Spiral extrusion of aluminum/copper composite for future manufacturing of hybrid rods: A study of bond strength and interfacial characteristics

An axi-symmetric forward spiral composite extrusion (AFSCE) method is proposed to produce hybrid rods. This process involves extrusion of a composite sample through a die with engraved spiral grooves to create a near net shape product. The process can be easily performed and has better dimensional control than the existing bimetallic rod fabrication processes because of the zero shape change effect of this process. An analytical solution of shear deformation during AFSCE in the radial direction of the hybrid sample is first presented. To demonstrate the production of composite rods using the process, an experimental case study of an Aluminum and Copper (Al/Cu) sample at elevated temperature and in the presence of a back pressure is presented. Microstructure characterizations of the Al/Cu interface and the neighboring regions revealed the formation of a bonded layer with the possibility of intermetallic compounds present at the interface. Composite blanking proved good bonding strength between the parent materials. The results show that the AFSCE process has strong potential to be utilized for the fabrication of hybrid metal rods.