High-temperature oxidation behavior of two-phase iron-manganese-aluminum alloys

Oxidation behavior of two series of two-phase Fe-Mn-Al alloys in air up to 800degreesC was investigated. For the first series of alloys with various ratios of ferrite/austenite, the oxidation resistance of these alloys increased as the ferrite content increased. Two layers of oxide were formed mainly on the austenite grains, and oxidation in the ferrite phase was much less severe. The outer layer of the scale on austenite was enriched with Mn and Fe, while Al was concentrated in the inner layer. For the second series of alloys with nearly the same contents of ferrire and C but various contents of Cr, the addition of Cr changed the oxidation characteristics and increased the oxidation resistance. Cr assisted the formation of a dense film of alumina (Al2O3) to prevent further oxidation.