MOSCOW, Russia / EuroWire.IO / – In Chelyabinsk, during recent months, scientists from Russia and China have pioneered an ultrasonic welding technique that effectively doubles the strength of metal bonds. This innovative approach also prolongs the lifespan of welded parts by a factor of 1.9. The project was spearheaded by researchers at South Ural State University in Chelyabinsk, in collaboration with Chinese colleagues. The results, reported by TV BRICS and attributed to the university, demonstrate the method’s focus on joining metals with differing characteristics, such as steel and aluminium.
Engineers have historically faced significant difficulties when welding dissimilar metals, as brittle intermetallic layers tend to form at the junctions. These layers are prone to cracking under stress, weakening the entire assembly. The new ultrasonic welding technique aims to mitigate this issue during spot welding, a common process used in assembling car bodies and other structures. The university announced that the research was published in Engineering Fracture Mechanics.
The process incorporates ultrasonic vibrations of approximately 1,200 watts into traditional spot welding. This vibration refines the crystal structure within the weld, reducing crystal size by nearly five times, resulting in smaller, more uniform crystals rather than coarse ones. Additionally, the technique cuts the thickness of the brittle intermetallic layers at the joint between the two metals by half, enhancing the weld’s integrity.
Ultrasound eliminates air pockets within welds
Beyond refining the crystal structure, ultrasonic waves also expel trapped air bubbles during welding, creating denser joints with fewer internal flaws. Testing revealed that the strength of welded joints using this method doubled, and the lifespan of the components increased by 90%, or 1.9 times. The researchers highlighted that these welds are more resistant to sustained vibrations and mechanical stress without cracking, a vital trait for parts in moving vehicles.
The university did not specify exact strength metrics or detailed testing parameters in its announcement, opting instead for relative improvements. The researchers emphasized that this technique enhances the reliability of mixed-metal structures, which typically combine steel and aluminium to reduce weight while maintaining strength. Previously, weak joints limited the broader application of such designs. This project was a joint effort with Chinese partners.
Potential impact on automotive, aerospace, and construction sectors
The scientists believe that the ultrasonic welding method could find application in automotive, aerospace, and building industries. In automotive manufacturing, it could enable stronger connections between steel safety cages and aluminium doors, bonnets, and wings. Lighter hybrid structures might allow electric vehicles to increase their range per charge. In aviation, lighter airframes could carry more passengers or cargo while consuming less fuel. Reducing weight remains a crucial goal for both fields.
Within the construction domain, the new ultrasonic technique could be used to join metal components in bridges and skyscrapers. The university suggests such joints could outperform traditional monolithic concrete in holding assemblies together. While an exact timeline for commercial adoption has not been disclosed, South Ural State University has reported several applied research projects this year. The institution believes that this approach opens new avenues for creating lighter, more durable structures.