Papers
Mechanical Properties and Contact Damages of Nanostructured Silicon Carbide Ceramics
2007 Volume 115 Issue 1341 Pages 304-309
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2007 Volume 115 Issue 1341 Pages 304-309
Three types of nanostructured silicon carbide ceramics were prepared with additives of Al2O3 and Y2O3 as the primary sintering additives, together with 1 mass% CaO, 1 mass% MgO or 0.73 mass% AlN. The silicon carbides (SiC) containing tens of nanometers of grains were successfully fabricated using a two-step sintering process. The mechanical properties and contact damages of the nanostructured SiC ceramics were investigated in this study. The nanostructured SiC ceramics exhibited a hardness of~20 GPa, a strength of 400-700 MPa, and a toughness of 3.0 MPa•m1/2. The nature of the contact damage exhibited classical ring or cone cracks formed in a region of weak tension outside the contact rather than microcracks in the diffuse quasi-plastic zones as observed in heterogeneous microstructures consisting of micron-sized elongated grains.
