进给速度对MI工艺制备SiCf/SiC复合材料加工损伤的影响

Effect of Feed Rate on Machining Damage of SiCf/SiC Composites by MI Process

采用超声辅助磨削对MI工艺制备的SiC_(f)/SiC复合材料表面进行磨削加工,研究了进给速度对复合材料性能的影响。结果表明:采用超声辅助磨削加工SiC_(f)/SiC复合材料表面时,加工区域出现纤维脱粘、断裂、破碎及基体裂纹和脱落现象,且纤维与基体界面会有裂纹产生。当进给速度提高时,复合材料表面损伤加重,导致其比例极限强度和最大载荷降低。进给速度由400 mm/min提高至1000 mm/min时,SiC_(f)/SiC复合材料的拉伸强度和弯曲强度分别降低4.7%和20.6%。

SiC_(f)/SiC composites was processed by ultrasound-assisted grinding,and the effect of feed rate on the machining damage of the composites by MI process was studied.The results show that when the surface of SiC_(f)/SiC composite is processed by ultrasound-assisted grinding,many machining defects will come into being,such as the fiber debonding,fracture,breakage,matrix crack and shedding.And the interface between the fiber and matrix also has cracks.With the increase of feed speed,the surface damage of the composite material is aggravated,which leads to the decrease of proportional ultimate strength and maximum load.When the feed rate increases from 400 mm/min to 1000 mm/min,the tensile strength and bending strength of SiC_(f)/SiC composites reduce by 4.7%and 20.6%,respectively.