碳化硅磨削损伤实验研究

Experimental Study on Grinding Damage of Silicon Carbide

摘要: 目的：为实现碳化硅陶瓷的高质量、低损伤磨削加工，本研究采用金刚石砂轮开展磨削实验。基于实际砂轮形貌特征，建立了砂轮磨粒运动轨迹模型以及未变形最大切屑厚度模型，系统分析了磨削过程中表面形貌、磨削力和亚表面损伤的变化规律。结合有限元仿真，进一步探讨了磨粒未变形最大切屑厚度对碳化硅陶瓷表面成型机制的影响。结果表明：随着砂轮进给速度、转速和磨削深度的增加，磨粒运动轨迹趋于交错密集。在此过程中，磨削表面沟槽残余最大高度显著降低，最大降幅从13.11 μm减小至4.85 μm；表面粗糙度也随之降低，最低达到Ra = 1.362 μm。亚表面损伤深度与切屑厚度及磨削力的变化趋势一致，随砂轮进给速度和磨削深度的增加而增大，随砂轮转速的增加而减小，其最大值为8.87 μm，最小值为4.82 μm。在实验所选的磨削参数范围内，磨粒实际切屑厚度处于碳化硅陶瓷临界切屑厚度的[−31.86%, 13.95%]区间内，表明材料去除机制介于塑性去除与脆性去除之间。

Abstract: Objective: To achieve high-quality and low-damage grinding of silicon carbide ceramics, this study conducted grinding experiments using diamond grinding wheels. Based on the actual grinding wheel topography, a grinding particle trajectory model and an undeformed maximum chip thickness model were established. The variation laws of surface topography, grinding force, and subsurface damage during grinding were systematically analyzed. Combined with finite element simulations, the influence of the undeformed maximum chip thickness of grinding particles on the surface formation mechanism of silicon carbide ceramics was further explored. The results showed that as the grinding wheel feed rate, rotational speed, and grinding depth increased, the grinding particle trajectories tended to be interlaced and dense. During this process, the maximum residual height of grinding surface grooves significantly decreased, with the maximum reduction from 13.11 μm to 4.85 μm; surface roughness also decreased, reaching a minimum of Ra = 1.362 μm. The subsurface damage depth followed the same trend as chip thickness and grinding force, increasing with the increase of grinding wheel feed rate and grinding depth, and decreasing with the increase of grinding wheel rotational speed. The maximum value was 8.87 μm, and the minimum value was 4.82 μm. Within the range of grinding parameters selected in the experiment, the actual chip thickness of grinding particles was within the interval of [−31.86%, 13.95%] of the critical chip thickness of silicon carbide ceramics, indicating that the material removal mechanism was between plastic removal and brittle removal.