Abstract:The deformation behavior and microstructure of Al alloy under strong cooling were investigated through thermal simulation. The results show that the microstructure of Al alloy solidified under strong cooling is mainly composed of dendrite structure. At a constant strain rate of ε^·＝0.117s^-1, no coupling process involving solidification and deformation occurs, and the microstructure belongs to deformed dendrite structure after solidification. The morphology of the dendrite structure is strongly sensitive to the strain rate. The coupling process of solidification and deformation occurs at a critical point when ε^·=0.10s^-1. Above this point, the dendrite structure bends and fractures when solidifying. With the strain rate increasing, the alloy microstructure transforms from closely-packed and well-organized dendrites to disintegrated and spheroidized dendrites. The larger the strain rate, the lower the deformation stress, and the finer the microstructure.

Key words: aluminum alloy; roll-casting; microstructure; deformation behavior