MOSCOW, Russia / EuroWire.IO / – A collaborative effort between scientists from Russia and China has resulted in an ultrasonic welding technique capable of doubling the strength of metal joints. This innovative approach also enhances the longevity of welded parts by 1.9 times. The research was spearheaded by experts at South Ural State University in Chelyabinsk, with cooperation from Chinese colleagues. The results, as reported by TV BRICS, are based on the university’s findings. The method specifically addresses joints between metals with contrasting properties, such as steel and aluminium.
Difficulties in connecting dissimilar metals have long challenged engineers, mainly because brittle intermetallic layers tend to form at the interface. These layers are prone to cracking under stress, weakening the overall structure. The new method is designed to minimize this risk during spot welding, a technique commonly used to join metal sheets in vehicle bodies and other assemblies. The university announced that their findings have been published in the journal Engineering Fracture Mechanics.
The process involves introducing ultrasonic vibrations with a power of approximately 1,200 watts during spot welding. These vibrations help refine the internal crystal structure of the metal within the weld, reducing crystal size by nearly five times according to the university. Instead of coarse crystals, the process results in small, uniform ones. Additionally, the method cuts the thickness of brittle intermetallic layers at the joint by 50%.
Ultrasound eliminates air pockets in welds
The ultrasonic vibrations also facilitate the removal of air bubbles from the metal during welding, resulting in denser welds with fewer internal flaws. Testing indicated that the joint strength was doubled using this new technique. The lifespan of components increased by 90%, or 1.9 times. Researchers noted that these welds can better endure prolonged vibration and mechanical loads without cracking, an essential aspect for parts in moving vehicles.
The university did not disclose specific strength measurements or detailed testing parameters in their announcement. The reported improvements are given in relative terms. The scientists emphasized that this method aims to enhance the reliability of structures made from mixed metals. Steel and aluminium are often combined to reduce weight while maintaining strength, but weak joints have historically limited such designs. The project was conducted in partnership with Chinese colleagues.
Potential applications in lightweight vehicles, aircraft, and infrastructure
According to the researchers, this ultrasonic welding technology could find use in automotive, aerospace, and building sectors. In vehicles, it could enable better bonding of steel safety cages with aluminium doors, bonnets, and wings. Lighter hybrid car bodies could extend driving range for electric vehicles. In aviation, lighter frames could carry more passengers or cargo with reduced fuel consumption. Weight reduction remains a major goal for both fields.
In construction, the method might be applied to metal joints in bridges and skyscrapers. The university suggested that such connections could outperform even monolithic concrete in strength. The timeline for industrial implementation of this technology remains unspecified. South Ural State University highlighted several applied research projects this year and stated that their new method opens up opportunities for creating lighter, more durable structures.