite specimens. [29][30][31][32][33][34][35] Significant improvements in strength, fracture toughness, and fatigue strength have been reported using graphene as fillers or reinforcements in nanocomposites. 36 Domun et al 32 incorporated GNPs at concentrations of 0.1, 0.25, 0.5, 0.75, and 1 wt% into epoxy resin and stated that maximum stiffness and fracture toughness at 0.25 wt% were increased by 5.6% and 51.2%, respectively.…”

“…They indicated that adding 0.2 wt% of GNPs increased 42%, 32.5%, and 16.8% ultimate tensile strength, Young’s modulus, and compressive strength, respectively. Moreover, Abbandanak et al 34 reported incorporation of GNPs improved flexural and Charpy impact properties of FMLs.…”

Mechanical Characterization of Graphene—Hexagonal Boron Nitride-Based Kevlar–Carbon Hybrid Fabric Nanocomposites

“…It can be observed from the graphs that the hy based composites have a maximum flexural strength and maximum flexural mod The addition of hBN filler improved 30% of flexural strength in the hBH3 comp whereas an 85% of improvement in the flexural modulus of the hBH3 composite wa served. A high modulus indicates that the material is tougher [31] and the addition of content improved flexural strength and modulus due to the uniform dispersion of cles [32], resulting in good bonding strength between the fiber and matrix. Additio due to the large surface area of hBN particles, contact with the matrix enables load tra to the matrix and fibers [33].…”

“…From the figure, it can be noted that the addition of filler increased hardness up to an optimum value, beyond which a minor drop in hardness values in all composites was seen. A direct relationship between stiffness and modulus was established by [31], where the results were presented, following the criteria, and maximum modulus was observed at 0.3 wt.%. Indent images of graphene and hBN composites are shown in Figure 8c,d.…”

New Advances and Future Possibilities in Forming Technology of Hybrid Metal–Polymer Composites Used in Aerospace Applications

“…It was also found that both composites can be used as materials in the fire-designated zone. At the same time, investigations have been conducted on various nanofillers, including clay nanoparticles, graphene nanoplatelets, oxide nanoparticles, and carbon nanotubes, to improve the properties of FMLs [65][66][67].…”