单颗粒金刚石划擦工程陶瓷的断裂强度研究

摘要

为揭示磨削加工中砂轮单个磨粒对工程陶瓷断裂强度的作用规律,利用单颗粒金刚石磨具划擦模拟砂粒实际磨削过程.采用不同顶锥角与尖端圆弧半径的自制金刚石颗粒,改变划擦用量和冷却工况,划擦几种典型陶瓷材料表面并分析颗粒划擦作用对试件断裂强度的影响.结果发现,试件划擦后断裂强度随磨粒顶锥角和尖端圆弧半径的增大而提高；随工作台进给速度和划擦深度增加逐渐降低；与湿式划擦相比,干式划擦使陶瓷试件断裂强度趋于劣化.该变化规律符合磨削加工对试件强度特性的影响机制,证明单颗粒金刚石划擦试验的有效性.%To reveal the inherent laws between single abrasive particle of diamond wheel and fracture strength of engineering ceramics during the grinding,a special single diamond tool was introduced to substitute the actual wheel. With the diamond abrasive of diverse apex angles and tip radius, different scratching parameters and cooling condition were set before the surface scratching upon several types of engineering ceramics. Then,relationships on the experimental parameters and fracture strength were intensively investigated. The results show that the fracture strength of scratched ceramics increase with the rise of apex angle and tip radius of abrasive, reduce with the addition of feed rate and scratching depth. Besides, the fracture strength after wet scratching is always better than that of dry scratching. The findings accord with relevant patterns and mechanisms in grinding machining, which also verify the significance of single diamond scratching test.