In this study, the relationship between machinability, mechanical properties and microstructure of hBN-SiC composites was investigated. Manufacturing of the composites started with the calcination of raw materials at 850 °C for 16 h under a nitrogen atmosphere prior to mixing with 5 wt% of Al₂O₃:Y₂O₃ sintering additives and then powder mixtures were spark plasma sintered at 1850 °C for 17 min by applying 50 MPa pressure. Characterizations of the samples were carried out with FTIR, XRD, SEM and TEM methods. The physical and mechanical properties of the samples were determined with density measurement, Vickers hardness, Young's modulus, three-point bending, fracture toughness and drill test methods. The amount of in-situ formed hBN phase within the sintered composites was calculated by using the Rietveld method. The physical, mechanical and machinability properties of the composite were evaluated according to the calculated amount of hBN. The highest drilling speed during the test was obtained as 34.24 mm/min for the sample containing 29 wt% of hBN. Increasing the drill load from 19.61 N to 49.03 N resulted in 4.33 times increase in the drilling rate. TEM and STEM studies which were carried out for the microstructural investigations showed the internal defects as delamination bands within hBN phase formed during sintering. In addition to these analyses, novel precession electron diffraction method in TEM was utilized for orientation mapping to investigate any possible orientation relationship between SiC and in-situ synthesized hBN phase.

在这项研究中，研究了 hBN-SiC 复合材料的可加工性、机械性能和微观结构之间的关系。复合材料的制造开始于原材料在 850 °C 下在氮气氛下煅烧 16 小时，然后与 5 wt% 的 Al ₂ O ₃ :Y ₂ O _{3 混合}烧结添加剂，然后粉末混合物通过施加 50 MPa 压力在 1850 °C 下放电等离子烧结 17 分钟。用 FTIR、XRD、SEM 和 TEM 方法对样品进行表征。样品的物理和机械性能通过密度测量、维氏硬度、杨氏模量、三点弯曲、断裂韧性和钻头试验方法确定。使用 Rietveld 方法计算烧结复合材料中原位形成的 hBN 相的量。根据hBN的计算量评估复合材料的物理、机械和机械加工性能。对于含有 29 wt% hBN 的样品，在测试期间获得的最高钻孔速度为 34.24 mm/min。将钻孔载荷从 19.61 N 增加到 49.03 N 导致 4。钻孔速度提高33倍。为微观结构研究而进行的 TEM 和 STEM 研究表明，内部缺陷是在烧结过程中形成的 hBN 相内的分层带。除了这些分析之外，还利用 TEM 中的新型旋进电子衍射方法进行取向映射，以研究 SiC 与原位合成 hBN 相之间的任何可能的取向关系。