(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410083)
摘 要: 采用ER5356和ER5087焊絲對12 mm厚6082-T6鋁合金進行熔化極惰性氣體保護焊(MIG)后，通過顯微硬度測試、拉伸力學性能測試、光學顯微鏡(OM)、掃描電鏡(SEM)、電子背散射衍射(EBSD)和透射電鏡(TEM)等研究焊絲成分對焊接接頭力學性能與顯微組織的影響。結果表明：采用ER5087焊絲焊接的6082-T6鋁合金焊接接頭焊縫區(qū)晶粒更細小；抗拉強度、屈服強度、斷后伸長率以及焊接系數(shù)均高于ER5356焊絲焊接的6082-T6鋁合金焊接接頭的；兩種焊絲焊接的6082-T6鋁合金焊接接頭的硬度最低區(qū)域與拉伸斷裂位置均在距離焊縫中心10~15 mm處的熱影響區(qū)，該區(qū)域β″強化相聚集長大、粗化，導致析出相強化作用減弱，成為焊接接頭性能最薄弱區(qū)域。
關鍵字: 6082-T6鋁合金；MIG焊接；焊絲成分；力學性能；顯微組織
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:6082-T6 aluminum alloy plates were welded by metal inert welding method (MIG) with ER5356 welding wire and ER5087 welding wire. The effects of welding wire composition on the microstructure and properties of 6082-T6 aluminum alloy welded joints were analyzed by micro hardness and tensile mechanical properties test, optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffractometry (EBSD) and transmission electron microscopy (TEM). The results show that the grain size of 6082-T6 aluminum alloy welded joints of ER5087 welding wire is finer than that of welded joints of ER5356 welding wire, and the tensile strength, yield strength, elongation and welding coefficient are better than those of welded joints of ER5356 welding wire. The lowest hardness area and tensile fracture position of the 6082-T6 aluminum alloy welded joints are in the heat affected zone at 10-15 mm away from welding center. The strengthening phase β′′ aggregates and coarsens, and the strengthening effect is weakened, which becomes the weakest area of the welded joints.
Key words: 6082-T6 aluminum alloy; MIG welding; welding wire composition; mechanical properties; microstructure
