CREEP-BEHAVIOR OF AL-RICH FE-AL INTERMETALLICS

The compression creep behavior of two dual-phase intermetallic alloys (FeAl2-Fe2Al5 and FeAl3-Fe2Al5) was investigated over the temperature range 600-1000 degrees C. A normal primary creep stage, stress exponen t between 4 and 5, and normal creep transient after a stress increase for the FeAl2-Fe2Al5 and FeAl3-Fe2Al5 (T > 700 degrees C) materials su ggest that the creep behavior of both is controlled by a dislocation c limb process. The activation energy for creep for both materials is ab out 345 kJ mol(-1). For FeAl3-Fe2Al5 tested at 700 degrees C, a stress exponent of 3.3 and an inverse creep transient after a stress increas e suggest that viscous dislocation glide is the dominant deformation m echanism in this region. The activation energy for creep in this regio n is 280 kJ mol(-1). The creep strength for FeAl2-Fe2Al5 is significan tly lower than that for FeAl3-Fe2Al5. A comparison between FeAl3-Fe2Al 5 and various Ni and Ti aluminides reveals that FeAl3-Fe2Al5 has super ior specific strength except compared with TiAl.