Effect of Annealing on Microstructure and Tensile Properties of 5052/AZ31/5052 Clad Sheets

Three-layered 5052Al/AZ31Mg/5052Al (5052/AZ31/5052) clad sheets were fabricated by four-pass rolling and annealed under different conditions. Under the optimal annealing condition, homogeneous and equiaxial grains with an average AZ31 grain size of 5.24 µm were obtained and the maximum values of ultimate tensile strength and elongation of the clad sheet reached 230 MPa and 18%, respectively. Electron backscatter diffraction analysis showed that the AZ31 layer had a typical rolling texture with its c-axis parallel to the normal direction. The fraction of low-angle grain boundaries in the 5052 layer was nearly four times more than that in the AZ31 layer because of different deformation extent and recrystallization driving forces. The textures of Al₃Mg₂ and Mg₁₇Al₁₂ were similar to that of 5052 because of the deformation coordination during the rolling and recrystallization process. The orientation relationship between Mg₁₇Al₁₂ and AZ31 seemed to be (110) _Mg17Al12//(10−11) _AZ31.