Single Crystal Nickel-Base Superalloy

A modified alloy, known as Modified PWA1484, is a single-crystal nickel-base superalloy, developed under a NASA Marshall Space Flight Center contract for use as a turbine blade and vane alloy for the space-shuttle main engine(SSME). This alloy is a modified PWA 1484 composition that uses innovative thermal-process techniques to generate a microstructure specifically tailored for SSME application. The superalloy exhibits significantly better fatigue and crack-growth resistance than previous turbine-blade alloys (such as PWA1480), particularly under severe hydrogen-embrittling conditions.