Thermal Shock - An Interpretation of the Macroscopic Characteristic of Fracture

The following article describes the typical fracture characteristics observed in SSiC specimen after thermal shock experiments and correlation these qualitatively with the loading applied. The thermal shock was induced by rapidly heat thin discs of the material using a laser beam moving spirally outwards from the centre of the specimen disc. Using this method an increased temperature gradient was achieved beginning at the centre and progressing radially outward through the specimen. This temperature gravity ent therefore induced compressive stress within the specimen and tensile stresses in the cold edge region of the specimen. On reaching the critical failure stress, the specimen then fractured. In doing so the elastic energy stored within the specimen at this time was transformed partially in the formation of the cra surfaces. The relationship between this stored elastic energy and the pattern of fracture presented.