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运用分子动力学仿真模拟高速磨削下单颗金刚石磨粒切削单晶硅的过程,通过分析切屑、相变、位错运动并结合工件表面积的演变规律研究磨削速度对亚表层损伤和磨削表面完整性的影响.仿真结果显示:磨削速度的增大会加剧磨粒前端材料的堆积,超过200 m/s后增加不再明显.而加工区域的平均温度通过原子之间的挤压和摩擦会不断增大.在磨削温度、磨削力以及粘附效应的相互作用下,摩擦系数先增大后减小.晶格的变形、晶格重构和非晶相变导致切屑形成过程中的磨削力剧烈波动.研究结果表明:在加工脆性材料单晶硅过程中,随着磨削速度的升高亚表层损伤厚度先减小后增大.当磨削速度低于150 m/s时,随着磨削速度的升高,磨粒下方的原子晶格重新排列的时间缩短,非晶结构的产生减少,亚表层损伤厚度减小.当磨削速度超过150 m/s时,加工区域中的高温成为主导因素促进位错的成核、运动致使亚表层损伤厚度增大.
The molecular dynamics simulation was used to simulate the process of monocrystalline silicon abrasive cutting with single diamond abrasive in high-speed grinding. The effects of grinding rate on sub-surface damage and grinding were analyzed by analyzing the evolution of chip, phase transformation and dislocation movement combined with the surface area of workpiece. Surface integrity.The simulation results show that the increase of the grinding speed will aggravate the accumulation of the front end of the abrasive grain and the increase will not be obvious after more than 200 m / s, while the average temperature in the processing area is obtained by the squeezing and friction between the atoms Will continue to increase.At the interaction of grinding temperature, grinding force and adhesion effect, the friction coefficient first increases and then decreases.The lattice deformation, lattice reconstruction and amorphous phase transformation lead to the chip formation process The results show that the thickness of subsurface damage firstly decreases and then increases with the increase of grinding speed in the process of processing single crystal silicon of brittle material.When the grinding speed is lower than 150 m / s , The time of rearrangement of atomic lattice below the abrasive grain is shortened, the generation of amorphous structure is reduced and the thickness of the sub-surface damage is reduced with the increase of the grinding speed.When the grinding speed exceeds 150 m / s, High temperatures in the area become the dominant cause Promote dislocation nucleation, resulting in movement of subsurface damage thickness increases.