(1. 遼寧石油化工大學(xué) 機(jī)械學(xué)院，撫順 113001；
2. 鋼鐵研究總院，北京 100081；
3. 北京科技大學(xué) 新材料技術(shù)研究院，北京 100083)
摘 要: 采用ER5356和ER5087兩種焊絲對20 mm厚7A52鋁合金進(jìn)行冷金屬過渡+脈沖焊接(CMT+P)，從焊接缺陷、晶粒尺寸及析出相等多方面研究Zr添加對焊接接頭顯微組織及力學(xué)性能的影響。結(jié)果表明：兩種接頭成形良好且均無明顯缺陷，焊縫組織為鑄態(tài)的等軸枝晶，并發(fā)現(xiàn)條狀或塊狀的富鐵雜質(zhì)相AlFeMn以及黑色相Mg2Si。相比于ER5356焊絲，采用ER5087焊絲焊縫區(qū)的晶粒尺寸減小了28.7%，并存在圓形及橢圓形的納米級強(qiáng)化相Al3Zr。兩種接頭均獲得較高的抗拉強(qiáng)度，使用ER5356焊絲的接頭強(qiáng)度約為293 MPa，達(dá)到母材強(qiáng)度的59.4%，而使用ER5087焊絲焊接接頭的強(qiáng)度更高，約為316 MPa，焊接系數(shù)達(dá)到64.1%。兩種接頭的拉伸斷裂位置均位于焊縫處，拉伸斷口也均以韌窩為主并伴隨明顯的撕裂棱，表現(xiàn)為韌性斷裂特征。
關(guān)鍵字: 7A52鋁合金；CMT+P焊接；焊絲成分；顯微組織；力學(xué)性能
（1. School of Machinery, Liaoning University of Petrochemical Technology, Fushun 113001, Chain;
2. Central Iron and Steel Research Institute, Beijing 100081, China;
3. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:Cold metal transfer+pulse welding(CMT+P) of 20 mm thick 7A52 aluminum alloy was carried out with ER5356 and ER5087 welding wires. The effects of Zr addition on the microstructure and mechanical properties of welded joints were studied from the aspects of welding defects, grain size and precipitation. The results show that the two joints are well formed and have no obvious defects. The weld microstructure is as cast equiaxed dendrite, and strip or block iron rich impurity phase AlFeMn and black phase Mg2Si are found. Compared with ER5356 welding wire, the grain size of weld zone with ER5087 welding wire is reduced by 28.7%, and there are round and oval nano-sized strengthening phase Al3Zr. Both kinds of joints obtain high tensile strength. The joint strength using ER5356 welding wire is about 293 MPa, reaching 59.4% of the base metal strength, while the joint strength using ER5087 welding wire is higher, about 316 MPa, and the welding coefficient is 64.1%.The tensile fracture position of both joints is located at the weld, and the hardness here is also the lowest, indicating that the weld is the weakest area of the whole joint. The tensile fracture is mainly dimple with obvious tearing edge, which is characterized by ductile fracture.
Key words: 7A52 aluminum alloy; CMT+P welding; welding wire composition; microstructure; mechanical property
