Simulating Elastic Wave Propagation in RR1000 Alloy: Impact of Grain Size and Texture

Abstract Nickel-based superalloys are the best suited for aero-engine parts because of their excellent high-temperature performance and long-term reliability. The Rolls Royce (RR)-1000 alloy is one of the prime materials used in aero-engine turbine discs; the microstructure of which is specially engineered to address fatigue failure at the inner radius and creep failure at the periphery. This study investigates the combined effect of grain size variation and crystallographic texture on the propagation of elastic waves in such microstructure. Subject to a thermomechanical environment, microstructural morphologies get affected by grain growth and texture formation, impacting their operational fulfillment and potentially leading to intergranular fractures. Elastic wave propagation technique is employed to characterize the microstructural morphologies, such as the grain size distribution with and without preferred orientation (texture). The results indicate that group wave velocity (Vg) is more sensitive to grain size and follows a definitive pattern with variation in grain size. In contrast, Vg remains largely unaffected in textured microstructure irrespective of variation in grain size. These findings offer novel insights for nondestructive evaluation (NDE) of next-generation superalloys used in demanding environments.