High Energy X-Ray Diffraction Technique for Monitoring Solidification of Single Crystal Castings

Abstract

X-ray diffraction has been used successfully to study metal solidification and temperature-dependent phase changes^1–3. However, this research used very thin specimens (a few mm at most), furnaces with low attenuation x-ray windows (beryllium, graphite, or polyimide), and low x-ray energies (< 50 keV). Since the penetration depth of low-energy x-rays is shallow, traditional x-ray diffraction is thus unable to probe the interior of thicker structures. Others have used higher energies to study thicker samples. Work, including that by Green⁴ and by Kopinek, et al⁵, extended x-ray diffraction investigations to energies exceeding 150 keV.