Effect of the electrical discharge machining on strength and reliability of TiN/Si3N4 composites

Conductive TiN/Si3N4 hot pressed composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity investigated. The dependence of surface texture, surface roughness, and materials removal rate on electrical discharge machining conditions including working voltage and feed rate were also analyzed. The flexural strength and strength reliability in terms of Weibull modulus of TiN/ Si3N4 processed by EDM and conventional cutting and polishing are compared. Higher working voltage and current, as well as higher content of TiN result in greater material removal rate. Comparison of the flexural strength and Weibull modulus of the composites processed by EDM with conventional polished samples revealed that the surface with low roughness lead to an increase in strength and reliability for electrical discharge machining.