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Sustematization Study of Toughening Mechanism in Ceramic-based Composites for Structural Use

结构用陶瓷基复合材料增韧机理的可持续化研究

基本信息

批准号：
03453077
负责人：
NISHIDA Toshihiko
金额：
$ 3.84万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

Main perpose of this project is to establish the universal standerd for evaluation and to systematize the toughening mechanism for structural ceramics and ceramic based composites. As the result of this project, ceramic-based materials can be classified the following three categories : (1) Brittle ceramics ( K_<IC> values of them are less than 5 MPa m^<1/2> ) (2) Toughened ceramics ( K_<IC> values of them are 5-10 MPa m^<1/2> in a general sense, and they almostly shows the some toughening-enhancement mechanisms during the crack extesion ) (3) Fever-reinforced ceramics ( They have microfracture processes accompanied by the main crack extension of fiber-reinforced brittle matrix composites with "weak" interface bonding ) and the following conclusions were presented from our fracture mechanics studies of some ceramics and ceramic-based composites.The general low of linear-fracture mechanics was applicable for matreials (1) if only the special attention should be paid to the testing. Because the resistance ageinst crack extension in materials (2) is affected by the stress-shielding due to the process zone formed at the crack tip, due to the wake formed along the fracture surface, accurate analysis by non-linear fracture mechanics based on the damage-free crack or notch will be required. For the precise evaluation of mechanical properties for matreials (3), pluralistic analysis under tiesile, compression and shear mode will be indispensable.

本课题的主要目的是建立结构陶瓷和陶瓷基复合材料的通用评价标准，并使结构陶瓷和陶瓷基复合材料的增韧机理系统化。根据本课题的研究结果，陶瓷基材料可分为以下三类：（1）脆性陶瓷（K_<IC>值小于5 MPa m^<1/2>）（2）增韧陶瓷（<IC>一般意义上的K_值为5-10 MPa m^<1/2>，在裂纹扩展过程中，它们都表现出一定的增韧机制（它们具有微断裂过程，伴随着具有“弱”界面结合的纤维增强脆性基体复合材料的主裂纹扩展）通过对一些陶瓷和陶瓷基复合材料的断裂力学研究，得出以下结论：（1）只要特别注意试验，线性断裂力学的一般规律对材料是适用的。由于材料（2）中的抗老化裂纹扩展性受到应力屏蔽的影响，该应力屏蔽是由于在裂纹尖端处形成的过程区，由于沿断裂表面沿着形成的尾流，因此将需要基于无损伤裂纹或缺口的非线性断裂力学的精确分析。为了准确地评价材料（3）的力学性能，必须进行拉伸、压缩和剪切模式下的多元分析。