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LEE FREDERICK and AUSTIN STAUB are with the Material Science and Engineering, University of Tennessee, Knoxville, TN. ALEXANDER PLOTKOWSKI and MICHAEL M. KIRKA are with the Manufacturing Demonstration Facility, Oak Ridge National Laboratory, Oak Ridge, TN and also with the Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN. MICHAEL HAINES is with Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN. EDWIN J. SCHWALBACH is with the Materials and Manufacturing Directorate, Air Force Research Lab, Wright-Patterson Airforce Base, OH. DAVID CULLEN is with the Materials Science and Technology Division, Oak Ridge National Laboratory. S.S. BABU is with the Material Science and Engineering, University of Tennessee, with the Manufacturing Demonstration Facility, Oak Ridge National Laboratory, with the Materials Science and Technology Division, Oak Ridge National Laboratory, with the Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, and also with the Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN. Contact e-mail: [email protected] This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (). Manuscript submitted January 22, 2018. Article published online August 1, 2018 5080—VOLUME 49A, OCTOBER 2018

I.

INTRODUCTION

THE high c¢ single crystal class of nickel-based superalloys, including CMSX-4, PWA 1484, and Rene N5, was developed to withstand the extreme conditions of jet engine turbines. The alloy chemistry and manufacturing routes evolved together to optimize microstructure characteristics to withstand dynamic loading conditions at temperatures higher than the homologous temperatures (i.e., 0.5 times melting point).[1] Withstanding these conditions was made possible by two aspects of the microstructure: (i) Using controlled manufacturing methods (e.g., directional solidification or single crystal casting) to create a crystallographic texture of face-centered cubic (FCC) c grains such that the {001} family of crystallographic planes are oriented along the loading direction; and (ii) by ensuring the correct volume fraction, shape, and size distribution of the L12 ordered c¢ phase within the c matrix.[2–4] Conventional manufacturing techniques are optimized to produce highly engineered microstructures based on the above requirements, but are limited in the complexity of geometries and unable to produce a controlled variation in microstructure. Additi