【摘要】 发展了一种高压渗流铸造法制备孔结构可控的新型泡沫铝．推导出孔结构参数的计算公式，并据此提出孔结构参数的控制和测量方法．制得的泡沫铝具有较理想的孔结构更多还原

【Abstract】 Metallic foams are porous metals with large pore diameters and high porosities. Two common methods to fabricate metallic foams are foaming technique and low pressure Permeating. But neither of them can control the pore structures of metallic foams precisely and freely. According to the principle of permeating casting, this paper puts forward an unique method called "high pressure Permeating casting" to fabricate a new type aluminium foams with controllable pore structures. To blend easy-burnt adjusting carrier HS and particulate carrier JY together to form a pre form, to put the preform in a special high pressure apparatus, then to Permeat liquid aluminium at high speed into the pores of the preform which is controlled by high pressure, there will be a composite of carrier and aluminium when aluminium has solidified. To remove the carrier from the composite by burning it out, the new type aluminium foams can be got finally. Since the Permeating speed is very high, the easy--burnt carrier has no time to burn or deform during the hightemperature and high pressure permeating process. However, the use of easy-burnt carrier (HS and JY) can greatly shorten the time to remove the carrier, thereby raise the fabricating efficiency a lot than low pressure Permeating method. As open-Pore metallic foams are more useful than close-pore opes, the carrier is in theform of preform in order to keep each pore of the aluminium foams open. The high pressure also gives liquid aluminium excellent permeating ability. The aluminium foams prepared by high pressure permeating casting have ideal pore structures while this method has industrial prospect. The properties of metallic foams greatly depend on the characteristics of their pore structures. But it wasvery difficult to describe and control the pore structures of metallic foams made by traditional methods.From the model of close-packed rigid spheres, this paper has derived the following formulas to calculate theparameters of pore structures of the new type aluminium foams including pore diameter d, porosity n, specific surface Sv and pore-open degree I:n= C+K, d= 2(1+m)R, Sv= 1.5C[2+(4-N)m+(2--N)m’2 / R, Where C and N are the compactibility and coordination number in the model respectively, K is the relative quantity of HS, m is the relative thickness of HS layer coating JY, and R is the radius of JY. Calculatedresults from these formulas show that HS not only keeps the pores open, but also plays a main role in adjusting the pore structures. On the basis of above formulas, methods which can control and measure the parameters of pore structures of new type aluminium foams are also proposed. The measured value of theparameters of some aluminum foams is in accord with calculated value. The formulas and methods are feasible for the fabrication processes of metallic foams.更多还原