ABSTRACT

Dual laser-beam bilateral synchronous welding (DLBSW) technology has been widely used in the connection of skin-stringer T-joint. In this study, DLBSW technology was performed to fabricate T-joint of 2219 aluminium alloy. Furthermore, the effect of laser power on grain morphology and microhardness of the T-joint was investigated. The microstructure of different parts was observed and the grain size was quantitatively analysed. The results show that the grain quantity and microhardness of the welded joint are increased significantly as the welding heat input increases. It is found that the influence of laser power on the grain size at the edge of the weld seam is greater than that in the centre of weld. Besides, the microhardness of the non-dendritic equiaxed zone decreases with the increase of laser power, which is caused by the decrease of Al element.

摘要

双激光束双边同步焊接（DLBSW）技术已广泛应用于蒙皮纵梁T型接头的连接。在本研究中，采用 DLBSW 技术制造 2219 铝合金 T 型接头。此外，还研究了激光功率对 T 型接头晶粒形貌和显微硬度的影响。观察不同部位的显微组织并定量分析晶粒尺寸。结果表明，随着焊接热输入的增加，焊接接头的晶粒数量和显微硬度显着增加。发现激光功率对焊缝边缘晶粒尺寸的影响大于焊缝中心的晶粒尺寸。此外，非枝晶等轴区的显微硬度随着激光功率的增加而降低，