【摘要】 激光焊接已成为有广阔前景的铝合金连接方式之一，但因焊接热输入高和匙孔不稳定而导致在铝合金中厚板激光焊接应用方面存在局限性。为解决上述问题，本文采用圆形振荡激光焊接和焊后热处理协同改善焊接质量和接头力学性能。以圆形振荡激光频率为变量，分析了其对焊接接头成形质量、微观结构和力学性能的影响。发现振荡频率在200 Hz时，焊接接头焊缝区晶粒尺寸较常规激光焊接减小，接头抗拉强度可达(264.96±1.33) MPa，约为母材强度的61.19%。固溶水淬+人工时效处理后，晶界偏析减少，在焊接区出现纳米级析出相，抗拉强度进一步升高至(386.35±5.65) MPa，约为母材强度的89.23%。本文研究成果可为2219-T6铝合金中厚板圆形振荡激光焊接提供理论依据和工艺参考。更多还原

【Abstract】 Laser welding is a highly promising joining method for Al alloys. However, certain limitations such as elevated thermal input and keyhole instability are associated with its application in medium-thickness aluminium alloy plates. To address these issues, circular oscillating laser welding combined with post-weld heat treatment was employed to improve the formation quality and mechanical properties of the welds. The effects of the frequency of circular oscillating laser on the forming quality, microstructure, and properties of the welds were analyzed. At an oscillation frequency of 200 Hz, the grain size in the weld zone was reduced compared to single laser welding, and the maximum tensile strength of the weld was observed to reach(264.96±1.33) MPa, representing approximately 61.19% of the base metal. Following the post-weld heat treatment of "solid solution and artificial aging", the grain boundary segregation was diminished. Nanoscale precipitated phases are present in the weld zone. Furthermore, the tensile strength was augmented to(386.35±5.65) MPa, representing approximately 89.23% of the strength of the base metal. The results of this study can provide a theoretical basis and technological reference for the circular oscillating laser welding of medium-thickness 2219-T6 aluminium alloy plates.更多还原