A novel high-performance Co-Al-W-based superalloy for additive manufacturing

Abstract

An unprecedented high-γ' content Co-Al-W-based superalloy ZGH688 has been proposed for laser-directed energy deposition (L-DED), which exhibits excellent crack-resistant and mechanical properties. In this alloy, the volume fraction of γ' phase is 77.5 ± 5.5 %, surpassing other typical Ni/Co superalloys fabricated by additive manufacturing technique. Meanwhile, the γ' precipitate shows an excellent cubic degree with a 47.7 ± 7.6 nm side length. A series of crack evaluation criteria show that the composition of ZGH688 alloy falls into the crack-free zone. Additionally, this work validates that the modeling approach to defect optimization in Ni-based superalloys is suitable for Co-Al-W-based alloys. Finally, the newly AMed ZGH688 alloy demonstrates superior mechanical behavior under both room and high temperatures compared with other as-built Ni/Co-based superalloys. This work demonstrates the enormous potential of the freshly Co-Al-W-based superalloys in additive manufacturing for high-temperature applications.