Laser powder bed fusion of difficult-to-print γ′ Ni-based superalloys: A review of processing approaches, properties, and remaining challenges

Metal additive manufacturing (AM) promises a revolution with the potential to fabricate more complex, lighter, and higher performance components while simplifying supply chains and reducing material waste. However, many of the superalloys that are critical to applications requiring superior high-temperature properties are also challenging to process using fusion-based AM. The number of publications on this topic has grown significantly in the past five years, reflecting a growing interest within industry and academia. This article reviews and discusses the challenges associated with powder bed fusion - laser beam (PBF-LB) of γ′ Ni-based superalloys and recent approaches that have enabled their processing. This includes process parameter optimization, alloy modification, and heat treatment, all of which have been shown to produce material with reduced defect density. Additionally, the properties of γ′ Ni-based superalloys made with PBF-LB and conventional (cast and wrought) processes are compared and the reasons for the observed differences are discussed. Current and future research trends are provided based on the current outstanding challenges and prevailing theories in the literature, as well as an outlook on the adoption of PBF-LB γ′ Ni-based superalloys in industry.