Fabrication of an Al Foam/Dense Steel Composite by Friction Welding

Abstract

Al foam is lightweight with superior shock-absorbing properties but has low tensile and bending strengths. This has spurred efforts to form composites of Al foam with dense materials. In this study, we examined the possibility of fabricating composite structures of Al foam and dense steel with strong metal bonding by employing friction welding. The use of friction welding is expected to facilitate the fabrication of Al foam/dense steel composites by a simple process with low environmental impact. It is shown that this procedure is capable of fabricating an Al foam/dense steel composite in which the Al foam completely fills the hollow in the dense steel. An Fe–Al intermetallic compound (IMC) layer with a thickness on the order of 10 µm was found throughout almost the entire interface between the Al foam and the dense steel. Therefore, it is shown that an Al foam/dense steel composite with strong metal bonding can be fabricated.