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Title: Alumina forming iron base superalloy

Abstract

An austenitic stainless steel alloy, consists essentially of, in weight percent 2.5 to 4 Al; 25 to 35 Ni; 12 to 19 Cr; at least 1, up to 4 total of at least one element selected from the group consisting of Nb and Ta; 0.5 to 3 Ti; less than 0.5 V; 0.1 to 1 of at least on element selected from the group consisting of Zr and Hf; 0.03 to 0.2 C; 0.005 to 0.1 B; and base Fe. The weight percent Fe is greater than the weight percent Ni. The alloy forms an external continuous scale including alumina, and contains coherent precipitates of .gamma.'-Ni.sub.3Al, and a stable essentially single phase FCC austenitic matrix microstructure. The austenitic matrix is essentially delta-ferrite-free and essentially BCC-phase-free.

Inventors:
; ;
Publication Date:
Research Org.:
ORNL (Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States))
Sponsoring Org.:
USDOE
OSTI Identifier:
1151771
Patent Number(s):
8,815,146
Application Number:
13/440,639
Assignee:
UT-Battelle, LLC (Oak Ridge, TN) ORNL
DOE Contract Number:
AC05-00OR22725
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Yamamoto, Yukinori, Muralidharan, Govindarajan, and Brady, Michael P. Alumina forming iron base superalloy. United States: N. p., 2014. Web.
Yamamoto, Yukinori, Muralidharan, Govindarajan, & Brady, Michael P. Alumina forming iron base superalloy. United States.
Yamamoto, Yukinori, Muralidharan, Govindarajan, and Brady, Michael P. Tue . "Alumina forming iron base superalloy". United States. doi:. https://www.osti.gov/servlets/purl/1151771.
@article{osti_1151771,
title = {Alumina forming iron base superalloy},
author = {Yamamoto, Yukinori and Muralidharan, Govindarajan and Brady, Michael P.},
abstractNote = {An austenitic stainless steel alloy, consists essentially of, in weight percent 2.5 to 4 Al; 25 to 35 Ni; 12 to 19 Cr; at least 1, up to 4 total of at least one element selected from the group consisting of Nb and Ta; 0.5 to 3 Ti; less than 0.5 V; 0.1 to 1 of at least on element selected from the group consisting of Zr and Hf; 0.03 to 0.2 C; 0.005 to 0.1 B; and base Fe. The weight percent Fe is greater than the weight percent Ni. The alloy forms an external continuous scale including alumina, and contains coherent precipitates of .gamma.'-Ni.sub.3Al, and a stable essentially single phase FCC austenitic matrix microstructure. The austenitic matrix is essentially delta-ferrite-free and essentially BCC-phase-free.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 26 00:00:00 EDT 2014},
month = {Tue Aug 26 00:00:00 EDT 2014}
}

Patent:

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  • A series of iron-base alloys have been oxidized at P/sub o2/.2*10/sup -1/ atm and at P/sub 02/.10/sup -18/ atm. The morphologies of the Al/sub 2/O/sub 3/ scales depend on the heating rate, Cr content and P/sub o2/ of the environment. When the specimens are slowly introduced in the hot zone and oxidized in air, all form Al/sub 2/O/sub 3/ scales with a convoluted morphology. The extent of the convolutions decreases with increase in Cr content. When rapidly heated and oxidized in air, the low Cr-containing alloys form internal oxides and a surface scale of Al/sub 2/O/sub 3/ which shows nomore » convolutions. In the higher Cr containing alloys, internal oxidation is limited. In the low P/sub o2/ environment, the binary alloy fails to form a protective Al/sub 2/O/sub 3/ scale. All other alloys form external Al/sub 2/O/sub 3/ scales which show little or no convolutions. 3 refs.« less
  • This patent describes an improved nickel-base superalloy capable of being cast as a single crystal by directional solidification, having an improved balance of high temperature strength and high temperature oxidation and corrosion resistance consisting essentially of, by weight: 7-12% Cr, 1-5% Mo, 3-5% Ti, 3-5% Al, 5-15% Co, 3-12% W, 2-6% Ta, up to 10% Re, up to 2% Cb, up to 3% V, up to 2% Hf, balance Ni and incidental impurities, further characterized wherein the superalloy has no added C, B, and Zr and, if present, the elements, are at impurity levels, the alloy having an Al:Ti ratiomore » from about 0.5 to about 1 while maintaining the Cr:Al ratio from about 1.5-4.« less
  • This is a nickel-base superalloy with excellent weldability and high strength. Its composition consists essentially of, by weight percent, 10-20 iron, 57-63 nickel, 7-18 chromium, 4-6 molybdenum, 1-2 niobium, 0.2-0.8 silicon, 0.01-0.05 zirconium, 1.0-2.5 titanium, 1.0-2.5 aluminum, 0.02-0.06 carbon, and 0.002-0.015 boron. The weldability and strength of this alloy give it a variety of applications. The long-time structural stability of this alloy together with its low swelling under nuclear radiation conditions, make it especially suitable for use as a duct material and controlling element cladding for sodium-cooled nuclear reactors.
  • This patent describes a substantially iron-free nickel-base alloy. It comprises (in weight percent): about 12% to 24% chromium, about 5% to 20% cobalt; and 1% to 8.5% of at least one member of the group consisting of molybdenum, tungsten and rhenium; about 2% to 23% tantalum; about 0.003% to 0.05% boron; less than about 1% iron; and the balance essentially nickel the alloy having a rupture life of at least 100 hours at a stress of 90 ksi at 1300{degrees}F. and a substantial volume fraction of gamma double prime phase.
  • This is a nickel-base superalloy with excellent weldability and high strength. Its composition consists essentially of, by weight percent, 10-20 iron, 57-63 nickel, 7-18 chromium, 4-6 molybdenum, 1-2 niobium, 0.2-0.8 silicon, 0.01-0.05 zirconium, 1.0-2.5 titanium, 1.0-2.5 aluminum, 0.02-0.06 carbon, and 0.002-0.015 boron. The weldability and strength of this alloy give it a variety of applications. The long-time structural stability of this alloy together with its low swelling under nuclear radiation conditions, make it especially suitable for use as a duct material and controlling element cladding for sodium-cooled nuclear reactors.