Dissimilar friction stir welding
Dissimilar friction stir welding (DFSW) is the application of friction stir welding (FSW), invented in The Welding Institute (TWI) in 1991, to join different base metals including aluminum, copper, steel, titanium, magnesium and other materials. It is based on solid state welding that means there is no melting.
Source: Wikipedia — Dissimilar friction stir welding (CC BY-SA 4.0)