MOSCOW, Russia / EuroWire.IO / – Researchers from Russia and China have pioneered an ultrasonic welding technique that effectively doubles the tensile strength of metal connections. This innovative process also boosts the durability of welded parts by 1.9 times. The project was spearheaded by scientists at South Ural State University in Chelyabinsk, collaborating with their counterparts from China. The results were reported by TV BRICS, citing the university. This method is specifically designed to enhance joints between dissimilar metals, such as steel and aluminium.
For many years, combining different metals has posed significant challenges for engineers. The formation of brittle intermetallic layers at the interface often leads to cracking under stress, compromising overall integrity. The new ultrasonic welding approach aims to mitigate this issue during spot welding, a common technique used to join metal sheets in automotive bodies and various assemblies. According to the university, these findings have been published in Engineering Fracture Mechanics.
The process incorporates ultrasonic vibrations of approximately 1,200 watts into traditional spot welding. These vibrations refine the crystal structure within the weld, with the university reporting that crystal sizes decrease by nearly fivefold. The crystals become smaller and more uniform, replacing coarse structures. Additionally, the technique reduces the thickness of the brittle intermetallic layers at the joint by half, enhancing overall weld quality.
Ultrasound Eliminates Air Bubbles in Welds
Ultrasound application during welding also facilitates the removal of air pockets from the metal, resulting in denser welds with fewer internal flaws. Testing demonstrated that the strength of the joint doubled using this method, while the lifespan of the components increased by 90%, or 1.9 times. The researchers highlighted that these welds are more resistant to long-term vibration and mechanical stress, reducing the risk of cracking. Such fatigue resistance is crucial for parts in moving vehicles.
The university’s announcement did not include specific strength metrics or detailed testing parameters; the improvements were expressed in relative terms. The team described their approach as a means to enhance the reliability of hybrid-metal structures. Combining steel with aluminium remains a popular strategy for reducing weight without sacrificing strength, but weak joints between the two have limited previous applications. This research was conducted as a joint effort with Chinese partners.
Potential for Lighter Vehicles, Aircraft, and Construction
The scientists indicated that this ultrasonic welding technology could find application in the automotive, aerospace, and building sectors. In automobiles, it could facilitate the joining of steel safety cages with aluminium doors, hoods, and wings. Lighter hybrid frames might enable electric vehicles to achieve longer travel distances per charge. In aviation, lighter airframes could carry more passengers or cargo while consuming less fuel. Weight reduction is a primary objective in both industries.
In construction, the method could be used to create more durable metal joints in bridges and skyscrapers. The university noted that such joints could potentially outperform monolithic concrete in strength. The timing for commercial deployment of this technology has not yet been announced. South Ural State University has reported multiple applied research projects this year. The institution emphasized that this method opens new avenues for developing structures that are both lighter and stronger.