Fabrication of Multi-Functional Sintered Materials with Graded Compositional Distribution

具有梯度成分分布的多功能烧结材料的制造

基本信息

批准号：
03453064
负责人：
WATANABE Ryuzo
金额：
$ 4.42万
依托单位：
TOHOKU UNIVERSITY
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

A laser beam differential temperature heating test and a hydrogen/oxygen burner flame heating test were made on the graded specimens of metal and ceramics, fabricated under the design scheme established in the forgoing two years. An acoustic emission monitoring was used to detect the crack formation in the specimen during heating and cooling cycle. Vertical cracks were observed to be formed during cooling cycle of testings. The vertical cracks propagated by further heating and cooling, and they eventually coalesce to result in the spallation of the ceramic layr from specimen surface. Finite element analysis on the stress state in the specimen was done using the measured temperature distribution, and it has shown that a large compressive stress is generated during heating period at the ceramic surface to cause non-elastic deformation of the ceramic layr. The non-elastic deformation will cause during cooling peiod tensile stress, which will exceed the intrinsic strength of the ceramics and result in the formation of the vertical cracks. From the microstructural observations of the crack propagation in the composite structures consisted of metal and ceramic phase the improvement of the ductility of the ceramic-rich regions has been found to be indispensible for the retention of the heat resisrtance of this kind of functionally gradient materials. Such an improvement will be realized by an control of the connectivity of the metal phase in the ceramic-rich region through a process optimization. The heat insulating performance is evaluated by thermal resistance of the material, and its value is a characteristic parameter, along with the heating temperature of the vertical crack formation, for the thermomechanical performance of functionally gradient materials. The concept of the microstructual control of graded materials, particulary with respect to the connectivity of the phases involved, will be applied to the other kind of functionally gradient materials, such as ther

激光束差分温度加热测试和氢/氧燃烧器加热测试是在金属和陶瓷的分级标本上进行的，该标本是在预防两年中建立的设计方案下制造的。使用声发射监测来检测在加热和冷却周期期间样品中的裂纹形成。在测试的冷却周期中观察到垂直裂纹形成。垂直裂纹通过进一步的加热和冷却传播，最终结合起来，从而导致样品表面的陶瓷外差剥落。使用测量的温度分布对试样中的应力状态进行有限元分析，并表明在陶瓷表面的加热期间产生了较大的压缩应力，以引起陶瓷Layr的非弹性变形。在冷却PEIOD拉伸应力期间，非弹性变形将导致，这将超过陶瓷的内在强度，并导致垂直裂纹的形成。从复合结构中的裂纹传播的微观结构观察来看，由金属和陶瓷阶段组成，已经发现，富含陶瓷区域的延展性的改善是必不可少的，对于保留这种功能梯度材料的热分子的保留。通过控制陶瓷丰富区域中金属相的连通性通过过程优化，将实现这种改进。通过材料的热电阻来评估热绝缘性能，其值是一个特征参数，以及垂直裂纹形成的加热温度，用于功能性梯度材料的热机械性能。分级材料的微结构控制的概念，涉及相关阶段的连通性，将应用于另一种功能上的梯度材料，例如