Fabrication and mechanical properties of Fe sub 3 Al-based iron aluminides

Technical Report · Thu Mar 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/6596000· OSTI ID:6596000

Sikka, V K; McKamey, C G; Howell, C R; Baldwin, R H

Iron aluminides based on Fe{sub 3}Al are ordered intermetallic alloys that offer good oxidation resistance, excellent sulfidation resistance, and lower material cost than many stainless steels. These materials also conserve strategic elements such as chromium and have a lower density than stainless steels. However, limited ductility at ambient temperature and a sharp drop in strength have been major deterrents to their acceptance for structural applications. This report presents results on iron aluminides with room-temperature elongations of 15 to 20%. Ductility values were improved by a combination of thermomechanical processing and heat-treatment control. This method of ductility improvement has been demonstrated for a range of compositions. Melting, casting, and processing of 7-kg (15-lb) heats produced at the Oak Ridge National Laboratory (ORNL) and 70-kg (150-lb) commercial heats are described. Vacuum melting and other refining processes such as electroslag remelting are recommended for commercial heats. The Fe{sub 3}Al-based iron aluminides are hot workable by forging or extruding at temperatures in the range of 850 to 1100{degree}C. rolling at 800{degree}C is recommended with a final 50% reduction at 650{degree}C. Tensile and creep properties of 7- and 70-kg (15- and 150-lb) heats are presented. The presence of impurities such as manganese an silicon played an important role in reducing the ductility of commercially melted heats. 7 refs., 60 figs., 12 tabs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/FE
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6596000
• Report Number(s): ORNL/TM-11465; ON: DE91001001
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010400* -- Coal
Lignite
& Peat-- Processing
014000 -- Coal
Lignite
& Peat-- Combustion
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ALUMINIUM ALLOYS
ANNEALING
COHERENT SCATTERING
CONVERSION
CORROSION RESISTANCE
CREEP
CRYSTAL STRUCTURE
DIFFRACTION
DUCTILITY
ENERGY SOURCES
FABRICATION
FAILURES
FOSSIL FUELS
FRACTURES
FUELS
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
IRON ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
SCATTERING
TENSILE PROPERTIES
X-RAY DIFFRACTION