Preparation Of Graphene/Al Composites And Investigation Of Mechanical Properties

Graphene is an ideal reinforcement for composite materials because of its high fracture strength.While the investigation of the metal matrix composites reinforced by graphene still needs a lot of experimental support.In addition,at present,the investigation of the metal powder for laser 3D printing is not enough.Based on this background,the composite powder is prepared with the graphene oxide(GO)by the improved Hummers and the Al powder modified by the PVA.The GNS(graphene nanosheets)/Al composites was prepared by three different methods,cold pressing sintering(CPS),spark plasma sintering(SPS)and laser 3D printing.Effects of the three different shaping methods on the density and mechanical properties of the composites were studied.Optical microscopy(OM),laser scanning confocal microscope(LSCM),scanning electron microscope(SEM)with EDS analysis,X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)were used to characterize and analysis the composites.Conclusions were drawn as follows:(1)The GNSs were all distributed uniformly in the GNS/Al composites prepared by all the three methods,CPS,SPS and laser 3D printing methods.The interface bonding between the GNSs and Al matrix is good,and there is no agglomeration of the GNSs in the composites and there is no brittle phase of Al4C3 formed in the composites.(2)There still some unreduced GO remains in the GNS/Al composites which is prepared by CPS shaping method,but the GO in the GNS/AI cornposites prepared by SPS can be reduced well.(3)When the additive amount of the GO is 0.3 wt%,the density of the GNS/Al composites is highest,and the density of the composite prepared by SPS and CPS methods are 95.4%and 92.1%,respectively.(4)With the 0.3 wt%additive amount of GO,the microhardness of the composites prepared by CPS,SPS and laser 3D printing technics is 22.01 HV,22.39 HV and 77.5HV,respectively.The compressive yield strength and ultimate strength of the composites prepared by SPS method are 62.7 MPa and 79.9 MPa,respectively.