This paper investigates the effect of different tool pin morphologies on the inter-mixing capability, microstructure, mechanical properties, corrosion, fracture, and wear behaviors of the dissimilar friction stir welded AA6061-T6 alloy--Al 20wt% Mg2Si composite. Grooved shoulder tools with varying pin profiles such as tapered cylindrical, threaded tapered cylindrical, and triangular tapered pins were used for joining the base materials. The parameter combination of 80 mm/min travel speed and 1000 r/min rotation speed (at which no visible flow-induced defect was obtained) was used for this study. Among the pin profiles, the triangular tapered pin produced significantly improved intermingling/inter-material flow, fragmentation, and dispersion of the primary Mg2Si particles in the AA6061-T6/Al-Mg2Si joint. The triangular tapered tool reduced the average grain sizes of the AA6061 alloy and the Mg2Si particles from 18.4 to 4.6 µm and from 115 to 7.5 µm, respectively. Intermetallic phases of Mg2Si, AlFe, Al3.21Si0.47, and Al0.7Fe3Si0.3 are formed in the weld nugget of all the AA6061/Al-Mg2Si joints. The tensile strengths of the joints fabricated with tapered cylindrical, threaded tapered cylindrical, and triangular tapered tools are 108, 139, and 141 MPa, respectively. Abrasive wear is promoted in the joints fabricated with triangular tapered tool due to the homogeneous dispersion and fragmentation of the inherent hard Mg2Si particles. The corrosion attack is dependent on the fragmentation level of the Mg2Si phase. Triangular tapered pin tool is recommended for dissimilar Al/composite welding due to favorable tool-induced material flow, dispersion, and fragmentation of reinforcement.

中文翻译：

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Mg2Si 颗粒对 AA6061-T6 和 Al-Mg2Si 复合材料搅拌摩擦焊机械、磨损和腐蚀行为的影响

本文研究了不同工具销形貌对异种搅拌摩擦焊接 AA6061-T6 合金--Al 20wt% Mg2Si 复合材料的混合能力、微观结构、机械性能、腐蚀、断裂和磨损行为的影响。使用锥形圆柱销、螺纹锥形圆柱销和三角形锥形销钉等具有不同销钉轮廓的带槽肩工具来连接基材。本研究使用 80 mm/min 行进速度和 1000 r/min 旋转速度（在该速度下未获得可见的流动诱导缺陷）的参数组合。在销轮廓中，三角形锥形销显着改善了 AA6061-T6/Al-Mg2Si 接头中初级 Mg2Si 颗粒的混合/材料间流动、破碎和分散。三角形锥形刀具将 AA6061 合金和 Mg2Si 颗粒的平均晶粒尺寸分别从 18.4 到 4.6 µm 和从 115 到 7.5 µm。所有AA6061/Al-Mg2Si接头的焊核中均形成Mg2Si、AlFe、Al3.21Si0.47和Al0.7Fe3Si0.3金属间相。用锥形圆柱、螺纹锥形和三角形锥形工具制造的接头的抗拉强度分别为 108、139 和 141 MPa。由于固有的硬质 Mg2Si 颗粒的均匀分散和破碎，在用三角形锥形刀具制造的接头中促进了磨料磨损。腐蚀侵蚀取决于 Mg2Si 相的碎裂程度。由于有利的工具引起的材料流动、分散、