White Beam Transmission Topography of Nickel-Based Alloy Single Crystal Turbine Blades using Synchrotron Radiation

Abstract

X-ray diffraction in metals and alloys involves only low energy x-rays because of the typical interatomic spacings encountered in single crystals of these materials. Since these low energy diffracted x-rays are readily absorbed in alloys involving elements of higher atomic numbers, a diffraction imaging technique in transmission is not necessarily trivial for these materials. Several nickel-based alloy single crystal turbine blades have been examined using the x-ray diffraction technique known as “White Beam Transmission Topography”, (WBTT), in combination with the extremely high flux of low energy x-rays available from the National Synchrotron Light Source at Brookhaven National Laboratory. The technique is described, and diffraction images are presented and discussed for several specific cases.