Investigation of the partition coefficients in the Ni-Fe-Nb alloys: A thermodynamic and experimental approach

Jairo Valdes, Dong Eung Kim, Shun Li Shang, Xingbo Liu, Paul King, Zi Kui Liu

Research output: Contribution to conferencePaperpeer-review

Abstract

The Nb containing Ni-based superalloys used for the production of large castings are highly sensible to the formation of macrosegregation defects like freckles and white spots. Production cost can be reduced by better prediction of the freckle formation. The most accepted freckling criterion is the one based on the Rayleigh number, which requires accurate determination of the partition coefficients for the solute elements. In this work, the partition coefficients of Nb and Fe on the ternary system Ni-Fe-Nb were studied by experimental measurements and by thermodynamic calculations. Modified DTA experiments were performed for model alloys, and a thermodynamic database for the Ni-Fe-Nb ternary system was developed. Most of the calculated partition coefficients using the developed model agree well with the experimental data. One exception to this, as will be discussed later, is the partitioning coefficient of Fe for the alloy containing 36 wt. %Fe.

Original languageEnglish (US)
Pages333-337
Number of pages5
StatePublished - 2008
Event11th International Symposium on Superalloys, Superalloys 2008 - Champion, PA, United States
Duration: Sep 14 2008Sep 18 2008

Other

Other11th International Symposium on Superalloys, Superalloys 2008
CountryUnited States
CityChampion, PA
Period9/14/089/18/08

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics

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