Thermodynamic Description of the γ' Phase in the Co-Al-W Based Superalloys

Abstract:

The phase equilibrium and the precipitation behavior of the γ' phase in the Co-Al-W-Ni-Cr superalloys were studied by thermodynamic method. The phase equilibrium of the Co-Al-W-15Ni-5Cr alloy at 900 was calculated, and it was found that there were a γ' single-phase region and a γ+γ' two-phase region. The effects of Al/W ratio on the precipitation of the γ' phase were studied, and it was clear that higher mole fraction of the γ' phase can be obtained with the Al/W ratio of 2.5. The stability of the γ' phase can be improved by adding of Ni, as well as the servicing temperature of the Co-Al-W based superalloys. The results obtained in this work can be used for the developing of the new-type Co-based superalloys.

• Periodical: Materials Science Forum (Volumes 747-748)
• Pages: 654-658
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.747-748.654
• Online since: February 2013
• Authors: Shu Yu Yang, Min Jiang, Lei Wang
• Keywords: Alloy Design, CALPHAD, Co-Al-W Based Superalloys, Phase Diagram, Thermodynamic Calculation

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