- Mar 12, 2019-
The foam aluminum sandwich panel has the excellent performance of the foamed aluminum material and solves the shortcoming of the low strength of the single foamed aluminum. It is a new functional material with excellent comprehensive performance and has broad application prospects in the fields of automobile manufacturing, aviation and aerospace. At present, the preparation of foam aluminum sandwich panels at home and abroad mainly adopts the adhesive and powder metallurgy foaming method. The foamed aluminum sandwich panels produced by the adhesive process have poor heat resistance and corrosion resistance, and the use environment of the products has certain limitations. The powder metallurgy foaming process is the main preparation method of foam aluminum sandwich panels which have been studied in recent years. In the traditional powder metallurgy foaming process, the combination of the core is mainly completed by the hot pressing process, the bonding strength is low, the density of the core powder is not ideal, and the size of the hot pressing die is limited, and the large-sized sandwich material cannot be produced. .
(1) High-performance foamed aluminum sandwich panel material can be prepared by rolling composite powder metallurgy foaming process. The rolling composite process can achieve high density of core powder, and the sandwich panel obtained after foaming has good foam. The structure and core form an ideal metallurgical bond.
(2) The foaming temperature of the foamable composite board is 615 to 620 ° C. If the temperature is too high, defects such as large-sized connecting holes may appear in the core layer.
(3) When the foaming temperature is 620 °C, the foaming time is 4 to 6 minutes, which is a more optimized process condition. If the foaming time is too long, the foam layer will collapse.
The manufacturing process of the metal foam material generally employs a fusion method and a powder metallurgy method. If metal foam materials are used as structural members, they must be considered for their connection to other materials. The most common method of joining dense metals is welding. However, for metal foams, welding is very difficult because the solidification of the molten foam pore structure during welding causes a reduction in volume. Bonding and soldering are used in most metal honeycomb structures. In this bonding method, the bonding strength of the bonding agent controls the mechanical properties of the entire honeycomb structure, but the adhesive bonding is only suitable for low temperature applications. At high temperatures, aging will occur, which will bring great obstacles to its application.
This joining method also has this disadvantage for aluminum foam. In addition, the traditional process is almost the first to make the aluminum foam bare board, and then the panel and foam aluminum are connected, the process is cumbersome.
In the powder densification method, the powder is placed between the two metals to be joined for rolling connection and then directly foamed in the furnace. This method overcomes the disadvantages of the binder connection and achieves the purpose of metallurgical bonding. It also shortens the process and saves energy.
(1) The steel panel foam aluminum sandwich structure can be successfully prepared by the powder and steel plate rolling process, but the combination of pores and micropores in the foaming process is an important factor affecting the pore structure.
(2) The enrichment of titanium particles on the pore walls plays a positive role in the stability of the pores.
(3) Bending and wrinkling occur on the wall of the hole during solidification, so the control of the solidification process is also very important.