Attenuation and Grain Noise Parameters in Ni-Base Alloys
The frequency dependent ultrasonic attenuation and grain noise were determined for samples of three alloys often used in jet aircraft engine turbine discs: Waspalloy, IN-100, and Ti-6246. In addition to propagation of longitudinal waves, also shear waves were considered. The frequency dependence was extracted from broadband echos received through a low attenuation buffer. A key feature of the results for IN-100 is the presence of a low concentration of micropores which appear to influence the scattering of ultrasound and therefore the attenuation and material noise values. Of the three alloys, Waspalloy was found to have the highest attenuation value and Ti-6246 the lowest.