(哈爾濱工業(yè)大學(xué) 現(xiàn)代焊接生產(chǎn)技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室, 哈爾濱 150001)
摘 要: 以鋁硅共晶合金為填充材料，采用激光熔釬焊的方法對(duì)鋁/鈦異種合金進(jìn)行焊接，獲得了同時(shí)具有熔焊和釬焊雙重特征的焊接接頭。由于激光局部加熱并且有很高的冷卻速度，發(fā)現(xiàn)在鈦合金附近的釬焊界面形成了特殊的形態(tài)結(jié)構(gòu)。結(jié)果表明，獲得的鈦合金釬焊區(qū)界面金屬間化合物厚度很薄，僅在10 μm以下。焊縫上部界面金屬間化合物較厚，主要呈鋸齒狀；焊縫下部界面金屬間化合物厚度不足1 μm，呈薄層狀。界面金屬間化合物的主要成分為TiAl3，以Ti(SixAl1−x)3結(jié)構(gòu)的置換固溶體形式存在。底部界面容易成為裂紋產(chǎn)生的源頭，裂紋多沿界面附近焊縫中的共晶組織擴(kuò)展，接頭的平均抗拉強(qiáng)度為鋁母材的85%左右。
關(guān)鍵字: 鈦合金；鋁合金；激光熔釬焊；金屬間化合物
（State Key Laboratory of Advanced Welding Production Technology, Harbin Institute ofTechnology, Harbin 150001, China）
Abstract:With Al-Si eutectic filler wire, Al/Ti dissimilar alloys were joined by the laser welding-brazing process, and the joints with the characters welding and brazing were gained. Due to the local heating of laser and the high cooling rate of the welding seam, special morphology at the interface of titanium substrate and filler metal was found. The results indicate that the maximum of the intermetallic compounds layer is less than 10 μm. Moreover, the thickness and structure of the interface layer at different positions of the same joint are various. At the top of the joint, the layer is thick and presents serrated-shape; at the bottom, the thickness of the interface layer is less than 1μm and exhibits lamellar-shape. In addition, TiAl3 is the main phase of the interface layer, which is a typical substitution solid solution of Ti(SixAl1−x)3. Crack starts at the bottom of the joint and grows in the eutectic structure of the seam metal near the brazing interface. The average tensile strength of the joint is up to 85% of that of the Al base metal.
Key words: titanium alloy; aluminum alloy; laser welding-brazing; intermetallic compound
