Analysis of Production Techniques for Metal Foams of Iron and Steel

Metallic foams are engineering materials. Metallic foams are used for various applications such as crashworthiness, heat exchangers, fuel cells, implants, water, and air purifiers because of their low density, high heat dissipation capacity, and high sound and vibration damping ability. Currently, mostly low-density metal foams like aluminum, magnesium, and titanium are produced largely because low-density metal foams are easy. For high-density metals, the flux of matter in the pores is generated during foaming due to its high weight. Therefore, significant porosity is achieved. On the other hand, the cost of the foams of aluminum, titanium, magnesium, and other low-density metals is relatively high. Also, the strength and thermal resistance of foams of aluminum and magnesium are low. Due to the problems above, researchers have developed inexpensive material foams such as iron and steel. Still, the foaming of these materials is relatively complex because of their very high density. Various iron and steel foam fabrication techniques have been developed to produce low-cost foams. Some of them are reviewed in detail in the present work. Casting and powder metallurgy was found to be the two most common techniques to produce iron and steel foams. Foams produced by powder metallurgy had more uniform porosity and mechanical properties than the porosity and mechanical properties of foams produced by casting.