Effect of aluminium content on environmental embrittlement in binary iron-aluminum alloys

Journal Article · Wed Jul 15 04:00:00 EDT 1992 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(92)90110-Z· OSTI ID:7163449

Vyas, S; Viswanathan, S; Sikka, V K ^[1]

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1. Metals and Ceramics Div., Oak Ridge National Lab., Oak Ridge, TN (US)

Interest in iron-aluminum alloys has existed for the last sixty years, on account of their attractive properties including low density, excellent oxidation resistance, and conservation of strategic elements. This paper reports that recent investigations have focused on the ordered Fe{sub 3}Al-based alloys containing 15.9 wt % Al, and FeAl-based alloys containing about 22 wt % Al. However, the poor room-temperature ductility and sharp drop in strength at temperatures above 600{degrees} C in these alloys have been major deterrents to their acceptance in structural applications. In particular, the poor room-temperature ductility has been shown to be the result of environmental embrittlement in the presence of water vapor; ductility as measured by total elongation in heat-treated tensile specimens has been shown to be significantly higher in oil-quenched samples and samples tested in vacuum than in air-cooled samples tested in air. The increase in ductility in samples tested in vacuum has been assumed to be due to the absence of water vapor in the test environment, essential to the formation of atomic hydrogen involved in the embrittlement mechanism. The increase in ductility in oil-quenched specimens may be assumed to be due to the presence of a film of oil on the specimen surface that serves to provide a barrier to water vapor in air and, thus, prevent the generation of hydrogen on the surface from the reaction of aluminum in the alloy with water vapor.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7163449
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 27:2; ISSN SCRME; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
AIR
ALLOY SYSTEMS
ALLOYS
ALUMINIUM
ALUMINIUM ALLOYS
BINARY ALLOY SYSTEMS
DUCTILITY
ELEMENTS
ELONGATION
EMBRITTLEMENT
FILMS
FLUIDS
GASES
HEAT TREATMENTS
HYDROGEN
IRON ALLOYS
MECHANICAL PROPERTIES
METALS
NONMETALS
OILS
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
QUANTITY RATIO
QUENCHING
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
TENSILE PROPERTIES
THIN FILMS
VAPORS
WATER VAPOR
YIELD STRENGTH