Measuring grain boundary character distributions in Ni-base alloy 725 using high-energy diffraction microscopy

• Published in: Metallurgical and materials transactions. B, Process metallurgy and materials processing science Vol. 48; no. 1
• Main Authors: Bagri, Akbar, Hanson, John P., Lind, J. P., Kenesei, Peter, Suter, Robert, Gradecak, Silvija, Demkowicz, Michael J.
• Format: Journal Article
• Language: English
• Published: United States ASM International 25.10.2016
• Subjects: Grain boundary character distr ibution (GBCD); High-energy diffraction microscopy (HEDM); MATERIALS SCIENCE; Microstructure; Nickel-base alloy 725
• ISSN: 1073-5615; 1543-1916

We use high-energy X-ray diffraction microscopy (HEDM) to characterize the microstructure of Ni-base alloy 725. HEDM is a non-destructive technique capable of providing three-dimensional reconstructions of grain shapes and orientations in polycrystals. The present analysis yields the grain size distribution in alloy 725 as well as the grain boundary character distribution (GBCD) as a function of lattice misorientation and boundary plane normal orientation. We find that the GBCD of Ni-base alloy 725 is similar to that previously determined in pure Ni and other fcc-base metals. We find an elevated density of Σ9 and Σ3 grain boundaries. We also observe a preponderance of grain boundaries along low-index planes, with those along (1 1 1) planes being the most common, even after Σ3 twins have been excluded from the analysis.