Strengthening of steel/Al foam sandwich tube interface through in situ synthesis of Al/Ni Intermetallics

Metal- foam filled tubes as a set of thin walled sandwich structures have unique properties in which the impact energy absorption is the most important among them. It is proved that the shear strength of core-shell interface plays a decisive role on increasing the amount of energy absorbed in these kinds of structures. In this research the Al foam was fabricated using sintering-dissolution process (SDP) in situ in the tube. At the same time, a composite layer was synthesized with the aim of exothermic reaction of the formation of aluminum- Nickel intermetallic compounds during the sintering process. Furthermore, The X-Ray Diffraction and Electron Dispersive Spectroscopy(EDS) Analysis both proved the formation of diverse Nickel Aluminide's, when the optical and scanning electron microscopy evaluations exhibited a good continuity and metallurgical bonding of the core-shell interface and the structure of a Nickel Aluminide's composite which was fabricated in situ. Eventually, Microhardeness examination showed an improvement of interfacial strength in the final product