Phase Equilibria in Nb-Si-Mo Ternary Alloys at 1 273 K and 2 073 K

Phase equilibrium in Nb-Si-Mo ternary alloys (＜37.5 at.% Si) at 1 273 K and 2 073 K is investigated by using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The partial isothermal section at 1 273 K, which contains four single-phase regions, five two-phase regions and two three-phaso regions, is basically the same as that at 1 973 K. However, when the temperature increases to 2 073 K, the three-phase region of Nbss α-(Nb(Mo))sSi3 β-(Nb,Mo)5Si3 obviously moves towards the Nb-rich comer. This suggests that Nb-Si-Mo ternary alloys remain stable at least up to 1 973 K.