Thermal shock behavior of iron-particle-toughened alumina

The thermal shock behavior of an alumina monolith and two alumina-iron cera mic-matrix composites has been investigated by superimposing the measured K -R-curves of the materials onto the theoretically generated curves of the t hermally induced stress intensity factor. Predictions of the critical-tempe rature differentials and retained strengths after quenching are in good agr eement with the experimental data. The inclusion of metallic particles into an alumina matrix improves the thermal shock resistance, although the incr ease in toughness is not solely responsible for this improvement. There is a decrease in thermal stress-intensity factor that is generated for the com posites; this decrease is due to a reduction in the Young's modulus and/or Plot modulus. However, the increased toughness for large crack lengths may offer increased damage resistance for severe thermal shock treatments.