基于航空航天领域减重的需求，铝锂合金激光焊接越来越受到国内学者的广泛关注。对2 mm厚2060-T8铝锂合金进行激光平板对接焊和焊缝微观组织形貌分析，并通过熔池流动机制解释铝锂合金熔焊焊缝边缘等轴细晶区(EQZ)的形成机理。分析认为，激光热作用及熔池对流的影响导致焊缝边缘不同区域异质形核质点的数量与分布有所不同，使上部EQZ宽度较窄，“腰部”EQZ宽度相对较大。此外，根据熔池流动机制，在焊缝边缘上部及“腰部”的部分形核质点会沿上熔合线切线方向被带入熔池，并在此基础上形核长大形成一条延伸至焊缝内部的等轴晶带。

Based on the demand of weight reduction in the aeronautic and aerospace field, laser welding of aluminum-lithium alloys has received more and more attention from domestic scholars. The laser butt welding of 2 mm thick 2060-T8 Al-Li alloys is conducted and the micro-morphologies of weld seam is investigated. Moreover, the formation mechanism of the fine equiaxed grain zones (EQZ) at the boundary of fusion weld seam is clarified based on the molten pool flow mechanism. The analysis results show that the effects of laser heating and molten pool convection make the amounts and distributions of heterogeneous nucleation particles in different boundary regions of weld seam different, the EQZ width in the upper part is narrow and the EQZ width in the waist part is relatively large. In addition, part of the nucleation particles in the upper part and waist part of the weld boundary are brought into the molten pool along the tangent direction of the upper fusion line according to the molten pool flow mechanism, and on this basis, the grain grows to form a curved colony of equiaxed grains extended into weld seam.