(1. 東北石油大學(xué)材料科學(xué)與工程系，大慶 163318；
2. 蘭州理工大學(xué)省部共建有色金屬先進(jìn)加工與再利用國家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 采用Al-Si共晶釬料對TC4鈦合金與2A12鋁合金異種合金進(jìn)行鎢極氬弧焊接，研究焊接電流對焊接接頭顯微組織和力學(xué)性能的影響。結(jié)果表明：當(dāng)焊接電流為110~120 A時，焊接接頭的抗拉強(qiáng)度最高可達(dá)158 MPa，此時焊接接頭上部斷裂在焊縫中，下部斷裂在鈦合金與焊縫的界面上。焊縫組織主要由α(A1)基體和在晶界析出的A1-Si共晶相組成，而鈦合金與液態(tài)釬料在接頭界面上部化學(xué)反應(yīng)形成3種不同形態(tài)的TiAl3金屬間化合物，而在接頭界面下部只形成針狀的τ1金屬間化合物。當(dāng)焊接電流達(dá)到并超過140 A時，接頭界面化合物厚度顯著增至300 μm左右，導(dǎo)致抗拉強(qiáng)度急劇下降。
關(guān)鍵字: 鈦/鋁異種合金；鎢極氬弧焊；界面組織；斷裂行為
（1. Department of Materials Science and Engineering, Northeast Petroleum University, Daqing 163318, China;
2. State Kay Laboratory of Advanced Processing and Recycling of Nonferrous Metals,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The butt joining of TC4 titanium alloy to 2A12 aluminum alloy was conducted by gas tungsten arc welding using Al-Si eutectic filler wire, and the effects of the welding current on the microstructure and mechanical properties of the weld joint were analyzed. The results show that the maximum tensile strength of 158 MPa is achieved, the top joint fractures in the seam, and the bottom joint fractures at the interface between the titanium alloy and seam at welding current of 110–120 A. The seam consists of α(Al) and Al-Si eutectic phase precipitated at the grain boundary. The reaction layer consists of the continuous layer TiAl3 phases, the block-like and the long rod-like TiAl3 phase at the top part of the interfacial area of the weld joint. At the bottom part of the interfacial area, the reaction layer includes only the needle-like τ1 phase. The joint strength abruptly decreases with increasing the interfacial layer thickness up to approximately 300 μm as the welding current increases to 140 A.
Key words: Ti/Al dissimilar alloy;gas tungsten arc welding;interfacial reaction; fracture behavior
