Amorphization at the welded boundary between 5052 aluminum alloy and zirconium by friction stir diffusion bonding

Abstract

Microstructure at the boundary between 5052Al and zirconium foils subjected to friction stir diffusion bonding (FSDB) was examined by transmission electron microscopy (TEM). 5052Al and zirconium foils were welded by travelling of a rotating tool with microindention only into the 5052Al foil. The welding strength of the specimens was higher than the fracture strength of the 5052Al foil. An amorphous layer with a thickness of 2 to 100 nm was found at the welded boundary by edge-on TEM observation. An amorphous phase at a welded boundary has been also reported for other dissimilar metal welding, e.g. aluminum and iron alloys, which exhibits high welding strength. Microstructural evolution at the welded boundary is discussed for dissimilar welding of 5052Al and zirco-nium.