MOSCOW, Russia / EuroWire.IO / – A collaborative effort between scientists from Russia and China has resulted in an innovative ultrasonic welding process capable of doubling the tensile strength of metal joints. This approach also enhances the durability of welded parts by a factor of 1.9. The research team, led by experts at South Ural State University in Chelyabinsk, collaborated closely with colleagues from China. The results, reported by TV BRICS and citing the university, focus on welds connecting dissimilar metals such as steel and aluminium.
Engineers have long faced difficulties when welding different metals together due to the formation of brittle intermetallic layers at the interface, which tend to crack under stress and compromise the overall integrity of the structure. The newly developed method aims to mitigate this issue during spot welding—a common technique used to assemble car bodies and other metal structures. According to the university, the findings have been published in the journal Engineering Fracture Mechanics.
The process involves injecting ultrasonic vibrations of approximately 1,200 watts into the welding operation. These vibrations promote a refinement of the metal’s crystal lattice within the weld zone. The university states that the crystal size diminishes by nearly five times, resulting in a uniform and fine-grained structure rather than a coarse one. Additionally, this technique reduces the thickness of brittle intermetallic layers at the joint by 50%.
Ultrasound Eliminates Air Bubbles in Welds
Furthermore, the ultrasonic component helps expel trapped air bubbles from the metal during welding, producing denser welds with fewer internal flaws. Testing revealed that the strength of welded joints using this method was doubled, while the lifespan of the components increased by 90%, or 1.9 times. Researchers noted that these welds demonstrate improved resistance to long-term vibration and mechanical load, which are essential qualities for parts in moving machinery.
While the university did not specify absolute strength metrics or detailed experimental conditions, the improvements were expressed in relative terms. The researchers emphasized that their approach enhances the reliability of structures made from dissimilar metals, particularly steel and aluminium, which are often combined to achieve weight reduction without sacrificing strength. Historically, weak joints between these materials have limited design options. This project was conducted jointly with Chinese experts.
Potential Impact on Lightweight Vehicles, Aircraft, and Construction
The scientists indicated that this ultrasonic welding technique could find applications across various sectors, including automotive, aerospace, and civil engineering. In automobiles, it could facilitate joining a steel safety cage with aluminium doors, bonnets, and wings. This would enable the creation of lighter hybrid body structures, helping electric cars to extend their driving range per charge. In the aviation industry, lighter aircraft frames could carry more passengers or cargo while reducing fuel consumption. Achieving weight savings remains a vital objective for both fields.
In construction, the method might be employed to bond metals in bridges and skyscrapers. The university suggests that such joints could potentially outperform monolithic concrete in strength. However, the timing for the technology’s transition into commercial use remains unspecified. South Ural State University has reported multiple applied research initiatives this year, emphasizing that this innovative method broadens prospects for building lighter, yet more durable, structures.
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