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Metallurgical Transactions A

, Volume 17, Issue 4, pp 651–661 | Cite as

The effects of replacing the refractory elements W, Nb, and Ta with Mo in nickel-base superalloys on microstructural, microchemistry, and mechanical properties

  • John P. Collier
  • Paul W. Keefe
  • John K. Tien
Mechanical Behaviour

Abstract

The effects of an atom-for-atom substitution of Mo for Ta, Nb, or W on the mechanical properties of three typical nickel-base superalloys are discussed relative to the changes in the composition of the γ, γ′, and carbide phases. W partitions to they phase in the IN738 alloy system, but to the γ′ in the U710 alloy. In addition, Mo was found to be more soluble in either the γ or γ′ phase when W partitioned to that phase. Ta, and possibly Nb, decreases the solubility of Mo in the γ′ phase. Mo was found to be a greater antiphase boundary strengthener than W. However, initial data indicate that Mo does not strengthen the γ′ phase as much as Ta. The substitution of Mo for W had detrimental effects on the elevated temperature yield strengths of the modified U710 and IN738 alloys as well as on the creep-stress rupture resistance of the IN738 alloy. The substitution of Mo for Ta also decreased the creep-stress rupture resistance of the modified B1900 alloy.

Keywords

Metallurgical Transaction Scanning Transmission Electron Microscopy Carbide Phase Critical Resolve Shear Stress Refractory Element 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© The Metallurgical of Society of AIME 1986

Authors and Affiliations

  • John P. Collier
    • 1
  • Paul W. Keefe
    • 2
  • John K. Tien
    • 1
  1. 1.Columbia UniversityNew York10027
  2. 2.The Special Metals CorporationUtica

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