MOSCOW, Russia / EuroWire.IO / – Researchers from South Ural State University in Chelyabinsk, in partnership with colleagues from China, have pioneered an ultrasonic welding technique that doubles the tensile strength of metal joints. The innovation also prolongs the lifespan of welded components by 1.9 times. TV BRICS highlighted the findings, citing the university. This method is specifically designed to improve welds between metals with different characteristics, such as steel and aluminium.
For many years, connecting dissimilar metals has posed significant challenges for engineers due to the formation of brittle intermetallic layers at the contact points, which tend to crack under stress, compromising the integrity of the assembly. The new approach aims to mitigate this issue during spot welding, a process commonly employed in manufacturing car bodies and similar structures. The university disclosed that the research was published in Engineering Fracture Mechanics.
This technique involves integrating ultrasonic vibrations of approximately 1,200 watts into the spot welding process. These vibrations help refine the crystal structure within the weld, reducing crystal size by nearly five times, resulting in finer, more uniform crystals instead of coarse ones. Additionally, the method cuts the thickness of the brittle intermetallic layers at the joint in half.
Ultrasound Eliminates Air Bubbles in Welds
The ultrasonic treatment also expels trapped air bubbles from the metal during welding, leading to denser welds with fewer internal flaws. Experimental results demonstrated that the joint strength was doubled with this new technique, and the lifespan of the welded parts increased by 90%, or 1.9 times. The scientists noted that the enhanced welds can better endure long-term vibrations and mechanical stresses without cracking, which is essential for parts in moving vehicles.
The university’s announcement did not include specific strength measurements or detailed testing parameters, instead reporting the improvements in relative terms. The researchers emphasized that this method can enhance the reliability of hybrid-metal structures, particularly those combining steel and aluminium to reduce weight while maintaining durability. Historically, weak joints between these metals have limited such innovative designs. The project was a joint effort with Chinese partners.
Potential Applications in Vehicles, Aerospace, and Construction
According to the researchers, the ultrasonic welding process could find applications across the automotive, aerospace, and construction sectors. In automotive manufacturing, it might facilitate attaching steel safety cages to aluminium doors, bonnets, and wings. The resulting lighter hybrid structures could enable electric vehicles to achieve longer ranges per charge. In aviation, lighter aircraft frames could carry more passengers or cargo while reducing fuel consumption. Weight reduction remains a critical goal in both industries.
Within construction, the new method could be used for metal connections in bridges and high-rise buildings. The university claims that such joints may be stronger than monolithic concrete. However, there has been no indication of when this technology might be adopted at an industrial scale. South Ural State University has announced several applied research projects this year, emphasizing that the ultrasonic welding approach opens new avenues for creating lighter, more durable structures.