【作者】 李占杰；

【导师】 房丰洲；

【作者基本信息】 天津大学 ， 机械制造及其自动化， 2013， 博士

【摘要】 为解决单晶金刚石切削黑色金属时产生严重磨损这一制造领域难题，本研究在综述国内外研究现状的基础上提出一套综合解决方案，即采用表面改性、研究新的可金刚石切削模具材料及超声振动辅助切削相结合的方法，以求实用化并推广扩展到其他难加工材料的超精密加工，例如碳化钨材料的高精高效加工。主要研究工作和成果有如下几个方面：(1)深入研究了表面改性方法，探索了部分新元素对金刚石可切削性的影响，结果表明：N元素有助于减少刀具磨损提高刀具寿命，N、Si和Al元素有助于获得光学级质量的表面，而B元素对钢铁材料的金刚石可加工性起负面作用，这些有益的探索为开发新材料提供了依据；(2)探索了深层渗氮工艺并对渗氮后的纯铁进行了金刚石可切削性实验，结果表明：氮化铁物质本身具有被单晶金刚石加工出镜面质量的潜质；(3)提出了整体单相可控氮化铁粉末冶金钢这一新型模具材料，初步切削实验已经证明了其具有较好的金刚石可切削性，此新材料的研制有望进一步揭示表面改性方法减少金刚石刀具磨损的机理；(4)借助分子动力学仿真重点研究了水基切削液和超声振动切削的分离特性对金刚石刀具磨损和工件表面质量的影响，为研制超声振动辅助切削系统提供了依据；(5)用研制的新型超声振动辅助切削系统进行了STAVAX模具钢切削实验，研究了工艺参数对单晶金刚石刀具磨损的影响，以及对不同轮廓形状（平面、凹/凸曲面及非球面）和不同尺寸大小的工件表面质量的影响，通过切削实验确定出了最优工艺参数，使工件表面粗糙度达到10nm以内同时对金刚石刀具磨损起到了有效抑制作用，刀具寿命显著延长；(6)对研制的超声振动辅助切削系统进行了可加工材料的扩展研究，初步对碳化钨材料进行超声振动切削并获得了10nm以内的表面粗糙度，并针对碳化钨材料的硬脆性对金刚石刀具磨损的影响，提出了负前角倾斜超声振动切削方法。更多还原

【Abstract】 Diamond tools are subject to catastrophic wear in conventionally machiningferrous metals. In order to reduce wear, an integral solution was proposed in thisdissertation, i.e., the combination of surface modification, development of novelsuitable-for-diamond-cutting material and ultrasonic vibration assisted cutting.Extended investigation was also conducted on tungsten carbide, an ideal moldmaterial for precision glass molding by using the developed ultrasonic vibrationcutting system. The main research works and conclusions are summarized as follows:1. Workpiece surface modifications were further studied by investigating newpenetrated elements. It is found that N is beneficial to improve the tool life; N, Siand Al may help to obtain an optical quality surface; B plays the negative role indiamond machinability of steels. This would be useful for developing novelsuitable-for-diamond-cutting materials on which nanometric surface finish can beachieved.2. Deeper nitriding process was explored and the diamond turnability of nitridedpure iron was conducted. It is found that the compound layer of Fe2-3N and Fe4Nhas the potential to be diamond machined to a mirrorlike surface.3. A novel material, powder-sintered FexN (or compounded with some otherelements like aluminum to reduce pores), was proposed on which nanometricsurface quality can be obtained by diamond cutting.4. Molecular dynamics simulation was used to investigate the physical effect ofwater as lubricant and the effect of separation duration of ultrasonic vibrationcutting on diamond tool wear and surface quality.5. The diamond turnability of STAVAX stainless steel was investigated by using thenovel developed ultrasonic vibration cutting system. The effects of processparameters on diamond tool wear and surface quality of the workpieces withdifferent profiles and dimensions were investigated and surface roughness within10nm with no clear tool wear was obtained by using the optimal parameters.6. Extended investigation was also conducted on tungsten carbide by using thedeveloped ultrasonic vibration cutting system. Surface roughness within10nmwas obtained but with some abrasive wear and microchipping in the diamond tool.To solve the problem, an inclined ultrasonic vibration cutting with negative rake angle was put forward.更多还原