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采用金相显微镜(OM)、扫描电镜(SEM)、微机控制电子万能试验机对ZL101A焊丝MIG焊焊接6061-T6铝合金焊接接头固溶+时效处理前后的显微组织、力学性能进行研究。结果表明,焊接接头经固溶+时效处理后,只有3个区,基体区、熔合区以及焊缝区,无明显的热影响区。基体组织中Mg2Si强化相、未熔Si相有所减少;焊缝区晶界及晶粒内部时效析出的Mg2Si强化相增多,且弥散分布。焊接接头在较高的抗拉强度和伸长率下断裂处在焊缝区,抗拉强度达到293.3MPa,是母材的94.6%,伸长率为6.8%,是母材的56.7%。未经处理的焊接接头断裂处在热影响区。处理前后的焊接接头断裂形式均为典型的韧性断裂。
The microstructure and mechanical properties of Z61101 welding wire MIG welding 6061-T6 aluminum alloy welded joint before and after solution treatment were studied by OM, SEM and computer controlled electronic universal testing machine. The results show that there are only three zones, matrix zone, fusion zone and weld zone after solution treatment and aging treatment. There is no obvious heat affected zone. The microstructure of Mg2Si strengthened phase and the unmelted Si phase decreased. The grain boundary of the weld zone and the Mg2Si strengthened phase precipitated within the grain boundary increased, and dispersed. Welded joints at the higher tensile strength and elongation fracture in the weld zone, the tensile strength of 293.3MPa, 94.6% of the base metal, elongation of 6.8%, is 56.7% of the base metal. Untreated welded joints break in the HAZ. Before and after treatment of the welded joints are all typical forms of fracture toughness fracture.