Low cycle fatigue of Fe3Al-based iron aluminide with and without Cr

The low cycle fatigue (LCF) behavior of two hot extruded alloys with the compositions Fe–27.1Al and Fe–26.4Al–4Cr (at%) containing microalloying additions of Nb, Zr, C, and B was investigated at room temperature and 300 °C in air. The LCF tests were carried out in strain control with strain amplitudes in the range of εa = 0.2–0.7% with frequencies of 1 or 3 Hz. During fatigue, strong cyclic hardening was observed. No significant influence of the Cr addition on the tensile properties and the LCF behavior was noticed. Similarly, a heat treatment of 100 h at 800 °C did not change the microstructure or the LCF behavior noticeably. For cycle numbers below ∼10 000, the fatigue resistance at 300 °C tended to be higher than that at room temperature, and vice versa.