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Ceramic-metal composites prepared via tape casting and melt infiltration methods.

机译：通过流延铸造和熔渗法制备的陶瓷金属复合材料。

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摘要

Melt infiltration of preforms prepared by tape casting and lamination has been accomplished using a short-time infiltration process that significantly suppresses reaction product formation. For layered materials produced via infiltration of laminated ceramic tapes, of particular interest is the effect that a large change in microstructure has on infiltration, phase formation, and mechanical properties. Hardness of the fine scale composite layers is approximately three times higher than coarse scale layers, due to greater strength of the fine B4C network. Fractography showed that crack propagation occurred by brittle fracture of the carbide and ductile extension of the metal. Despite large differences in hardness, the fracture mode of the fine and coarse scale microstructures appears identical.; Fluid flow modeling for tape casting was conducted with a Newtonian slurry under a parallel blade, and the effect of beveling the blade based on a one dimensional flow model is shown. The discussion on slurry deformation after the blade exit suggests that the mode of slurry deformation depends on the relative importance of the pressure gradient and wall shear and that the existence of zero shear plane might have a negative effect on particle alignment in the tape. The analysis of the flow under a beveled blade predicts that this configuration is more advantageous than the parallel blade for productivity and parallel blade is better for producing uniform particle alignment and thinner tape. Also, the one dimensional flow model for the beveled blade is shown to be a valid approximation of the fluid behavior below a blade angle of 45 degrees.; The flow visualization study on tape casting was conducted with a transparent apparatus and model slurry. Most investigators have concluded that the shear stress between the doctor blade and moving carrier causes the particle alignment, but, according to the result of visualization experiment, some degree of particle alignment is already established in the reservoir.; The fluid flow concept of tape casting is incorporated with a metal infiltration technique to prepare the ceramic-metal composites with tailored porosity and pore orientation. Boron carbide-aluminum system was used to prepare the composites, and its stiffness constants were investigated. The aligned metal ligaments rarely affect the stiffness constant anisotropy which appears to be caused by tape casting operation.
机译：通过带式浇铸和层压制备的预成型坯的熔体渗透已经使用显着抑制反应产物形成的短时渗透过程完成。对于通过层压陶瓷带的渗透产生的层状材料，特别令人关注的是微观结构的巨大变化对渗透，相形成和机械性能的影响。由于精细的B4C网络的强度更高，因此精细尺寸复合材料层的硬度大约是粗糙尺寸层的三倍。断口扫描显示，裂纹扩展是由碳化物的脆性断裂和金属的延展性延伸引起的。尽管在硬度上有很大的差异，但细微和粗尺度微观结构的断裂模式似乎相同。在平行叶片下用牛顿浆料进行流延铸造的流动模型，并显示了基于一维流动模型对叶片进行斜切的效果。关于叶片退出后的泥浆变形的讨论表明，泥浆变形的方式取决于压力梯度和壁剪切的相对重要性，零剪切平面的存在可能对胶带中的颗粒排列产生负面影响。对斜切刀片下的流动的分析预测，这种配置在生产率上比平行刀片更有利，而平行刀片在产生均匀的颗粒排列和更薄的胶带方面更好。同样，斜角叶片的一维流动模型显示为叶片角在45度以下时流体行为的有效近似值。使用透明设备和模型浆料对流延进行流动可视化研究。大多数研究人员认为，刮刀和移动的载体之间的剪切应力会导致颗粒排列，但是根据可视化实验的结果，储层中已经建立了一定程度的颗粒排列。带铸的流体流动概念与金属渗透技术结合在一起，以制备具有定制孔隙率和孔方向的陶瓷-金属复合材料。用碳化硼-铝体系制备复合材料，并研究其刚度常数。对准的金属韧带很少影响似乎由带式浇铸操作引起的刚度常数各向异性。

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  • 作者

    Kim, Hyun Jun.;

  • 作者单位

    Purdue University.;

  • 授予单位 Purdue University.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 90 p.
  • 总页数 90
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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