接头组织
(1. 北京科技大学 材料科学与工程学院, 北京 100083；
2. 中国航天科技集团公司 第一研究院703所, 北京 100076)
摘 要: 研究用合金化Ag-Cu-Ti粉、 Ti粉、 C粉组成的混合粉末真空无压钎焊再结晶SiC陶瓷和Ti合金， 采用X射线衍射、 扫描电镜和能谱仪对接头的组织结构进行了分析。 结果表明： 在67.6%Ag-26.4%Cu-6%Ti(质量分数)粉末中加入相当于15％~30%TiC(体积分数)的(Ti+C)粉末(Ti与C摩尔比为1∶1)， 经920℃, 30min真空钎焊， Ti和C原位合成TiC， 形成以TiC晶粒强化的连接良好的复合接头； 形成的TiC分布于Ag相、 Cu-Ti相中； TiC的形成明显降低了接头的热应力。 过量的(Ti+C)粉末则导致反应不完全， 容易在连接层中产生孔洞， 影响接头强度； 焊接过程中， Ti由钛合金扩散进入连接层， Cu也有部分从连接层中扩散进入钛合金。
关键字: SiC陶瓷； Ti合金； 原位合成TiC； 连接； 复合钎焊
（ 1. School of Materials Science and Engineering,
University of Science and Technology Beijing,
Beijing 100083, China;
2. 703 Institute of the First Academy,
China Aerospace Science and Technology Corporation,
Beijing 100076, China）
Abstract: By using the mixed powder of Ti, C (mole ratio of Ti to C is 1∶1) powders for in-situ synthesizing TiC in 15%-30%TiC (volume fraction) and alloying 67.6%Ag-26.4%Cu-6%Ti (mass fraction) powder as vacuum non-pressure brazing material, sound brazed joints of SiC ceramics /Ti alloy were acquired at 920℃ for 30min. The joints were investigated by X-ray diffractrometry, scanning electron microscopy, and energy dispersive spectrometry. The results show that TiC grains are in-situ synthesized and distribute in Ag and Cu-Ti phases of the bonding layers, distinctly lowering the thermal stress of the joints. However, excess amount of (Ti + C) powder easily brings about the formation of pores and incomplete reactions of Ti and C in the bonding layers, which are detrimental to the joints' strengths. During brazing process, Ti element in Ti-alloy and Cu element in the bonding layer interdiffuse.
Key words: SiC ceramics; Ti-alloy; in-situ synthesizing TiC; bonding; composite-brazing
