By Mark Norfolk on Tuesday, February 2nd, 2016
The solid-state nature (i.e. no melting) of ultrasonic bonding permits joining of dissimilar metals without the formation of brittle intermetallics seen in fusion processes. A wide range of material combinations have been successfully bonded using the technology while still maintaining their own individual metallic properties; such as, Al/Cu, Al/Fe and Al/Ti are routinely joined. Fabrisonic has also worked with exotic combinations such as Ta/Fe, Ag/Au and Ni/Stainless. In theory, with enough ultrasonic power, the process should be able to bond any dissimilar metals.
One great application for welding dissimilar metals is production of transition joints. In many industries, there is often a need to transition from metal A to metal B. For instance, in liquefied natural gas systems, part of the system is made from aluminum and other parts from stainless. Welding aluminum to stainless is very difficult with fusion based 3D metal printing because it creates intermetallic compounds that are highly brittle. Solid-state welding is the best approach to making these types of joints. Fabrisonic can 3D print custom transition joints from many dissimilar metal combinations. The picture below is a two inch thick slab of metal. The first inch is 304 stainless to which another inch of 5052 aluminum has been printed one layer at a time.