NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Predicting the Location of Low-Angle Boundaries in Single-Crystal Castings
Published
Author(s)
R E. Napolitano, Robert J. Schaefer
Abstract
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.
Napolitano, R.
and Schaefer, R.
(2008),
Predicting the Location of Low-Angle Boundaries in Single-Crystal Castings, Journal of Materials Science
(Accessed October 22, 2025)