Effects of alloy stoichiometry on environmental embrittlement in L1[sub 2]-ordered (Co,Fe)[sub 3]V alloys

Journal Article · Sun Nov 15 04:00:00 EST 1992 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(92)90075-P· OSTI ID:6859505

Nishimura, C ^[1]; Liu, C T ^[2]

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1. National Research Inst. for Metals, Tokyo (Japan)
2. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

Recent studies have demonstrated that a large number of ordered intermetallics exhibit environmental embrittlement in air at ambient temperatures. The embrittlement involves the decomposition of water vapor at metal surface, resulting in the generation of atomic hydrogen that diffuses into the alloys and causes brittle intergranular fracture. The authors' recent studies have shown that Ll[sub 2]-ordered (Co, Fe)[sub 3]V alloys containing 25 at. % V exhibit the environmental embrittlement. For instance (Co[sub 78]Fe[sub 22])[sub 3]V alloy showed a high ductility of 36% when tested in vacuum at room temperature, whereas the ductility decreased to 20 and 16% when tested in air and distilled water, respectively. In this paper, the study of environmental embrittlement in (Co,Fe)[sub 3]V is extended to include effects of alloy stoichiometry. Hypostroichiometric alloys containing less than 25 at.% V were prepared and tensile tested in various environments at room temperature. The results are compared with those from the stoichiometric (CO,Fe)[sub 3]V alloy and other Ll[sub 2] intermetallics and discussed based on available models predicting the grain-boundary cohesive strength.

• OSTI ID: 6859505
• Journal Information: Scripta Metallurgica et Materialia; (United States), Journal Name: Scripta Metallurgica et Materialia; (United States) Vol. 10; ISSN SCRMEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360103 -- Metals & Alloys-- Mechanical Properties
360105 -- Metals & Alloys-- Corrosion & Erosion
664400 -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALLOYS
ATOM TRANSPORT
COBALT ALLOYS
COBALT BASE ALLOYS
CRYSTAL STRUCTURE
DUCTILITY
EMBRITTLEMENT
ENVIRONMENTAL EFFECTS
FLUIDS
GASES
GRAIN BOUNDARIES
HYDROGEN EMBRITTLEMENT
INTERMETALLIC COMPOUNDS
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NEUTRAL-PARTICLE TRANSPORT
RADIATION TRANSPORT
STOICHIOMETRY
TENSILE PROPERTIES
VANADIUM ALLOYS
VAPORS
WATER VAPOR