【摘要】 热压烧结制备了单向连续石英纤维补强的石英复合材料。研究了热压压力和烧结温度对复合材料的析晶行为及力学性能的影响,借助扫描电镜和透射电镜等手段观察和分析了材料的显微结构并用X射线衍射法鉴别物相变化。结果表明热压烧结温度和压力对复合材料中方石英的析出有着显著的促进作用;而热压中石英纤维比石英基体易于析晶是造成复合材料力学性能下降的主要因素。在1250℃,12MPa热压制备的样品抗弯强度能达到113.9MPa。更多还原

【Abstract】 Unidirectional continuous silica fiber reinforced silica (SiO_2f/SiO₂) composites were prepared by hot-pressing. The influences of the hot-pressing pressure and temperature on crystallization behavior and the mechanical properties of the composite were studied. The microstructure and phase composition of the fibrous composites were examined by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results reveal that the increase of the sintering temperature and the hot-pressing pressure can promote the formation of cristobalite in the fibrous composites. The significant crystallization of the silica fiber with the increase of sintering temperature is responsible for the degradation of mechanical properties. The flexural strength of the fibrous composites reaches 113.9MPa by hot-pressing at 1250℃ under 12MPa.更多还原