Recent advances in alloy design of Ni{sub 3}Al alloys for structural use

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:464296

Liu, C T; George, E P

This is a comprehensive review of recent advances in R&D of Ni{sub 3}Al-based alloys for structural use at elevated temperatures in hostile environments. Recent studies indicate that polycrystalline Ni{sub 3}Al is intrinsically quite ductile at ambient temperatures, and its poor tensile ductility and brittle grain-boundary fracture are caused mainly by moisture-induced hydrogen embrittlement when the aluminide is tested in moisture- or hydrogen-containing environments. Tensile ductility is improved by alloying with substitutional and interstitial elements. Among these additives, B is most effective in suppressing environmental embrittlement and enhancing grain-boundary cohesion, resulting in a dramatic increase of tensile ductility at room temperature. Both B-doped and B-free Ni{sub 3}Al alloys exhibit brittle intergranular fracture and low ductility at intermediate temperatures (300-850 C) because of oxygen-induced embrittlement in oxidizing environments. Cr is found to be most effective in alleviating elevated-temperature embrittlement. Parallel efforts on alloy development using physical metallurgy principles have led to development of several Ni{sub 3}Al alloys for industrial use. The unique properties of these alloys are briefly discussed. 56 refs, 15 figs, 3 tabs.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 464296
• Report Number(s): CONF-961017--20; ON: DE97004712
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BORON ADDITIONS
CARBURIZATION
CHROMIUM ALLOYS
COMPARATIVE EVALUATIONS
EMBRITTLEMENT
EROSION
HEAT RESISTING ALLOYS
INTERMETALLIC COMPOUNDS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
NICKEL BASE ALLOYS
REVIEWS