刀具介观几何特征抗磨损机理及其对钛合金高速铣削表面完整性影响规律研究

Titanium alloy has excellent comprehensive performance, which is an ideal material for many industries such as aerospace，automobile and so on. But the application of titanium alloy has been suppressed to a great extent for its poor machinability. Breakthrough point of the project is meso-geometry feature of the cutting tool including surface micro-texture and cutting edge radius. The constitutive model of titanium alloy is established which is suitable for the simulation of high speed cutting process. According to research results of mechanical, thermal and wearing features of a new micro-texture ball-end mill embodied in a high speed cutting process, its wear mechanism is explained, the effect of meso-geometry feature on its wear properties are revealed with a quantitative description, and the hierarchical structure evaluation model is established at the same time. Based on surface features of the workpiece, a model is established for the evaluation of surface roughness. The mechanisms are explained which is about work hardening and residual stress. And the regularity is determined which is about surface integrity affected by meso-geometry feature of the cutting tool. The design criteria for meso-geometry feature of cutting tool are described, and process characteristics for the processing of cutting tool are analyzed. Optimization method for meso-geometry feature of the cutting tool is proposed, and the active control is realized which optimizes surface feature of high speed milling thin-walled titanium alloy workpiece and wear of the cutting tool.

钛合金具有优异的综合性能，是航空航天、汽车等行业的理想用材。但由于钛合金切削加工性能差，在很大程度上制约了它的应用。目前，突破刀具技术及切削工艺的限制，实现钛合金高效、高质量加工已成为先进制造技术研究领域内的热点问题。 本项目以刀具介观几何特征（表面微织构、切削刃口圆角半径）为切入点，建立了适用于高速切削过程模拟的钛合金本构模型；研究了新型微织构球头铣刀高速铣削过程中的力、热以及磨损特性，阐明了新型刀具的磨损机理，定量描述了介观几何特征对刀具磨损性能的影响，建立了其切削性能的系统递阶层次结构评价模型；研究了工件的表面特性，建立了工件表面粗糙度评价模型，论述了工件中加工硬化和残余应力的形成机理，确定了刀具介观几何特征对工件表面完整性的影响规律；阐述了刀具介观几何特征的设计准则，分析了其加工工艺特点；提出了刀具介观几何特征的优化方法，实现了钛合金薄壁件高速铣削表面特性及刀具磨损的主动控制。

为了提高刀具的耐磨性，突破刀具技术及切削工艺的限制，实现钛合金高效、高质量加工，本项目以硬质合金球头铣刀介观几何特征为切入点，结合钛合金高速铣削加工特点，研究了刀具介观几何特征抗磨损机理及其对钛合金高速铣削表面完整性影响规律。.研制了用于激光制备球头铣刀微织构的装置，优化了激光加工工艺参数，基于激光烧蚀性能和铣削实验，提出了微织构减摩机理，即微织构置入能减小前刀面实际刀-屑接触区长度，有效捕捉切屑磨粒，降低磨粒磨损，保护刀具，延长刀具寿命；通过有限元仿真和摩擦磨损实验分析了不同参数微织构置入对刀具抗磨减摩作用的影响规律；建立了刀具受力密度函数和热流密度函数，获得了钛合金铣削过程中热负荷与切削力共同作用下刀具的力-热耦合场，进一步揭示了刀具破损机理；基于钛合金铣削实验，分析了微织构参数及切削行程对已加工表面完整性的影响规律，建立了表面完整性预测模型；最后，通过钛合金铣削磨损仿真分析和试验研究，建立了刀具磨损预测模型，同时建立了以织构参数为设计变量，以刀具磨损最低、工件表面质量最优为目标函数的多目标优化模型，实现了球头铣刀介观几何特征的优化设计。.本研究为探讨介观几何特征对球头铣刀切削性能以及对钛合金表面质量的影响机制奠定了坚实的工作基础。同时对认识到微织构对刀具性能的影响提供了重要的启示性线索。项目资助已发表论文7篇，待发表4篇，其中SCIE和EI双检2篇，SCIE检索1篇，EI检索3篇，核心期刊4篇，会议论文1篇。撰写专著1部。获专利授权4项，其中发明专利1项，实用新型专利3项。申请发明专利8项。培养博士研究生2名，均在读。培养硕士生14名，其中5名已经取得硕士学位，4名完成毕业论文撰写预计2018年3月参加毕业答辩，5名在读。项目投入经费82万元，累计支出60.0683万元，结余21.9317万元，各项支出基本与预算相符。剩余经费将用于本项目研究后续支出。