Microstructure And Mechanical Properties Of SiC/Al Laminated Composite Fabricated By Surface Spraying Assisted Rolling

Metal matrix composites have the advantages of high specific strength,wear resistance,electrical conductivity,thermal conductivity and low expansion rate.It is widely used in aerospace,electronics and devices.With the development of science and technology,the traditional metal matrix composites can no longer meet the higher performance requirements.By learning from the microstructure of biomaterials and adjusting the composite configuration of synergistic and coupling effects between different components in the composite,it is more conducive to explore the performance potential of metal matrix composites.Therefore,through the design of composite configuration composites,SiC/Al laminated composites were prepared by hot rolling,and the microstructure and properties of the laminated composites were analyzed,in order to provide theoretical guidance and experimental basis for the development of preparation methods and performance characteristics of aluminum base composite.In this thesis,with the aid of surface spraying of mixed slurry of silica sol carrying SiC reinforcement,SiC/Al laminated composites were prepared by hot rolling method,and the microstructure and mechanical properties were studied.Meanwhile,the preparation process was optimized,so as to explore the influence of layered structure and reinforcement shape on the microstructure,phase and mechanical properties of laminated composites.The elongation of composite plate decreased from 8.4%to 4.2%.The results show that SiC particles are evenly distributed along the interlayer of aluminum foil,and the surface of SiC particles is covered with Si O₂.The coating of silica sol can make SiC particles adhere to the surface of aluminum foil substrate,at the same time,it can achieve better spreading and good interface bonding under the effect of normal rolling force.The introduction of SiC particles makes the grain size of aluminum foil substrate layer more refined and uniform,and improves the tensile strength of SiC/Al laminated composites.The fracture behavior includes ductile fracture and interlayer debonding tearing of single-phase aluminum foil substrate layer,in which interlayer debonding has a negative effect on the toughness of aluminum substrate and reduces the elongation of the composites.The mechanical properties of SiC/Al laminated composites are greatly affected by the way of lamination.In the case of equal thickness.In the same thickness layer structure,the increase of the number of layers will affect the normal rolling force at the interface,so that the particles between the layers can not be well spread,the interlayer bonding force is weak,and the tensile strength decreases from 154mpa to 126mpa;For the alternate layer structure with different thickness,the combination of thin layer and thick layer is good.The existence of thin layer makes the elongation of laminated composite increase from 5.4%to 7.1%with less loss of tensile strength（about 12 MPa）.The microstructure,phase distribution,mechanical properties and fracture behavior of SiC/Al composites with different reinforcements are similar.As SiC whiskers are easy to wind during spraying and rolling,they exist in lamellar composites in the form of large-size clusters,which can reduce the tensile strength of the composite plate.