Research On Mechanism Of Pore Stability Of Foam Aluminum By Powder Compact Metallurgy Method

Aluminum foam is a kind of unique porous foam material, and it is also a kind ofcomposite material made up of the pores and the aluminum. So, its functional and structural isvery broad. The characteristic of aluminum foam is low density and high porosity and thefunction of aluminum foam is acoustic absorption, noise reduction and shock absorption. Inrecent years, due to its unique characteristic, aluminum foam has been the main research ofstudy by scholars all over the world.PCM method is used for this paper through adding the pure aluminum powders, Mgpowders and Si powders and different granularity TiH2as foaming agent to produce theprecursor by extrusion. Then foam through different temperature to the precursor. This paperstudies the TiH2particle size and the content of Mg to the effect of pore structure and thedegree of expansion of foam body, to produce the best foam by setting the optimumparameters through the experiment. Then the corresponding foaming mechanism research canbe studied and further to study the combined mechanism of multiple precursor.The experiment results show that: the different particle size of TiH2has a great influencefor aluminum foaming. The higher of TiH2particle size, the greater of the releasing hydrogentemperature and the more consistency of the particle size. When the foaming temperaturereached740℃，the content of TiH2is0.4%, the particle size in the range of200-300mesh, theexpansion degree of aluminum foam is the highest and lower density and with the moreuniform and stable pore structure. When the Al-8Si powders used as substrate, the content ofMg is4%and the content of TiH2is1%, the foaming temperature reached690℃，the highestexpansion degree of foam body and stable pore structure can be produced. The high expansiondegree of foam combined can be produced when the Al-4Mg-8Si can be choosed. The oxidefilm is a kind of mechanical combination mechanism which combined by mechanical forceproduced by expansion. The oxide film is impossible to erase whether adding some alloypowders or not. And the foam internal body combined by the mechanism of metallurgicaldiffusion.