采用CO₂激光焊接厚度为2 mm的LZ92镁锂合金板，研究了焊接接头的显微组织、物相组成、显微硬度与拉伸性能。结果表明：LZ92镁锂合金焊接接头成形良好，焊缝中无明显气孔、裂纹等缺陷；母材与焊缝的物相组成相同，由α相、β相和中间相Mg₇Zn₃组成；母材由等轴状β相和枝晶状与颗粒状α相组成，热影响区由粗大的β相和少量细小颗粒状α相组成，焊缝中大量细针状和细小颗粒状α相均匀分布在β相中，β相晶界消失；焊缝的硬度最高，母材的次之，热影响区的最低；焊接接头的抗拉强度为158 MPa，为母材的86.8%，断后伸长率为27%；焊接接头的拉伸断口位于影响区与焊缝间的熔合线处，断口由韧窝和解理面组成，断裂形式为混合型断裂。

LZ92 magnesium lithium alloy plate with thickness of 2 mm was welded by CO₂ laser, and the microstructure, phase composition, micro-hardness and tensile properties of the welded joint were studied. The results show that LZ92 magnesium lithium alloy welded joint had good formability, and no obvious pores and cracks were found in the weld. The phase composition of the base metal and the weld was the same, consisting of α phase, β phase and intermediate phase Mg₇Zn₃. The base metal was composed of equiaxed β phase and dendritic and granular α phase; the heat-affected zone was composed of coarse β phase and a few fine granular α phase; a large amount of fine needle and granular α phases evenly distributed in the β phase in the weld and the grain boundaries of β phase disappeared. The hardness of the weld was the highest, followed by the base metal, and the hardness of the heat affected zone was the lowest. The tensile strength of welded joint was 158 MPa, which was 86.8% that of the base metal, and the elongation was 27%. The tensile fracture of the welded joint was located at the fusion line between the heat-affected zone and the weld; the fracture was composed of dimples and cleavage surfaces, indicating the fracture form was a mixed fracture.