Fabrication of a Porous Fe-Al Intermetallic Alloy with Ultrahigh Open Porosity

Herein, a porous Fe-Al intermetallic material with ultrahigh open porosity is prepared via the multistep sintering process using a Fe-Al-Mn powder mixture as the raw material. The microstructure, phase composition, Mn sublimation, and open porosity of the sintered Fe-Al-Mn compacts are investigated. The compacts sintered at temperatures <= 700 degrees C are composed of the newly formed Fe/Mn-based solid solutions, intermetallic phases, and the original elemental particles without the sublimation of Mn. The open porosities of the 650- and 700 degrees C-sintered compacts are approximate to 39.83 and approximate to 47.19 vol%, respectively. After sintering at 1250 degrees C, Mn is rarely left in the porous body, and a single Fe-Al intermetallic phase with an even chemical composition is generated. The open porosity of the 1250 degrees C-sintered compacts is approximate to 66.67 vol%, superior to other reported porous Fe-Al materials, and its strength is approximate to 22.5 MPa, which is competitive as well. This work may open a new strategy to design and optimize the high-quality porous Fe-Al alloy in future.