MOSCOW, Russia / EuroWire.IO / – Researchers from Russia and China have introduced an ultrasonic welding technique that doubles the tensile strength of metal joints. This method also prolongs the lifespan of welded parts by 1.9 times. The development was led by scientists at South Ural State University in Chelyabinsk, in collaboration with Chinese colleagues. TV BRICS highlighted these findings, referencing the university. The approach focuses on welding connections between metals with differing properties, such as steel and aluminium.
Creating reliable bonds between dissimilar metals has historically posed a significant challenge for engineers. Intermetallic layers that are brittle often develop at the interface. These layers are prone to cracking under stress, weakening the overall structure. The new method aims to minimize this issue during spot welding. Spot welding is extensively used in assembling car bodies and other structures. The university stated that the research was published in the journal Engineering Fracture Mechanics.
The innovation involves adding ultrasonic waves with an approximate power of 1,200 watts to the spot welding process. These vibrations enhance the crystal structure of the metal within the weld. The university reports that the crystal size decreases by nearly five times. The resulting crystals are small and uniform instead of coarse. Additionally, the process reduces the brittle intermetallic layers at the joint by half in thickness.
Ultrasound eliminates trapped air in welds
Ultrasound also expels air bubbles during welding. This leads to denser welds with fewer internal flaws. Testing revealed that joint strength was doubled using this method. The lifespan of the components increased by 90%, or 1.9 times. The scientists noted that the welds are better equipped to endure prolonged vibration and mechanical forces without cracking. Such fatigue resistance is vital for parts in moving vehicles.
The university did not disclose exact strength values or detailed testing data. The improvements were described in relative terms. The researchers presented this approach as a way to improve the reliability of mixed-metal structures. Steel and aluminium are frequently combined to reduce weight while maintaining strength. Previously, weak joints limited such designs. The project was conducted jointly with Chinese experts.
Potential for lighter vehicles, aircraft, and structures
The scientists mentioned that the technology could benefit industries like automotive, aerospace, and construction. In automobiles, it could connect steel safety cages to aluminium doors, bonnets, and wings. Lighter hybrid bodies could enable electric cars to travel further on a single charge. In aviation, lighter fuselages could carry more passengers or cargo, reducing fuel use. Weight reduction remains a key target in both sectors.
In construction, the method might be used for metal joints in bridges and skyscrapers. The university stated that such joints could be stronger than monolithic concrete. It has not specified when the technology might see industrial application. South Ural State University reported several applied research projects this year. The university believes this method can help develop lighter, more durable structures.