Effect of melting process and aluminium content on the microstructure and mechanical properties of Fe-Al alloys

Abstract

This paper presents the effect of air induction melting with flux cover (AIMFC) versus vacuum induction melting (VIM) on the recovery of alloying element, reduction of impurities, workability and mechanical properties of Fe-(7-16mass%)Al alloys. Three Fe-Al alloy ingots containing 7, 9 and 16 mass% Al were prepared by both AIMFC and VIM. All these ingots were hot-forged and hot-rolled at 1 373 K and were further characterized with respect to chemical composition, microstructure and mechanical properties. The recovery of aluminium as well as reduction of oxygen during both AIMFC and VIM is excellent. AIMFC ingots exhibit low level of sulphur and high concentration of hydrogen as compared to VIM ingots. VIM ingots of all the three alloys were successfully hot worked. However, AIMFC ingots of only those Fe-Al alloys containing lower concentration of aluminium could be hot worked. The tensile properties of hot-rolled Fe-7mass%Al alloy produced by AIMFC and VIM are comparable. The present study clearly demonstrates that it is feasible to produce sound ingots of low carbon Fe-7mass%Al alloy by AIMFC process with properties comparable to the alloy produced by VIM. © 2010 ISIJ.