LAUSR

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.