The influence of composition on environmental embrittlement of iron aluminides
- Rensselaer Polytechnic Institute, Troy, NY (United States)
The effects of water vapor in air and hydrogen gas on the tensile and fatigue crack growth behavior of Fe{sub 3}Al alloys has been studied at room temperature. Fe-28a%Al-5a%Cr alloys to which either Zr alone or Zr and C have been added have been tested in controlled humidity air environments as well as in 1.3 atm hydrogen or oxygen gas and in vacuum. As with other Fe{sub 3}Al alloys, oxygen produces the lowest crack growth rates as well as the highest critical stress intensities and tensile ductility in each of the alloys tested. However, while Zr lowers crack growth rates in the Paris regime, there is no apparent beneficial effect on crack growth thresholds. Hydrogen gas also produces unusual results. While crack growth rates are very high in hydrogen in the Paris regime for all alloys, hydrogen only lowers the crack growth threshold relative to air in ternary Fe-28Al-5Cr; it does not lower the threshold in the Zr-containing alloys. Fracture path tends to be transgranular in all alloys and environments. The results will be discussed in the light of possible effects of Zr on oxide formation.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- OSTI ID:
- 458948
- Report Number(s):
- ORNL/FMP--96/1; CONF-9605167--; ON: DE97050349; CNN: Subcontract 19X-SF521C
- Country of Publication:
- United States
- Language:
- English
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