Investigation of moisture-induced embrittlement of iron aluminides. Interim report
- Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Materials Engineering
Alloy FA-129 undergoes an increase in crack propagation rate and a loss of fracture toughness in moisture-bearing and hydrogen gas environments. A similar effect is seen on ductility of FA-129 in tensile tests. The embrittling effect in air is attributed to oxidation of aluminum in the alloy by water vapor to produce Al{sub 2}O{sub 3} and hydrogen gas. Alloy FAP-Y, which is disordered and contains only 16 a%Al is embrittled by hydrogen gas in a manner similar to that of FA-129. However, laboratory air had little effect on the crack growth rates, fracture toughness, or tensile ductility. The lower aluminum content apparently is insufficient to induce the Al-H{sub 2}O reaction. TEM and SEM analyses of microstructure and fracture surfaces were consistent with the change in fracture toughness with order and environment. Testing at elevated temperatures reduces crack growth rates in FA-129, and increases fracture toughness and ductility. This is consistent with the well documented peak in hydrogen embrittlement in structural alloys at or near room temperature. Elevated temperature affects the degree of embrittlement in a complex manner, possibly changing the rates of several of the processes involved.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Materials Engineering
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10147420
- Report Number(s):
- ORNL/Sub-90-SF521/02; ON: DE94010881
- Resource Relation:
- Other Information: PBD: 19 Apr 1994
- Country of Publication:
- United States
- Language:
- English
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