Effect of processing on mechanical properties of an Fe–8.5 wt.% Al–1.1 wt.% C alloy

A Fe–8.5 wt.% Al–1.1 wt.% C alloy was melted under a flux cover by air induction melting (AIM). Subsequent processing of the AIM ingots through electroslag remelting (ESR) resulted in a significant improvement in ductility. This may be attributed to the refined axially oriented grain structure, free from internal defects observed in the ESR ingots. The alloy exhibited a significantly higher yield strength at test temperatures up to 500°C than those reported for complex Fe–Al alloys with comparable aluminium contents. This may be due to dispersion strengthening caused by the presence of a large volume fraction of Fe3AlC0.5 precipitates in the alloy. Though the addition of carbon may decrease ductility, it allows commercial production of alloys with reasonable (8%) room temperature ductility, melted using cheap raw materials and a low cost melting procedure. The high carbon ESR alloy offers the best ductility reported for cast Fe–Al alloys with similar aluminium contents.