Oxidation behavior of FeAl alloys with and without titanium

The influence of Ti addition on the high temperature oxidation behavior of FeAl intermetallic alloys in air at 1000 degreesC and 1100 degreesC has bee n investigated. The oxidation kinetics of FeAl alloys was examined by the w eight gain method and oxide products were examined by XRD, SEM, EDS and EPM A. The results showed that the oxidation kinetic curves of both Ti-doped an d binary Fe-36.5Al alloys could be described as different parabolas that fo llowed the formula: (DeltaW/S)(2) = K(p)t + C. The parabolic rate constant, K-p values are approximately 2.4 and 3.3 mg(2) cm(-4) h(-1) for Fe-36.5Al alloy and about 1.3 and 2.0 mg(2) cm(-4) h(-1) for Fe-36.5Al-2Ti alloy when oxidizing at 1000 degreesC and 1100 degreesC respectively. The difference between Fe-36.5Al and Fe-36.5Al-2Ti alloy is not only in the surface morpho logy but also in the phase components. In the surface there is only alpha - Al2O3 oxide for Fe-36.5Al alloy while there are alpha -Al2O3 and TiO oxides for Fe-36.5Al-2Ti alloy. The effects of Ti addition on the oxidation resis tance of FeAl alloy were addressed based on the microstructural evidence. ( C) 2001 Kluwer Academic Publishers.