纳米复合钎料钎焊SiO2玻璃陶瓷与TC4的机理及Ti调控界面行为研究

The lightweight construction made of ceramic and metal has the great advantage of weight reduction and energy saving, which is quite important and has a promising prospect in the aerospace field. The brittle reaction layer formed in the ceramic-metal joint seriously affects the joint quality. The present work focuses on the the joining of SiO2 glass ceramic and Ti alloy, according to the Ti behaviors of dissolution, reaction and diffusion, an active brazing method utilising the nano particles/metal composite interlayer and Ti contained in Ti alloy base is proposed for joining SiO2 to Ti alloy. The metallurgical reaction mechanism of composite interlayer at Ti alloy side is studied based on welding metallurgical principle and Fick's law of diffusion. Calculating of Ti concentration in liquid filler, setting up the mathematical model of Ti alloy dissolution thickness and realizing the prediction and control of Ti alloy dissolution quantity are performed on the basis of Nernst dissolution theory. According to the thermodynamics and dynamics analysis of interaction between Ti and composite filler and SiO2 glass ceramic, the controlling mechanism of Ti on interface reaction can be illustrated and then the active brazing mechanism of SiO2 glass ceramic and Ti alloy as well as the mechanism of nano particles reinforcement would be clarified. The high quality joint can be acquired as well. The research in the present work not only provides a novel method for active brazing Ti alloy to ceramic and other non-metal materials, but also offers the theory basis to some extent for dissolution control of base material, braze alloys selection and micro-controlling of reaction products in such method.

陶瓷和金属轻质结构因减重节能效果显著而在航空航天领域具有广泛应用前景，然而，二者连接时极易形成脆性层，影响接头质量。本课题以SiO2与钛合金为对象，以钛合金母材中Ti的溶解、反应和扩散行为为主线, 提出采用纳米复合钎料并利用钛合金自身活性元素Ti实现陶瓷与钛合金的钎焊。依据焊接冶金学基本原理及菲克扩散定律，研究钛母材侧冶金反应，利用溶解理论对钎缝中Ti浓度进行计算，构建钛合金在钎料中溶解厚度的数学模型并预测与控制其溶解量。基于Ti与复合钎料及SiO2的反应热力学与动力学分析，解明Ti调控界面反应的机理，阐明SiO2与钛合金的钎焊机理及纳米颗粒强化机制，实现SiO2玻璃陶瓷与钛合金的高质量连接。本研究可为钛合金与非金属材料的连接提供一种新思路，也为该思路下母材溶解控制、钎料选择及反应产物的微观调控提供一定理论依据。

为解决陶瓷与金属轻质结构连接时易形成脆性层、接头强度下降的问题，本课题以钛合金母材中Ti的溶解、反应和扩散行为为主线，采用纳米复合钎料并利用钛合金自身活性元素Ti实现了SiO2陶瓷与TC4合金的优质钎焊。研究了工艺参数对接头微观组织及抗剪强度的影响规律。通过对SiO2陶瓷与TC4合金钎焊过程中钛合金母材溶解行为的分析，建立了液态钎料对钛合金母材溶解的物理模型，揭示了钎焊过程中Ti浓度的变化规律，推导出钛合金母材溶解量的控制方程，实现了对钛合金母材溶蚀的有效控制。完成了SiO2陶瓷侧反应层生长动力学分析，阐明了陶瓷侧反应层的形成过程及机理，获得了反应层生长动力学方程，揭示反应层生长厚度与钎焊温度和保温时间的关系。顺利完成了研究计划所规定的各项研究内容，达到了预期的研究目标，取得了丰富而显著的研究成果。截至目前，项目组人员参加国内外学术会议4人次，培养博士生1名，硕士生3名，发表论文共计14篇，其中SCI检索论文11篇，EI论文3篇；申请国家发明专利7项，其中已授权4项。