Electron-beam welding of Zr-based bulk metallic glasses

Electron-beam welding of Zr-based bulk metallic glass (BMG) plates with an excellent glass forming ability and thermally stable supercooled liquid state has been tried to overcome the subject of joining in metallic glasses. A Zr41Be23Ti14Cu12Ni10 BMG plate with a thickness of 3.5 mm was successfully welded together with keeping the amorphous structure, but a Zr55Al10Ni5Cu30 BMG plate resulted in crystallization of the bead and heat-affected zone (HAZ). In the successfully welded Zr41Be23Ti14Cu12Ni10 BMGs, no defect or crack was observed around the bead and heat-affected zone. The tensile strength of the welded BMG was identical with that of the original BMG. Furthermore, electron-beam welding of the Zr41Be23Ti14Cu12Ni10 BMG plate to crystalline Zr metal or Ti metal was tried. The welding to Ti metal was failed due to formation of a brittle intermetallic compound phase in the interface. On the other hand, the Zr41Be23Ti14Cu12Ni10 BMG plate was successfully welded to the Zr metal with ductile interface. The BMG around the interface kept the amorphous structure and ductility. Formation of any crystalline phases except for hcp-Zr was not observed around the interface.