Non-dendritic structural 7075 aluminum alloy by liquidus cast and its semi-solid compression behavior

Fine, equiaxed, non-dendritic structure needed by semi-solid processing was obtained by liquidus cast, i.e. 7075 wrought aluminum alloy cast from liquidus temperature. The microstructures after heat treatment at different temperatures and time in the semi-solid range were observed, and the compression deformation behavior at different temperatures (490-600 deg C) and strain rates (5x10 exp -3 approx5s exp -1 ) was investigated by means of Gleeble-1500 thermal-mechanical simulator. The results show that the deformation resistance of the non-dendritic structure attained by liquidus cast in semi-solid is remarkably lower than that of conventional dendritic structure. The formability of non-dendritic structure is better than that of dendritic structure.