(1. 中南大学 材料科学与工程学院,长沙 410083;
2. 中南大学 有色金属材料科学与工程教育部重点实验室,长沙 410083)
摘 要: 采用ER5356和ER5087焊丝对12 mm厚6082-T6铝合金进行熔化极惰性气体保护焊(MIG)后,通过显微硬度测试、拉伸力学性能测试、光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)等研究焊丝成分对焊接接头力学性能与显微组织的影响。结果表明:采用ER5087焊丝焊接的6082-T6铝合金焊接接头焊缝区晶粒更细小;抗拉强度、屈服强度、断后伸长率以及焊接系数均高于ER5356焊丝焊接的6082-T6铝合金焊接接头的;两种焊丝焊接的6082-T6铝合金焊接接头的硬度最低区域与拉伸断裂位置均在距离焊缝中心10~15 mm处的热影响区,该区域β″强化相聚集长大、粗化,导致析出相强化作用减弱,成为焊接接头性能最薄弱区域。
关键字: 6082-T6铝合金;MIG焊接;焊丝成分;力学性能;显微组织
(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