Ceramic body reinforced with coarse silicon carbide whiskers and method for making the same

A ceramic composite comprising:

• a substrate wherein the substrate comprises a ceramic matrix and coarse silicon carbide whiskers:
• the ceramic matrix comprising between about 50 volume percent and about 99 volume percent of the substrate, and the coarse silicon carbide whiskers comprising between about 1 volume percent and about 50 volume percent of the substrate;
• the ceramic substrate having a fracture toughness (KIC) between about 4.0 MPam1/2 and about 8.0 MPam1/2;
• and
• the substrate having a silicon carbide whisker density as measured in silicon carbide whiskers per square millimeter equal to or less than about 1500 times the volume percent of silicon carbide whiskers, but in a density sufficient for the ceramic substrate to have the fracture toughness.

A ceramic cutting tool comprising:

• a ceramic composite having a rake face and a flank face, the rake face and the flank face intersect to form a cutting edge;
• the ceramic composite is made by compacting a starting powder blend comprising:
• between about 50 volume percent and about 99 volume percent of a ceramic matrix, and between about 1 volume percent and about 50 volume percent coarse silicon carbide whiskers,
• the ceramic composite having a fracture toughness (KIC) of greater than about 4.0 MPam1/2, and
• the ceramic composite having a silicon carbide whisker density corresponding to the content of the silicon carbide whiskets equal to or less than the value as represented by the line A-B of FIG. 8, but in a density sufficient for the ceramic composite to have the fracture toughness.