Initial development of nickel and nickel-iron aluminides for structural uses

Technical Report · Wed Aug 01 00:00:00 EDT 1984

DOI:https://doi.org/10.2172/6316935· OSTI ID:6316935

Liu, C. T.; Jemian, W.; Inouye, H.; Cathcart, J. V.; David, S. A.; Horton, J. A.; Santella, M. L.

Initial development of ductile nickel and nickel-iron aluminides has concentrated on boron-doped Ni/sub 3/Al alloyed with iron and other elements. The aluminide can dissolve no more than 15 at. % Fe, beyond which formation of both transformed B2 phase (..beta..') and disordered fcc phase (..gamma..) is observed. Nickel-iron aluminides were tensile tested as a function of temperature. Iron additions strengthen Ni/sub 3/Al effectively at temperatures to 850/sup 0/C. The yield stress of the nickel-iron aluminides increases with test temperature and reaches a maximum around 650/sup 0/C. The high-temperature strength of the aluminides can be further improved by alloying with less than 2 at. % Hf. Hafnium-modified aluminides are stronger than commercial superalloys, including some cast superalloys. Hot corrosion behavior of nickel-iron aluminides was determined in quartz capsules and in a circulating loop system containing a supply of CaSO/sub 4/ at temperatures to 871/sup 0/C (1600/sup 0/F). The combined results from these tests showed the dependence of sulfidation on oxygen partial pressure and verified that the sulfidation attack of aluminides in capsule tests was caused by oxygen depletion in a closed system with a limited supply of oxygen. The aluminides exhibited superior oxidation resistance in air at temperatures to 1100/sup 0/C. The ductile aluminides are prone to hot cracking during welding. However, they can be electron beam welded successfully under closely controlled conditions. Boron content and welding speed affect the weldability of the aluminides.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6316935
• Report Number(s): ORNL-6067; ON: DE84016641
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360100* -- Metals & Alloys
ALLOYS
ALUMINIUM ALLOYS
CHEMICAL REACTIONS
CORROSION RESISTANCE
CORROSION RESISTANT ALLOYS
FABRICATION
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INTERMETALLIC COMPOUNDS
IRON ALLOYS
JOINING
MATERIALS
MECHANICAL PROPERTIES
NICKEL ALLOYS
OXIDATION
SULFIDATION
TENSILE PROPERTIES
WELDING