Additive Manufacturing of Co-Based Superalloys via Direct Ink Writing

Additive manufacturing of superalloys enables innovative, geometrically complex designs combined with excellent mechanical properties. Here, we developed an additive manufacturing method based on direct ink writing (DIW), to fabricate a high-performance Co-based superalloy. The ink consists of metal powders, polymer binders, and volatile solvents. The deposited architectures are thermally sintered to near-full density, followed by ageing. The sintered Co-based superalloy exhibits a homogeneous microstructure of equiaxed grains with MC carbides uniformly distributed in the FCC matrix, which leads to a high ultimate tensile stress in excess of 1.2 GPa and a large tensile ductility over 20% at room temperature. The outstanding combination of strength and ductility originates from the coherent γ′ nanoprecipitates and deformation-induced stacking faults, as revealed by in situ synchrotron X-ray diffraction and high-resolution transmission electron microscopy. The introduced additive manufacturing approach provides new opportunities to print a wide range of superalloys for high-temperature applications.