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【机械类毕业论文中英文对照文献翻译】金刚石刀具机械研磨过程中材料的去除机理,机械类毕业论文中英文对照文献翻译,机械类,毕业论文,中英文,对照,文献,翻译,金刚石,刀具,机械,研磨,过程,材料,去除,机理

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金刚石刀具机械研磨过程中材料的去除机理李增强，宗文俊，孙 涛，董 申（哈尔滨工业大学精密工程研究所，哈尔滨 150001）摘要：该材料，移除为的钻石切割工具的机械研磨的机制被照亮在的原子论的的的的规模。在研磨过程中研磨区，相转变材料去除的主要原因。因此，金刚石单晶和刚性金刚石磨粒的标本的三维模型的建立与援助的分子动力学（MD）模拟。所有的原子之间的力量计算Tersoff潜力。后认为，与一个1.5晶格常数的的一定的的切削深度研磨进行了数值模拟。通过监测模型内的原子的位置，在金刚石研磨地区的钻石立方结构转变为无定形碳的微观结构进行了鉴定。完成在钻石的四面体结构的扁平化结构的变化。这验证了原子的径向分布函数的研磨和联合国研磨regions.Meanwhile的，研磨试验产生的碎片，通过XRD（X射线衍射）分析比较。的结果表明，的相位转型会发生确实。关键词：金刚石刀具；机械研磨；材料去除机理；分子动力学仿真 这是一个重要途径，把光学表面与天然金刚石刀具获得高的精度。处理工作件表面具有较低的表面粗糙度和残余应力，小于常规方法加工的变质地区。 钻石是最重要的物质，在超精密加工的切削工具，它是一种理想的最大的硬度和耐磨性的任何材料的塑性变形的脆性固体，具有非常高的维同质。金刚石刀具刃磨方法的关键技术，获得锋利的切削半径，良好的表面质量和几何公差小1。有许多方法，如研磨，离子束溅射，热化学抛光，等离子抛光，氧化腐蚀和激光侵蚀等锐化最常见和最有效的方法是研磨2。在研磨材料去除机制有一个报表很多，如微切割理论3，热磨损理论4，电磨损理论5和断裂理论的努力方向 6，等等。然而，这些解释是只有在特殊情况令人满意。大多数人所接受的解释是，从SP3杂化轨道的碳转换到SP2作为由面包车Bouwelen证明，在研磨7，格里洛8，本手册所有提及和现场9。到目前为止，一些人已证实它在原子水平。 极其强大的技术分子动力学（MD）模拟涉及解决有关的物质在原子水平的研究背景的经典多体问题。由于没有替代方法能够在所需水平的细节处理这个问题的广泛，分子动力学方法已被证明是不可或缺的纯粹与应用研究，由Rapaport表明10。分子动力学分析是一个有效的方法，在学习压痕，附着力，耐磨损和摩擦，表面缺陷，并在原子尺度的纳米切割。如今，医师分析已经被调查基于AFM的纳米光刻过程中使用的原子力显微镜工具11和硅原子在单晶硅表面改性12。因此，它是一种有效的方式来处理的材料去除机制，研磨使用分子动力学模拟。 所有上述，本研究将集中在材料，消除金刚石机械研磨使用三维的MD模拟的机制。和机械研磨的微观现象，将介绍和讨论。1研究方法1.1仿真建模在开始时，介绍了金刚石刀具机械研磨过程。斯凯夫使用了从灰铸铁中的“条纹”（径向槽举行金刚石磨粒）。通过膜表面的橄榄油，之前几克拉分级金刚石颗粒均匀揉入准备使用。斯凯夫在高速运行，钻石刀具研磨应用负载。在这个过程中，金刚石磨粒固定在斯凯夫。所以，这个过程属于固定研磨抛光类13。因此，始建金刚石单晶和刚性金刚石磨粒的标本模型，如图1所示。图7-1 关于金刚石切割工具机械研磨的分子动力学仿真模型晶格的标本和砂砾属于钻石的立方系统。该系统的晶格常数为0.356 67纳米，这是作为一个代表。试样的控制量必须足够大，消除边界effects.Taking考虑到这一点的，被选为最佳控制量的基础上增加控制音量大小，直到进一步增加并不影响原子的位移和速度的迭代过程由于研磨。一个最佳规模为50A15A30A，183930原子组成的。此外，周期性的边界条件是在z方向，以减少仿真规模的影响。标本包括原子3种，即：边界原子，恒温原子和牛顿atoms.To的限制的刚体运动的标本，在标本固定在空间的左侧和底部层的边界原子包含牛顿atoms.Thermostat原子也被用来确保合理向外热传导远离控制volume.Thermostat原子和牛顿原子服从牛顿第二law.The排在前面的标本（100）表面，这是暴露球形金刚石磨粒grit.The了一个8A的半径，它与深度h的标本下滑17,116 atoms.And组成。开展对金刚石研磨的分子动力学模拟之前，重要的是要确保所选择的潜在功能提供了一个可靠的模拟结果。在目前的模拟tersoff潜力，决定在这个模拟14钻石的原子之间的相互作用。 Tersoff碳势参数如下：= 1,393.6 EV，= 347.6 EV，= 34.879 nm.1，= 22.119nm.1，= 1.572,410.7，N = 0.727,51，C = 380,49，D = 4.384，H = .0.570 58，r = 0.18纳米，和S = 0.21纳米。位置和原子的速度Verlet方法，确定由前川和伊藤表明15为了模拟在室温条件下研磨，钻石的原子排列在perfectdiamond立方结构的晶格参数等于其均衡值0.5 FS，通过扩大在每一个特殊的时间step.In这个模拟恒温原子的速度保持在293 K时的环境温度环境温度，被选定为时间步长，获得了很高的精度。这由Lammps软件16，模拟计算和可视化的VMD软件17。的研磨速度100A 1.5A切割研磨长度的深度和40A。前仿真，标本已放宽为10 000个时间步以保持热平衡。1.2实验研磨实验测试仪器显示带有平均0.1m.They的半径在Fig.2.The磨料金刚石磨粒斯凯夫的120 mm.The钻石刀具半径涂在环固定于通过一个特殊的fixture.Then的手臂，斯凯夫运行在3000r/min（ca.38米/秒），5这是通过调整重量地方获得的列印负荷下，研磨工具。碎片收集30分钟lapping.Thereafter后，进行了X射线衍射研究由岛津XRD-6000型。图7-2 研磨装置示意图.2结果与讨论2.1分子动力学分析3D视图和截面模拟如图3所示。当金刚石磨粒到specimen.The地区的削减，包括这些晶格是在shape.The地区的半椭圆形金刚石磨粒和中心O左位下，附近的金刚石磨粒的晶格扭曲。和椭圆的长轴是在同一方向的部队组成。此外，该地区移动离开钻石砂砾幻灯片。如图4所示，A1 - A2A3的，其中O1O2表示的workpiece.It的的表面，去除材料不都槽completely.Some材料两侧被删除和形式的芯片极了。这是一个切割过程。然而，现有的A1和A2显示犁地也occurs.So这种状态是春耕陪同的切削状态。图7-3 磨粒切削后的微观结构图7-4 凹槽的横截面 如图5所示，在切割过程中有三个关键点，首先，附近的金刚石磨粒原子被迫作出一些位移，从他们最初的position.The包括这些原子的晶格扭曲之间扭曲格和完美的晶格little.The边界是沿着金刚石（111）表面（黑线）图（一）所示。原子位移变得更大，随着金刚石磨粒滑动left.More和更多的原子偏离他们的的初始position.The格，包括这些原子更大歪曲seriously.The阶段转变，金刚石立方金刚石转变成非晶质石墨开始在此moment.That年底说，从SP3杂化轨道转换到SP2上几个原子（黑眼圈）。其次，下面的金刚石磨粒的晶格有最坏的失真和小面沿（111）表面延伸到更深的层的边界，在图5（b）所示。更多的原子转变从钻石的立方金刚石的非晶质石墨，尤其是那些在黑暗中圈。此外，一些原子钻石grit.Thirdly，一些格与最小化的力量恢复了一点，在图5（c）所示。然而，有相变的原子不能恢复到其初始阶段，特别是那些在黑暗中圈。因此，凹槽是表面上的钻石标本左。图7-5 不同状态下截面A中的原子分布图2.2 变形的形成从这个模拟图，我们可以发现立方金刚石的相变决定于其四面体结构的变形程度，如图（6）所示。图（7）展示了此变形随时间的变化。 图7-6 图5中环形区域内金刚石晶格的单晶体结构图7表明了当磨粒切削过后，四面体结构发生了变形。如图7（b）所示，当磨粒切削到A截面时，将发生严重的变形。四面体结构稍微变得平坦。图（7）c所示，四面体马上又发生了很严重的变形，导致它的四个顶点基本在同一平面上，甚至有些四面体结构被破坏了。此时，相变发生了。图7-7 图6中的结构在磨粒作用后其四面体的变形情况2.3一对相关函数图8和图9各自列出了试样和切屑的相关函数。图8中的曲线与径向分布函数（RDF）一样，由许多清晰的波峰组成。图9却只有两个波峰，但波峰是连续的，它表明了碎屑原子里存有无定形结构。因此，我们可以确定，在切削过程中同时发生着相变。图7-8 样本原子的一个相关函数图图7-9 碎屑原子的一个相关函数图2.4 X射线衍射图10表明了使用X射线衍射分析了研磨实验中碎屑的产生过程。它表明碎屑中含有无定形碳、微小金刚石颗粒或碎片以及含碳铁（如）。因此，无定形碳是在研磨的过程中产生的，这与模拟结果相符合。图7-10 实验中碎屑产生过程的X射线衍射分析3总结（1） 通过分子动力学分析建立了一个关于金刚石刀具原子和金刚石磨粒的三维模型，在一个特定的深度进行模拟切削。（2） 变形区的随边界沿表面（111）呈现出有规则的分布，边界内部仅仅发生细微的分裂。（3） 金刚石磨粒和样本之间的相互作用导致了相变的产生，并随着磨粒的移动发生了无定形变化。可以通过对总体结构和一对相关函数的比较来分析这个过程。另外，也可以通过磨削实验进行论证。第 7 卷 第 1 期 2009 年 1 月 纳 米 技 术 与 精 密 工 程 Nanotechnology and Precision Engineering Vol.7 No.1 Jan. 2009 收稿日期：2008-01-17. 基金项目：国家自然科学基金资助项目（50705025）. 作者简介：李增强（1980 ），男，博士研究生.通讯作者：孙 涛，教授，. Material Removing Mechanism for Mechanical Lapping of Diamond Cutting ToolsMaterial Removing Mechanism for Mechanical Lapping of Diamond Cutting Tools LI Zeng-qiang，ZONG Wen-jun，SUN Tao，DONG Shen （Center for Precision Engineering， Harbin Institute of Technology， Harbin 150001， China） Abstract：The material removing mechanism for mechanical lapping of diamond cutting tools was illuminated at the at-omistic scale. In lapping process， phase transformation of the lapping region was the main reason for the material removal. Thus a three-dimensional model of a specimen of the diamond monocrystal and rigid diamond grit was built with the aid of the molecular dynamics（MD）simulation. The force between all of the atoms was calculated by the Tersoff potential. After that， lapping with a certain cutting depth of 1.5 lattice constants was simulated. By monitoring the positions of atoms within the model， the microstructure in the lapping region changes as diamond transformed from its diamond cubic structure to amorphous carbon were identified. The change of structure was accomplished by the flattening of the tetrahedron structure in diamond. This was verified by comparing the radial distribution functions of atoms in the lapping and un-lapping regions. Meanwhile， the debris produced in lapping experiment was analyzed by XRD（X-ray diffraction）. The results show that the phase transformation happens indeed. Keywords：diamond cutting tools； mechanical lapping； material removing mechanism； molecular dynamics simulation 金刚石刀具机械研磨过程中材料的去除机理 李增强，宗文俊，孙 涛，董 申 （哈尔滨工业大学精密工程研究所， 哈尔滨 150001） 摘 要：从原子量级揭示了金刚石刀具机械研磨过程中材料的去除机理研磨过程中， 研磨区域原子的相变是材料去除的主要原因 使用分子动力学方法建立了金刚石刀具和刚性金刚石磨粒的三维模型 采用 Tersoff 势函数计算了所有原子之间的作用力， 并以 1.5 个晶格的切深进行了研磨过程模拟 通过观测模型内部原子位置的变化发现，研磨区域刀具原子的晶胞在研磨过程中被压扁， 发生了从金刚石体心立方结构向无定形碳结构的转变 计算了研磨区域原子研磨前后的径向分布函数， 进一步验证了该相变过程 同时， 使用 X 射线衍射方法分析了研磨实验过程中产生的碎屑， 分析结果表明研磨过程中确实有相变发生 关键词：金刚石刀具； 机械研磨； 材料去除机理； 分子动力学仿真 中图分类号：TG580.1 文献标志码：A 文章编号：1672-6030（2009）01-0031-05 It is an important way to turn the optical surface with natural diamond cutting tools to obtain high accu-racy. The processed work-pieces surface has lower sur-face roughness and residual stress， and smaller meta-morphic region than those machined in usual ways. Diamond is the most important material to make cutting tools in the ultra-precision machining， for it is an ideal brittle solid with the greatest hardness and resistance to plastic deformation of any material and has very high dimensional homogeneity. The sharpening method of diamond cutting tools is the key technology to obtain sharp cutting radius， good surface quality and small geometric tolerance1. There are many sharpening methods such as lapping， ion beam sputtering， thermal chemistry polishing， plasma polishing， oxide etching and laser erosion， etc. The most common and effective method is lapping2. The mechanism of the material removal in lapping has a lot of statements， such as the 32 纳 米 技 术 与 精 密 工 程 第 7 卷 第 1 期 micro-cleavage theory3， the thermal abrasion theory4，electro-abrasion theory5 and theory of fracture taking place in the hard direction6，etc. However，these ex-planations are only satisfactory in the particular situa-tion.The explanation accepted by most people is that the hybridized orbit of the carbon converts from sp3 to sp2 in lapping，as demonstrated by van Bouwelen7，Grillo8，Hird and Field9. As yet，few man has veri-fied it at the atomistic level. The extremely powerful technique of molecular dynamics（MD）simulation involves solving the classi-cal many-body problem in contexts relating to the study of matter at the atomistic level. Since there is no alterna-tive approach capable of handling this broad range of problems at the required level of detail，molecular dy-namics methods have been proved indispensable in both pure and applied research，as demonstrated by Rapa-port10. Molecular dynamics analysis is an effective method in studying indentation，adhesion，wear and friction，surface defects and nano-cutting at the atom-istic scale. Nowadays，MD analysis has already been employed to investigate the AFM-based nanolithogra-phy process using an AFM tool11 and atomic surface modification in monocrystalline silicon12. Therefore， it is an efficient way to approach the mechanism of the material removal in lapping using molecular dynamics simulation. From all the above，this study will focus on the material removing mechanism in diamond mechanical lapping using three-dimensional MD simulation. And the microcosmic phenomena in mechanical lapping will be presented and discussed. 1 Methods 1.1 Simulation modeling At the beginning，the mechanical lapping process of diamond cutting tools is introduced. The scaife used was made from a grey cast iron and was medium “striped”（radial grooves to hold diamond grit）.It was prepared for use by applying a film of olive oil to the surface，before a few carats of graded diamond grits were rubbed evenly into it. With the scaife running at a high speed，a diamond cutting tool was lapped by ap-plying a load. In this process，the diamond grit was fixed in the scaife. So，the process belongs to the fixed abrasive polishing category13. Therefore，a model of a specimen of the diamond monocrystal and rigid dia-mond grit was built，as shown in Fig.1. Fig.1 Molecular dynamics simulation model of mechanical lapping of diamond cutting tools The crystal lattice of the specimen and the grit be-longed to the diamond cubic system. The lattice con-stant of this system was 0.356 67 nm， which was repre-sented as a. The control volume of the specimen must be large enough to eliminate boundary effects.Taking this into consideration， an optimum control volume was chosen based on an iterative process of increasing the control volume size until further increases did not affect the displacements and velocities of the atoms due to lapping. An optimum size of 50a15a30a was ob-tained， consisting of 183,930 atoms. Moreover， the pe-riodic boundary condition was used in the z-direction to reduce the effects of the simulation scale. The specimen included three kinds of atoms ，namely ：boundary atoms， thermostat atoms and Newtonian atoms.To re-strict the rigid-body motion of the specimen， the bound-ary atoms in the left and bottom layers of the specimen that were fixed in space were used to contain the New-tonian atoms.Thermostat atoms were also used to ensure reasonable outward heat conduction away from the con-trol volume.Thermostat atoms and the Newtonian atoms obey the Newtons second law.The top surface of the specimen was（100）surface， which was exposed to the grit.The spherical diamond grit had a radius of 8a，consisting of 17,116 atoms.And it slid on the specimen with the depth of h. Before carrying out the molecular dynamics simulation on the lapping of diamond， it is important to ensure that the chosen potential function gives a reliable result for the simulation. Tersoff potential was used in the present simulation to dictate the interaction among the diamond atoms in this simulation14. The parameters in Tersoff potential for carbon were as follows ：A=1,393.6 eV， B=347.6 eV，=34.879 nm1， =22.119 nm1，=1.572,4107，n=0.727,51 ，c=380,49 ，d= 4.384， h=0.570 58， R=0.18 nm， and S=0.21 nm. Posi-2009 年 1 月 李增强等：金刚石刀具机械研磨过程中材料的去除机理（英文） 33 tions and velocities of the atoms were determined by the Verlet method as demonstrated by Maekawa and Itoh15. To simulate lapping under room-temperature conditions， the diamond atoms were arranged in a per-fect diamond cubic structure with the lattice parameters equal to their equilibrium values at an ambient tempera-ture of 293 K. The ambient temperature was maintained by scaling the velocities of the thermostat atoms at every special time step.In this simulation， the 0.5 fs was selected as the time step to obtain a high accuracy. This simulation was calculated by the Lammps software16， and visualized by the VMD software17. The velocity of the lapping was 100a with 1.5a in cut-ting depth and 40a in lapping length. Before the simula-tion， the specimen had been relaxed for 10 000 time steps in order to maintain the thermal balance. 1.2 Experiment The test apparatus of lapping experiment is shown in Fig.2.The abrasive used was diamond grit with an average radius of 0.1 m.They were coated on the scaife in a ring with a radius of 120 mm.The diamond cutting tool was fixed on the arm by a special fixture.Then， the tool was lapped with the scaife running at 3 000 r/min(ca.38 m/s)， under a load of 5 N which was ob-tained by adjusting the place of the weight. The debris was collected after 30 min lapping.Thereafter， the XRD studies were carried out by SHIMADZU XRD-6000. Fig.2 Schematic diagram of the lapping apparatus 2 Results and discussions 2.1 Molecular dynamics analysis The 3D view and cross-section view of the simula-tion are shown in Fig.3. The crystal lattices near the diamond grit are distorted when the diamond grit cuts into the specimen.The region including these crystal lattices is half-ellipse in shape.The region is under the diamond grit and a bit left to the center o. And the major axis of the ellipse is in the same direction as the compo-sition of forces. Furthermore，this region moves left as the diamond grit slides. As shown in Fig.4，A1+A2A3，where O1O2 represents the surface of the workpiece.It shows that the removal materials do not pole up on both sides of the groove completely.Some materials are removed and form chips. It is a cutting process. Whereas，the exist-ing A1 and A2 show that ploughing also occurs.So this state is the cutting state accompanied by ploughing. （a）3D view of debris forming （b）A cross-section view of the specimen shown ,in（a）（point o is the center of the grit） Fig.3 Microstructure of specimen after the grit sliding A1, A2Section area of the bulge materials; A3Section area of the groove Fig.4 Section of the grooves in the longitudinal direction There are three key points in lapping，as shown in Fig.5. Firstly，atoms near the diamond grit are forced to make some displacement from their initial posi-tion.The crystal lattices including these atoms distort a little.The boundary between the distorted lattices and the perfect lattices is along the diamond（111）surface（the black lines）as shown in Fig.5（a）.The displace-ments of the atoms become bigger and bigger along with the diamond grit sliding left.More and more atoms deviate from their initial position.The lattices including these atoms distort seriously.The phase transformation that the diamond cubic diamond transforms into amor-phous graphite starts on a few atoms（in the dark circles）at the end of this moment.That is to say that the hybridized orbit converts from sp3 to sp2. Secondly，the lattices below the diamond grit have the worst distortion and the boundary faceting along the（111）surface ex-tend to the deeper layer，as shown in Fig.5（b）. More atoms transform from diamond cubic diamond to amor-34 纳 米 技 术 与 精 密 工 程 第 7 卷 第 1 期 phous graphite ， especially those in the dark cir-cle.Besides， some atoms are taken away by the diamond grit.Thirdly， some lattices revert a little with the force minimizing， as shown in Fig.5（c）. However， the atoms which have the phase transformation cannot revert to their initial phase，especially those in the dark circle. Therefore，the groove is to the left on the surface of the diamond specimen. （a）Point o to be about to cross section A （b）Point o on section A （c）Point o passed section A Fig.5 Scattergrams of atoms in longitudinal section A in different states 2.2 Bond formation From the simulation， it is found that the phase transformation is due to the flattening of the tetrahedron structure in diamond cubic diamond， as shown in Fig.6. The position transformation at progressive time steps is demonstrated in Fig.7. Fig.6 Crystal cell of the diamond crystal lattice taken out from the circular region in Fig.5（a） As shown in Fig.7（a）， the tetrahedron is de-formed when the grit slides close. And the deforma-tion is serious when the grit cuts into section A，as shown in Fig.7（b）. The tetrahedron is flattened a little. Soon after，the tetrahedron deforms badly，as shown in Fig.7（c）.Its four vertexes are almost on a plane and some bonds are broken. At the same time the phase transformation is accomplished. Fig.7 Change of the tetrahedron marked in Fig.6 when the grit slides 2.3 Pair correlation function The pair correlation functions of the specimen and the chip are shown in Fig.8 and Fig.9 respectively.The curve in Fig.8 is syllabified to a lot of clear peaks，which are the same as the diamonds radial distribution fuction(RDF). However， there are only two peaks in Fig.9, and the peaks are continued, which illuminates that amorphous exists in debris atoms. Therefore， it is sure that the phase transformation takes place in lap-ping. Fig.8 Pair correlation function of specimen atoms Fig.9 Pair correlation function of debris atoms 2.4 XRD Fig.10 shows the X-ray diffraction（XRD） analy-sis of the debris produced in the lapping experiment. It demonstrates that the amorphous carbon，small dia-mond particles or chips and Fe-C compositions（like 2009 年 1 月 李增强等：金刚石刀具机械研磨过程中材料的去除机理（英文） 35 Fe7C3 and Fe5C2）exist together in the debris. Conse-quently，the amorphous carbon is produced in lapping，which corresponds to the simulation result. Fig.10 XRD analysis of the debris produced in the experiment 3 Conclusions （1）A three-dimensional MD model about the at-oms of diamond cutting tools and diamond grit is built by using the molecular dynamics. Lapping at a special cutting depth is simulated. （2）The boundary of the transformation zone is regular ， faceting along（111）surface. The micro-cleavage only occurs inside this boundary. （3）Interaction between the diamond grit and dia-mond specimen leads to a phase transformation event. An amorphous transformation appears as the grit slides. And it is expounded from the comparison between the bond formatting and pair correlation function. Moreover，it has also been proved in the lapping ex-periment. References： 1 Yuan Z J， Yao Y X， Zhou M，et al. Lapping of single crystal diamond toolsJ CIRP Annals-Manufacturing Technology， 2003， 52（1）： 285-288. 2 Uegami K， Tam