Development of iron aluminides
Iron aluminides based on Fe{sub 3}Al are of interest to the Fossil Energy Program because of their excellent oxidation and corrosion resistance, especially in sulfur-bearing atmospheres. The work at Oak Ridge National Laboratory (ORNL) has centered on developing Fe{sub 3}Al-based alloys with improved ambient temperature ductilities and increased strengths at temperatures of 600--700{degree}C. We now believe that what in the past has been described as inherent'' brittleness in this system is actually caused by a dynamic environmental embrittlement involving atomic hydrogen. We have made great strides in understanding this embrittling phenomenon and are now producing, through composition modification and thermomechanical processing, alloys with room temperature ductilities of >10% and tensile yield strengths at 600{degree}C of as high as 500 MPa. Creep rupture lifes of over 200 h at 593{degree}C and 207 MPa can be produced through alloy modifications to induce precipitate strengthening. This paper summarizes our present efforts in improving the high temperature creep strength and the present status of our understanding of the role of composition, heat treatment, and microstructure on improving room temperature tensile properties by minimizing environmental embrittlement in this system. 14 refs., 4 figs., 2 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOE/FE
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6845474
- Report Number(s):
- CONF-900546-6; ON: DE90012206
- Resource Relation:
- Conference: 4. conference on fossil energy materials, Oak Ridge, TN (USA), 15-17 May 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
EMBRITTLEMENT
IRON BASE ALLOYS
SULFUR
CORROSIVE EFFECTS
ANNEALING
CORROSION RESISTANT ALLOYS
CREEP
FOSSIL FUELS
INTERMETALLIC COMPOUNDS
METALLURGICAL EFFECTS
MICROSTRUCTURE
RECRYSTALLIZATION
TEMPERATURE DEPENDENCE
TENSILE PROPERTIES
ALLOYS
CRYSTAL STRUCTURE
ELEMENTS
ENERGY SOURCES
FUELS
HEAT TREATMENTS
IRON ALLOYS
MECHANICAL PROPERTIES
NONMETALS
010400* - Coal
Lignite
& Peat- Processing
360105 - Metals & Alloys- Corrosion & Erosion
360103 - Metals & Alloys- Mechanical Properties