接頭組織
(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院, 北京 100083；
2. 中國航天科技集團(tuán)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粉組成的混合粉末真空無壓釬焊再結(jié)晶SiC陶瓷和Ti合金， 采用X射線衍射、 掃描電鏡和能譜儀對接頭的組織結(jié)構(gòu)進(jìn)行了分析。 結(jié)果表明： 在67.6%Ag-26.4%Cu-6%Ti(質(zhì)量分?jǐn)?shù))粉末中加入相當(dāng)于15％~30%TiC(體積分?jǐn)?shù))的(Ti+C)粉末(Ti與C摩爾比為1∶1)， 經(jīng)920℃, 30min真空釬焊， Ti和C原位合成TiC， 形成以TiC晶粒強(qiáng)化的連接良好的復(fù)合接頭； 形成的TiC分布于Ag相、 Cu-Ti相中； TiC的形成明顯降低了接頭的熱應(yīng)力。 過量的(Ti+C)粉末則導(dǎo)致反應(yīng)不完全， 容易在連接層中產(chǎn)生孔洞， 影響接頭強(qiáng)度； 焊接過程中， Ti由鈦合金擴(kuò)散進(jìn)入連接層， Cu也有部分從連接層中擴(kuò)散進(jìn)入鈦合金。
關(guān)鍵字: SiC陶瓷； Ti合金； 原位合成TiC； 連接； 復(fù)合釬焊
LIU Hui-yuan1, MAO Jian-ying2, LI Hai-gang2
（ 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
