脉冲光纤激光-MIG复合焊接A7N01铝合金接头组织及力学性能

Microstructure and Mechanical Properties of A7N01 Aluminum Alloy Joint Welded by Pulsed Fiber Laser-MIG Hybrid Welding

研究了光纤激光的连续输出、脉冲调制输出与MIG电弧复合焊接A7N01铝合金的工艺特性,并对比研究了两种激光输出方式下焊接的A7N01铝合金接头组织和力学性能。结果表明:脉冲与连续激光-MIG复合焊接铝合金焊接接头主要差异在于焊缝内部气孔数量和分布位置不同。脉冲激光在一定程度上能起到增强熔池流动性,促使气泡上浮的作用,焊缝气孔的数量明显减少,只有少量气孔分布在焊缝的上方;但过高的脉冲频率会引起焊缝内部气孔数量的增加。在频率为20 Hz的脉冲激光作用下,焊缝组织得到了一定程度的改善,接头的柱状晶区宽度有所减小,接头的抗拉强度及冲击韧性也有一定程度的提高。

The process characteristics of A7N01 aluminum alloy produced by continuous output, and pulse modulated output of fiber laser and MIG arc hybrid welding were studied, and the microstructure and mechanical properties of the A7N01 aluminum alloy welded joint under the two laser output modes were also investigated. The results show that the main difference of the welded joint with pulsed laser and continuous laser is that the number and distribution of the pores in the weld are different. The pulsed laser can enhance the fluidity of the molten pool and promote the bubbles floating in a certain extent, and the number of weld pores significantly decreases, only a small amount of pores are distributed above the weld. But too high pulse frequency causes the increase of the pores number in the weld. Under the action of pulsed laser with frequency of 20 Hz, the weld structure improves in a certain extent, the width of columnar crystal zone decreases, and the impact toughness and tensile strength are improved in some extent.