6005A铝合金摆动激光焊接组织及力学性能研究

目的 优化铝合金摆动激光焊焊接接头组织结构，减少焊接缺陷，提高接头机械性能。方法 采用无摆动、三角摆动和无穷摆动3种模式对6005A铝合金进行焊接。采用金相显微镜、扫描电子显微镜、能谱仪对焊接接头的组织结构和元素分布进行表征；使用显微硬度计及拉伸试验机对接头进行力学性能测试；利用扫描电子显微镜分析拉伸断口的形貌特征。结果 与无摆动和三角摆动两种模式相比，无穷摆动模式下焊缝成形最佳，晶粒尺寸最小，元素分布最均匀，这得益于复杂的双向循环摆动设计对熔池产生的强烈搅动效果。无摆动、三角摆动、无穷摆动模式下焊核平均显微硬度分别为66HV、72HV、77HV;3种模式下接头平均抗拉强度分别为183.21、205.52、215.80MPa；断裂模式分别为解理断裂、解理断裂+韧窝断裂及韧窝断裂模式。无穷摆动模式同样显示出最佳的力学性能。结论 铝合金摆动激光焊接采用无穷摆动模式可以获得组织均匀细小、无焊接缺陷且综合性能优良的焊接接头，该模式十分适合铝合金材料的焊接。

Microstructure and Mechanical Properties of 6005A Aluminum Alloy by Oscillating Laser Welding

The work aims to optimize the structure of the oscillating laser welded joints, reduce the welding defects and improve the mechanical properties of the joints. 6005A aluminum alloy was welded in three patterns:without oscillation, triangle oscillation and infinite oscillation. The microstructure and element distribution of the welded joints were characterized with metallographic microscope, SEM and EDS. The mechanical properties of the joints were tested with microhardness tester and tensile tester. The morphology of tensile fracture was analyzed with SEM. The results showed that the infinite oscillation pattern had the best weld seam formation, the smallest grain size and the most uniform element distribution compared with the without oscillation and triangle oscillation patterns, due to the strong stirring effect of the complex double-cycle oscillation design on the molten pool. The average microhardness of the weld cores in without oscillation, triangle oscillation, and infinite oscillation patterns was 66HV, 72HV, and 77HV. The average tensile strength of the joints of the three patterns was 183.21, 205.52, and 215.80 MPa, respectively. Their fracture modes were destructive fracture mode, destructive fracture + dimple fracture mode, and dimple fracture mode, respectively. The infinite oscillation pattern also showed the best mechanical properties. Aluminum alloy oscillating laser welding with infinite oscillation pattern can obtain welded joints with fine structure and excellent comprehensive properties but without welding defects. This pattern is very suitable for the welding of aluminum alloy materials.