Research On Microstructure And Properties Of SiCp/6061Al Composites Sintered By High Pressure

High sintering method was used to fabricate SiC particle reinforced 6061Al matrix composites in this study,and two kinds of granularity of micron and nanometer were used as the reinforcement.The effect of SiC particle volume fraction,sintering pressure and sintering temperature on the microstructure and properties had been investigated.The main results are as follows:1)The SiC particles show uniform distribution phenomenon by mixed powder technology of nano-Al cladding micron SiC particles.Sintering pressure and temperature can promote the particles re-arrangement of SiC particles and improve the dispersion uniformity,reduce agglomeration phenomenon.2)The result of XRD diffraction of micron SiCp/Al composites shows that interdiffusion of Al and Si element is observed by linear scanning on boundary transition layer when the temperature is 600?,Al₄C₃ phase appears,which illustrates that a interfacial reaction between SiC particles and Al matrix happened at high temperature.3)The density,electric conductivity of micron and nano sized SiCp/Al composites decrease with increasing the volume fraction of SiC particles,while the hardness of composites increases with increasing the volume fraction of SiC particles,which can increases wear property.The wear property of micron SiCp/Al composites is better than nano-SiCp/Al composites.The wear mechanism of micron SiCp/Al composites is main abrasive wear and delamination wear,while the mechanism of nano-SiCp/Al composites is main fatigue wear.Baceuse the SiC particle is very small,formed abrasive dust can not cut the surface easily.4)For micron SiCp/Al composites,increasing the sintering pressure can improve dispersion of SiC particle,increase the density and hardness of composites.When the sintering pressure is 5.2GPa,micron SiC particles fracture during the sintering process,fractured SiC particles would become cracks in friction and wear process,which reduces wear property.5)The density,hardness and wear property first increase and then decrease of micron SiCp/Al composites with the sintering temperature increasing because of a slight agglomeration phenomenon of SiC particles appears at the sinering temperature of650?and 750?.The wear property of macron SiCp/Al composites is best at sintering temperature of 600?,just some slight spalling and shollow scratches appear.While the density of nano-SiCp/Al composites increases with the sintering temperature increasing.When the temperature is 650?,Al₄C₃ phase reduces the hardness and wear property of nano-SiCp/Al composites because of the interface bonding strength reduced by Al₄C₃phase.