Characterization of Single-Crystal Dendrite Structure and Porosity in Nickel-Based Superalloys Using X-Ray Micro-Computed Tomography

Abstract

X-ray micro-computed tomography system has been used for visualization in two- (2-D) and three dimensions (3-D) of the dendrite structure and pores in single-crystals fabricated by Bridgman investment casting technique. The system described in the paper reconstructs 3-D geometry from a set of 2-D images obtained by multiple slicing of an X-ray radiography image. The results obtained in this study demonstrate the effect of withdrawal rate on the primary dendrite arm spacing and porosity in single-crystal made of CMSX-4 alloy.