Aluminum foam sandwich (AFS) possesses excellent performance of light weight, high specific strength and stiffness, impact resistance, etc., which can be widely used in rail transit vehicles, aviation and aerospace industry and military field. In this paper, the bonding tests between steel sheets and aluminum foam have been done. In the tests, steel sheets pretreated by hot dipping were chosen as the reinforcement and a foamable precursor compacted by powder metallurgy as the core. The three-layer composite was connected by hot pressing and the aluminum foam sandwich was prepared by the later heating quickly. The results showed that the steel sheets coated by Zn-55wt.%Al alloy can be combined with the foamable precursor by liquid phase diffusion welding. The AFS with diffusion bonding interface can be also obtained by baking in furnace

Titanium foam has been the focus of special attention for its specific structure and potential applications in purification, catalyst substrate, heat exchanger, biomaterial, aerospace and naval industries. However, the liquid-state foaming techniques are difficult to use in fabricating Ti foam because of its high melting temperature and strong chemical reactivity with atmospheric gases. Here, the fabrication of Ti foams via the powder metallurgy route was carried out by utilizing both magnesium powders and magnesium particles as spacer holders, and Ti powders as matrix metal. The green compacts containing Ti powder, Mg powder and Mg particles were heated to a certain temperature to remove the magnesium and obtain the Ti foam. The results show that the porosities of the obtained Ti foam are about 35–65%, and Young’s modulus and yield strength are found to be in the ranges of 22–126 MPa and 0.063–1.18 GPa, respectively. It is found that the magnesium powders play a more important role than the magnesium particles in the deformation and the densification of the green compact during the pressing, and the pore structure of Ti foam depends on the amount and the size of the magnesium spacer holders after sintering.