Mechanistic insights into the evolution of L1₂ coherent precipitates in supersaturated Al-X (X = Sc, Zr, Er) alloys: A chemomechanical phase-field study for high-strength high-temperature aluminum alloys

This study delves into the evolution of a large number of L1₂ coherent precipitates within a supersaturated Al-X (X = Sc, Zr, Er) alloy through extensive phase-field simulations. The investigation incorporates a chemomechanical cross-coupling mechanism, accounting for the interplay between mechanical relaxation and diffusion. This coupling is addressed by considering the influence of solute atom concentration on the elastic constants of the matrix phase. The dependencies of elastic constants on solute concentration are determined through density functional theory calculations. The analysis reveals differences in precipitation kinetics among the alloys, characterized by temporal evolution plots of energy components during phase transformation. Al₃Er precipitates exhibit the highest growth rate, attributed to Er's high diffusive and mechanical flux in the Al–Er system. The precipitate morphology was defined by isotropic interfacial and elastic-free energy. The results provide valuable insights for the design of high-strength aluminum multicomponent alloys, particularly in applications demanding enhanced mechanical properties.