Phase equilibria in the Al–C–Ni–W quaternary system

• Critical evaluation of Al–Ni–W, Al–C–W, Al–C–Ni and C–Ni–W systems is presented.
• A thermodynamic database of the Al–C–Ni–W system is constructed.
• The solubility of W in the L12 phase in the WC-40 vol.% AlNi3 alloy is calculated.
• The effect of replacement of Co by Ni/AlNi3 on the phase relationship is studied.

Based on a critical literature review, the Al–C–Ni and C–Ni–W ternary systems are thermodynamically reassessed using the CALPHAD (CALculation of PHAse Diagrams) method. The calculated phase equilibria and thermodynamic properties can well reproduce the experimental data. The Al–C–Ni–W thermodynamic database is then established using descriptions of the accepted ternary systems. The calculated solubility of WC in AlNi3 is in good agreement with the experimental result. The computed solubility is used to describe the hardness–solubility dependence along the WC–AlNi3 section according to the solid solution strengthening mechanism. The effect of substitution of Co by Ni and AlNi3 as the binder phase on the phase relations in the WC-based cemented carbides is also investigated using the present thermodynamic parameters. Good agreement between calculated and experimental results indicates that the current thermodynamic database could provide an efficient guidance for designing and developing innovative WC–AlNi3 cemented carbides.