Study On Preparation And Properties Of (SiC_p+Gr_p)/Cu Composites

Composite materials of SiCp/Cu, Grp/Cu and (SiCp+Grp)/Cu were prepared respectively by powder metallurgy. The microstructure, thermal expansion, thermal conductivity, electrical conductivity, bending strength and wear resistance of composites are investigated using variety of instruments, such as optical microscope, scanning electron microscopy, transmission electron microscopy, thermal expansion analyzer, thermal conductivity testers, eddy current conductivity meter, universal testing machine and the friction and wear testing machine. The relationships between microstructure and performance were analysed.The results show that reinforced particle is distributed uniform and microstructure more denser in the matrix of composite materials using powder metallurgy technology. The density of composite materials were incressed by the second pressure and the second burning.The density, thermal conductivity and electrical conductivity of composite materials are decrease with the increasing of particle reinforced volume fraction. Re-sintered conductivity of the composite 8.1% on average, after sintering than a sintered density could be increased by 5.1% on average.One of the same volume fraction of Grp or SiCp enhanced the conductivity of copper composite is same or less. Increase the volume fraction of reinforcement particles can effectively reduce the coefficient of thermal expansion of composite materials. Performance of different ceramic and Grp reinforcement SiCp particulate reinforced metal matrix mixing, the most common physical properties of (SiCp + Grp)/Cu composites between the same volume fraction of SiCp/Cu and Grp/Cu composites due to their role.Hardness and bending strength of Grp/Cu composite are drastically decrease with increase the content of Grp. Weakening of the trend becomes weaker when the Grp particle volume fraction more than 10%. The hardness of the matrix Cu are significantly increased by add SiCp, SiCp/Cu composite hardness and bending strength with increasing volume fraction of SiC particles increases, SiC content is greater than 15% of the hardness increasing trend after the change relatively flat.However, the hardness and bending strength of (SiCp + Grp)/ Cu composites are in between the same volume fraction of SiCp or Grp single-reinforced composites.The friction properties of SiCp/Cu composite material turned into optimize with the SiCp volume fraction increase. The friction properties of Grp/Cu composite material turned into optimize with the SiCp volume fraction increasein in 10%, it turn into decrease however volume fraction exceed 10%. The friction property of xSiCp+yGrp/Cu composite material was better than SiCp/Cu and Grp/Cu composite material. In this experimental conditions,due to carrying role of SiCp particles and good solid lubrication of graphite, the composite of (10% Grp +20% SiCp)/Cu has better friction and wear characteristics than others.