MOSCOW, Russia / EuroWire.IO / – Researchers from Russia and China have pioneered an ultrasonic welding process that effectively doubles the tensile strength of metal joints. This innovative approach also increases the durability of welded parts by a factor of 1.9. The project was spearheaded by scientists at South Ural State University in Chelyabinsk, in partnership with colleagues from China. The findings, reported by TV BRICS and based on university research, specifically target the joining of dissimilar metals such as steel and aluminium.
Creating reliable bonds between different metals has historically posed difficulties for engineers due to the formation of brittle intermetallic layers that crack under stress, weakening the overall structure. The new ultrasonic technique aims to minimize this issue during spot welding, a common method for attaching metal sheets in vehicle bodies and other assemblies. According to the university, the results were published in Engineering Fracture Mechanics.
The process involves integrating ultrasonic vibrations with a power output of approximately 1,200 watts into the welding procedure. These vibrations refine the internal crystal structure of the metal within the weld, reducing crystal size by nearly five times and creating a uniform, fine-grained pattern. Additionally, this method cuts the thickness of the brittle intermetallic layers at the joint by half.
Ultrasound Eliminates Air Bubbles for Stronger Welds
During welding, ultrasound also expels trapped air bubbles from the metal, leading to denser welds with fewer internal flaws. Testing revealed that joint strength was doubled with this new technique, and the lifespan of the components increased by 90%, or 1.9 times. The researchers noted that these welds are more resistant to prolonged vibration and mechanical stress, reducing the risk of cracking—an essential feature for parts in moving vehicles.
While the university did not disclose specific strength measurements or detailed testing parameters, the improvements were expressed in relative terms. The scientists emphasized that this approach enhances the reliability of structures composed of mixed metals like steel and aluminium, often used to achieve weight reduction without sacrificing strength. Past challenges with weak joints between these metals have limited such designs, but this new method offers a promising solution. The research was conducted jointly with Chinese experts.
Potential Impact on Lightweight Vehicles, Aircraft, and Construction
The scientists believe this ultrasonic welding advancement could be applied across the automotive, aerospace, and construction sectors. For automobiles, it enables stronger connections between steel safety cages and aluminium doors, bonnets, and wings, facilitating the creation of lighter hybrid bodies that extend electric vehicle ranges. In aviation, lighter airframes could accommodate more passengers or cargo, reducing fuel consumption. Weight reduction remains a key objective in both industries.
In construction, the ultrasonic method could be used for metal joints in bridges and skyscrapers. The university claims such joints could outperform monolithic concrete in holding capacity. The timeline for industrial adoption remains unspecified. South Ural State University has reported several applied research initiatives this year, highlighting the method’s potential to produce structures that are both lighter and more durable.