DAMAGE-TOLERANT LAMINATED COMPOSITES IN THERMAL-SHOCK

Alumina is very susceptible to thermal shock which often leads to catastrophic failure. The addition of tape-cast nickel layers to laminated alumina can increase its tolerance to damage induced during thermal shock.The fracture behaviour after thermal shock of laminated composites showed non-catastrophic failure during loading at room temperature. The retained strength of the laminates was determined for a wide range of quenching-temperature differences (DELTAT = 150-1200-degrees-C). The retained strength and critical quenching-temperature difference, DELTAT(c), of the laminated composites were a significant improvement over the values for the respective monolithic alumina. This improvement in behaviour can be related to the compressive residual stress in the alumina layers and ductile-layer crack blunting.