Fracture behavior of Cr{sub 2}Nb-based intermetallics

Technical Report · Fri Dec 30 23:00:00 EST 1994

DOI:https://doi.org/10.2172/81045· OSTI ID:81045

Cook, J A; Liaw, P K ^[1]; Liu, C T ^[2]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
2. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

Microstructural evaluations and mechanical testing of Laves-phase alloys based on Cr{sub 2}Nb were examined in order to determine phase relationships with heat treating temperatures up to 1,600 C. At ambient temperatures, single-phase Cr{sub 2}Nb alloys are very hard and brittle due to the complicated crystal structure (C-15). The following results were revealed through examination of the Cr-Cr{sub 2}Nb two-phase region: (a) with increasing amounts of the soft chromium-rich phase, the compression strength and hardness decrease; (b) the annealing treatments studied provided the best break-up of the brittle Laves-containing eutectic phase in the 94 at.% Cr-6 at.% Nb (CN-7) alloy; (c) annealing for 1 hour at 1,600 C + 4 hours at 1,200 C drastically improved the room temperature strength and compressive ductility over previous annealing treatments. Previous studies have shown that the introduction of a soft chromium phase has promising effects in improving the mechanical properties of brittle Cr{sub 2}Nb Laves-phase alloys.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 81045
• Report Number(s): CONF-941016--7; ON: DE95013223
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CHROMIUM BASE ALLOYS
EXPERIMENTAL DATA
INTERMETALLIC COMPOUNDS
LAVES PHASES
MECHANICAL PROPERTIES
MECHANICAL TESTS
MICROHARDNESS
MICROSTRUCTURE
NIOBIUM ALLOYS
PHASE STUDIES
USES