Preparation Of Aluminum Foam Sandwich Reinforced By Steel Sheet As Panel

Closed-cell aluminum (Al) foams are kinds of new style structural and functional composite materials, having the advantages of lightweight, high specific stiffness, high energy absorption and good electromagnetic shielding etc. To widen the application of aluminum foam, the preparation of aluminum foam sandwich panels (AFS) by PM-route has become one of the most important researches currently. In this paper, We prepare the precursor by the method of powder metallurgy and use the steel as face sheet to study the preparation of the AFS in order to promote the application of aluminum foam in rail transit, aerospace industry and military equipment.In this paper, air-atomized Al powder and titanium hydride (TiH2) powder were used as the main raw materials. Mg powder was used as the metal additive. Some researches on the process of preparation of AFS such as the preparation of the precursor, the improvement of foaming process, the surface treatment of the steel panels, the pre-combination of the steel panels and the precursor, the foaming process of the AFS, and so on, were accomplished. In addition, the influence of the vacuum environment on the foaming process was studied and the aluminum foam was prepared by FOAMGRIP. The main conclusions are showed as follows:(1) The air-atomized Al powder was used as the matrix material, TiH2powder as the foaming agent, and Mg powder as the metal additive. The ratio of the basic materials to mixing ball is2.6:1.When the basic materials were mixed in the bottle of2L over1.5h, the Mg powder and TiH2particles can be distributed uniformly.(2) When the precursor was sintered at450℃for2h after cold compression, the micro gaps of the precursor is greatly reduced and the dense of the precursor increases. When foaming in atmosphere, the foams with uniform cell structures can be achieved.(3) The best foaming process of the PM-route precursor is:the foaming temperature is 700℃～750℃, the time is6-8min and the size of aluminum and magnesium powders is48～74μm.(4) The Al-12Ca-3Ca alloy and pretreated TiH2can be used to make the precursor by FOAMGRIP. Then we can get the foams with uniform cell structures at620℃or650℃.(5) After hot compression, the steel sheet, which was hot-dipped in Zn-5%Al alloy, Zn-55%Al alloy, and the pure aluminum can be bonded with the precursor. The AFS with the metallurgical bonding interface can be obtained finally.