Effect of Gr content and hot extrusion on tensile properties of (Nano-SiCp+Gr)/Cu composites fabricated by powder metallurgy

Novel hybrid Cu matrix composites reinforced by graphite (Gr) particle with volume fraction of 5% - 15% and nano-SiC particle (nano-SiCp) with volume fraction of 3% have been prepared by powder metallurgy. The results show that Gr and nano-SiCp distribute uniformly in the Cu matrix. With increasing the volume fraction of Gr, the tensile strength of the composites decreases from 114 to 51 MPa and the elastic modulus decreases from 75 to 60 GPa. Compared with the sintered composites, the tensile properties including elastic modulus, tensile strength, yield strength and tensile elongation of the hot-extruded (nano-SiCp+Gr)/Cu composites are improved greatly due to higher relative density of the composites and more uniform distribution of Gr and nano-SiCp, in addition to finer grain size of the matrix as a result of dynamic recovery and recrystallization which occur during hot extrusion process.