Microstructural Evolution, Precipitation Behavior, and Mechanical Property Response of Cast Al-Li-Cu-Cd-Mn-Zr-Ti Alloy

The microstructural evolution and mechanical properties of cast Al-Li-Cu-Cd-Mn-Zr-Ti alloy during heat treatment are investigated systematically. In these findings, it is shown that the as-cast alloy exhibits fine and equiaxed grains. During the solid solution treatment, Al20Cu2Mn3 dispersoids effectively restrict grain growth, and reducing the solid solution time has a similar effect. Subsequently, the precipitation behavior and its effect on the mechanical properties during the aging process are revealed. Al3(Ti, Zr) particles are uniformly distributed throughout the matrix, acting as nucleation sites for delta ', theta ', and T1 precipitates. Overtime, delta ' precipitates gradually coarsen and decrease in number, and some delta ' precipitates attach to Al3(Ti, Zr) particles, forming core-shell Al3(Li, Ti, Zr) phases. At the same time, plate-shaped theta ' and T1 precipitates emerge and coarsen. After aging at 160 degrees C for 24 h, the alloy exhibits an excellent combination of strength (yield strength =293.3 +/- 4 MPa, ultimate tensile strength =468.0 +/- 3 MPa) and ductility (elongation =9.6 +/- 0.4%), surpassing those reported in other cast Al-3Li-2Cu-X alloys. Critically, the underlying mechanisms behind the microstructure and mechanical properties are discussed extensively, providing valuable insights for the advancement of cast Al-Li alloys. In this study, the microstructural evolution, particularly precipitation behavior, and mechanical properties of cast Al-Li-Cu-Cd-Mn-Zr-Ti alloy during heat treatment are systematically examined. It provides a detailed discussion of the underlying mechanisms involved. After aging at 160 degrees C for 24 h, the alloy exhibits an excellent combination of strength and elongation, surpassing other cast Al-3Li-2Cu-X alloys reported in the literature.image (c) 2024 WILEY-VCH GmbH