Research On Microstructure And Properties Of SiCp/6061Al Composites Prepared By Hot-pressed Sintering

SiCp/6061Al composites with single micron and nano-micron double scale particles were prepared by hot-pressed sintering in this paper.The microstructure and properties of the composites were studied in depth.The experimental results show that sintering temperature,Si C particle volume fraction,Si C particle size and heat treatment process have great influence on the structure and properties of the composites.Micro-SiCp/6061Al composites were prepared at different sintering temperatures,the results show that the diffusion distance between Al and Si elements increases,and the bonding strength between Si C and matrix increases with the increase of sintering temperature.The XRD result shows that the main phases are Al and Si C below 490 ?,but the Al4C3 phase is detected with the sintering temperature of 510 ?,indicating that the interface reaction occurs at this time,and the reasonable sintering temperature is 490 ?.Micro-SiCp/6061Al composites were prepared at 490 ?,the results show that with the increase of Si C particle volume fraction,the distribution uniformity of Si C particles and the density decrease,the microhardness increases,the tensile strength and wear resistance first increase and then decrease,and the elongation decreases.When the volume fraction of Si C particle is 30%,the wear resistance of the composite is the best and the tensile strength is the highest.30%SiCp/6061Al composites with different particle sizes were prepared.The results show that when the Si C particle size is 16 ?m,the distribution of Si C particles in the matrix is the most uniform,and the interface bonding and comprehensive properties are the best.The fracture modes are mainly interfacial tearing and Si C particle fracture,and the wear modes are mainly abrasive wear and slight adhesion wear.The structure and properties of nano-micron double scale SiCp/6061Al composites were studied.The result shows that the tensile strength and elongation of the composite are the highest when the volume fraction of nano-Si C particle is 0.8%.The result of solution treatment shows that the solubility of the second phase in the matrix increases with the increase of solution temperature.When the solution temperature is 530 ?,the Mg2 Si phase almost completely dissolved,and the structure and mechanical properties of the composite further improve.The result of aging treatment shows that the microhardness and tensile strength of the composite increase first and then decrease with the increase of aging time.When the aging time is 10 h,the microhardness and tensile strength are respectively 158.5 HV and 370 MPa,which reach the maximum.