Residual Stresses in Hot Pressed Si sub 3 N sub 4 Grooved by Single-Point Grinding

Hot pressed silicon nitride plates were grooved by single diamond points with varying degrees of flatness mounted on a wheel rotating at varying speeds. The plates were divided into bars and the remaining strengths were measured. The depths of damage were measured and used to calculate the theoretical strengths. The differences between the measured strengths and the theoretical strengths are attributed to the presence of residual loads acting to wedge open the cracks. 15 ref.--AA