MOSCOW, Russia / EuroWire.IO / – The application of ultrasonic welding by scientists from Russia and China has resulted in metal joints that are twice as strong, with a nearly 1.9-fold increase in the lifespan of welded components. This advancement was achieved through collaborative efforts led by researchers at South Ural State University in Chelyabinsk, alongside colleagues from China. The findings were reported by TV BRICS, citing the university. The innovation focuses on creating robust joints between dissimilar metals such as steel and aluminium.
Engineers have traditionally faced difficulties when joining different types of metals, as brittle intermetallic layers tend to form at the interface. These layers are prone to cracking under stress, compromising structural integrity. The new ultrasonic approach aims to minimize this issue during spot welding—a technique extensively used in manufacturing car bodies and other assemblies. According to the university, the research was published in the journal Engineering Fracture Mechanics.
This method involves incorporating ultrasonic waves with an approximate power of 1,200 watts into the spot welding process. The vibrations promote a refinement of the metal’s crystal structure within the weld, with crystal size decreasing by nearly five times. The crystals become smaller and more uniform, replacing coarse structures. Additionally, the process reduces the brittle intermetallic layers at the joint by half, enhancing joint quality.
Ultrasound clears air bubbles from welds
Beyond structural improvements, ultrasound helps expel trapped air bubbles from the weld during formation. This results in denser welds with fewer internal flaws. Testing revealed that the strength of the joints doubled using this technique, and the expected service life of the components increased by 90%, or 1.9 times. The researchers noted that these welds exhibit greater resistance to prolonged vibration and mechanical stress, reducing the risk of cracking. Such fatigue resistance is critical for parts in moving vehicles.
The university did not disclose specific strength metrics or detailed testing conditions in its announcement, reporting improvements in relative rather than absolute terms. The researchers emphasized that their approach aims to enhance the reliability of mixed-metal structures. Steel and aluminium are frequently combined to reduce weight while maintaining strength, but historically, weak joints have limited these applications. This project was conducted collaboratively with Chinese partners.
Implications for lighter transportation and infrastructure
The development could have significant impacts across automotive, aerospace, and construction sectors. In vehicle manufacturing, it might facilitate stronger connections between steel safety cages and aluminium doors, bonnets, and wings. Such lightweight hybrid structures could enable electric vehicles to achieve longer ranges per charge. In aviation, reducing weight of airframes could allow for increased passenger or cargo capacity while lowering fuel consumption. Weight reduction remains a central goal for both industries.
In construction, the ultrasonic welding method could be applied to metal joints in bridges and skyscrapers, potentially offering a stronger alternative to monolithic concrete. The university has not specified when this technology might be adopted industrially. South Ural State University has announced several applied research initiatives this year and suggests that this technique opens new pathways toward designing lighter, more durable structures.