Methods for casting high strength, high ductility lightweight metal components are provided. The casting may be die-casting. A molten lightweight metal alloy is introduced into a cavity of a mold. The molten lightweight metal alloy is solidified and then a solid component is removed from the mold. The solid component is designed to have a thin wall. For example, the solid component has at least one dimension of less than or equal to about 2 mm. In this way, a chill zone microstructure is formed that extends across the at least one dimension of the solid lightweight metal alloy component. The solid component thus may be substantially free of dendritic microstructure formation, enabling more extensive alloy chemistries than previously possible during casting. Such methods may be used to form high strength, high ductility, and lightweight metal alloy vehicle components.