Iron aluminides: From alloy development to processing
Martin Palm, Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany
Iron aluminides are a potentially cost effective replacement for stainless steels and Ni-base superalloys. They show outstanding corrosion and wear resistance and do have comparable low densities. Though, lack in strength at high temperatures and limited ductility at room temperature hampered their application for a long time.
Based on the determination of suitable phase diagrams a number of alloy concepts have been developed. Respective alloys were produced and their basic properties have been established. It showed that both strength and ductility can be markedly increased. Currently, in a number of collaborations with industry, processing of these novel iron aluminide alloys is investigated. Substantial refinement of the microstructure can be achieved by industrial processing thus further enhancing the ductility of the alloys.
The presentation will focus on alloys with Al contents between 22 to 35 at.% Al. A short review about strengthening of these alloys by various strategies and the respective effect on ductility will be given. These efforts have led to a number of alloys which are of interest for a broad variety of applications. Current industrial approaches of producing parts by casting, forging, rolling and additive manufacturing will be presented and properties resulting from the different processing technologies will be discussed.