Friction Stir Extrusion of AZ31 Magnesium Alloy Rod

Magnesium (Mg) and its alloys are lightweight and possess biodegradable properties that are attractive for structural applications in the transportation and biomedical sectors. However, Mg possess hexagonal closed pack (HCP) crystal structure that makes room temperature forming difficult, thus necessitating multi-stage high-temperature processes to obtain desired shape and properties. In this context, we have used Friction Stir Extrusion (FSE), a severe plastic deformation process, to fabricate some basic structural building blocks such as rods. In FSE, heat is generated through friction between a rotating tool and workpiece, and downward movement of the rotating tool forges the material to the desired shape through severe plastically deformation in a single step. FSE assists in engineering the microstructure of the prepared components, enabling control over its mechanical and corrosion response. Here we report on Mg rods produced by FSE using commercially available AZ31 feedstock. In this paper, initial findings of the FSE processed AZ31 properties show how grain size can be engineered across the rod microstructure.