单颗磨粒划擦SiC_(f)/SiC复合材料试验研究

Experimental Research on Single Abrasive Grain Scratch Woven SiC_(f)/SiC Composite

为研究纤维增强SiC陶瓷基复合材料磨削机理,进行单颗磨粒划擦试验。搭建试验平台,采用电镀后的单颗金刚石磨粒划擦SiC_(f)/SiC复合材料,实时采集划擦力。利用SEM图像对材料去除后的表面与存在的表面损伤形式进行表征,从而揭示磨粒形状、划痕深度与SiC纤维取向对磨削机理的影响。试验结果表明,SiC_(f)/SiC复合材料划擦过程中,扁平状磨粒产生的法向划擦力明显大于尖锐状磨粒,而纤维取向对划擦力影响较小。SiC_(f)/SiC复合材料的加工形态从韧性到脆性转变主要取决于切削深度,大部分延性域加工出现在扁平磨粒和纤维取向γ=0°情况,且脆延性转变切削深度在3μm之内。

In order to study the grinding mechanism of woven fiber reinforced SiC ceramic matrix composites,a single abrasive particle scratch test was conducted.Build a test platform,use the single diamond abrasive grain after electroplating to scratch the SiC_(f)/SiC composite material,and collect the scratching force in real time.SEM images were used to characterize the surface after material removal and the existing surface damage patterns,revealing the effects of abrasive particle shape,scratch depth and SiC_(f) orientation on the grinding mechanism.The test results show that during the SiC_(f)/SiC composite scratching process,the normal scratching force generated by the flat abrasive particles is significantly greater than that of the sharp abrasive particles,while the fiber orientation has less effect on the scratching force.The transition from toughness to brittleness of the processing morphology of SiC_(f)/SiC composites mainly depends on the cutting depth.Most of the ductile field processing occurs in the case of flat abrasive grains and fiber orientation γ=0°,and the cutting depth of brittle ductile transition is within 3 μm.