单晶硅纳米切削中C—C键断裂对金刚石刀具磨损的影响

发布时间：2018-10-26 13:22

【摘要】：本文基于分子动力学方法模拟金刚石刀具纳米切削单晶硅,从刀具的弹塑性变形、C—C键断裂对碳原子结构的影响以及金刚石刀具的石墨化磨损等方面对金刚石刀具的磨损进行分析,采用配位数法和6元环法表征刀具上的磨损碳原子.模拟结果表明:在纳米切削过程中,金刚石刀具表层C—C键的断裂使其两端碳原子由sp3杂化转变为sp2杂化,同时,表面上的杂化结构发生变化的碳原子与其第一近邻的sp2杂化碳原子所构成的区域发生平整,由金刚石的立体网状结构转变为石墨的平面结构,导致金刚石刀具发生磨损;刀具表面低配位数碳原子的重构使其近邻区域产生扭曲变形,C—C键键能随之减弱,在高温和高剪切应力的作用下,极易发生断裂;在切削刃的棱边上,由于表面碳原子的配位严重不足,断开较少的C—C键就可以使表面6元环中碳原子的配位数都小于4,导致金刚石刀具发生石墨化磨损.
[Abstract]:In this paper, based on the molecular dynamics method, we simulate the elastoplastic deformation of diamond cutting tool in nanocrystalline silicon. The effect of C-C bond fracture on the structure of carbon atom and the graphitization wear of diamond tool were analyzed. The wear of carbon atom on the tool was characterized by coordination number method and 6-element ring method. The simulation results show that the fracture of C-C bond in the surface layer of diamond cutting tool changes the carbon atoms at both ends from sp3 hybrid to sp2 hybrid in the process of nano-cutting, and at the same time, The area formed by the carbon atom with the first neighboring sp2 hybrid carbon atom on the surface of the hybrid structure is flat, and the three-dimensional network structure of the diamond is transformed into the planar structure of the graphite, which results in the diamond tool wear. The reconstruction of the low coordination number of carbon atoms on the surface of the cutting tool results in the distortion of the adjacent region and the weakening of the bond energy of the C-C bond. It is easy to fracture under the action of high temperature and high shear stress. On the edge of the cutting edge, because of the serious shortage of the coordination of the surface carbon atoms, disconnecting the C-C bond can make the coordination number of the carbon atoms in the surface 6 element ring less than 4, which leads to the graphitization wear of diamond cutting tools.
【作者单位】：哈尔滨工业大学机电工程学院;
【基金】：中国博士后科学基金(批准号:2013M541362) 黑龙江省自然科学基金(批准号:E201308)资助的课题~~
【分类号】：TG71;TG501

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