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采用不同的焊接速度对5 mm厚6082-T6铝合金板材进行搅拌摩擦焊接,考察焊接速度对接头宏观形貌、微观组织和力学性能的影响。结果表明,固定旋转速度为1200 r/min,焊接速度为40~200 mm/min时可获得无缺陷的接头,焊接速度提高到400 mm/min时在接头前进侧形成孔洞缺陷。焊核区发生了动态再结晶,形成细小的等轴晶粒。随着焊接速度的增大,焊核区平均晶粒尺寸减小,当焊接速度为200 mm/min时,焊核区平均晶粒尺寸为3.8μm。抗拉强度随着焊接速度的增大先增大后减小,当焊接速度为200 mm/min时,接头的抗拉强度达到最大值236 MPa,为母材的74.0%,断后伸长率为6.3%,断裂发生在后退侧热影响区,断裂机制为韧-脆混合型断裂。
Friction stir welding of 5 mm thick 6082-T6 aluminum alloy plate was carried out with different welding speeds, and the influence of welding speed on the macroscopic, microstructure and mechanical properties of the joint was investigated. The results show that when the welding speed is 40-200 mm / min and the fixed rotation speed is 1200 r / min, the defect - free joints are obtained when the welding speed is increased to 400 mm / min. The nugget zone dynamic recrystallization, the formation of small equiaxed grains. With the increase of welding speed, the average grain size of the nugget zone decreases. When the welding speed is 200 mm / min, the average grain size of the nugget zone is 3.8 μm. The tensile strength first increases and then decreases with the increase of welding speed. When the welding speed is 200 mm / min, the tensile strength of the joint reaches the maximum 236 MPa, which is 74.0% of the base material, and the elongation after fracture 6.3%, fracture occurred in the heat-affected zone on the reverse side, and the fracture mechanism was ductile-brittle mixed fracture.