Fractographic Analysis of Machining Cracks in Silicon Nitride Rods and Bars

G. D. Quinn, L K. Ives, S. Jahanmir, and P. Koshy, “Fractographic Analysis of Machining Cracks in Silicon Nitride Rods and Bars,” Fourth International Conference on the Fractography of Glasses and Ceramics IV, Alfred University, July 2000, Ceramic Transactions, American Ceramic Society, Westerville, OH.

A new fixture for flexural strength testing was used to evaluate the effects of machining on the flexural strength of a toughened sintered reaction-bonded silicon nitride. Different grinding procedures had various effects upon the flexure strength distributions. These effects were directly related to the size and severity of fractographically-measured machining cracks. Under certain conditions, grinding caused negligible damage and the specimens fractured from intrinsic material flaws.