Isothermal section at 1100 degrees C of the Fe-Ni-Ta system

Abstract

The isothermal section of the Fe-Ni-Ta system at 1100 degrees C was constructed using 6 diffusion couples and 10 alloys, the compositions of which were selected on the basis of the experimental results of the (Fe-Ni alloy)/Ta diffusion couples. The samples were examined by means of optical microscopy, scanning electron microscopy, and electron probe microanalysis. Experimental results showed no existence of ternary compounds at 1100 degrees C. The following five three-phase equilibria were observed: (1) (Ta) + Ta2Ni + Ta(Fe, Ni), (2) Fe2Ta + Ta (Fe, Ni) + TaNi2, (3) Fe2Ta + TaNi2 + TaNi3, (4) Fe2Ta + TaNi3 + (Fe, Ni), (5) TaNi3 + TaNi8 + (Fe, Ni). The compounds FeTa and NiTa formed continuous solid solution. The solubility of Fe in TaNi2 and TaNi3 was determined to be 18 and 7.8 at.%, respectively, while the solubility of Ni in Fe2Ta was estimated to be 40 at.%. (C) 2010 Elsevier B.V. All rights reserved.