Fracture mechanisms and mechanics of fiber-reiforced ceramic composites.

本研究项目的主要重点是通过理论和实验的考虑来研究纤维增强陶瓷基复合材料的微断裂强化和增韧过程和机制。调查结果已通过主要在国际主要期刊上发表的十篇技术论文进行了报道。本课题强调了控制纤维增强复合材料断裂韧性和强度的最基本的微断裂过程和机理；(a)第一次基质开裂，(b)裂缝尖端后裂缝面纤维桥接，(c)将断裂纤维拉出基质。相关的实验技术和理论考虑已经在这个项目中开发出来，用于定量分析这些微断裂过程。它们已被应用于断裂；(a)单向增强碳纤维/碳基复合材料，(b)二维增强碳纤维/碳基复合材料，(c)具有不同厚度（直径）增强纤维的碳纤维/氮化硅基复合材料。在实验和理论结果的基础上，对提高强度和韧性的结构陶瓷复合材料进行了材料设计。

The major focus of the research project is on the strengthening and toughening microfracture processes and mechanisms of fiber-reinforced ceramic matrix composites through theoretical as well as experimental considerations. The results of investigations have been reported through ten technical papers published mainly in major international journals.It is emphasized in this project that the most essential microfracture processes and mechanisms which controls the fracture toughness and strength of fiber-reinforced composites are; (a) first matrix cracking, (b) crack-face fiber bridging behind the crack-tip, and (c) pulling broken fibers out of matrix. Pertinent experimental techniques and theoretical considerations have been developed in this project for quantitatively analyzing these microfracture processes. They have been applied to the fracture of; (a) a unidirectionally reinforced carbon-fiber/carbon=matrix composite, (b) two-dimentionally reinforced carbon-fiber/carbon-matrix composites, and (c) carbon-fiber/silicon nitride-matrix composites having reinforcing fibers with different thicknesses (diameters).Based on the experimental and theoretical results, materials design for structural ceramic composites with improved strength and toughness was conducted.