Effect of Amorphous Phase on Mechanical Properties of SiC/Cu Composites

In this study, glassy phase is formed by SiO2-K2O addition to serve as amorphous grain boundary transition layer. SiC (SiO2-K2O) /Cu composite material were prepared by two-step coating method and hot pressing sintered below 770 degrees C, 30MPa for 1.5h, using alpha-SiC as main reinforced phase, SiO2-K2O as grain boundary and Cu as matrix. The Cu-SiC volume ratio was 75:25. The SiO2 contents were 5vol.%, 10vol.%, 15vol.%, 20vol.% and 25vol.% of the total volume of the SiC /Cu. XRD and SEM techniques were used to characterize the composite particles and the sintered compacts; Archimedes method, Vickers hardness tester, universal testing machine to test the apparent porosity of the composite materials, the Vickers hardness and the bending strength, respectively. The results showed that with increasing of glassy phase contents, the Vickers hardness and the bending strength first rise and then drop, at the same time, it shows the opposite tendency for the apparent porosity. The sintering samples with the SiO2 content of 15vol.% have the optimum mechanical properties, the Vickers hardness reached 1.49 GPa, and the bending strength was close to 235 MPa.