Solidification modeling of Nb bearing superalloys [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy, 1997.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:: 13 pages : digital, PDF file
Additional Creators:: Sandia National Laboratories, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

The solidification behavior of experimental Ni base and Fe base superalloys containing Nb, Si, and C was studied using differential thermal analysis (DTA) and microstructural characterization techniques. The solidification reaction sequences responsible for microstructural development were found to be similar to those expected in the Ni-Nb-C ternary system, where the solute-rich interdendritic liquid exhibited two eutectic-type reactions at the terminal stages of solidification: L → (γ + NbC) and L → (γ + Laves). A pseudo ternary γ-Nb-C approach was developed to provide a quantitative description of solidification behavior for these experimental alloys. Solute redistribution calculations in the model are based on a previous approach developed by Mehrabian and Flemings, with modifications made to account for the high diffusion rate of C in the solid. Solidification parameters for Nb and C were determined through DTA and electron probe microanalysis techniques and used as inputs to the model. Reasonable agreement is found between calculated volume fractions of the γ/NbC and γ/Laves constituents and those measured experimentally. The modeling results permit detailed descriptions of the relation between alloy composition and microstructural evolution during solidification.

Report Numbers:

E 1.99:sand--97-1669c
E 1.99: conf-970605--3
conf-970605--3
sand--97-1669c

Subject(s):

Materials Science

Other Subject(s):

Note:

Published through SciTech Connect.
08/01/1997.
"sand--97-1669c"
" conf-970605--3"
"DE97007150"
4. international special emphasis symposium on superalloys 718, 625, 706 and derivatives, Pittsburgh, PA (United States), 15-18 Jun 1997.
Robino, C.V.; DuPont, J.N.; Marder, A.R.

Funding Information:

AC04-94AL85000

View MARC record | catkey: 14454110