MOSCOW, Russia / EuroWire.IO / – In recent developments, researchers from Russia and China have introduced an innovative ultrasonic welding method that effectively doubles the strength of metal bonds. This technique not only enhances joint robustness but also increases the lifespan of welded parts by 1.9 times. Led by scientists from South Ural State University in Chelyabinsk, the collaborative work involved partners from China. TV BRICS highlighted these findings, attributing the results to the university. The new approach is particularly aimed at welding joints between metals with differing characteristics, such as steel and aluminium.
For many years, joining dissimilar metals has posed significant engineering challenges. Often, brittle intermetallic layers form at the interface, which are prone to cracking under stress and compromise the overall structure. The new ultrasonic welding technique seeks to mitigate this issue during spot welding, a common process used in fabricating car bodies and other assemblies. According to the university, the research was published in the journal Engineering Fracture Mechanics.
This method involves applying ultrasonic vibrations of approximately 1,200 watts to the welding process. The vibrations promote refinement of the metal’s crystal structure within the weld zone. The university reports that the size of these crystals diminishes by nearly five times, resulting in a finer, more uniform microstructure compared to coarse crystals. Additionally, the process reduces the brittle intermetallic layer thickness at the joint by 50%, enhancing joint integrity.
Ultrasound eliminates air pockets, strengthening welds
During welding, ultrasound also expels trapped air bubbles from the metal, producing denser, defect-free welds. Experimental results demonstrated that the joint strength was doubled with this ultrasonic assistance. Furthermore, the lifespan of the welded components increased by 90%, or 1.9 times, indicating a significant improvement. The scientists noted that these welds are better equipped to endure continuous vibration and mechanical loads without cracking, which is especially vital for components subjected to fatigue, such as in vehicles.
The university did not specify exact strength values or detailed test conditions in their announcement, only mentioning that improvements are relative. The researchers emphasized that this approach aims to enhance the reliability of structures involving mixed metals. Combining steel and aluminium is common to achieve lighter yet durable constructions, but weak joints have historically limited such designs. The research was conducted as a joint effort with Chinese collaborators.
Potential for lighter vehicles, aircraft, and infrastructure
According to the scientists, the ultrasonic welding technology could find applications across automotive, aerospace, and construction sectors. In the automotive industry, it could facilitate the joining of steel safety cages to aluminium doors, bonnets, and wings. Such lightweight hybrid structures might enable electric vehicles to travel longer distances on a single charge. In aeronautics, reducing weight of airframes could allow for increased passenger or cargo capacity while decreasing fuel consumption. Both industries prioritize weight reduction as a crucial objective.
Within the construction field, the method could be utilized for metal joints in bridges and skyscrapers. The university suggested that these welds might outperform solid concrete connections in terms of strength. Though the team has not specified when the technology might become commercially available, South Ural State University has announced multiple applied research initiatives this year. The institution believes this technique opens new pathways for developing lighter, yet more resilient, structural materials.