聚晶金刚石复合片非脆性去除磨削机理研究

Study of non-brittle removal mechanism in grinding of polycrystalline diamond compact

聚晶金刚石(polycrystalline diamond,PCD)的磨削是PCD刀具制造中的关键环节,磨削参数的变化影响PCD的去除方式,进而决定刀具的切削性能.通过扫描电镜观察分析腐蚀后的PCD磨削表面微观形貌,研究了金刚石砂轮磨削PCD中的刻划作用、滑擦作用和热化学反应等非脆性去除机理,及其与磨削参数的关系.结果表明:刻划作用仅在砂轮磨粒较锋利时产生作用,多存在于湿磨初期;砂轮磨钝后,滑擦作用和热化学反应是PCD的主要去除方式,且滑擦作用与热化学反应同时发生.通过设计一组特殊磨削试验,间接证明了磨削后的PCD表面存在由热化学反应产生的软化层.

Grinding of polycrystalline diamond （PCD） is an important process in PCD cutter manufacturing. The grinding parameters can strongly influence the removal form of PCD, and determine the performance of the cutting tool. Non-brittle removal mechanism of PCD including scoring effect, sliding effect and thermochemical reaction, as well as their relations with grinding parameters, are investigated by examining the surface micro-morphology of pre-etched PCD specimens using scanning electron microscopy. The experimental results indicate that scoring effect, which is functional in the initial stage of wet grinding, happens only when the wear particles of diamond wheel are sharp. On the contrary, sliding effect and thermochemical reaction, which happen simultaneously, are the main removal mechanisms when wear particles of diamond wheel are blunt. At last, a special group of grinding experiments are carried out and the existence of a softened layer caused by thermochemical reaction on the ground surface of PCD is confirmed indirectly.