微-纳米复合陶瓷超声振动磨削的塑性-脆性转变特征研究

基于工件超声振动磨削的单磨粒运动模型,建立超声振动磨削单磨粒最大切削厚度agm ax公式;基于压痕断裂力学,给出硬脆材料超声振动磨削塑性-脆性转变临界条件,进行超声振动磨削与普通磨削对比试验,应用SEM和AFM分析陶瓷磨削表面微观形貌特征,重点研究磨削参数对其塑性-脆性转变特征的影响。研究结果表明,砂轮平均磨粒尺寸是影响塑性-脆性转变最为主要的因素,砂轮速度对其影响次之,磨削深度对塑性-脆性转变的影响最小;得出只有当agm ax小于临界切削深度agc时,才能实现硬脆材料塑性域磨削的重要结论。

Brittle ductile Transition of Micro-nano Composite Ceramics Using Ultrasonic Vibration Grinding

The motion model of the contact between abrasive particle and workpiece in two-dimension ultrasonic vibration grinding was analyzed,the maximum cutting depth of a grain were obtained.Based on indentation fracture mechanics,the critical condition of ultrasonic vibration grinding brittle-ductile transition was analyzed theoretically.The ultrasonic vibration and conventional diamond grinding of Al_2O_3-ZrO_(2(n)) ceramics were performed in order to investigate the effect of ultrasonic vibration grinding conditions on the brittle-ductile transition mechanism,the micro-topography of the grinding surface were observed by AFM and SEM.Experiment results indicated that only when the maximum cutting depth of a grain less than critical depth,ductile regime grinding of ceramics can be realized,the grit size,workpiece velocity and grinding depth can affect the brittle-ductile transition.