Experimental investigation and thermodynamic optimization of the Al–Ni–Sc ternary system

Phase equilibria of the Al–Ni–Sc system were investigated by combination of key experiments and thermodynamic modeling. The isothermal sections of the Al–Ni–Sc ternary system in the (Al, Ni)-rich region at 873K and 673K were investigated using the electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The solubilities of the binary phases in the ternary system were measured. According to the experimental results in this work and related literature, the Al–Ni–Sc ternary system has been optimized by means of the CALPHAD (CALculation of PHAse Diagrams) method. Isothermal sections at 1273, 1173, 873 and 673 K were reproduced. The calculated thermodynamic and phase equilibria data for the ternary system agree well with the experimental data. This work can be used as a basis for the multi-component thermodynamic database of Al-based alloys.