RESONANT ULTRASOUND SPECTROSCOPY FOR DEFECT DETECTION IN SINGLE CRYSTAL SUPERALLOY CASTINGS

Resonant ultrasound spectroscopy (RUS) has been combined with forward finite element (FE) models of resonance for detection of grain structure defects in single crystal Ni-based superalloys. The nondestructive evaluation (NDE) potential of RUS is demonstrated with experiments on Mar-M247 single crystals that were shot peened and solution heat treated to induce surface recrystallization. FE models using self-consistent elastic properties and variable recrystallization depths show excellent agreement with RUS measured results, allowing for the effect of recrystallization on resonance to be isolated and quantified. The validated FE modeling framework is then extended to a turbine blade model for exploring RUS as a NDE technique of grain structure defects in complex geometry components. Extension of RUS to evaluate defects, anomalies, and damage mechanisms relevant to manufacturing process control and component life-cycle management is also discussed.