基于SEM在线纳米切削的加工极限及材料去除机理研究

The research of nano-cutting mechanism is the key of pushing forward the technology development of nano-manufacturing. The project will focus on the research of nano-cutting mechanism and its manufacturing integrity based on the focused energy beam technology (electron, ion, photon). The optimized design of the nano-cutting platform which is based on the dual beam system(FIB/SEM) will be conducted in the project. The key tasks, such as nanocutting online observations by SEM, manufacturing quality and the analysis of the integrity in-situ characterization, which exist in the progress of nano-cutting, will be researched in the project. Besides, the research of the technology of nano-manufacturing and microscopic characterization using the focused energy beam will be conducted for the research of the nano-cutting. The competitive and coordinated features among the tool edge, cutting specific energy and surface quality will be clarified to optimize and guide the manufacturing of the diamond tools for nano-cutting. The FIB original thinning and EBSD, Raman spectra of microscopic energy beam characterization techniques will be combined to explain the distribution of the subsurface damage, and the research of the recovery of surface damage by femtosecond laser will be conducted. Also, the exploratory research of improving the ultimate cutting ability will be conducted. The nano-cutting models of the diamond tools will be initially established by the way of combining the characterization analysis with theoretical simulation of the material modification of the edge pushing zone. The nano-cutting technology specifications and manufacturing strategy of improving the integrity of the nano-cutting will be explored to establish by the way of combining the focused energy beam technology with the ultra-precision cutting.

纳米切削材料去除机理和极限加工能力研究是推动纳米切削加工技术发展的关键，项目拟开展基于聚焦能量束（离子、电子、光子）技术的金刚石刀具纳米切削机理及其制造完整性的研究。建立聚焦离子束/扫描电镜(FIB/SEM)双束系统在线纳米切削及切削力在线检测平台，围绕纳米切削材料去除机理、极限切削能力、单晶硅纳米切削中金刚石刀具磨损抑制策略、加工亚表面相变和微裂纹等损伤分布规律及其有效修复方法等研究内容，深入开展聚焦能量束纳米制造及微观表征分析。结合FIB原位纳米减薄技术与EBSD、拉曼光谱等能量束微观表征技术，阐明纳米切削加工的亚表面损伤分布规律，开展亚表面损伤的飞秒激光修复研究。阐明刀具刃口锋锐度与加工质量的协同竞争机制，建立纳米切削材料去除模型、提高纳米切削制造完整性和极限加工能力的策略。项目的实施将有助于把特种加工三束技术与超精密加工技术有机融合，推动纳米切削技术和相关机理研究更好的发展。

纳米切削材料去除机理和极限加工能力研究是推动纳米切削加工技术发展的关键。碳化硅作为新型的半导体材料，相对于单晶硅的加工，其更高的硬脆性对金刚石纳米切削加工提出了更高的挑战。项目建立了聚焦离子束/扫描电镜(FIB/SEM)双束系统在线纳米切削及切削力在线检测平台，面向单晶硅、碳化硅等样品，开展了金刚石刀具的纳米切削机理、极限加工能力及制造完整性的相关基础研究。提出了SEM在线纳米切削的刀具二次电子阴影精密对刀方法，开展了刀杆刚度优化设计及SEM在线纳米切削加工的切削力提取方法。建立了聚焦离子束修形修锐金刚石刀具的加工方法和策略，实现了刃口半径大于15nm的金刚石刀具可控制备，实现了5nm切削厚度的单晶硅极限加工，切屑变形系数达到了2.5。随着切削厚度逐渐增大到刃口半径及以上，纳米切削的切屑变形系数稳定在1.5左右。开展了SEM在线观测、电子束背散射衍射EBSD和TEM分析等微观表征分析，研究了超快激光修复离子注入改性材料的相关基础研究，基于电子束背散射衍射菊池带衬度等研究了单晶硅纳米切削的残余应力、晶格转动和相变，阐明了刀具刃口锋锐度与加工质量的协同竞争机制，开展了SEM在线观测的单晶硅连续塑性切削加工，分析了连续切削的脆塑转变的物理机制。基于SEM在线观测、分子动力学MD仿真和拉曼光谱显微表征分析，阐明了单晶硅、碳化硅等典型硬脆材料纳米切削加工的材料去除机理，探究了单晶铜、单晶硅的金刚石刀具极限纳米切削加工能力，研究了离子注入辅助、应力辅助等提高碳化硅纳米切削加工能力的加工方法。项目的探索研究对系统建立硬脆材料纳米切削材料去除模型、建立提高纳米切削制造完整性和极限加工能力的加工策略具有重要价值。发表论文18篇，受邀成为SCI期刊JMES副主编，大会主席2次，共主席/分会主席2次，特邀报告8次，培养研究生15人。