Mechanical Properties of Fe₃Al Intermetallic Matrix Composites

Abstract

Iron aluminides are of considerable interest due to their low cost, relatively high melting point, relatively low density, and excellent resistance to oxidation, sulfidation and molten salts. However, poor ductility and fracture toughness at room temperature hinder their use as a structural material. Refining of the microstructure is known to be one method to increase the room temperature ductility. Mechanical alloying (MA) is an easy way to obtain fine microstructures. In addition, pulse discharge sintering (PDS) is a new technology which suppresses grain growth during sintering because the sparks generated during sintering break the surface oxide layer of the powder particles and thus speed up the sintering process. Therefore, the combination of MA and PDS processes results in final products with very fine microstructures. Fe-28at.%Al alloy and its composite reinforced with 5vol.% of TiB2 particles were fabricated by the MA-PDS process. The mechanical properties of these materials were improved significantly as compared to conventionally processed materials.