Creep behavior of Al-rich FeAl intermetallics

Abstract The compression creep behavior of two dual-phase intermetallic alloys (FeAl 2 -Fe 2 Al 5 and FeAl 3 -Fe 2 Al 5 ) was investigated over the temperature range 600–1000 °C. A normal primary creep stage, stress exponent between 4 and 5, and normal creep transient after a stress increase for the FeAl 2 -Fe 2 Al 5 and FeAl 3 -Fe 2 Al 5 ( T > 700 °C) materials suggest that the creep behavior of both is controlled by a dislocation climb process. The activation energy for creep for both materials is about 345 kJ mol −1 . For FeAl 3 -Fe 2 Al 5 tested at 700 °C, a stress exponent of 3.3 and an inverse creep transient after a stress increase suggest that viscous dislocation glide is the dominant deformation mechanism in this region. The activation energy for creep in this region is 280 kJ mol −1 . The creep strength for FeAl 2 -Fe 2 Al 5 is significantly lower than that for FeAl 3 -Fe 2 Al 5 . A comparison between FeAl 3 -Fe 2 Al 5 and various Ni and Ti aluminides reveals that FeAl 3 -Fe 2 Al 5 has superior specific strength except compared with TiAl.