Friction surfacing assisted refilled friction stir spot welding of AA6061 alloy and Q235 steel
Friction surfacing assisted refilled friction stir spot welding of AA6061 alloy and Q235 steel
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DOI：
10.1016/j.jmapro.2022.03.006
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发表时间：
2022-05
影响因子：
6.2
通讯作者：
Mingrun Yu;Hongyun Zhao;Zili Zhang;Li Zhou;Xiaoguo Song
中科院分区：
文献类型：
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作者：
Mingrun Yu;Hongyun Zhao;Zili Zhang;Li Zhou;Xiaoguo Song
在不搅拌钢液的情况下，采用补料搅拌摩擦点焊方法，在AA 6061合金和Q235钢表面堆焊一层1 mm厚的堆焊层，实现了AA 6061合金和Q235钢的良好连接。涂层由高度细化的晶粒组成。材料在搅拌区发生剪切变形，在弯钩区和热机械影响区发生挤压变形，导致焊缝中不同的主导织构。由于增强的原子扩散，从界面描绘了富Fe层，并且该层的厚度随着套管在焊接期间插入更深而增加。由于Fe在Al中的溶解度远低于实测含量，在富Fe层中形成了Al 13 Fe 4、Al 5 Fe 2等Al-Fe金属间化合物。在本研究中，最佳抗剪强度达到7.31 kN。焊缝沿焊缝边界和Al/钢界面沿着断裂。断裂起始于AA 6061板与涂层之间的差距边缘，并沿着焊缝边界扩展，导致剪切韧窝和刻面外观。而熔深为2.9mm的点焊接头主要沿着Al/钢界面断裂，这是由于界面处金属间化合物过度形成所致。
The AA6061 alloy and Q235 steel were well joined by refilled friction stir spot welding without stirring steel, as a 1 mm thick coating was deposited on the steel by friction surfacing before welding. The coating was composed of highly refined grains. The materials experienced shear deformation in the stir zones and the extrusion in hook and thermo-mechanical affected zones, resulting different predominant textures in the weld. A Fe-rich layer was depicted from the interface due to the enhanced atomic diffusion, and the layer's thickness increased as the sleeve plunged deeper during welding. Al-Fe intermetallics, including Al13Fe4, Al5Fe2, formed in the Fe-rich layer, since the solubility of Fe in Al was far lower than the measured content. The optimal shear strength reached 7.31 kN in this study. The welds fractured along the weld boundary and the Al/steel interface. The fracture initiated at the edge of the gap between AA6061 plate and coating, and propagated along the weld boundaries, resulting in the shear dimples and the faceted appearance. However, the spot weld with 2.9 mm penetration was fractured along the Al/steel interface mainly, which was attributed to the over formed intermetallics at the interface.