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本试验研究就采用扩散型CO2 激光粉末焊接技术的铝合金焊接接头进行组织及性能的分析。拉伸实验的结果表明 :对于无间隙的对接焊接头 ,采用不填粉的激光焊接工艺时的抗拉强度明显低于采用填充粉末焊接工艺 ,而且断裂也是发生在焊缝部位。但是拉伸实验的过程中可以看到明显的屈服发生在母材 ,而不是焊缝。采用填粉的激光焊接工艺时则是在母材产生屈服和最终的断裂 ;对于有间隙的对接焊接头 ,采用填粉工艺时 ,其抗拉强度不低于母材的最大间隙达 0 5mm。另外 ,采用填粉工艺的对接焊接头 ,其冷弯角可达 180°、硬度和母材相当 ;其焊缝的金相组织 ,基底为Al+Si共晶与α-Al的均匀混合物 ,其上分布有结晶时先析出的纯Si;当焊接速度偏低时 ,会发生紧邻熔合线的焊缝部位的断裂。启裂区为准解理形貌 ,扩展区面积较大并且是以准解理为主的混合断口形貌 ,终断区为韧性断口形貌
The experimental study on the use of diffusion-type CO2 laser powder welding aluminum alloy welded joints for the organization and performance analysis. Tensile test results show that: For gapless butt welded joints, using unfilled laser welding process when the tensile strength was significantly lower than the use of filler powder welding process, and the fracture occurred in the weld site. However, during the tensile test, it can be seen that apparent yielding occurred in the base metal, not the weld. The use of the filler laser welding process is the yield and ultimate fracture in the base metal; for gap butt welded joints, the use of powder technology, the tensile strength of not less than 0 5mm maximum gap of the base metal. In addition, the butt-welded joint adopting the powder filling process has a cold-rolling angle up to 180 ° and a hardness equivalent to that of the base metal. The microstructure and the base of the weld are a homogeneous mixture of Al + Si eutectic and α-Al, On the distribution of crystallization of the first precipitation of pure Si; when the welding speed is low, there will be welded seam line weld fracture. The area of the crack is quasi-cleaved, the area of the expanded zone is larger and the mixed fracture morphology is dominated by quasi-cleavage, and the fracture zone is the ductile fracture morphology