【作者】 李莹；

【导师】 巩亚东；

【作者基本信息】 东北大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 在当今社会,随着纳米科学与技术的迅猛发展,越来越多的行业对高精密微型零部件的需求量有持续增加的趋势,以尺度微小和结构复杂为特征的微小型化技术具有越来越广阔的应用前景。而单晶零件也因为具有良好的热、疲劳和蠕变性能,能减少精密仪器的误差,避免信号的失真和衰弱,增强传输性能等优点,已经得到了越来越广泛的应用,给我们的生活带来了极大的便利。因此,我们有必要对典型单晶零件微铣削及其再结晶工艺性能进行深入研究。首先,介绍了单晶组织结构,从刀具刃口圆弧半径、最小切削厚度以及微铣削次摆线原理等方面对微铣削加工机理和再结晶机理进行了理论分析,并对微铣削加工过程中的铣削力来源和己加工表面表面粗糙度的影响因素进行了理论分析,确定了表面粗糙度的计算公式。其次,运用有限元分析软件ABAQUS建立典型的面心立方晶系工件与刀具的模型,选定合适的Hill材料本构参数,并选用合理的铣削参数对其进行微尺度铣削加工过程的仿真研究,探究铣削速度以及不同晶面对铣削力的影响规律。再次,选择单晶DD5、Inconel 600、K445三种镍基高温合金零件分别进行正交实验,探究铣削速度、铣削深度、进给速度对铣削力和表面粗糙度影响的主次顺序,寻找最优切削参数组合并总结工艺特性。最后,选择单晶DD98零件,分别进行切削参数单因素实验和热处理温度单因素实验,通过超景深显微镜和扫描电子显微镜对加工表面再结晶层组织进行观察,探究切削参数和热处理温度对再结晶现象的影响规律,提出抑制再结晶形成的方法和手段,并总结单晶零件微铣削及再结晶工艺性能。此外,由于微铣削过程中产生的铣削温度与刀具磨损以及刀具使用寿命都有着密切的关系,甚至因此而影响被加工工件的表面质量,因此本文也以单晶DD98作为实验材料,通过一组单因素实验,初步探究了铣削参数对铣削温度的影响规律。更多还原

【Abstract】 In today’s society,with the rapid development of nano-science and technology,the demand for high-precision micro-parts of many industries increased significantly,micro-miniaturization technology characterized by scale small and complex structure has the broad prospective application.While the single crystal components has been used more widely and has brought great convenience to our lives because it has the benefits of good heat,fatigue and creep performance,reducing the error of precision instruments,avoiding distortion and weakness of signal and enhancing the transmission performance.Therefore,it is necessary for us to study the micro-milling and recrystallization processing property of typical single crystal components.Firstly,the structure of single crystal is introduced.The micro-milling mechanism and recrystallization mechanism are analyzed from the aspects of the radius of tool edge,the minimum cutting thickness and the principle of micro-milling trochoid.The source of milling force and the influencing factors of the machined surface roughness are analyzed theoretically,and the formula of the surface roughness is determined.Secondly,the finite element analysis software ABAQUS is used to model the typical face-centered cubic crystal workpieces and tools,and the appropriate Hill material constitutive parameters and milling parameters are selected to simulate the milling process to investigate the influence of milling speed and milling planes on milling forces.Thirdly,three kinds of nickel-base superalloy components named single crystal DD5,Inconel 600 and K445 were selected to carry out orthogonal experiments to investigate the influence order of spindle speed,milling depth and feed rate on milling force and surface roughness,find out optimal cutting parameters combination and summarize the process characteristics.Finally,single-crystal DD98 components were selected to carry out single-factor experiment of cutting parameters and heat-treating temperature respectively.Super-depth microscope and scanning electron microscope were used to observe the recrystallization layer to investigate the effects of cutting parameters and heat treatment temperature on recrystallization,propose the methods and means of inhibiting the recrystallization,and summarize the processing performance of micro-milling and recrystallization of single crystal components.In addition,the milling temperature in the micro-milling process is closely related to tool wear and tool life,even affects the surface quality of the workpiece,so this thesis takes the single crystal DD98 as the experimental material and discuss the influence of milling parameters on milling temperature through a set of single factor experiment.更多还原