Experimental determination of the phase diagrams of the Co-Ni-X (X = W, Mo, Nb, Ta) ternary systems using diffusion multiples. (February 2018)

• Record Type: Journal Article
• Authors: Zhu, Lilong; Wei, Changdong; Jiang, Liang; Jin, Zhanpeng; Zhao, Ji-Cheng
• Is Part Of: Intermetallics. Volume 93(2018:Feb.)
• Page Start: 20
• Page End: 29
• Publication Date: 2018-02
• Subjects: A. Intermetallics -- B. Phase stability -- C. Heat treatment -- D. Microstructure -- F. Electron microprobe -- G. Aero-engine components; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2017.11.005
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: Phase stability information regarding the formation of the topologically close packed (TCP) phases is critical for the design of advanced Ni-based and Co-based superalloys that contain high concentrations of refractory elements. Isothermal sections of the Co-Ni-W, Co-Ni-Mo, Co-Ni-Nb and Co-Ni-Ta systems at both 900 °C and 800 °C were constructed for the first time from electron probe microanalysis (EPMA) and electron backscatter diffraction (EBSD) measurements on two Co-CoAl-Cr-Mo-Ni-Nb-Ta-W diffusion multiples. The new data will serve as experimental input to future thermodynamic assessments of the Co-Ni-X ternary systems in order to improve the thermodynamic databases for the design and development of advanced Ni-based and Co-based superalloys. Graphical abstract: Highlights: Eight ternary phase diagrams established using only two diffusion multiples. First Co-Ni-W, Co-Ni-Mo, Co-Ni-Nb & Co-Ni-Ta at 900 & 800 °C reported. The results are valuable input to designing Ni-based & Co-based superalloys.