No abstract

No abstract

The effect of carbon content (0.01

Iron aluminides produced by the electroslag refining technique, having the compositions: (1) Fe-16Al-1C, (2) Fe-10Al-1C, and (3) Fe-8Al-1C were used to investigate the effect of Al on the oxidation behaviour of the Fe-1C-Al system at 700 to 1000 C. Prior to oxidation studies, phase and microstructure of alloys were analysed. The carbide phase, Fe 3 AlC 0.69 , was found to be distributed in the Fe 3 Al matrix in alloy 1 and (Fe-Al) matrix in alloys 2 and 3. The low Al content alloys displayed inversion in the oxidation kinetics below 800 C, while, high Al content alloy displayed inversion phenomena at 1000 C. The mechanism involving inversion in oxidation kinetics was found to be different in the two cases. In the former, it was attributed to the preferential oxidation of Al, while in the latter, to the phase transformation within the Al 2 O 3 . Carbides in the alloy having low Al content showed instability during oxidation.

No abstract

No abstract

No abstract

Effect of aluminium and carbon content on the microstructure and mechanical properties of FeAl-C alloys has been investigated. Alloys were prepared by combination of air induction melting with flux cover (AIMFC) and electroslag remelting (ESR). The ESR ingots were hot forged and hot rolled at 1373 K. As rolled alloys were examined using optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to understand the microstructure of these alloys. The ternary Fe-Al-C alloys containing 10 . 5 and 13 wt-%Al showed the presence of three phases: FeAl with disordered bcc structure, Fe 3 Al with ordered DO 3 structure and Fe 3 AlC 0 . 5 precipitates with L91 2 structure. Addition of high concentration of carbon to these alloys resulted in excellent hot workability and superior tensile at room temperature as well as tensile and creep properties at 873 K. An increase in Al content from 9 to 13 wt-% in Fe-Al-C alloys containing the same levels of carbon has no significant influence on strength and creep properties at 873 K, however resulted in significant improvement in room temperature strength accompanied by a reduction in room temperature ductility.