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Metallurgical Transactions A

, Volume 16, Issue 10, pp 1863–1870 | Cite as

The influence of cobalt, tantalum, and tungsten on the elevated temperature mechanical properties of single crystal nickel-base superalloys

  • M. V. Nathal
  • L. J. Ebert
Mechanical Behaviour

Abstract

The influence of composition on the tensile and creep strength of [001] 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 ofγ′ volume fraction,γ-γ′ lattice mismatch, and solid solution hardening.

Keywords

Metallurgical Transaction Creep Rate Lattice Mismatch Creep Resistance Misfit Dislocation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© The Metallurgical of Society of AIME 1985

Authors and Affiliations

  • M. V. Nathal
    • 1
  • L. J. Ebert
    • 2
  1. 1.NASA Lewis Research CenterCleveland
  2. 2.Case Western Reserve UniversityCleveland

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