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基于建立的新型三维仿真模型,采用分子动力学方法模拟单晶铜(100)表面纳米加工过程,研究材料的去除机理和纳米加工过程中系统的温度分布与演化规律。仿真结果表明:系统的温度分布呈同心型,切屑温度最高,并且在金刚石刀具中存在较大的温度梯度。采用中心对称参数法区分工件中材料缺陷结构的形成与扩展。位错和点缺陷是纳米加工过程中工件内部的主要缺陷结构。工件中的残余缺陷结构对于工件材料的物理属性和已加工表面质量具有重要影响。位错的成核与扩展、缺陷结构的类型均与纳米加工过程中系统的温度有关。加工区域温度升高有利于位错从工件表面释放,使工件内部位错结构进一步分解为点缺陷。采用相对高的加工速度时,工件中残留缺陷结构较少,有利于获得高质量的加工表面。
Based on the new three-dimensional simulation model established, molecular dynamics simulation was used to simulate the nano-fabrication of single-crystal copper (100) surface. The removal mechanism of the material and the temperature distribution and evolution of the system during the nano-fabrication process were studied. The simulation results show that the temperature distribution of the system is concentric, the chip temperature is the highest, and there is a large temperature gradient in the diamond tool. Center symmetry parameter method is used to distinguish the formation and expansion of the material defect structure in the workpiece. Dislocations and point defects are the major defect structures within the workpiece during the nano-fabrication process. The residual defect structure in a workpiece has a significant effect on the physical properties of the workpiece material and on the machined surface quality. The nucleation and propagation of dislocations, the types of defect structures are all related to the temperature of the system during the nano-fabrication process. Increasing the temperature in the processing region is conducive to the release of dislocations from the workpiece surface, so that the dislocation structure inside the workpiece is further decomposed into point defects. When using a relatively high processing speed, the residual structure of the workpiece less, is conducive to obtaining high-quality machined surface.