Study On Process And Performance Of Graphene-Aluminum Base Composite By Laser Deposition

With the development of aerospace and other national defense science and technology industries,the development and research on the properties of aluminum matrix composites have attracted more and more attention.Aluminum matrix composites are strategic materials which are widely used at present.As the unique structure and properties of the reinforcing phase itself and its bonding with the interface of the aluminum matrix affect the comprehensive properties of the composites,the properties of the aluminum alloy can be improved by reinforcing phase.Graphene is not only a special SP2 hybrid orbital connection structure,but also a 2D nano-material with a thickness of 0.34 nm,which is very suitable for use as reinforcement phase.Laser deposition manufacturing is a new technology which can form three-dimensional structure parts near net directly from digital model.This process can improve the shortcomings of traditional processing technology,and can provide an effective way of short cycle,low cost and high quality for the preparation of graphene-aluminum matrix composites.In this paper,graphene/Scalmalloy(new high-strength aluminum-magnesium alloy)aluminum-based composite powders were prepared by using expanded graphene nanosheet as reinforcement phase and optimizing the low-temperature vacuum wet ball milling process.The morphology and reflectivity of the powders were studied.The laser deposition process parameters were optimized by orthogonal experiments,Scalmalloy and composite samples were prepared,and the effect of expanded graphene content on the microstructure and mechanical properties of the Scalmalloy composite was analyzed,and the strengthening mechanism of graphene was further clarified.Composite powders and samples were characterized by scanning electron microscopy(SEM)and X-ray diffractometer(XRD).The characterization results show that the sphericity and reflectivity of the composite powder meet the requirements.With the increase of the expanded graphene content,the test found that the mechanical properties of the composites first increased and then decreased.When the mass fraction of expanded graphene is 0.1 wt.%,the hardness of the tested composites can reach 138.1(HV0.2),the tensile strength can reach 422.5 MPa,and the yield strength can reach 340.1 MPa without reducing the elongation.Compared with Scalmalloy matrix,hardness,tensile strength and yield strength are increased by 24.6%,10.7%and 8.4%.