Effects of a Tantalum Addition on the Morphological and Compositional Evolutions of a Model Ni-AL-Cr SuperalloyThe effects of a 2.0 at.% addition of Ta to a model Ni-Al-Cr superalloy aged at 1073 K are assessed using scanning electron microscopy and atom-probe tomography. The addition of Ta results in appreciable strengthening, and the morphology is found to evolve from a bimodal distribution of spheroidal precipitates, to cuboidal precipitates aligned along the elastically soft <001>-type directions. Tantalum is observed to partition preferentially to the gamma -precipitate phase and decreases the mobility of Ni in the gamma- matrix sufficiently to cause an accumulation of Ni on the gamma-matrix side of the gamma -precipitate/gamma-matrix heterophase interface.
Document ID
20090007810
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Booth-Morrison, Christopher (Northwestern Univ. Evanston, IL, United States)
Seidman, David N. (Northwestern Univ. Evanston, IL, United States)
Noebe, Ronald D. (NASA Glenn Research Center Cleveland, OH, United States)