Additive Manufacturing of Nickel-Based Superalloy Single Crystals with IN-738 Alloy

The production of non-weldable nickel-based superalloys, especially single-crystal superalloys, is important for additive manufacturing. Single-crystal specimens of non-weldable nickel-based superalloys were produced by electron beam selective melting using an IN-738 alloy. In this study, single-crystal nickel-based superalloy specimens of different sizes were prepared by a multiple preheating process and tight control of the melting parameters without the need for a grain selector or single-crystal seed for the first time. Electron backscattered diffraction measurements were performed to confirm the presence of a single crystal. The transition boundaries between the polycrystalline and single-crystal regions at the edges and bottom of the samples were characterized to analyze the formation of single crystals.