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采用光纤激光与变极性钨极惰性气体复合填丝焊接A7N01铝合金,经工艺参数优化,得到了成形良好、无缺陷的焊接接头。研究了这些接头的显微组织、拉伸和疲劳性能,并分析了疲劳断裂特征及断口形貌。研究结果表明,接头主要由细晶区、柱状晶和等轴树枝晶组成;焊态下接头抗拉强度均值为320 MPa,约为母材的75%;自然时效30天后,抗拉强度均值提高到369 MPa,达到母材的83%;断裂位置位于焊趾应力集中处,拉伸断口呈明显的韧窝状,为典型的韧性断裂;接头的疲劳极限为115 MPa。
A7N01 aluminum alloy was welded by fiber laser and variable polarity Tungsten inert gas compound filler wire. Through the optimization of process parameters, a well-formed and defect-free welded joint was obtained. The microstructure, tensile and fatigue properties of these joints were studied, and the fatigue fracture characteristics and fracture morphology were analyzed. The results show that the joints mainly consist of fine-grained zone, columnar and equiaxed dendrites. The average tensile strength of welded joints is 320 MPa, which is about 75% of that of base metal. After 30 days of natural aging, the mean value of tensile strength increases To 369 MPa, up to 83% of the base metal. The fracture site is located at the weld toe stress concentration point, and the tensile fracture is obviously dimpled, which is a typical ductile fracture. The fatigue limit of the joint is 115 MPa.