Improvements on Metallic From Produced by P/M Method

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Cellular metals are of interest both the viewpoint of stiff lightweight structures and theire functional efficiencies in sound absorption, impact energy absorption, electromagnetic shielding and vibration damping, In the present project, a powder metallurgical technique for the production of foamed cellular aluminum has been studied. Foamed aluminum specimens expanded under a buldging-restrictive condition in a steel sleeve show relatively uniform cell structures with nearly spherical pores both in cross and longitudinal sections. Two parameters, rugness and roundness factors, are newly introduced as quantitative measures to express the shape of pores in foamed products. It is determined that the shape of pores strongly depends on porosity and that the Voronoi's cell is adaptive for cell structures of highly expanded aluminum foams. Forming techniques for metallic foam products are also established ; forming characteristics of a closed-die expansion forming for rather complex foam parts and expansion extrusion for foamed metal bars are investigated.