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Predicting the Location of Low-Angle Boundaries in Single-Crystal Castings



R E. Napolitano, Robert J. Schaefer


A set of nickel-based superalloy single-crystal investment castings was produced and evaluated for crystal perfection. Defect structures near the seed emergence point and other geometric features were examined using x-ray topography. Topographic images were compared with metallographically observed dendritic structures to establish a convergence-fault criterion for the location of low-angle boundaries. A trip-growth model for simulation of the growth of the dentritic network was developed. This model predicts the local primary growth direction and identifies regions of convergent growth. A connectivity parameter is used to map the locations which are most vulnerable to convergence-fault formation. Predictions are compared with experimental observation.
Journal of Materials Science


defect prediction, dendritic growth, low-angle boundaries, single-crystal casting


Napolitano, R. and Schaefer, R. (2008), Predicting the Location of Low-Angle Boundaries in Single-Crystal Castings, Journal of Materials Science (Accessed June 21, 2024)


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Created October 16, 2008