为了消除匙孔和避免硬母材对针的磨损等问题，使用无针搅拌工具的搅拌摩擦搭接焊（FSLW）焊接 Al／Al 和 Al／Cu 组合的搭接接头。在不同的拘束条件下：a）上板 Al 母材边缘一边夹紧一边自由；b）上板 Al 母材边缘两边全部用夹具夹紧，分别用直径为20 mm 和30 mm 的无针搅拌工具对厚约2 mm 的 Al／Al、Al／Cu 组合板材实施搅拌摩擦焊工艺。针对 Al／Al 组合（软组合），无论采取哪种装夹方式，都能得到良好的焊接接头；针对 Al／Cu 组合，当采用（a）方式装夹时，上板未夹紧的一边出现明显地延展变形，易得到稳定可靠的搭接接头，当采用（b）方式装夹时，只有在增加压入深度和增大搅拌头直径（增加热输入）的情况下，才能得到部分焊合的搭接接头，若在搭接界面预置 Zn 箔作为钎料（搅拌摩擦钎焊，FSB），可以明显改善接头的强度。%To eliminate the keyhole and wear of pin by strong base metal,friction stir lap welding (FSLW)of Al/Al and Al/Cu sheets (each one was 2 mm thick)combinations using a pin free tool (20 mm and 30 mm diameter shoulder)were conducted under the different constraints,namely,the edge of the top sheet of Al was in free state or was constrained by jig.It was found that Al/Al combination (soft combination)could be effectively joined regardless of initial constraint type before welding.However,for Al/Cu combination,when the edge of the top sheet was not fixed by jig (in free state),sound joint was reliably obtained owing to the spreading deformation at the edge of the top sheet,while when the edge of the top sheet was fixed by jig,joining was achieved only under intense heating and deep plunge depth.In this case with constraint and insufficient heating,the insertion of Zn foil filler metal at joint interface could significantly improve interfacial joining owing to evident dissolution of Al top sheet.The new process using filler metal in FSLW was called friction stir brazing (FSB).
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