ELECTRO-DISCHARGE MACHINING OF TRANSFORMATION TOUGHENED ZrO - NbC CERAMIC COMPOSITE

Publisher Website
Google Scholar
Abstract
Electroconductive transformation toughened ZrO2 and NbC ceramic composite was machined with an electro-discharge machining (EDM) method. Effects of EDM conditions on roughness of machined surfaces were examined. Surface damage caused during machining was evaluated with flexural strength of machined specimens. Fracture surfaces of EDMed bending specimens were observed by scanning electron microscopy (SEM). It was observed that the strength of EDMed members was decreased with increases in pulse current, pulse duration and duty factor. Pulse duration and pulse current had a great influence on the roughness of machined surfaces. When the pulse duration was large enough, noticeable delaraination in the surface layer occurred. The highest flexural strength of an EDMed specimen attained was about 1 GPa. The X-ray diffraction patterns of surface layers were changed by machining.