Experimental investigation and thermodynamic assessment of phase equilibria in the Al–Cr–Ta ternary system

Abstract

The Al–Cr–Ta ternary system was investigated through a combination of experiments and thermodynamic modeling. The determination of the liquidus projection involved the microstructural characterization of 29 as-cast alloys using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Sublattice models were proposed for the phases according to their crystal structures and homogeneity ranges. Based on the experimental results, the Al–Cr–Ta ternary system was thermodynamically assessed by the CALculation of PHase Diagrams (CALPHAD) approach. The liquidus projection, isothermal sections, and vertical sections of the ternary system were calculated. A set of self-consistent thermodynamic parameters for the Al–Cr–Ta ternary system was obtained with a satisfactory agreement between the experimental and calculated results. The present work could be significant for the practical application of novel cemented carbides and future thermodynamics assessment of complex multicomponent systems.