SiCf/SiC复合材料大深径比小孔的激光加工研究

Laser processing of small holes with large aspect ratio in SiCf/SiC composites

  • 摘要: 碳化硅纤维增强碳化硅陶瓷基复合材料(SiCf/SiC复合材料)具有各向异性、高硬度和低导电性等特点,导致其大深径比小孔难以加工。飞秒激光加工和水导激光加工属于先进激光加工方法,具有加工质量可控、自动化加工、加工成本低等优势,是解决SiCf/SiC复合材料大深径比小孔的优选技术方案。采用了飞秒激光旋切制孔和水导激光制孔方法,在3 mm厚SiCf/SiC复合材料上加工出深径比为10的小孔。分析了小孔入口、出口、孔壁的形貌及物相,对比了小孔的孔径、孔壁粗糙度及加工效率。结果表明,激光加工的孔出口质量均优于入口质量,飞秒激光旋切制孔具有孔口锋利、圆度好、锥度小等优点,水导激光制孔具有孔口光滑清洁、孔壁光洁、加工效率高等优点。针对SiCf/SiC复合材料耐热构件大深径比小孔加工需求,应综合考虑加工质量、加工效率、加工工况等因素,选择合适的制孔技术。

     

    Abstract: SiC fiber reinforced SiC ceramic matrix composites (SiCf/SiC composites) are characterized by anisotropy, high hardness, and low electrical conductivity, which makes it difficult to process small holes with a large aspect ratio. Femtosecond laser processing and water-guided laser processing are advanced laser processing methods that offer the advantages of controllable processing quality, automated processing, and low processing cost, making them preferred technological solutions for addressing the challenge of small holes with large aspect ratios in SiCf/SiC composites. The femtosecond laser rotary drilling (FLRD) and the water jet guided laser drilling (WJGLD) are adopted to produce small holes with an aspect ratio of 10 in 3 mm thick SiCf/SiC composites. The morphology and physical phases of the entrance, exit, and wall of the small holes were analyzed, and the hole diameter, wall roughness, and processing efficiency of the small holes were compared. The results show that the exit quality of the laser-processed holes is better than the entrance quality, and the FLRD has the advantages of a sharp orifice, good roundness, and small taper, while the WJGLD laser has the advantages of smooth and clean orifices, clean hole walls, and high processing efficiency. To address the demand for small holes with large aspect ratios in heat-resistant components of SiCf/SiC composites, suitable drilling technology should be selected by considering factors such as processing quality, processing efficiency, and processing conditions.

     

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