| 摘要: |
| SiC纤维具有良好的耐高温抗氧化特性,是陶瓷基复合材料的关键原材料之一。在高温陶瓷基复合材料制备过程及实际服役过程中,均需对SiC纤维进行高温热处理。为了获得SiC纤维在高温工艺过程及高温服役过程中的性能变化规律,通过对SiC纤维进行高温氩气和空气环境热处理,研究了热处理对SiC纤维拉伸性能及微观形貌等的影响,并对支撑纤维的工艺性能和使用性能进行了分析。将国产二代SiC纤维分别置于1 000 ℃的氩气环境和空气环境热处理30 h,并采用纤维电子强力仪测试了纤维的拉伸性能；使用扫描电子显微镜（SEM）、X射线衍射分析（XRD）及拉曼光谱等分析手段,分析了SiC纤维的微观结构及化学成分的演变情况；探讨了SiC纤维高温氧化过程、纤维表面变化与力学性能衰退之间的关系。研究结果表明:国产二代SiC纤维在1 000 ℃氩气环境热处理30 h后,其性能基本不变化,纤维内部SiC微晶结晶度提高有利于性能提升；而1 000 ℃空气环境热处理30 h使得SiC纤维表面氧化出现SiO2层及孔洞,初始光滑的纤维表面变粗糙,导致SiC纤维拉伸强度显著降低约26%。 |
| 关键词: SiC纤维 氧化损伤 拉伸强度 热处理 结晶 高温 |
| DOI：10.11918/202105061 |
| 分类号:TG178 |
| 文献标识码:A |
| 基金项目:国家自然科学基金(51972027) |
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| Effect of high temperature heat treatment on properties of domestic second-generation SiC fiber |
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PI Huilong1,WANG Yiguang2
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(1.School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China; 2.Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081)
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| Abstract: |
| As a key ceramic matrix composite material, SiC fiber has good high temperature resistance and oxidation resistance properties. High temperature heat treatment of SiC fiber is necessary in the preparation and actual service of high temperature composite materials. In order to understand the performance of SiC fiber during high temperature process and high temperature service process, through the high temperature argon and air treatments of SiC fiber, the influence of heat treatment on the tensile properties and microstructure properties of SiC fiber was analyzed, and the process performance and service performance of SiC fiber were investigated. In this study, the domestic second-generation SiC fibers were subjected to argon and air heat treatments at 1 000 ℃ for 30 h, and the tensile properties of the fibers were tested by fiber electronic strength tester. The microstructure and chemical composition evolution of the SiC fibers were tested and analyzed by means of scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectrometer. The relationship between the oxidation process of SiC fibers at high temperature, the variation of fiber surface, and the deterioration of the mechanical properties was discussed. Results show that the properties of the domestic second-generation SiC fibers were basically unchanged under the conditions of argon environment and heat treatment (1 000 ℃, 30 h), and the increase in crystallinity of SiC micro-crystal in the fiber was useful for its performance improvement. While the air environment and heat treatment (1 000 ℃, 30 h) led to the surface oxidation of the SiC fibers with SiO2 layer and porosity, and the surface of the initially smooth fiber became roughness, resulting in decrease in the tensile strength of the SiC fiber by about 26%. |
| Key words: SiC fiber oxidative damage tensile strength heat treatment crystallization high temperature |
