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Study on High Temperature Impact Fracture Toughness of Toughened Ceramics

增韧陶瓷高温冲击断裂韧性研究

基本信息

批准号：
02650063
负责人：
KISHIMOTO Kikuo
金额：
$ 1.34万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Ceramic Materials have significant features as compared with metallic alloys, i. e., high temperature strength, hot-corrosion resistance and oxidation resistance much greater than those of metallic alloys. However, there is problem which is come from their brittle or non-ductile nature. Therefore, we need a knowledge of impact fracture toughness at elevated temperatures to use ceramics as hot-section components. The purpose of the present project is to investigate a simple method to determine the impact fracture toughness of ceramics materials at high temperatures. The research works are summarized as follows :(1) An inverse method in which the impact load was estimated from the impact response of the body was studied. in order to overcome the difficulties in obtaining the stable data due to noise contained in data, a method based on the Wiener filtering theory was presented.(2) methods to measure the impact fracture toughness of ceramic materials at elevated temperature were examined and the usefulness of the one-point-bend test was demonstrated.(3) Simple formulae of the J-integral for the one-point bend specimens has been derived by applying a plastic zone correction to the formulae of the dynamic stress intensity factors.(4) Impact fracture toughness tests were carried out on an alumina and alumina-zirconia composite at temperatures up to 1200ﾟC. It was found that the fracture toughness values of both materials increased with the loading rate, and that of alumina was almost constant at temperature up to 1200ﾟC, while that of alumina-zirconia composite decreased with test temperature.(5) Impact fracture toughness tests were performed on alumina-aluminum composite materials. It was found that the fracture toughness values of the tested materials decreased with testing temperature while increased with the loading rate.

陶瓷材料与金属合金相比具有显著的特点，即：即，高温强度、耐热腐蚀性和抗氧化性远高于金属合金。然而，存在来自其脆性或非延展性性质的问题。因此，我们需要在高温下的冲击断裂韧性的知识，使用陶瓷作为热段组件。本项目的目的是研究一种简单的方法来确定陶瓷材料在高温下的冲击断裂韧性。主要研究内容如下：（1）研究了由车身的冲击响应反推车身冲击载荷的方法。摘要为了克服数据中含有噪声而难以获得稳定数据的问题，提出了一种基于维纳滤波理论的方法。(2)研究了在高温下测量陶瓷材料的冲击断裂韧性的方法，并证明了单点弯曲试验的有用性。(3)通过对动应力强度因子公式进行塑性区修正，导出了单点弯曲试样J积分的简单公式。(4)在高达1200 ℃的温度下对氧化铝和氧化铝-氧化锆复合材料进行了冲击断裂韧性测试。结果表明，两种材料的断裂韧性值均随加载速率的增加而增加，其中氧化铝的断裂韧性值在1200 ℃以下基本不变，而氧化铝-氧化锆复合材料的断裂韧性值随加载速率的增加而降低。(5)对氧化铝-铝复合材料进行了冲击断裂韧性试验。试验结果表明，材料的断裂韧性随试验温度的升高而降低，随加载速率的增加而增加。