超声辅助螺旋磨削SiCf/SiC陶瓷基复合材料

Ultrasonic assisted helical grinding of SiC;/SiC ceramic matrix composites

针对SiC纤维增强SiC陶瓷基复合材料(SiC;/SiC)存在加工质量差、材料去除困难等问题,开展金刚石砂轮超声辅助螺旋磨削SiC;/SiC陶瓷基复合材料试验,研究其出口质量、孔壁形貌及孔壁表面粗糙度。结果表明:与传统制孔相比,超声辅助螺旋磨削制孔出口处材料无大面积崩边;砂轮磨削速度方向与纤维方向的夹角θ的周期性变化导致孔壁表面形貌呈现规律性变化。当θ在0°/180°时,纤维与基体多发生脱黏现象;当θ在45°时,纤维多发生剪切断裂;当θ在90°时,纤维多发生挤压断裂;当θ在135°时,纤维既发生剪切断裂又发生挤压断裂;孔壁表面粗糙度Sa在θ为90°时最低,在θ为135°时最高。在一定范围内,表面粗糙度Sa随着超声振幅的增大而降低,最大降幅为38.7%;随着进给速度的增大而升高,最大增幅为39.3%。

SiC fiber reinforced SiC ceramic matrix composites(SiC;/SiC)have problems such as poor machining quality and difficult material removal.To study these problems,SiC;/SiC composites were processed by ultrasonic-assisted helical grinding.The exit quality of hole,hole wall morphology and three-dimensional surface roughness of hole wall were explored.The results show that compared with traditional hole making,the material at the exit of the hole made by ultrasonic-assisted helical grinding has no large area chipping.The periodic change of the angleθbetween the direction of the cutting speed of the grinding wheel and the fiber direction leads to regular changes in the surface morphology of the hole wall.Whenθis 0°/180°,the fiber and the matrix are debonded.Whenθis 45°,the fiber is sheared and fractured.Whenθis 90°,the fiber is crushed and fractured.Whenθis 135°,the fiber has both shear fracture and extrusion fracture.The hole wall surface roughness Sa is the lowest value whenθis 90°,and Sa is the highest value whenθis 135°.Within a certain range,the surface roughness value Sa decreases with the increase of the ultrasonic amplitude,with a maximum decrease of 38.7%,and increases with the increase of the feed rate,with a maximum increase of 39.3%.