Experimental investigation of phase equilibria in the Ni-Ta-Si refractory alloy system

Three isothermal sections of the Ni-Ta-Si ternary system at 1300, 1100 and 900 degrees C were constructed in the whole composition range and analysed using electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. In addition to the known ternary G, E, H and C14 phases, a new compound with the composition of Ni23-25Ta39-40Si35-38 was detected for the first time, herein designated as the F phase. Furthermore, the continuous (Ni, Si)Ta-2 phase was found to be stable and the composition range of the ternary C14 Laves phase was revised to be Ni39-54Ta26-33Si13-27. The newly determined phase equilibria in the Ni-Ta-Si ternary system can be useful in guiding alloying strategies or composition design of Ni-based superalloys. (C) 2021 Published by Elsevier B.V.

Automated summary

The study on the Ni-Ta-Si ternary system revealed the discovery of a new F phase and a revision of the composition range of the C14 Laves phase, providing guidance for alloy strategies or designing compositions for Ni-based superalloys.