Preparation And Mechanical Properties Of Graphene Reinforced Aluminum Composites

Graphene is a two-dimensional (2D) material, have the excellent physical andmechanical properices, is considered to be the ideal reinforcement for metal matrixcomposite(MMC). However, graphene is very easy to aggregation in the metalmatrix, has become the key to the development of graphene reinforced metal matrixcomposites. Therefore to seek a new preparation technology is crucial to thedevelopment of graphene reinforced metal matrix composites. In this paper, graphenereinforced aluminum matrix composite were fabricated for the first time through theelectrostatic self-assembly and hot pressing. In this way make the graphene evenlydispersed in the aluminum matrix. Furthermore, the fabrication process and structure,properties, interfacial bonding of graphene reinforce Al composites were discussed.In this work, we preparation of graphene oxide(GO) with Hummers method, andthen added to the treated with cationic surface active agent of positive chargealuminum powder with electrostatic self-assembly, use charge attract to makegraphene oxide uniform adsorption on the surface of aluminum powder, then usinghot pressing preparation of graphene reinforced aluminum matrix composite. TheGO and composite were characterized by, metallographic microscope (OM), X-raydiffraction(XRD) and scanning electronmicroscopy (SEM) and other methods werestudied to the dispered of graphene and the structure, mechanical properties ofcomposite with different surfactant and graphene contents.That graphite has been effectively stripped and has less layers of graphene oxide.The graphene oxide mainly exist such as hydroxyl, carboxyl and carbonyl groups,these groups make graphene oxide has a strong negative charge and graphene oxideevenly dispersed on the surface of aluminum powder, with no obvious phenomenonof aggregation.The surfactant content not only has an important influence on graphene oxide dispersion, but also affected the mechanical properties of composite material. Whenthe surfactant concentration is5wt.%in the microstructure of the composite isobviously thicker carbon layer, prevent the combination between aluminum powders.Compare with surfactant is1wt.%，the tensile strength decline50%， hardnesshaved a little increase.Composite hardness and tensile strength first increase then decrease withincreasing content of graphene. When the content of graphene reached0.3wt.%ofcomposite achieve the best performance, compared to the pure aluminium the tensilestrength increased by21%, the hardness increased by30%. The fracturemorphology of the composite material analysis found that the main show a brittlefracture and ductile fracture characteristics, the elongation decreased obviously.Graphene are mainly distributed in the border of the composite, see the phenomenonof pull out and fracture state.