Abstract Silicon nitride–titanium nitride (Si3N4–TiN) ceramic composite was machined by wire-electro discharge machining (WEDM) to characterize the surface integrity and to investigate its effect on fatigue performance. Dry sliding wear behaviour of Si3N4–TiN sliding against EN32 steel was also tested. The polished and machined surfaces were examined for finding the hardness. The wire-EDM cut surface was examined with scanning electron microscope (SEM) for obtaining its microstructure. The wire-EDM of silicon nitride–titanium nitride produced a rough recast surface with different types of defects like micro-cracks, micro-pores, globules, droplets and surface craters. The material deposition to work specimen after machining was scrutinized by EDAX composition analyzer. The polished surface and wire-EDM cut surface were examined for determining the fatigue performance and it was observed that a deficiency of 25–35% in fatigue life in wire-EDM cut surface than that of the polished surface. Also, the wire-EDM cut surface exerts very high tensile residual stress compared to the polished surface. From the results, it is evident that the polished surface exhibits better surface finish and fatigue life, higher wear resistance and micro-hardness than that of the machined surface.

中文翻译：

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Si3N4–TiN 电火花加工后的表面完整性、疲劳性能和干滑动磨损行为

摘要 氮化硅-氮化钛 (Si3N4-TiN) 陶瓷复合材料通过线电火花加工 (WEDM) 进行加工，以表征表面完整性并研究其对疲劳性能的影响。还测试了 Si3N4-TiN 与 EN32 钢滑动的干滑动磨损行为。检查抛光和机加工表面以确定硬度。用扫描电子显微镜 (SEM) 检查电火花线切割表面以获得其微观结构。氮化硅-氮化钛的线切割产生了粗糙的重铸表面，具有不同类型的缺陷，如微裂纹、微孔、小球、液滴和表面凹坑。通过EDAX成分分析仪仔细检查加工后工件样品的材料沉积。检查抛光表面和电火花线切割表面以确定疲劳性能，观察到电火花线切割表面的疲劳寿命比抛光表面的疲劳寿命短 25-35%。此外，与抛光表面相比，电火花线切割表面会产生非常高的拉伸残余应力。结果表明，抛光表面比机械加工表面具有更好的表面光洁度和疲劳寿命，更高的耐磨性和显微硬度。