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The influence of cobalt, tantalum, and tungsten on the elevated temperature mechanical properties of single crystal nickel-base superalloysThe influence of composition on the tensile and creep strength of 001-line oriented nickel-base superalloy single crystals at temperatures near 1000 C was investigated. Cobalt, tantalum, and tungsten concentrations were varied according to a matrix of compositions based on the single crystal version of MAR-M247. For alloys with the baseline refractory metal level of 3 wt pct Ta and 10 wt pct W, decreases in Co level from 10 to 0 wt pct resulted in increased tensile and creep strength. Substitution of 2 wt pct W for 3 wt pct Ta resulted in decreased creep life at high stresses, but improved life at low stresses. Substitution of Ni for Ta caused large reductions in tensile strength and creep resistance, and corresponding increases in ductility. For these alloys with low Ta-plus-W totals, strength was independent of Co level. The effects of composition on properties were related to the microstructural features of the alloys. In general, high creep strength was associated with high levels of gamma-prime volume fraction, gamma-gamma-prime lattice mismatch, and solid solution hardening.
Document ID
Document Type
Reprint (Version printed in journal)
Nathal, M. V.
(NASA Lewis Research Center Cleveland, OH, United States)
Ebert, L. J.
(Case Western Reserve University Cleveland, OH, United States)
Date Acquired
August 12, 2013
Publication Date
October 1, 1985
Publication Information
Publication: Metallurgical Transactions A - Physical Metallurgy and Materials Science
Volume: 16A
ISSN: 0360-2133
Subject Category
Metallic Materials
Accession Number
Distribution Limits

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