Factors Affecting Thermal Stress Resistance of Ceramic Materials

ing from temperature gradients in a cylinder were derived by Duhamel (1838).‘ Since that time, about thirty papers have appeared which mainly consider the calculation of thermal stresses in an infinite cylinder subjected to temperature gradients. It is apparent that thermal stresses are not a new or uninvestigated phenomenon. The first quantitative treatment of thermal stress fracture in ceramic materials was prepared by Winkelrnann and Schott (1894).2 Hovestadt and Everhart (1902)3 gave a correct solution for the case of infinitely rapid cooling. A number of investigators considered testing methods for glasses and for refractories and their correlation with service results. Norton ( 1926)4 studied the problem and first suggested that shear stresses must be considered as well as tensile stresses. More recently, several investigators, particularly those interested in special refractory applications, have considered the problem of thermal stresses from both theoretical and experimental points of view. New attempts have been made to define and to measure a material property which can be called “resistance to thermal stresses.” Although these attempts have not been completely successful in a quantitative way, they have led to a much improved understanding of the factors that contribute to thermal stress resistance. It is the purpose of the present paper to consider these factors and their effect on thermal stress resistance. T hundred years ago equations for the thermal stresses aris-