MECHANICAL-BEHAVIOR OF ALUMINA SILICON-CARBIDE NANOCOMPOSITES

The fracture behavior of Al2O3 containing 5 vol % 0.15 mum SiC particles was investigated using indentation techniques. A significant increase in strength was achieved by the addition of SiC particles to the base Al2O3. Specifically, the strength increased from 560 MPa for Al2O3 to 760 MPa for the composite samples (average values for unindented hot-pressed bars tested in four-point bending). After annealing for 2 h at 1300-degrees-C, the average strength of the composite samples increased to about 1000 MPa. Toughness was estimated using indentation-strength data. While there was a slight increase in toughness, the increase was not sufficient to account for the increase in the unindented strength on SiC particle addition. It is suggested that the observed strengthening and apparent toughening were due to a machining-induced compressive surface stress.