Studying Thermal Shock Resistance of Ceramic Materials Based on Their Structural Sensitivity to a Stress Concentrator

A method for determining the thermal shock resistance of ceramic materials is proposed based on their structural sensitivity to a stress concentrator controlling fracture during thermal loading. For this purpose, a prismatic sample with a specially created notch (stress concentrator) was subjected to thermal cycling realized by heating it to 850°C and cooling with a water jet (20°C). The coolant was supplied to the notch apex of the heated sample (local thermal shock (LTS) technique). By using the LTS technique, the thermal shock resistance of the following 3 types of ceramic materials was studied: α-Al 2 O 3 (type 1), α-Al 2 O 3 – β-SiC whiskers (20 vol.%) (type 2) and t-ZrO 2 partially stabilized with Y 2 O 3 (3.5 mol.%) (type 3). Type 2 ceramics has the highest thermal shock resistance, type 3 ceramics—the lowest, and type 1 ceramics occupies an intermediate position among the studied materials, which is associated with the specifics of formation and distribution of thermal defects in the structure of these ceramic materials as a result of using the LTS technique. The advantage of the latter consists in an explicit reproducibility of the results of determining thermal shock resistance ( R T ) within the studied batch of samples (measurement accuracy 3 – 5%).