铝合金高功率光纤激光焦点三维振动焊接关键技术及机理研究

Developing laser welding technology of aluminum alloy confirms with the national strategic development. The welded aluminum alloys, however, still suffer from serious limitations like the porosity, poor welding process stability, and the low welding efficiency. In this project, to overcome those inherent limitations of conventional laser fusion welding processes, a novel approach, namely high-power fiber laser spot three-dimensional vibration welding, is proposed for the manufacturing of aluminum alloys. The aims of the project are: to build up the technical and theoretical frame of high-power fiber laser spot three-dimensional vibration welding, based on the intensive research on the understanding of physical processes, such as the dynamic characteristics of keyhole, the flow characteristics of the molten pool, the forming time/speed of keyhole, the matching relationship between laser spot vibration and the formation time of keyhole, the physical mechanism of the improved welding efficiency, and the formation low of the weld seams and the evolution low of microstructure under the stirring effect of the laser spot three-dimensional vibration, developing the laser spot therr-dimensional vibration dynamic focusing device. The research results can establish the theoretical foundation for optimization of laser spot three-dimensional vibration welding technology of aluminum alloy, and the development and application of high-power fiber laser welding technology in our country.

研究和发展铝合金激光焊接技术符合国家的战略发展决策，但传统激光焊接方法焊接铝合金仍然存在气孔多、过程稳定性差、焊接效率低等瓶颈问题。本项目申请人提出一种高功率光纤激光焦点三维振动焊接新方法，有望突破铝合金传统熔焊制造方法的固有局限。项目将深入系统地研究高功率光纤激光焦点三维振动焊接深熔小孔的动态特性行为、熔池的流动特征、小孔形成的特征时间、激光焦点振动参数与小孔形成时间/速度的匹配关系、以及焊接效率提高的物理机理等，探寻高功率光纤激光焦点三维振动焊接优化工艺条件、以及熔池搅拌作用下焊缝的形成规律和组织性能演变规律，开发出焦点三维振动动态聚焦焊接新装置，构建高功率光纤激光焦点三维振动焊接技术和理论框架体系。为铝合金高功率光纤激光焦点三维振动焊接技术的优化，以及该技术在我国的发展和应用奠定基础。

针对光纤激光深熔焊接过程中影响接头质量的焊缝成形差、气孔缺陷、飞溅大等焊接缺陷，瞄准轻质的铝合金和耐热的高温合金两种不同金属材料在航空航天领域的应用需求，开展了焦点三维振动激光焊接工艺的研究。通过系统深入的理论和实验研究，完成了焦点三维振动对焊缝成形和小孔型气孔的影响规律、焊接动态过程特性行为及影响因素、焦点振动焊接物理机制、焊接接头组织性能及力学性能及焦点三维振动控制关键技术及调控装置的研究，揭示了焦点三维振动对铝合金激光焊接质量调控机理和GH3128激光焦点旋转点焊大宽深比焊缝成形机理；获取了2060铝锂合金激光焦点旋转填丝焊接和GH3128薄壁构件激光焊接随焊高频冲击复合焊接方法；实现了激光焦点旋转半径连续可调一体式焊接工作头设计及样机制造。通过研究揭示了高功率光纤激光焦点三维振动焊接对深熔小孔的动态行为、小孔型气孔的抑制、熔池流动及凝固的可控调制机制、焦点振动频率/幅度与小孔及熔池形成特征时间的匹配关系及物理机理等，获取了光纤激光焦点旋转焊接优化的焦点旋转参数及熔池搅拌作用下焊缝成形和组织性能演变规律，掌握了焊接工艺—焊缝成形—接头组织—接头性能之间的对应关系，建立了光纤激光焊接物理过程及热源模型，获取焊接温度场的演变规律，开发出焦点旋转半径连续可调一体式焊接工作头、双层焊接喷嘴等新装置，以及焦点旋转点焊和激光焦点旋转填丝焊接等新工艺方法，构建了光纤激光焦点三维振动焊接的理论和技术框架体系。为光纤激光焦点旋转焊接技术的产业化应用奠定了基础。