The effectsof annealing process on the hardness, microstructure, Si diffusion, and the sagging resistance of cold-rolled 4343/3003/4343 Al alloy clad sheets and their 3003 Al alloy core sheets were experimentally investigated through hardness tests, EBSD observations, EDS analysis, and sagging test.The results showedthat with the increase of annealing temperature, the hardness of both clad sheet and core sheet decreased, while thesaggingresistancesof both clad and core sheets achieved maximum values after annealing at 380℃ for 1h. After annealing at 380℃, the clad layer contained fine and equiaxedrecrystallized grains; the core layer was composed of fully recrystallized coarse grains elongated along the rolling direction. The Si diffusion from the clad layer to the core zone was limited. After annealing at a higher temperature of 440℃ or 550℃, thesaggingresistance of clad sheets worsened precipitously. The grains in the clad layer grew up, obscuring the interface between the clad and core layer; the recrystallized grains in the core layer became finer. Significant amount of Si penetrated into the core layer through the accelerated diffusion. Compared with the microstructure refinement, Si diffusion is the main factor influencing thesaggingresistance.
