焊接方法对6061铝合金接头性能影响的研究

Research on Effect of Welding Ways on Joint Performance of Aluminum Alloy

针对6061铝合金采用TIG、MIG和FSW的焊接方法所得到的焊接接头性能进行试验研究,测试了3种方法得到的焊接接头的抗拉强度σb和延伸率δ,并对接头的微观组织和断口形貌进行了观察和分析,结果表明:搅拌摩擦焊接头的综合力学性能最好,MIG焊的接头强度要高于TIG焊接头的强度;搅拌摩擦焊接头的组织比母材细小,而熔化焊接头的晶粒中弥散着大量的析出相质点;TIG焊试样断口的韧窝比较浅,在韧窝附近有类似于准解理断裂的光滑平台,而MIG焊试样断口的韧窝也要比TIG焊试样断口的韧窝深,而FSW焊缝区的断口的韧窝尺寸要比TIG焊接头的韧窝小而深,许多小韧窝集聚成尺寸较大的韧窝。

The performances of 6061 aluminum alloy joints welded with TIG, MIG and FSW method are studied. The parameters σb and δ are tested as well as the microstructure and fractograph are analyzed. Results show that the general performance of FSW joint is best. The strength of MIG joint is higher than that of TIG joint. The grain of FSW joint is finer than that of base metal. More precipitates can be found in the grain of fusion welding joints. The cavities in the frac^ograph of TIG joint are shallower and there is some smooth platform similar to the quasi cleavage crack near the cavities. The cavities of fracture by MIG are deeper than that by TIG. The cavities of fracture by FSW are deeper and smaller than that by TIG. Some small cavities gather and form some big cavities.