铝/镁搅拌摩擦焊-钎焊焊接接头微观组织结构

目的研究不同工艺参数下钎料Zn的添加对Al/Mg异种金属搅拌摩擦焊-钎焊焊接接头组织和性能的影响。方法以厚度为0.05 mm的纯Zn作为钎料,对3 mm厚的2A12-T4态铝合金和4 mm厚的AZ31变形镁合金,进行搅拌摩擦焊-钎焊的复合焊接,分析锌夹层的添加对接头微观组织与力学性能的影响。结果当添加Zn中间层时,接头钎焊区缓解了拉伸断裂趋势,在焊接速度为23.5 mm/min,旋转速度为375 r/min时,接头抗拉剪力达到5.5 k N,复合焊接接头的钎焊焊缝由搭接区、固相扩散区、钎焊区组成。结论钎料的添加有效阻止了Al-Mg系金属间化合物的形成。

Microstructure of Al/Mg Joints Produced by Friction Stir Welding-brazing

The paper aims to study influences of adding brazing filler metal Zn under different process parameters on microstructure and mechanical properties of Al/Mg joints made by friction stir welding-brazing. Pure Zn with a thickness of 0.05 mm was used as brazing filler metal. The friction stir welding-brazing was used to weld 3 mm thick 2A12-T4 aluminum alloy and 4 mm thick AZ31 deformed magnesium alloy. The effects of Zn interlayer on microstructure and mechanical properties of joints were analyzed. When adding Zn intermediate layer, the joint brazing zone alleviated the tensile fracture trend. When the welding speed was 23.5 mm/min and the rotating speed was 375 r/min, the tensile shear of the joint reached 5.5 kN. The Brazing weld of composite welded joints was composed of overlapping areas, solid phase diffusion areas and brazing areas. The addition of brazing filler metal effectively prevents the formation of Al-Mg intermetallic compounds.