MOSCOW, Russia / EuroWire.IO / – Scientists from Russia and China have developed an ultrasonic welding technology that doubles the strength of metal joints. The method also extends the service life of welded components by 1.9 times. The work was led by researchers at South Ural State University in Chelyabinsk, working with colleagues from China. TV BRICS reported the results, citing the university. The technique targets joints between metals with different properties, such as steel and aluminium.
Joining dissimilar metals has long been a challenge for engineers. Brittle intermetallic layers tend to form where the two materials meet. These layers can crack under load and weaken the whole structure. The new method aims to reduce that risk during spot welding. Spot welding is widely used to join metal sheets in car bodies and other assemblies. The university said the findings were published in the journal Engineering Fracture Mechanics.
The technique adds ultrasonic waves with a power of around 1,200 watts to the spot welding process. The vibration refines the crystal structure of the metal inside the weld. According to the university, crystal size falls by nearly five times. The crystals become small and uniform rather than coarse. The process also halves the thickness of the brittle layers that form at the joint between the two metals.
Ultrasound removes air bubbles from welds
The ultrasound also drives air bubbles out of the metal during welding. That produces denser welds with fewer internal defects. Tests showed that joint strength doubled with the new method. The service life of components increased by 90%, or 1.9 times. The researchers said the welds can better withstand prolonged vibration and mechanical stress without cracking. Such fatigue resistance is a key requirement for parts in moving vehicles.
The university did not publish absolute strength values or detailed test parameters in its announcement. The gains were reported in relative terms. The researchers described the approach as a way to make mixed-metal structures more reliable. Steel and aluminium are often combined to reduce weight while keeping strength. Weak joints between the two metals have limited such designs in the past. The work was carried out as a joint project with Chinese colleagues.
Lighter cars, aircraft and buildings in view
The researchers said the technology could be used in the automotive, aerospace and construction industries. In cars, it could help join a steel safety cage to aluminium doors, bonnets and wings. Lighter hybrid bodies could allow electric vehicles to travel further on a single charge. In aviation, lighter airframes could carry more passengers or cargo while using less fuel. Weight savings are a key goal for both sectors.
In construction, the method could be used for metal joints in bridges and high-rise buildings. The university said such joints could hold together more strongly than monolithic concrete. The researchers have not said when the technology could reach industrial use. South Ural State University has reported several applied research projects this year. The university said the method opens new possibilities for producing lighter and stronger structures.