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对5 mm厚的2219高强铝合金进行了搅拌摩擦焊单道对接焊,通过拉伸试验观察断口处的显微组织,研究了焊接接头的断裂部位特征。结果表明,接头的断裂部位在焊核与母材的边界或热力影响区。当焊接热输入量合适时,沿焊缝热力影响区断裂的试样在焊缝横截面上的形貌为V型和45°的剪切断裂,其接头的抗拉强度和伸长率较高。焊接热输入量过大时,沿焊缝厚度方向的“抽吸-挤压”作用减弱,在焊缝的紊流区形成孔洞缺陷,在焊核与母材的交界处形成弱连接,导致焊接接头沿焊核边界断裂,在焊缝横截面上的形貌呈阶梯型和S型,其接头的抗拉强度和伸长率较低。
The 5 mm thick 2219 high strength aluminum alloy was subjected to friction stir welding single pass butt welding. The tensile test was used to observe the microstructure of the fracture, and the fracture site characteristics of the welded joint were studied. The results show that the fracture site of the joint is at the boundary between the weld core and the base metal or the thermal influence zone. When the amount of welding heat input is appropriate, the specimens fractured along the weld heat affected zone have V-shaped and 45 ° shear fractures on the cross-section of the weld, and the joint tensile strength and elongation are higher. When the welding heat input is too large, the effect of “suction-squeeze” along the weld seam thickness is weakened, and the hole defects are formed in the turbulence zone of the weld seam, weak connection is formed at the junction of the weld core and the base metal, Resulting in the weld along the nuclear boundary fracture, the weld cross-section of the morphology was ladder and S-type, the joint tensile strength and elongation is low.