Review on Additive Manufacturing of Single-Crystal Nickel-based Superalloys

The conventional fabrication process for single-crystal nickel-based superalloy materials is directional solidification, which is classified as casting. With the rapid development of additive manufacturing (AM) technologies, a novel process for fabricating single-crystal superalloys has become possible. This article reviews recent research on the AM of single-crystal nickel-based superalloys. Laser AM technologies, particularly directed energy deposition, are mainly used to repair single-crystal materials. Electron beam powder bed fusion is an innovative method for the direct fabrication of single-crystal materials. Accordingly, the mechanisms of single-crystal formation during AM are analyzed to elucidate the potential of this process route. Furthermore, this article discusses the challenges faced by AM for single-crystal fabrication, and provides perspectives on the trends of future developments.