The effect of an oxide dispersion on the critical Al content in Fe-Al alloys

Oxide-dispersed iron aluminides with Al contents ranging from 10 to 28 at.% were oxidized in air at temperatures between 600 and 1300 degrees C in ord er to determine the critical Al content necessary to form a protective, ext ernal alumina scale. A Y2O3-Al2O3 dispersion, performed similarly to an Al2 O3 dispersion, indicated little effect of Y on the critical Al content. Com pared to ingot-processed iron aluminides, the addition of an oxide dispersi on reduced the critical Al content at 900 degrees C. This reduction is attr ibuted to the finer grain size in the oxide-dispersed Fe-Al.