超声振动辅助划擦高体分铝基碳化硅的刀具磨损特性

Wear characteristics of cutting tools in ultrasonic vibration assisted scratching high volume fraction SiC particle reinforced aluminum matrix composites

为研究高体分SiCp/Al复合材料旋转超声加工中金刚石刀具的磨损规律,制备了圆锥形单颗金刚石工具,分别进行了单颗金刚石普通磨损试验和超声振动辅助磨损试验,通过对比分析两种试验结果,得出超声振动对金刚石刀具磨削高体分SiCp/Al复合材料时磨粒磨损规律的影响。试验结果表明:普通磨损试验中金刚石磨粒的磨损形式主要为宏观崩裂和磨耗磨损,而超声振动辅助磨损试验中金刚石磨粒的磨损形式主要为微小破碎和磨耗磨损。超声振动作用能显著降低试验过程中的切削力,减小摩擦因数,缓解金刚石磨粒与材料的黏附作用。金刚石磨粒在轴向上叠加了超声频的振动速度,其切入材料的合成速度增大,使金刚石磨粒内部尺寸较小的裂纹更易扩展,磨粒所受切削力方向不断发生改变,因此不易形成较大的宏观崩裂,金刚石磨粒的使用寿命得到延长。

To study the wear mechanism of diamond cutting tools in rotary ultrasonic machining high volume fraction SiC particle reinforced aluminum matrix composites,a conical single diamond tool was prepared to conduct ordinary wear test and ultrasonic vibration assisted wear test respectively.By comparing and analyzing the results,the influence of ultrasonic vibration on the grain wear of diamond cutting tools was obtained in grinding high volume fraction SiC particle reinforced aluminum matrix composites.The results show that the diamond grain mainly undergoes macro-cracking and abrasion in ordinary wear test,while the form of diamond grain wear is mainly micro-breaking and abrasion in ultrasonic vibration assisted wear test.The ultrasonic vibration can reduce the cutting force and thefriction coefficient.The adhesion between the diamond grain and the material is alleviated.The velocity of the diamond grain is superimposed with vibration velocity along the axial direction.So its speed increases when the diamond grain cuts into the material and small cracks in the diamond grain expand.Moreover,the direction of the cutting force is constantly changing to make it difficult to form large macro-crack,so that the service life of diamond grain is prolonged.