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研究Al-Mn-Mg铝合金板材的Si含量(0.1%~0.5%,质量分数)对其脉冲激光焊接性能的影响。试验材料为实验室制备的0.45 mm厚的H16态板材。激光焊接试验后发现,当Si含量低于0.34%时,焊池里没有产生裂纹;但是,当Si含量增加到0.47%时,焊池里有裂纹产生。微观组织观察表明,当Si含量低的时候,晶界上残留的共晶相呈不连续的点状分布;当Si含量高的时候,晶界上残留的共晶相变成连续分布。这种现象可以解释增加Si含量对激光焊接性能产生的不利影响。
The effect of Si content (0.1% ~ 0.5%, mass fraction) on the pulsed laser welding performance of Al-Mn-Mg aluminum alloy sheet was studied. The test material was a laboratory-made 0.16 mm thick H16 plate. After the laser welding test, no cracks were found in the weld pool when the Si content was less than 0.34%; however, cracks were generated in the weld pool when the Si content increased to 0.47%. The microstructure observation shows that when the content of Si is low, the eutectic phase remains discontinuously distributed in the grain boundary. When the Si content is high, the eutectic phase remains continuously distributed on the grain boundary. This phenomenon can explain the adverse effect of increasing the Si content on laser welding performance.