High temperature tensile and creep properties of a cast aim and ESR intermetallic alloy based on Fe3Al

A high carbon intermetallic Fe-16 wt.% A1-1.1 wt.% C alloy based on Fe3Al was melted under a flux cover by air induction melting (AIM). The AIM ingots exhibited excellent elevated temperature tensile properties in the temperature range (600–800°C) studied, in contrast to poor properties expected in ingots melted without a flux cover. Subsequent processing of the AIM ingots through electroslag remelting (ESR) resulted in improvement in ductility. However, the AIM ingots exhibited better creep properties because of their coarser gain structure. The presence of large (1.1 wt.%) amount of carbon in the alloy resulted in significant improvement in elevated temperature tensile as well as creep properties over those reported for Fe3Al based intermetallic alloys with lower carbon contents. These improvements in mechanical properties are attributed to the extensive precipitation of Fe3AlC phase and to the formation of a duplex Fe3Al-Fe3AlC structure at such high levels of carbon. It is suggested that carbon may be an important alloying addition to Fe3Al-based intermetallic alloys.