Experimental and thermodynamic study of tantalum-containing iron-base alloys reinforced by carbides: Part II — Case of (Fe, Ni, Cr)-base austenitic steels

Experiments and thermodynamic calculations were performed for three alloys based on both iron and nickel in equal quantities, containing 30 wt% of chromium, 0.2 to 0.4 wt% of carbon and 3 to 6 wt% of tantalum. Solidus and liquidus temperatures were determined for the three alloys, and the natures and fractions of the existing phases at 1000, 1100 and 1200 ∘C were characterized. These experimental data were compared to values calculated by Thermo-Calc, as well as to such results obtained on previous similar alloys separately based on iron or on nickel. Generally, there is a good agreement with calculations. Tantalum carbides in (Fe, Ni) base alloys are less present than in Fe-base alloys, but more present than in Ni-base alloys for the same carbon, chromium and tantalum contents.