MOSCOW, Russia / EuroWire.IO / – A collaborative effort between scientists from Russia and China has resulted in an innovative ultrasonic welding technique that effectively doubles the strength of metal joints. Additionally, this method prolongs the durability of welded parts by 1.9 times. The project was directed by researchers at South Ural State University located in Chelyabinsk, in partnership with colleagues from China. The results, reported by TV BRICS and citing the university, focus on welding joints between metals with differing properties, such as steel and aluminium.
For a long time, joining dissimilar metals has posed significant challenges to engineers. The formation of brittle intermetallic layers at the contact point often leads to cracks under stress, undermining the overall integrity of the structure. The newly developed approach aims to mitigate this problem during spot welding, a technique commonly used for attaching metal sheets in automotive bodies and other assemblies. The university mentioned that these findings have been published in the journal Engineering Fracture Mechanics.
This process incorporates ultrasonic vibrations of approximately 1,200 watts into standard spot welding. These vibrations help refine the metal’s crystal structure within the weld zone, reducing crystal size by nearly five times and resulting in a finer, more uniform grain structure. Moreover, the method cuts the thickness of the brittle intermetallic layers in half at the joint, significantly enhancing joint quality.
Ultrasound eliminates air bubbles within welds
A key advantage of ultrasound application during welding is the removal of trapped air bubbles, leading to denser welds with fewer internal flaws. Testing revealed that joint strength was doubled using this technique, while the longevity of the components increased by 90%, or 1.9 times. The researchers emphasized that these welds demonstrate improved resistance to prolonged vibration and mechanical stress, reducing the risk of cracking—an essential feature for parts in moving vehicles.
The announcement from the university did not specify absolute strength metrics or detailed testing parameters. Instead, the improvements were expressed in relative terms. The scientists presented this method as a means to enhance the reliability of structures composed of different metals, such as steel and aluminium, which are often combined to achieve weight reduction without sacrificing strength. Previous designs faced limitations due to weak joints, but this new approach could help overcome those issues. The project was conducted jointly with Chinese researchers.
Potential for lighter vehicles, aircraft, and infrastructure
According to the researchers, this ultrasonic welding technology has potential applications across the automotive, aerospace, and construction sectors. For instance, in automotive manufacturing, it could enable stronger joins between steel safety cages and aluminium doors, bonnets, and wings. Developing lighter hybrid bodies could significantly extend the range of electric vehicles on a single charge. In the aviation industry, lighter airframes could carry more passengers or cargo while consuming less fuel, with weight reduction being a shared priority for both sectors.
In construction, this method could be used to create more robust metal joints for bridges and high-rise buildings. The university noted that such joints could outperform traditional monolithic concrete in terms of strength. The timeline for industrial deployment remains unspecified. South Ural State University highlighted several applied research initiatives this year and believes this technique offers new opportunities for producing lighter yet stronger structural elements.