Journal of Materials Science

, Volume 31, Issue 15, pp 3929–3936 | Cite as

Precipitation characteristics of μ-phase in wrought nickel-base alloys and its effect on their properties

  • H. M. Tawancy
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Abstract

Thermal exposures consisting of 1–16000 h at 540, 650, 760, and 870°C were used to study the susceptibility of selected nickel-base alloys to precipitation of μ-phase and its effect on mechanical strength and corrosion resistance. Analytical electron microscopy and X-ray diffraction were used to characterize the μ-phase. A μ-phase of the type Mo6Ni7 in nickel-base alloys was found to be stabilized by critical concentrations of iron in an excess of about 3 wt%. Generally, the μ-phase had a characteristic defect structure consisting of twins and stacking faults, and it exhibited a preferential tendency for precipitation at existing molybdenum-rich carbide particles within the alloy matrix and at grain boundaries. Precipitation of μ-phase was found to produce a moderate loss of room-temperature tensile ductility; however, it resulted in a considerable degradation of impact toughness and corrosion resistance. In contrast, it had no significant effect on elevated temperature tensile properties. A correlation was found to exist between the Ni/Fe + Co ratio as well as the Mo + W content of the alloy and susceptibility to precipitation of μ-phase.

Keywords

Corrosion Resistance Impact Toughness Analytical Electron Microscopy Carbide Particle Alloy Matrix 
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

© Chapman & Hall 1996

Authors and Affiliations

  • H. M. Tawancy
    • 1
  1. 1.Materials Characterization Laboratory Metrology, Standards, and Materials Division, Research InstituteKing Fahd University of Petroleum and MineralsDhahranSaudi Arabia

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