Abstract | A process utilizing a powder metallurgy (PM) approach was developed to produce open-cell metallic foams. A metallic powder, a solid polymeric binder and a chemical foaming agent are dry mixed together. The molded mixture is then subjected to a three-step thermal treatment resulting in foaming, debinding, and sintering. In this study, the microstructure and properties of iron-base foams (pure iron and Fe-1.05 w/o C) obtained by means of this process are described. The final material is highly porous (90 v/o porosity) and has an interconnected pore network. The structure of the resulting material is relatively complex and exhibits three levels of porosity, namely, main cells, windows, and microporosity. The compressive mechanical properties of the foams are affected by the density and composition of the material Compressive yield strength, modulus, and energy absorbed increase with density. In addition, the compressive yield strength and energy absorbed increase significantly with carbon content while the modulus is relatively unaffected. The structure and properties of the foams are attractive for lightweight structures and in applications involving energy absorption. The process is relatively simple and the ferrous foams are a low-cost alternative to aluminum foams. |
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