HS31-X40 (also known as X-40) is a solid-solution cobalt-base alloy powder for laser powder bed fusion and directed energy deposition of gas turbine nozzle guide vanes, combustion liners, and transition duct hardware. Its high chromium and tungsten content provides strong resistance to sulfidation, oxidation, and thermal fatigue cracking in aggressive gas turbine combustion environments. Qualified under B50TF185, it serves aerospace, military, and power generation applications where additive manufacturing enables the production of complex nozzle geometries previously achievable only through investment casting.