磨粒半径对金刚石研磨加工影响机制的仿真研究

为解析金刚石磨粒尺寸变化对金刚石材料研磨质量的影响机制,利用分子动力学方法建立球形刚性金刚石磨粒研磨金刚石工件的模型,研究不同磨粒半径下的磨削力变化规律和应力、相变分布.结果表明:磨粒半径从6a增大到20a(a为金刚石晶格常数),磨削平均法向力和平均切向力均线性增加,但平均法向力增量为平均切向力的3倍;磨粒与工件间的剪...

Simulation study on influence mechanism of abrasive radius on diamond grinding

To analyze the influence mechanism of diamond grain size change on the grinding quality of diamond material, a molecular dynamics method was used to establish the grinding model of spherical rigid diamond grain grinding diamond workpiece, and the grinding force variation law, the stress and the phase transformation distribution under different abrasive grain radii were studied. The results show that when the abrasive grain radius increases from 6a to 20a (a is the lattice constant of diamond), the average normal force and the average tangential force increase linearly, but the increment of the average normal force is 3 times of that of the average tangential force. The shear effect between the abrasive grain and the workpiece is smaller and compared extrusion and friction, and the fluctuation amplitude of the grinding force becomes larger, which indicates that the dislocation formation of workpiece is more severe. At the same time, the strong compressive stress zone formed under the abrasive grain expands and so do the concentrated tensile stress zone caused by friction in the area behind the abrasive grain and the amorphous transformation zone.The number of the defects behind the grinding zone increases, and the machined surface quality of the workpiece becomes worse. When the indentation depth of the abrasive grains with radii of 10a, 15a and 20a is 2 nm, the microhardness of the workpiece surface after abrasive grains scribing is 2.8%, 9.6% and 18.3% lower than that without abrasive grain scribing, respectively. The increase of the abrasive radius will significantly reduce the surface mechanical properties of the workpiece.