Phase equilibria of the Fe-Nb-Ti system at 900 °C

The isothermal section at 900 °C of the Fe-Nb-Ti system was determined using the diffusion couple approach with the aid of equilibrated alloys. The specimens were examined by means of optical microscopy, scanning electron microscopy, and electron probe microanalysis. No ternary compound was found. The isothermal section consists of five single-phase regions, six two-phase regions and two three-phase regions. The solubility of Nb in TiFe were determined to be 6 at.%, and the solubility of Ti in μ-Nb19Fe21 to be 23.6 at.%. NbFe2 and TiFe2 form a continuous solid solution (Nb, Ti)Fe2.