Slow crack growth in ternary B2 iron aluminides at room temperature

Journal Article · Thu Dec 15 00:00:00 EST 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90474-X· OSTI ID:6890668

Schneibel, J H; Specht, E D ^[1]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Division

While the humidity-induced embrittlement has been studied extensively, it is not clear at the present time how to best alleviate or eliminate it in FeAl. While protective coatings may improve ductilities they will lose their effectiveness once macroscopic cracks have formed. Humidity-induced embrittlement may also be alleviated by processing designed to develop more resistant microstructures, or possibly by adding alloying elements capable of trapping hydrogen in order to keep it away from crack tips. The purpose of this paper is to explore the effect of macroalloying additions on slow crack growth in B2 iron aluminides. Since the fracture toughness testing technique employed is most reliable for low fracture toughnesses, a high Al content of 45 at. % was chosen [it is well known that the fracture toughness of FeAl decreases as the Al content increases]. Small amounts of B and Zr were added in order to strengthen the grain boundaries. Since Al is thought to be the primary element responsible for humidity-induced embrittlement, its concentration was chosen to be the same in all three alloys investigated. Care was taken to process the alloys in the same way, and to make sure that they had comparable microstructures. It was also verified that there were no significant amounts of second phases which might invalidate a comparison between the different alloys.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6890668
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 31:12; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRACK PROPAGATION
CHROMIUM
METALLURGICAL EFFECTS
IRON ALLOYS
MANGANESE
NICKEL
BORON
EXPERIMENTAL DATA
INTERMETALLIC COMPOUNDS
ZIRCONIUM
ALLOYS
DATA
ELEMENTS
INFORMATION
METALS
NUMERICAL DATA
SEMIMETALS
TRANSITION ELEMENTS
360103* - Metals & Alloys- Mechanical Properties