Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/03—Alloys based on nickel or cobalt based on nickel
  • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
  • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
  • C22C19/057—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being less 10%
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C19/00—Alloys based on nickel or cobalt
  • C22C19/03—Alloys based on nickel or cobalt based on nickel
  • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
  • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
  • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion

Definitions

• the present invention relates to a nickel-based alloy as well as to articles such as blades of turbomachinery made of this nickel-based alloy and a process for producing a corresponding nickel-based alloy.
• turbomachines such as stationary gas turbines or aircraft engines
• nickel-base alloys and in particular nickel-based superalloys for example as blade materials
• these materials have sufficient mechanical strength for the high mechanical loads even at high operating temperatures.
• such materials must also have a high creep resistance when used in turbomachinery under the given environmental conditions with high operating temperatures and high mechanical loads due to centrifugal forces.
• Nickel-base alloys are understood to mean alloys whose main alloy constituent, ie the alloy constituent with the highest proportion, is nickel.
• Nickel-based superalloys in turn, refer to alloys with a high proportion of alloyed constituents which have intermetallic precipitates for particular hardening of the material.
• Corresponding nickel base superalloys, such as IN718, CMSX-4, PWA1497 or René N6, have specific microstructures that dictate the favorable high temperature properties of the materials.
• such nickel-base superalloys exhibit cube-shaped precipitates of a y 'phase in a ⁇ matrix, such that precipitation hardening occurs through the y' phase.
• the alloy constituents in the y-matrix also cause solid-solution hardening.
• the invention proposes to optimize the property profile of a nickel-based alloy and for the efficient use and variable use of alloy constituents, a nickel-based alloy having a chemical composition with 8 to 13 at.% Aluminum, 3 to 14 at.% Cobalt, 4 to 12 at.% Chromium, 0.6 to 8 at.% Molybdenum, 0 to 6 at.% Rhenium, 0.5 to 4 at.% Tantalum, 0.5 to 4 at.% Titanium, 0.3 to 3.5 at.% Tungsten, 0 to 4 at.% Germanium, 0 to 0.6 at.% Hafnium, 0 to 4 at.% Ruthenium and the balance nickel and unavoidable impurities.
• the chemical composition is further selected to be a microstructure having a matrix of y phase and precipitates can be formed from the y 'phase, wherein the y' phase component in the temperature range from 1000 ° C. to 1100 ° C. is 50% by volume to 80% by volume, preferably 60% by volume to 80% by volume and in particular 70 ° Vol.% To 80 vol.%.
• the y 'volume fraction can be adjusted in particular by the appropriate choice of the proportions of germanium, aluminum, titanium and tantalum.
• the aluminum content is minimized, while the proportion of germanium, titanium and / or tantalum is maximized for each element alone or in total for several or all of these elements, wherein the boundary condition that the y '- Phases - proportion should amount to 50 vol.% To 80 vol.% In the structure of the nickel-based alloy.
• the aluminum content may be in particular in a range of plus 30%, in particular plus 20%, preferably plus 10% of the minimum aluminum content to the minimum of aluminum content at given or maximum proportions of germanium, titanium and tantalum for the maintenance of y '- Phases - fraction can be chosen within the chemical composition given above. Accordingly, the proportion of germanium, tantalum and / or titanium in each case alone or for several or all of these elements can be selected in ranges corresponding to the respective maxima of the fraction minus 30%, in particular minus 20%, preferably minus 10% to the maximum correspond.
• the boundary condition of a y 'phase fraction of 50% by volume to 80% by volume should be adhered to, so that in each case the corresponding minima or Maxima for the respective fractions can be determined for a minimum or maximum or middle or intermediate proportion of the y 'phase, ie for example for 50% by volume, 65% by volume and 80% by volume y' phase in the microstructure at a temperature range of 1000 ° C to 1100 ° C.
• the aluminum content may be selected in the range of 9 to 12 at.%, Preferably 10 to 12 at.%.
• the proportions of molybdenum and / or tungsten can be chosen in a particular way to both optimize the y - phase solid solution hardening of the matrix by incorporating appropriate alloying constituents in the y phase, as well as to improve the resistance of the y 'precipitates.
• the alloying constituents be chosen so that the y' precipitates are as much as possible in their original shape and size remain.
• the alloy composition is important in that the alloying composition can also be used to optimize the incorporation of foreign atoms into the y phase.
• the nickel-based alloy may be further selected such that the distribution ratio of tungsten and / or molybdenum from the y-matrix to the y 'precipitates is adjusted so that the concentration of tungsten and / or molybdenum in the matrix relative to the respective concentration of Tungsten and / or molybdenum in the y 'phase is greater than 1, in particular greater than or equal to 1.5.
• This distribution ratio of the concentration of tungsten and / or molybdenum from the y-phase to the y '-phase can also be influenced by the adjustment of the chemical composition of the alloy with regard to the constituents tantalum, titanium and / or germanium.
• the nickel base alloy can be optimized so that the alloy has a solidus temperature of more than 1300 ° C and / or that the ⁇ / ⁇ 'mismatch in the temperature range of 1000 ° C to 1100 ° C in the range of - 0.15 % to - 0.25%, with the y - / ⁇ 'mismatch being the difference in lattice constants of the two phases ⁇ and ⁇ ' normalized to the averaged value of the lattice constant.
• impurities or trace elements such as bismuth, selenium, thallium, lead, tellurium or sulfur can be minimized to technically possible purity ranges.
• An alloy containing about 10 at.% Al, 14 at.% Co, 7 at.% Cr, 2 at.% Mo, 2.5 at.% Ta, 3 at.% Ti and 2.5 at.% W and balance nickel designed according to the present invention has optimized properties in terms of the volume fraction of the y 'phase, the liquidus temperature, the solid solution hardening, the coarsening of the y' precipitates and the ⁇ / ⁇ 'mismatch.
• the ⁇ / ⁇ 'mismatch is -0.25% and the solidus temperature is 1301 ° C.
• the proportion of y 'phase is 46 mol .-% and the concentration of W and Mo in the y - phase, each with about 3.5 at.% Is so high that they contribute significantly to solid solution hardening.
• the proportion of W and Mo in combination with the selected concentrations of the other alloying constituents causes the coarsening of the y 'phase to be hindered at high use temperatures.
• the alloy is outstandingly suitable for applications at high temperatures, such as in turbomachines and in particular in aircraft turbines.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Powder Metallurgy (AREA)

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Citations (4)

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• 2014
  • 2014-04-04 EP EP14163477.4A patent/EP2927336A1/fr not_active Withdrawn
• 2015
  • 2015-04-02 US US14/677,743 patent/US10487376B2/en not_active Expired - Fee Related

Patent Citations (4)

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