中文摘要：

采用高功率CO2激光焊机焊接3.7mm厚的2195-T8铝锂合金,研究了不同焊接工艺参数对焊缝成形质量的影响,并对优化焊接工艺条件下焊态和固溶时效态焊接接头的显微组织及力学性能进行了比较。结果表明：焊态接头焊缝区的硬度为81.81HV,比母材的下降了32.3%,接头的抗拉强度为296 MPa,比母材的下降了49%;经固溶时效处理后,焊缝的组织更加均匀,晶界及晶内析出了许多弥散且均匀分布的T1（Al2CuLi）强化相,焊缝硬度和接头的抗拉强度比热处理前的分别提高了25.6%和13.7%。

英文摘要：

2195-T8 Al-Li alloy with thickness of 3.7 mm was welded by using high power CO2 laser welding machine. The effect of welding process parameters on quality of welding joint was investigated, and the mierostructure and mechanical properties between as-welded and post-weld solution-aging joints under the optimal welding parameters were compared. The results show that the microhardness of as-welded joint weld seam was 81.81 HV, which had decreased by 32.3% than that of the base metal and the average tensile strength of as-welded joint weld seam was 296 MPa, which had decreased by 49% than that of the base metal. After solution-aging treatment, the microstrueture of the weld seam became more homogeneous, and lots of strengthening phases T1 （Al2 CuLl） evenly reprecipitated in the grain boundaries and inside the grains. Meanwhile, the mierohardness and the tensile strength had increased by 25.6% and 13.7 % than that of weld seam without solution-aging treatment, respectively.