MOSCOW, Russia / EuroWire.IO / – Researchers from South Ural State University in Chelyabinsk, in collaboration with Chinese colleagues, have developed an ultrasonic welding technique that effectively doubles the strength of metal joints. This innovative method also increases the durability of welded parts by 1.9 times. TV BRICS highlighted these findings, referencing the university. The new process is designed to enhance joints between metals with differing properties, like steel and aluminium.
Creating reliable bonds between dissimilar metals has traditionally been a significant hurdle for engineers. The formation of brittle intermetallic layers at the interface often leads to cracks under stress, compromising the integrity of the entire structure. This new approach aims to mitigate that issue during spot welding, a technique commonly employed to assemble metal sheets in vehicle bodies and other structures. The university announced that their research was published in Engineering Fracture Mechanics.
The process involves integrating ultrasonic vibrations with a power of approximately 1,200 watts into the spot welding procedure. These vibrations help to refine the metal’s crystal structure within the weld zone, reducing crystal size by nearly five times. Instead of coarse crystals, the process produces smaller, uniform structures. Additionally, the method cuts the thickness of brittle layers at the joint in half, enhancing the overall joint quality.
Ultrasound eliminates air pockets from welds
During welding, ultrasound also drives out trapped air bubbles from the metal, resulting in denser welds with fewer internal flaws. Testing revealed that the strength of joints created with this method doubled, and the lifespan of the components increased by 90%, or 1.9 times. The researchers emphasized that these welds can better endure prolonged vibrations and mechanical loads without cracking. Such resistance to fatigue is especially important for parts in moving vehicles.
The university’s announcement did not include specific strength measurements or detailed testing protocols. The reported improvements were expressed in relative terms. The scientists see this technique as a way to enhance the reliability of structures made from mixed metals. Combining steel and aluminium is a common strategy to reduce weight while maintaining strength, but weak joints have historically limited such designs. This research was conducted as a joint project with Chinese partners.
Implications for lighter vehicles, aircraft, and infrastructure
The researchers indicated that this ultrasonic welding technology could find applications across the automotive, aerospace, and construction sectors. In automobiles, it could be used to bond a steel safety cage to aluminium doors, hoods, and wings. Creating lighter hybrid frames could help electric cars achieve longer ranges per charge. In aviation, reducing aircraft weight could enable larger passenger capacities or cargo loads while lowering fuel consumption. Weight reduction remains a critical aim in both industries.
In construction, this method could be utilized for metal joints in bridges and high-rise buildings, with the potential for these connections to outperform monolithic concrete in strength. The university has not specified when this technology might be adopted industrially. South Ural State University has announced several applied research initiatives this year, emphasizing that this technique offers promising avenues for developing lighter yet more durable structures.