Microstructures of and crack extension in laminated Si–Ti–C–O fabrics/mullite matrix composites
Microstructures of and crack extension in laminated Si–Ti–C–O fabrics/mullite matrix composites
复制标题
层状 Si-Ti-C-O 织物/莫来石基复合材料的微观结构和裂纹扩展
DOI：
10.1016/s0254-0584(00)00461-2
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发表时间：
2001
影响因子：
4.6
通讯作者：
M. Shibuya
中科院分区：
文献类型：
--
作者：
Y. Hirata;Ryoko Yamashita;M. Shibuya
将中值粒径为 1.7μm 的溶胶-凝胶处理的莫来石粉末和厚度为 270μm 的 Si-Ti-C-O 纤维（10vol.%）机织织物通过刮刀形成层状复合材料，并在 N2 气氛中、在 39MPa 的压力下、在 1500-1750°C 的温度下热压。通过分析透射电子显微镜对纤维内部以及纤维与莫来石基体之间的界面结构进行了表征。与没有莫来石基体的整体纤维相比，致密莫来石基体中的无定形纤维的热解受到抑制。热压过程中纤维的部分热解伴随着β-SiC的结晶、Ti元素从纤维内部向界面的扩散以及纤维内部孔隙的形成。在室温下测量了具有裂纹扩展的缺口复合材料的断裂抗力。在残余压应力作用下，Si-Ti-C-O织物层的主裂纹发生偏转，导致织物层附近的断裂抗力增加。
A sol–gel processed mullite powder of median size 1.7μm and woven fabrics with 270μm thick of Si–Ti–C–O fibers (10vol.%) were formed into laminated composites by doctor blade and hot-pressed at 1500–1750°C under a pressure of 39MPa in a N2atmosphere. The structures of fiber interior and interfaces between fibers and mullite matrix were characterized by analytical transmission electron microscopy. Pyrolysis of the amorphous fibers in dense mullite matrix was suppressed as compared with monolithic fibers with no mullite matrix. Partial pyrolysis of fibers during hot-pressing was accompanied by crystallization into β-SiC, diffusion of Ti element from inside the fibers to the interfaces and the formation of pores inside the fibers. The fracture resistance of the notched composite with crack extension was measured at room temperature. A main crack was deflected at the Si–Ti–C–O fabric layer under the compressive residual stress, leading to the increase of fracture resistance near the fabric layer.