An overview on phase equilibria and thermodynamic modeling in multicomponent Al alloys: Focusing on the Al–Cu–Fe–Mg–Mn–Ni–Si–Zn system

Knowledge of thermodynamics and phase diagram is a prerequisite for understanding many scientific and technological disciplines. To establish a reliable thermodynamic database, an integrated approach of key experiments and thermodynamic modeling, supplemented with first-principles calculations, can be utilized. In this paper, first investigations of phase diagram and thermodynamics of technologically important Al alloys (focusing on the Al–Cu–Fe–Mg–Mn–Ni–Si–Zn system, which covers the major elements in most commercial Al alloys) is reviewed with an emphasis on the need of the integrated approach. Second, the major experimental methods (X-ray diffraction, metallography, electron probe microanalysis, differential thermal analysis, diffusion couple method, and calorimetry), which are widely employed to provide phase diagram and thermodynamic data, are briefly described. Third, the basics of the first-principles calculations and CALPHAD are presented focusing on the integration of these two computational approaches. Case study for the representative Al–Fe–Ni ternary system is then demonstrated, followed by a thermodynamic modeling of the quinary Al–Fe–Mg–Mn–Si system and a brief summary to our recent activities on investigations of phase equilibria in multicomponent Al alloys.