The characteristic of Closed-cell aluminum foam is that each hole structure is relatively closed, and there is almost no communication between the holes. When Closed-cell aluminum foam is used as sound-absorbing material, the sound energy can not be consumed through the viscous friction between the holes, so the sound-absorbing coefficient of most Closed-cell aluminum foam is not very good; Semi open cell foam aluminum refers to the extrusion or bending of foam aluminum to change its shape, destroy part of its internal pore structure, make the pores no longer independent, form a semi open cell structure to make some pores connected, and have better sound absorption performance than Closed-cell aluminum foam; Open cell foam aluminum generally has three-dimensional tree shaped irregular continuous metal skeleton, which contains a large number of holes and the holes are connected with each other. The holes and metal skeleton form a complex three-dimensional tree network structure. Due to its special pore structure, the porosity of open cell foam aluminum can reach 90%, and its sound absorption performance is the best compared with closed cell and semi open cell foam aluminum.
As a typical porous metal material, Closed-cell aluminum foam has the advantages of light weight, high specific stiffness, high specific strength and strong impact absorption ability. It is widely used in aerospace, automobile transportation, military and other fields
