Abstract

The mechanical properties and the structure of the butt joints of Al–Mg–Si alloys made by friction stir welding are investigated. The ultimate tensile strength of the joints is found to be 0.82–0.87 depending on the alloy grade after welding. Fracture is shown to occur through the thermomechanical action zone on the side of tool motion. The bending angle of the joints (170°–180°) significantly exceeds the values typical of fusion welding. The hardness distribution in the joints has a W-shape characteristic of these alloys. Artificial aging after welding is shown to cause an increase in the strength coefficient of the joints to 0.92–0.96 at a bending angle of 160°–170°. Complete heat treatment, including quenching and artificial aging, is found to cause noticeable buckling of the welded joints and to be accompanied by a decrease in the strength and plastic properties of the joints because of grain growth in the mixing and thermomechanical action zones. After this treatment, the microhardness distribution within the welded joints is found to decrease and level off.

中文翻译：

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Al-Mg-Si铝合金对接接头的搅拌摩擦焊

摘要

研究了搅拌摩擦焊制备的Al-Mg-Si合金对接接头的力学性能和结构。根据焊接后的合金等级，发现接头的极限抗拉强度为 0.82-0.87。断裂是通过工具运动一侧的热机械作用区发生的。接头的弯曲角度 (170°–180°) 显着超过了熔焊的典型值。接头中的硬度分布具有这些合金的 W 形特征。焊接后的人工时效表明，在 160°–170° 的弯曲角度下，接头的强度系数增加到 0.92–0.96。完整的热处理，包括淬火和人工时效，研究发现，由于混合区和热机械作用区中的晶粒长大，导致焊接接头显着屈曲，并伴随接头强度和塑性性能的降低。在这种处理之后，发现焊接接头内的显微硬度分布降低并趋于平稳。