SiCp/Al复合材料超声磨削表面缺陷形成机理仿真研究

Simulation of formation mechanism of machined surface defects in ultrasonic grinding of SiCp/Al composites

对SiCp/Al复合材料超声磨削表面缺陷形成机理进行了仿真研究。研究结果表明,碳化硅颗粒的去除形式主要包括翻滚压入、破碎断裂和脱粘拔出3种。由于金刚石磨粒的推挤下压作用,碳化硅颗粒会出现应力集中现象,并由于与金刚石磨粒的相对位置不同而出现翻滚压入、局部破碎断裂、完全破碎断裂和脱粘拔出现象。碳化硅颗粒的破碎断裂和脱粘拔出形成的凹坑是加工表面的主要缺陷形式。超声振动作用使得碳化硅颗粒更易以小切屑或塑性的方式去除。同时,超声振动作用有利于排屑,从而改善提高了已加工表面质量。仿真结果与实验结果吻合良好。

With thEaim to improve the machined surface quality and machining efficiency,a micromechanics finite element model has been established,in which Al matrix,SiC particles and interface were modeled by using ABAQUS softwarEand python language.The formation mechanisms of defects on machined surfacEand the effect of ultrasonic vibration on the material removal process of SiC particles were simulated by means of this model.The simulation results show that therEare three kinds of material removal modes for SiC particles,including mode rolled and pulled in Al matrix,fractured modEand pulled-out mode.As a result of SiC particles fractured and pulled out,the pit was the main defect on the machined surface.The defects of the machining surface in the scratch tests werEanalyzed by scanning electron microscopy,and the validity of the simulation model was verified.