Yielding, hardening and creep behavior of iron aluminides

Engineering properties of powder processed iron aluminides (Fe-24 wt.% Al a lloy) obtained by hot extrusion and roll compaction of water atomized powde r were investigated to assist in the structural analysis of FeAl components exposed to short-time, thermal-mechanical loadings. The test matrix for hi gh-temperature deformation of FeAl incorporated powder processed sheet and bar product forms. Tensile, cyclic, creep and relaxation tests were carried out from room temperature to 750 degrees C on the bar products. Sheets wer e characterized for their tensile and creep properties. The experimental da ta were sufficient to provide rules for yielding, hardening and creep in th e temperatures range of 23-750 degrees C. The room temperature curve adjust ed for the temperature dependence of the modulus may be used for the yield and hardening behavior between 23 and 600 degrees C. Above 600 degrees C, t he yield can be obtained from the tensile curve for the temperature of inte rest. Exposure to 750 degrees C causes sufficient recovery and resets the k inematic and isotropic hardening parameters to their initial values. Variat ion of Young's modulus with increase of temperature is also presented. Limi ted creep behavior is also discussed. Structural analysis of the FeAl compo nents can be carried out using finite element modeling techniques with the availability of the tensile, cyclic, relaxation and creep behavior of FeAl at elevated temperatures. (C) 1998 Published by Elsevier Science S.A. All r ights reserved.