无针搅拌摩擦钎焊修复铝合金接头沟槽状缺陷研究

Aluminu Alloy Joints Groove Defect Repaired by Friction Stir Brazing with A Pinless Tool

提出利用无针搅拌摩擦钎焊(friction stir brazing,FSB)修复FSW接头的沟槽状缺陷的新思路。试验用Zn箔钎料包裹6061铝块填充6061铝合金板材上的截面为“U”形的月牙形人造缺陷,进行FSB修复。结果表明:缺陷修复后,原始U形待填充区界面整体向前进侧发生倾斜。填充的6061铝块和基体6061铝块已经焊合,沿厚度方向自上向下依次出现表层缺陷完全消失区、合金化区。缺陷完全消失区金属在轴肩强烈热-力联合作用下混合,呈现层状组织特征;U形界面中部为合金化区,母材与填充块均与Zn发生了共晶反应,实现了界面的去膜与间隙的填充。U形界面底部也实现了合金化,但出现离散分布的氧化膜碎屑。相同转速下,FSB缺陷修复接头的抗拉强度可以达到无缺陷表面搅拌摩擦加工处理试样的90.7%。

A new idea for repairing groove defect in friction stir welded joints by friction stir brazing(FSB) with a pinless tool was proposed. In the experiment, Zn foil solder was used to wrap 6061 aluminum block to fill the crescent shaped groove defect with section shape of "U" in 6061 Al alloy plate, and then FSB was used to repair the defects. The results show that the original U-shaped interface be to filled and repaired obviously twists towards advanced side after defect repairing. The filled6061 aluminum block and the 6061 aluminum block matrix are welded together, and the surface defect free zone and the alloying zone appear in the thickness direction from top to bottom in turn. The metal in the defect free zone is mixed under the combination of strong heat and force of the shaft shoulder, showing the characteristics of layered structure. The middle part of the U interface is the alloying area, the eutectic reaction of the base metal and the filled block with the Zn occurs, and the interfacial film removal and gap filling are realized. Alloying is also achieved at the bottom of the U interface, but discrete oxide film debris appears. The tensile strength of the FSB defect repaired joint can reach 90.7% of the sample treated by friction stir processing on the defect-free surface at the same speed.