THERMAL-SHOCK BEHAVIOR OF SILICON-NITRIDE FLEXURE BEAM SPECIMENS WITHINDENTATION CRACKS

The experimental results of thermal shock testing of silicon nitride f lexure beam specimens containing indentation cracks are presented. The thermal stress induced by water quenching is much greater in the tran sverse direction than in the longitudinal direction, resulting in an i nsensitivity of residual bend strength to temperature differences up t o 580-degrees-C. This result indicates that a flexure beam configurati on is not an appropriate geometry for thermal shock testing when therm al shock behavior is to be evaluated from residual bend strength data.