MOSCOW, Russia / EuroWire.IO / – Enhancing the durability of welded metal connections has become a crucial focus for industries aiming for lighter, stronger structures. In this context, scientists from Russia and China have pioneered an ultrasonic welding technique that significantly improves joint integrity. The innovative method not only doubles the strength of welded bonds but also prolongs the lifespan of components by 1.9 times. This research was led by experts at South Ural State University in Chelyabinsk, in collaboration with colleagues from China. The results, as reported by TV BRICS, highlight the potential of this approach for metal joints involving materials with differing properties, like steel and aluminium.
Dissimilar metal joining has long posed engineering challenges, mainly due to the formation of brittle intermetallic layers that compromise structural integrity. Such layers tend to crack under stress, weakening the entire assembly. The new ultrasonic welding method aims to address this issue during spot welding, a process extensively used in manufacturing vehicle bodies and other metal structures. The university confirmed that the research findings were published in the journal Engineering Fracture Mechanics.
The process incorporates ultrasonic vibrations with a power level around 1,200 watts into conventional spot welding. These vibrations refine the crystal structure within the weld, reducing the crystal size by nearly five times. The resulting microstructure features small, uniform crystals instead of coarse ones, and the process effectively cuts the thickness of the brittle intermetallic layers at the joint by 50%.
Ultrasound Eliminates Air Bubbles from Welds
The ultrasonic application also facilitates the removal of trapped air bubbles during welding, leading to denser, defect-free welds. Testing revealed that the joint strength was doubled using this technique, with the overall service life of the welded parts increasing by 90%, or 1.9 times. Researchers noted that these welds exhibit improved resilience against prolonged vibration and mechanical stress, reducing the risk of cracking. Such fatigue resistance is essential for parts used in moving vehicles.
The announcement from the university did not specify exact strength values or detailed testing conditions, instead reporting the improvements in relative terms. The scientists emphasized that their approach enhances the reliability of mixed-metal structures. Steel and aluminium are frequently combined to reduce weight without sacrificing strength, but weak joints have historically limited such designs. This project was conducted collaboratively with Chinese partners.
Potential for Lighter Vehicles, Aircraft, and Infrastructure
The researchers believe this technology could find applications across the automotive, aerospace, and construction sectors. In car manufacturing, it could enable the attachment of steel safety cages to aluminium doors, hoods, and wings, fostering lighter hybrid bodies that extend electric vehicle range. In aerospace, lighter airframes could carry more passengers or cargo while consuming less fuel. Weight reduction remains a primary objective in both industries.
For construction, the ultrasonic welding method could be employed to join metals in bridges and skyscrapers. The university suggested that such joints could be more robust than monolithic concrete structures. The timeline for industrial deployment remains unspecified. South Ural State University has reported several applied research initiatives this year, emphasizing that this technique opens promising avenues for creating lighter, yet stronger, structural elements.