Li Junye, Zhao Zhenguo, Li Junwei, Xiao Fujun, Qiu Rongxian, Xie Hongcai, Meng Wenqing
Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology, Changchun 130022, China.
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Micromachines (Basel). 2023 Mar 22;14(3):703. doi: 10.3390/mi14030703.
The plastic deformation behavior and microstructural changes in workpieces during ultra-precision machining have piqued the interest of many researchers. In this study, a molecular dynamics simulation of nano-cutting iron-carbon alloy (α-Fe) is established to investigate the effects of the fluid medium and cutting angle on workpiece temperature, friction coefficient, workpiece surface morphology, and dislocation evolution by constructing a molecular model of C12H26 as a fluid medium in the liquid phase using an innovative combined atomic approach. It is demonstrated that the presence of the fluid phase reduces the machining temperature and the friction coefficient. The cutting angle has a significant impact on the formation of the workpiece's surface profile and the manner in which the workpiece's atoms are displaced. When the cutting angle is 0°, 5°, or 10°, the workpiece's surface morphology flows to both sides in a 45° direction, and the height of atomic accumulation on the workpiece surface gradually decreases while the area of displacement changes increases. The depth of cut increases as the cutting angle increases, causing greater material damage, and the presence of a fluid medium reduces this behavior. A dislocation reaction network is formed by the presence of more single and double-branched structures within the workpiece during the cutting process. The presence of a fluid medium during large-angle cutting reduces the number of dislocations and the total dislocation length. The total length of dislocations inside the workpiece is shorter for small angles of cutting, but the effect of the fluid medium is not very pronounced. Therefore, small cutting angles and the presence of fluid media reduce the formation of defective structures within the workpiece and ensure the machining quality.
超精密加工过程中工件的塑性变形行为和微观结构变化引起了众多研究人员的兴趣。在本研究中,通过使用创新的组合原子方法构建C12H26作为液相流体介质的分子模型,建立了纳米切削铁 - 碳合金(α-Fe)的分子动力学模拟,以研究流体介质和切削角度对工件温度、摩擦系数、工件表面形貌和位错演化的影响。结果表明,液相的存在降低了加工温度和摩擦系数。切削角度对工件表面轮廓的形成以及工件原子的位移方式有显著影响。当切削角度为0°、5°或10°时,工件表面形貌沿45°方向向两侧流动,工件表面原子堆积高度逐渐降低,而位移变化面积增大。切削深度随切削角度的增加而增加,导致更大的材料损伤,而流体介质的存在减少了这种现象。在切削过程中,工件内部存在更多的单分支和双分支结构,形成了位错反应网络。大角度切削时流体介质的存在减少了位错数量和总位错长度。小切削角度时工件内部位错的总长度较短,但流体介质的影响不太明显。因此,小切削角度和流体介质的存在减少了工件内部缺陷结构的形成,保证了加工质量。