Effect of plastic deformation on microstructure and hardness of 2024/3003 gradient composite ingot prepared by continuous casting

The effects of plastic deformation on the evolution of microstructure and micro-hardness were studied on plates made from a cylindrical composite ingot of 2024/3003 aluminum alloys. This ingot was produced by double-stream-pouring continuous casting. The results show that the as-cast microstructure has a dominant influence on the evolution of microstructure and the distribution of micro-hardness of the composite ingot. The three layers in as-cast composite ingot were maintained after compression and roll processing. The micro-hardness in all three layers in the composite increased and the grain size in these layers appeared to decrease as the number of compression or rolling passes increased. The microstructure evolution in the direction parallel to the applied load can be evaluated qualitatively using a simplified lamination model. The distribution variation in micro-hardness measured along the direction normal to the applied load can be attributed to the movement of transition layer and diffusion of alloying elements.