Fracture Toughness Control in Functionally Gradient Material

功能梯度材料的断裂韧性控制

基本信息

批准号：
07045018
负责人：
WATANABE Ryuzo
金额：
$ 2.82万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07045018/
关键词：
functionaly graded materials composite materials fracture toughness thermal shock resistance thermal residual stress relaxation mechanical evaluation fracture mechanics indentation microfracture 破壊靱性

项目摘要

The international collaborative work between Tohoku University and The University of Washington on the evaluation of fracture toughness of FGMs were performed for three years with sharing research subjects between both contributors. Tohoku University took charge of the fabrication of FGM test pieces, testing of thermal shock property by burner heating test, as well as the valuation of the fracture toughness of FGMs by newly devised repeated Vickers indentation technique. The University of Washington, on the other hand, took part in the precise assessment of the fracture resistance that will be induced by the composition-graded layr. An unconventioanl hybrid approach using simultaneously optical measurement and numerical aclculation.The burner heating thermal shock test on a FGM of zirconia/stainless steel showed that the initiation of cracks depends on the thermal stress generation and on defect distribution within the material. The formation of vertical cracks on the ceramic surface during cooling period of the burner heating test were observed, and the propagation of the cracks was found to be effectively suppressed by the graded layr. The repeated Vickers indentation test provides us easy and fast assessment of the fracture toughness of FGMs. Micromechanical and fracture mechanical considerations showed that the repeated Vickers indentation method is suitable for the assessment of the fracture toughness of FGMs particularly for the thin FGM layrs. The hybrid method provides us the more detailed information on the propagation of the cracks in the graded layr, and will be a viable approach for the clarification of the mechanisms of the crack propagation and its cessation.The present collaborative work has provied fundamanetal information on the fracture mechanics of FGMs, and will contribute much to the progress of the FGM researches.

Tohoku大学与华盛顿大学在评估FGMS韧性的国际合作工作三年，在这两个贡献者之间共享研究对象。 Tohoku University负责FGM测试件的制造，通过燃烧器加热测试对热冲击特性进行测试，以及通过新设计的重复的Vickers凹痕技术对FGM的断裂韧性的估值。另一方面，华盛顿大学参与了对构成分级的Layr将引起的断裂抗性的精确评估。使用同时光学测量和数值算法的一种不同意的杂种方法。燃烧器加热热冲击试验在氧化氧基/不锈钢的FGM上进行的热冲击试验表明，裂纹的启动取决于热应力的产生，取决于材料内的缺陷分布。观察到燃烧器加热试验的冷却期间，陶瓷表面上垂直裂纹的形成，发现裂纹的传播被分级的Layr有效抑制。重复的Vickers凹痕测试为我们提供了对FGM的断裂韧性的简单快速评估。微力机械和断裂机械考虑因素表明，重复的维克斯压痕方法适合评估FGM的断裂韧性，尤其是对于薄的FGM Layrs。混合方法为我们提供了有关分级Layr裂纹传播的更详细的信息，这将是阐明裂纹传播机制及其停止的可行方法。目前的合作工作已提供了有关有关有关的基础知识的信息。 FGM的断裂力学，将为FGM研究的进展做出很大贡献。