Abstract: Evolution of microstructure and properties of 2××× series aluminum alloy aluminum clad thin plate during solution treatment were studied by means of metallographic microscope, scanning electron microscope, energy dispersive spectroscopy, differential scanning calorimetry and room temperature tensile test. The results indicate that after solution treatment, there are still large-sized AlCuFeMn and Al₂CuMg phases in substrate of the cold-rolled aluminum clad thin plate. However, with the increase of solution treatment temperature and the extension of holding time, the content of retained second phases in the substrate gradually decreases. The diffusion degree of Mg and Cu elements is relatively high in the aluminum coating and the transition zone, but there is no failure problem of the aluminum coating caused by severe element diffusion. When the solution treatment process is 500 ℃×20 min, the retained second phase content in the alloy is the lowest of 1.101%. After natural aging for 96 h, the yield strength of the aluminum clad thin plate is 286.5 MPa, the tensile strength is 458.0 MPa, and the elongation after fracture is 23.1%, good combination of strength and plasticity is obtained.

Key words: 2××× aluminum alloy, aluminum clad thin plate, solution treatment, microstructure, mechanical properties