Abstract
Porous metals, which contain large amount of pores inside, exhibit various unique physical and mechanical properties, such as low bulk density and high strain energy absorbing capability. In this presentation, a novel processing method (reactive precursor method) to synthesize high-melting point porous metals and an attempt to control the cell structure are discussed. A precursor is made by blending two or more kinds of elemental powders. The precursor is then heated to ignite an exothermic reaction between the elemental powders. The closed-cell porous structure is obtained when the maximum temperature during the reaction exceeds the melting point of the reaction product, and open-cell porous structure is obtained when the maximum temperature is below the melting point. Therefore, if the optimum porous structure is the closed cell, then an additive powder (exothermic agent powder) which releases large amount of heat of reaction should be additionally blended. By blending additive powders in the precursor, the maximum temperature can be controlled. Aside from the additive powders, replication powders are also used to extend the diversity of cell morphology. Closed, flat, open, bimodal-sized and high-porosity open pores are currently achieved by the reactive precursor process.
