Overview Aluminum: Cast Shop and AlloysNovelis Inc. recently introduced a multi-alloy, multi-layered, aluminum ingot solidification technology that allows the production of a variety of engineered clad products on a commercial scale. The technology allows selection of the appropriate combinations of clad and core alloys to produce desired mechanical properties as well as forming and surface characteristics superior to either monolithic material alone. It has been shown that the Novelis Fusion™ interface is oxide fi lm and porosity free. This article analyzes the interplay of the aforementioned alloy combinations giving particular attention to the cast intermetallics, the diffusion of silicon and magnesium, the population of secondary phase particles (dispersoids) at the interface, and the rate of diffusion.