MOSCOW, Russia / EuroWire.IO / – Researchers from Russia and China have created an ultrasonic welding process that doubles the tensile strength of metal connections. This innovative approach also prolongs the lifespan of welded parts by a factor of 1.9. The development was led by scientists at South Ural State University in Chelyabinsk, in collaboration with colleagues from China. TV BRICS highlighted the findings, citing the university. The method specifically targets joints between metals with differing properties, such as steel and aluminium.
Creating effective bonds between dissimilar metals has historically posed significant challenges for engineers. The formation of brittle intermetallic layers at the interface can lead to cracking under stress, compromising the entire structure. The newly developed technique seeks to mitigate this risk during spot welding, a process extensively used for joining metal sheets in automobile bodies and other assemblies. The university confirmed that the research was published in the journal Engineering Fracture Mechanics.
By introducing ultrasonic vibrations of approximately 1,200 watts into the welding process, the technique enhances the crystal structure of the metal within the weld zone. The university reports that the crystal size reduces nearly fivefold, resulting in smaller, more uniform grains instead of coarse structures. Additionally, the process cuts the thickness of the brittle intermetallic layers at the joint in half, improving overall joint integrity.
Ultrasound facilitates removal of trapped air in welds
During welding, ultrasound also promotes the expulsion of air bubbles from the metal, resulting in denser welds with fewer internal flaws. Testing demonstrated that the strength of joints created with this method is doubled. Moreover, the lifespan of the welded components increased by 90%, or 1.9 times. The scientists noted that these welds are more resistant to long-term vibration and mechanical stresses, which reduces the likelihood of cracking. Such improvements are particularly important for parts used in moving vehicles.
The university did not disclose specific strength measurements or detailed testing parameters in its public statement. The reported improvements are relative rather than absolute. The researchers emphasized that this approach aims to improve the reliability of structures made from mixed metals. Steel and aluminium are often combined to achieve weight reduction while maintaining strength, but weak joints between the two materials have previously limited their use. The project was conducted jointly with Chinese partners.
Potential applications for lightweight vehicles, aircraft, and infrastructure
According to the researchers, the ultrasonic welding technique could find practical use in the automotive, aerospace, and construction sectors. In automobile manufacturing, it could enable better joining of a steel safety cage with aluminium doors, bonnets, and wings. Such lighter hybrid structures could increase electric vehicle range by enabling more efficient weight management. In the aviation industry, lighter aircraft frames would allow for more passenger or cargo capacity, all while reducing fuel consumption. Weight reduction remains a critical goal for both industries.
In the realm of construction, the method could be employed to create stronger metal joints in bridges and skyscrapers. The university indicated that these joints could outperform monolithic concrete in durability. The timing for the technology’s commercial deployment remains unspecified. South Ural State University has reported several applied research projects this year and believes this method opens up new avenues for constructing lighter yet more durable structures.