SiC Whiskers and Particles Reinforced Al2O3 Matrix Composites and N2-HIP Post-Treatment

摘要

The dispersion processing of SiC whisker and particle and the mechanical properties of SiC particle and/or whisker reinforced AlzO3 composites were studied. With electrostatic repulsion and steric interaction methods, SiC whisker and particle were dispersed homogeneously in Al2O3 matrix and the flexure strength and fracture toughness of hot pressed SiCw-Al2O3 composite were up to 836 MPa and 8.1 MPa.m~1/2, respectively. The hot-pressed SiC-Al2O3 composites were futher Nz- HIP post-treated. The fiexural strength of N2-HIP post-treated SiC-Al2O3 composite was improved about 37-46 and the flexural strength of 1030 MPa was obtained. SEM and XRD analysis indicated that the nitnding reaction took place only on the surface of samples and the microstructure was improved. The grain size of surface reaction layer changed from about 2.0 pin to 0.5 mu m Finally, the strengthening mechanisms of the Nz-HIP post-treatment were discussed.