By Mark Norfolk on Wednesday, September 5th, 2018
Joining of dissimilar metals is becoming more important as industries seek to optimize each portion of a product by combining different alloys into one part. For example in the automotive industry, bodies of vehicles are being made with aluminum to drive out weight, while frames of the vehicle are still being made with steel. Welding of two dissimilar metals can be extremely challenging, as many combinations for a brittle intermetallic during fusion welding.
In the 3D printing space, current technology allows designers to print whatever shape they want in any location in a part. Engineers would like to take this further and print any material at any location in a part. However, when it comes to 3D printing with metals, the complex interactions of multiple metals in a melt pool can turn an engineer’s dream into a nightmare.
Ultrasonic Additive Manufacturing (UAM), a patented 3D metal printing technology, eliminates common limitations in the 3D metal printing space. UAM empowers engineers to build products with different metals while maintaining the mechanical properties of those metals. The UAM process uses ultrasonic sound waves to merge layers of metal foil together in the solid-state, meaning there is no melting of the metals required. The process produces true metallurgical bonds with full density and works with a variety of metals including aluminum, copper, stainless steel, titanium, and more. Dissimilar metals can be printed together due to the low-temperature welding process.
The solid-state nature of the ultrasonic bonding process used in UAM permits joining of dissimilar metals without the formation of brittle intermetallics as seen infusion processes. A wide range of material combinations has been successfully bonded using ultrasonics. Al/Cu, Ni/Stainless, and Al/Ti are routinely joined. Fabrisonic has also worked with exotic combinations such as Ta/Fe, Ag/Au, Al/Mo, and Al/Invar. This capability permits the creation of unique high-performance multi-material parts for a wide array of engineering applications.
The video linked below demonstrates Fabrisonic’s SonicLayer 7200 printing aluminum foils and then transitioning to copper foils. The entire thickness of the part is 100% metallurgically bonded, yet the low temperature developed during ultrasonic welding does not create brittle phases at the interface. As shown, the metal being printed can be changed layer by layer throughout the manufacturing process. This enables UAM to print complex metallic gradients as well as simple transition joints.
Customers of Fabrisonic have solved complex dissimilar metal challenges utilizing UAM. Some examples include:
— An oil and gas customer has leveraged UAM to print a transition joint from stainless steel to aluminum. This joint was used in a pipeline application and allowed the customer to make a quick and easy transition from aluminum pipe to steel piping.
— UAM has been used several times to create novel metallic gradients for armor. For instance, the US Army has researched varying layers of aluminum and titanium to develop gradients for armor applications.
— The aluminum and copper joint shown in this video is used regularly to create high performing heat exchangers. By printing copper in strategic locations, designers can wick heat out of a critical location without having to build the entire structure out of expensive and heavy copper material