New Ni-based superalloys designed for laser additive manufacturing

Highlights: • New Ni-based superalloys were designed using a "cluster-plus-glue-atom" model. • The Ni-based superalloys were fabricated by laser additive manufacturing. • Systematical study on microstructure and properties of the as-deposited alloys was performed. • The content of TCP phases can be controlled by adjusting the added amount of Cr-like elements. • The alloy with the fewest Laves phase has a novel combination of properties and weldability. -- Abstract: To balance the relationship between weldability and properties, a series of Ni-based superalloys with varying amount of Cr-like elements were designed using a "cluster-plus-glue-atom" model, and fabricated by laser additive manufacturing (LAM). The microstructure of the as-deposited superalloys consists of few topological close packet (TCP) phases distributed between γ-Ni dendrites with epitaxial growth characteristic. With the increase of Cr-like elements amount, TCP phases change from granular Laves phase to long-striped Laves phase plus acicular σ phase, and exhibit a trend of first decreasing and then increasing in amount. The mechanism for such microstructure evolution was analyzed. Performance tests reveal that the NiCr_like-2 alloy (Ni_54.8Fe_20.3Cr_17.3Mo_1.50Al_1.56 Nb_3.47Ti_1.22 at.%), which has the fewest amount of TCP phases, presents a novel combination of strength, ductility, high temperature oxidation-resistance, and good weldability.