Mechanical Properties of Reactive Air Brazed (RAB) Metal/Ceramic Joints. Part 1: Visco‐Plastic Deformation of Silver‐Based Reactive Air Brazes
Mechanical Properties of Reactive Air Brazed (RAB) Metal/Ceramic Joints. Part 1: Visco‐Plastic Deformation of Silver‐Based Reactive Air Brazes
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DOI：
10.1002/adem.201400072
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发表时间：
2014-12
影响因子：
3.6
通讯作者：
E. Skiera;J. Brandenberg;Chichi Li;T. Beck;L. Singheiser;B. Kuhn
中科院分区：
文献类型：
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作者：
E. Skiera;J. Brandenberg;Chichi Li;T. Beck;L. Singheiser;B. Kuhn
用于汽车应用的平面固体氧化物燃料电池系统的开发主要由轻量化设计和耐久性问题驱动。用于密封陶瓷和金属叠层组件的连接技术起着关键作用。快速和频繁的启动能力是客户满意度的必要条件。此外，系统的操作安全性和乘客安全性是密封件的可靠气密性的前提。基于反应性空气钎焊（RAB）的金属接头，利用银钎焊，是首选的玻璃陶瓷，因为它们潜在的更高的故障容限。全尺寸RAB接头的机械设计数据，特别是在高温下，是稀缺的，因此到目前为止，只能从散装银的文献数据估计。在高温下的详细变形和损坏机制在很大程度上是未知的，这进一步使堆设计中的目标导向钎焊开发和演变复杂化。提出了一种新的测试技术（对称双剪切测试），并成功地进行了全尺寸钎焊接头的表征。机械测试伴随着微观结构的扫描电子显微镜检查。结果表明，接头的高温变形和破坏受界面和基体性能的共同影响。钎焊基体控制弹塑性变形，而最大强度由钎焊/连接伙伴界面决定。接头的蠕变性能被发现与大块银的蠕变性能相关。
Development of planar solid oxide fuel cell systems for automotive application is mostly driven by light‐weight design and durability issues. The joining technology utilized to seal ceramic and metallic stack components plays a key role. Rapid and frequent start‐up capability is required for customer satisfaction. Furthermore, operational security of the system and passenger safety precondition reliable hermeticity of the seals. Metallic joints based on reactive air brazing (RAB), utilizing silver brazes, are preferred to glass ceramics because of their potentially higher failure tolerance. Mechanical design data of full‐scale RAB joints, especially at high temperature, are scarce and for this reason up to now only estimated from literature data of bulk silver. Detailed deformation and damage mechanisms at high temperature are largely unknown, what further complicates target oriented braze development and evolution in stack design. A new testing technique (symmetric double shear testing) was proposed and successfully carried out for the characterization of full‐scale braze joints. Mechanical testing was accompanied by scanning electron microscopy examination of microstructure. High temperature deformation and damage of the joints was uncovered to be influenced by both interfaces and matrix performance. The braze matrix governs elastic‐plastic deformation, while the maximum strength is determined by the braze/joining partner interfaces. The creep properties of the joints were found to correlate to that of bulk silver.