摘要: |
采用自制搅拌头试验了2A70-T6铝合金T型接头搅拌摩擦焊,并对焊缝抗拉强度进行了测试,且观察拉伸试样的断口形貌。结果表明:焊缝中前进侧过渡区的金属变化急剧,拉长的晶粒成流线状分布,返回侧过渡区的金属变化缓和,由焊核区细小晶粒缓慢过渡至母材较大的晶粒。由蒙皮与筋板组成的T型接头的水平界面线在搅拌针的搅拌作用下发生畸变,其中前进侧的界面线沿着焊核边缘向焊缝中延伸深度比返回侧大,返回侧的界面线在焊核边缘形成一个向上凸起的波峰。若焊缝底部的微小界面线未完全加工去除,拉伸试样以脆性和韧性的复合方式发生断裂,焊缝的抗拉强度约为325.5MPa;而正常的拉伸试样则以韧性的方式发生断裂,焊缝的抗拉强度约为376.7MPa。 |
关键词: 2A70-T6;T型接头;搅拌摩擦焊;断裂方式 |
基金项目: |
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Research on Fracture Way of Friction Stir Welding for Aluminum Alloy |
Zhang Kai1, Li Baohua Tang Zhongmin Yang Jiangwu2
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1. The Second Artillery Military Representative of Hongyang Machinery Plant, Xiaogan 432000;2. Hongyang Machinery Plant, Xiaogan 432000
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Abstract: |
Friction stir welding for T-joint of 2A70-T6 aluminum alloy is carried out by using self-designed welding tool. The tensile strength of weld is tested and the tensile sample fracture morphology is observed. The results show that the transition zone metal at the advancing side of the weld changes dramatically, the elongated grains distribute like streamline flow, the transition zone metal at the retreating side of the weld changes smoothly, the equiaxed fine grain in the nugget changes into large grain in the base metal. The level interface line of the T-joint distort under the stirring action of the pin, the interface line at the advancing side extends deeper than that at the retreating side, the interface line at the retreating side form an upward convex wave. If the small interface line at the bottom of the weld is not completely removed, the tensile specimen break with brittle and ductile fracture ways, and the the tensile strength is about 325.5Mpa; while the good tensile specimen break with ductile fracture ways, and the tensile strength is about 376.7Mpa. |
Key words: 2A70-T6;T-joint;friction stir welding;fracture way |