陶瓷表层结构梯度化缓解SiO2f/SiO2复合陶瓷/金属钎焊接头残余热应力的方法研究

项目名称： 陶瓷表层结构梯度化缓解SiO2f/SiO2复合陶瓷/金属钎焊接头残余热应力的方法研究

项目编号： No.51275497

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 机械、仪表工业

项目作者： 熊华平

作者单位： 中国航空工业集团公司北京航空材料研究院

项目金额： 80万元

中文摘要： 对于热膨胀系数相差十几倍、几十倍的SiO2f/SiO2复合陶瓷材料与金属的组合连接，如何采取有效的技术措施大大降低连接接头残余热应力，从而获得残余应力分布相对均匀、界面冶金结合稳定的接头，是一个有很大技术难度、值得研究的科学问题。 项目提出通过在陶瓷表面加工沟槽、再向沟槽中填入钎料或金属块的方法，在被焊陶瓷表层构造出梯度过渡层，然后再结合中间缓冲层，缓解陶瓷/金属接头的残余热应力。将开展陶瓷表层梯度结构的设计、陶瓷与金属界面微观分析与强度研究、焊后残余应力的数值模拟计算，揭示梯度化结构改善残余应力分布的规律，实现较大尺寸SiO2f/SiO2与金属的钎焊实验验证。 解决有巨大热膨胀系数差的陶瓷与金属连接技术难点，对于促进SiO2f/SiO2在高温结构材料、透波材料等领域应用具有实用意义，而且将在陶瓷/金属连接领域形成有效缓解接头残余应力的新途径，对于更广阔范围内的异种材料连接具有科学价值。

中文关键词： SiO2f/SiO2复合陶瓷材料；残余应力；梯度；有限元分析；强度

英文摘要： The mismatch in the thermal expansion coefficient between SiO2f/SiO2 ceramic matrix composite and metal is extremely great, that is, for the former it is only 0.33×10-6 K-1, in general, the latter is high up to 4.6~15.5×10-6 K-1 . And this makes it very difficult to join them together due to the induced great residual thermal stresses existed within the joints. Therefore it is of great importance to take measures to effectively decrease the residual thermal stresses and to achieve a stable joining interface between the two dissimilar materials. In this project a method of decreasing residual thermal stresses within the joint between SiO2f/SiO2 ceramic matrix composite and metal is newly proposed. That is, firstly, a series of grooves are machined mechanically at the surface of SiO2f/SiO2 composite to be jointed, and then they are filled with brazing fillers or metal pieces through brazing. This means that a graded structure is formed at the surface of the SiO2f/SiO2 composite, and thus the thermal expansion coefficient shows a gradient form its inner part to the surface layer. Subsequently, besides the graded structure in the surface layers, the traditional interlayer method for decreasing residual thermal stresses will also be applied in the joining of SiO2f/SiO2 composite to metal. It is believed that our new

英文关键词： SiO2f/SiO2 composite；Residual thermal stress；Graded；Finite element analysis；Strength