Sequential gravity casting in functionally graded aluminum alloys development

Aluminum alloys are widely used in the automotive field, for the excellent relationship between mechanical strength and lightness. In the recent years, the request for cleaner, lighter and more powerful engines, has led to the design of components subjected to higher thermo-mechanical stresses. Demanding exercise conditions can imply the presence of different properties that are never fulfilled by a single, homogeneous material. Various solutions have been developed using composites, surface modification techniques and Functionally Graded Material (FGM). This study has applied FGM concept to the traditional casting technology, in order to obtain a more performing product. To reach this goal, two different alloys were sequentially poured by gravity casting, each one delivering locally its properties to a specific volume of the casting. Beyond the morphological and microstructural analysis of the contact interface between the two alloys, the mechanical testing has shown promising results for future applications.