Jin Cong, Xu Chunguang, Li Peilu, Yin Peng, Gao Yunxi, Wang Yongqiang
Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing, 100081, China.
China North Vehicle Research Institute, Beijing, 100072, China.
Sci Rep. 2025 Apr 3;15(1):11466. doi: 10.1038/s41598-025-89545-5.
The analysis of MIG welding performance and welding deformation control of medium/high strength aluminum alloy plates is a hot topic of current research. By applying high-energy ultrasound during the MIG welding process to control the welding deformation and performance of welded joint of LC52 aluminum alloy plate, and comparing and analyzing it with the traditional MIG welded joint, the influence of high-energy ultrasound control process parameters on the welding residual stress distribution, welding deformation, mechanical properties, and microstructure of LC52 aluminum alloy welding test plate was mastered. The residual stress values and distribution state of high-energy ultrasonic welding compared with conventional welding were analyzed through the use of LCR wave stress detection method with conversion or broadband frequency. The microscopic grain structure of welded joint was studied by using metallographic optical microscopy, impact testing and tensile testing of welded joint were carried out and the fracture pattern of tensile specimens was observed by using scanning electron microscopy. The crystallization process of the welded joint was changed by injecting high-energy ultrasound in the MIG welding process, meanwhile, the process of weld solidification and heat transfer or diffusion based on the action of high-energy ultrasonic wave directly led to changes in the properties of the welded joint. The results showed that the welding residual stress was significantly reduced and homogenized in the MIG welding process of LC52 aluminum alloy plate based on certain timing constraints after the application of high-energy ultrasonic control. The average welding residual stress reduction rate and the stress homogenization rate of the plate under each detection depth reached more than 70.0% and 50.0%, respectively. The welding deformation was effectively controlled with reduction by 68.8%. In addition, the grain size and distribution state of microstructure in the weld zone, fusion and heat affected zone were refined and equalized by using this welding control process. Compared with the conventional welding method (i.e., not under regulation), the impact strength of the weld fusion and heat-affected zone under the action of high-energy ultrasonic waves were increased by 71.7% and 33.6%, respectively, and the tensile strength and elongation of the welded joint were increased by 24.0% and 46.7%, respectively, improving the fracture morphology of weld and then showing better mechanical properties. Therefore, the process of high-energy ultrasonic MIG welding was applied to control the welding deformation and improve the welding properties of LC52 aluminum alloy. The important support for improvement of the welding quality of aluminum alloy plate and even its stability and safety in service was provided by this study.
中/高强度铝合金板材的熔化极惰性气体保护焊（MIG）焊接性能分析及焊接变形控制是当前研究的热点。通过在MIG焊接过程中施加高能超声来控制LC52铝合金板材焊接接头的焊接变形及性能，并与传统MIG焊接接头进行对比分析，掌握了高能超声控制工艺参数对LC52铝合金焊接试板焊接残余应力分布、焊接变形、力学性能及微观组织的影响。利用转换或宽带频率的LCR波应力检测方法，分析了高能超声焊接与常规焊接相比的残余应力值及分布状态。采用金相光学显微镜研究了焊接接头的微观晶粒组织，对焊接接头进行了冲击试验和拉伸试验，并利用扫描电子显微镜观察了拉伸试样的断口形貌。在MIG焊接过程中注入高能超声改变了焊接接头的结晶过程，同时基于高能超声波作用下的焊缝凝固、传热或扩散过程直接导致了焊接接头性能的变化。结果表明，在施加高能超声控制并基于一定时间约束条件下，LC52铝合金板材的MIG焊接过程中焊接残余应力显著降低且趋于均匀化。各检测深度下板材的平均焊接残余应力降低率和应力均匀化率分别达到70.0%以上和50.0%以上。焊接变形得到有效控制，减小了68.8%。此外，采用该焊接控制工艺使焊缝区、熔合区和热影响区微观组织的晶粒尺寸及分布状态得到细化和均匀化。与传统焊接方法（即未进行调控）相比，高能超声波作用下焊缝熔合区和热影响区的冲击强度分别提高了71.7%和33.6%，焊接接头的抗拉强度和伸长率分别提高了24.0%和46.7%，改善了焊缝的断裂形貌，进而表现出更好的力学性能。因此，将高能超声MIG焊接工艺应用于控制LC52铝合金焊接变形及提高焊接性能。本研究为提高铝合金板材的焊接质量乃至其服役稳定性和安全性提供了重要支撑。
