Experimental investigation of phase equilibria in the Nb–Si–Ta ternary system

Abstract The phase equilibria in the Nb–Si–Ta ternary system at 1 373 K, 1 473 K and 1 573 K were investigated by means of back-scattered electron imaging, electron probe microanalysis and X-ray diffraction. The isothermal sections at 1 373 K, 1 473 K and 1 573 K consist of two three-phase regions and seven two-phase regions, without any ternary compounds. The compounds of NbSi2 and TaSi2, αNb5Si3 and αTa5Si3 form continuous solid solutions, respectively. The solubilities of Nb in Ta3Si and Ta2Si phases are extremely large, whereas the solubility of Si in the β(Nb, Ta) phase is relatively small.