Fang Yu, Yang Shanglei, Huang Yubao, Meng Xuan
Department of Material Processing Engineering, School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620, China.
Materials (Basel). 2022 Mar 23;15(7):2367. doi: 10.3390/ma15072367.
Cold metal transfer (CMT) fusion brazing technology was used to weld 6061 aluminum alloy and Q235 galvanized steel with ER4043 welding wire. The microstructure, hardness, tensile performance, and fatigue performance of the welded joint were observed and analyzed. The results show that the tensile strength of the welded joint is 110.83 MPa and the fatigue strength limit is 170 MPa. In the fatigue process, the coupon first undergoes cyclic hardening and then cyclic softening and a ratchet effect occurs. The coupon was broken at the interface layer or weld zone where the fatigue strength limit is the lowest. The fatigue crack initiation is mainly caused by: (1) inclusions and second-phase particles; and (2) porosity and incomplete fusion. When cracks encounter holes during expansion, the expansion direction will change. The fatigued coupon displays a toughness fracture in the instantaneous fracture zone.
采用冷金属过渡（CMT）熔钎焊技术，使用ER4043焊丝对6061铝合金和Q235镀锌钢进行焊接。对焊接接头的微观组织、硬度、拉伸性能和疲劳性能进行了观察与分析。结果表明，焊接接头的抗拉强度为110.83MPa，疲劳强度极限为170MPa。在疲劳过程中，试样先经历循环硬化，然后循环软化，并出现棘轮效应。试样在疲劳强度极限最低的界面层或焊接区断裂。疲劳裂纹萌生主要由以下原因引起：（1）夹杂物和第二相粒子；（2）气孔和未熔合。裂纹在扩展过程中遇到孔洞时，扩展方向会发生改变。疲劳后的试样在瞬时断裂区呈现韧性断裂。
