ACOUSTIC MICROSCOPY WALL THICKNESS MEASUREMENTS ON NICKEL BASED SUPERALLOY GAS TURBINE BLADES

摘要

Wall thickness measurements have been carried out on two single crystal nickel-based superalloy components, a specially cast testpiece and a gas turbine blade. The measurements on the testpiece yielded an optimized set of elastic constants for the superalloy. Mechanically and ultrasonically measured thicknesses agree to within 2% for the testpiece and 10% for the blade. Echo amplitude variations observed are in reasonable accordance with calculation. The simple analysis of the pulse transit time based on the phase velocity breaks down at the leading and trailing edges of the blade where the curvature is largest. A more detailed analysis taking into account this curvature is underway.