Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys

Definitions

• the present invention relates to a material for components of a gas turbine, in particular for components of an aircraft engine, with a matrix of a ferritic FeAlCr alloy and embedded ternary Laves phases based on FeTaAl and FeNbAl.
• gas turbines such as stationary gas turbines or aircraft engines
• rotating disks on which blades are arranged or so-called blisks artificial word for blade and disk, ie combined components of blades and disks
• blisks artificial word for blade and disk, ie combined components of blades and disks
• high-strength steels and nickel alloys at operating temperatures in the range of 650 ° C. used up to 730 ° C.
• the weight of the rotating components such as the discs and blisks and / or to increase the operating temperature.
• heat - resistant alloys iron - chromium - aluminum alloys and not FeAlCr - alloys, which are used for fuel cells, are in the DE 20 2011 106 778 U1 and the WO 2012/175067 described.
• the increased heat resistance or creep resistance is due to precipitations of the intermetallic phases of the type Fe 2 (M, Si) or Fe 7 (M, Si) 6 , wherein the metallic alloying element M is formed by the elements niobium and tungsten.
• a low specific weight contributes both to the performance of the gas turbine, as well as to weight reduction, especially in aircraft engines.
• the present invention proposes in the further development of the material of DE 10 2005 061 790 A1 respectively.
• US 8,012,271 B2 In addition to the ternary Laves phases in a ferritic iron - aluminum - chromium alloy, oxides for oxide dispersion strengthening and / or carbide precipitations are used to increase the strength.
• oxides for oxide dispersion strengthening and / or carbide precipitations are used to increase the strength.
• dispersion hardening with oxide particles and / or solidification by means of precipitation of carbides is possible in addition and enables a further improvement of the property profile.
• the ternary Laves phases based on FeTaAl and / or FeNbAl already ensure high strength and in particular high heat resistance or creep resistance of corresponding materials, the precipitation of additional carbides and / or the provision of further oxide particles can further increase the strength and heat resistance become.
• the three metals mentioned as main constituents form an ordered lattice structure in accordance with the Laves structure, although the Laves phases may nevertheless have additional constituents.
• Tantalum and niobium are exchanged and replaced.
• the ternary Laves phase FeTaAl can comprise 15% by weight to 65% by weight of iron, 1% by weight to 15% by weight of aluminum and 0.5% by weight to 65% by weight tantalum, while the ternary FeNbAl laves have Phase 15% by weight to 65% by weight of iron, 1% by weight to 15% by weight of aluminum and 0.5% by weight to 55% by weight of niobium.
• the FeOlCr ferritic alloy which forms the matrix for the ternary intermetallic Laves phases as well as for the oxide dispersion strengthening oxides and the carbides may contain 30% by weight to 90% by weight of iron, 6% by weight to 40% by weight.
• the ferritic FeAlCr alloy may comprise excess niobium, molybdenum and / or tantalum which has not been precipitated into corresponding carbides.
• niobium carbides, molybdenum carbides and / or tantalum carbides and mixed carbides thereof can be incorporated in the ferritic FeAlCr alloy as carbide precipitates.
• the material may comprise yttrium oxide particles incorporated in the FeAlCr alloy matrix.
• fracture toughnesses greater than or equal to 60 MPa ⁇ m and / or crack propagation resistances greater than or equal to 6 MPa ⁇ m and ultimate strengths greater than or equal to 8 MPa can be achieved at a density of 6 to 7 g / cm 3 .
• oxide particles For this, a sufficient amount of oxide particles must be added to a ferritic iron-aluminum-chromium alloy with the main constituent iron and the main alloying elements aluminum and chromium as well as other alloying constituents, such as yttrium or hafnium, in order to achieve a fine distribution of the oxide particles in the material. This can be done for example by mechanical alloying of powder materials. Particles of yttrium oxide can be used as oxide particles.
• ferritic iron - aluminum - chromium alloy niobium, molybdenum and / or tantalum and sufficient carbon can be added, so that with a corresponding annealing of the material and subsequent quenching next to the ternary Laves - phases based on FeTaAl and FeNbAl also fine distributed carbides excreted which, as an alternative or in addition to the described oxide particles, can contribute to a solidification of the ferritic FeAlCr alloy.
• the material thus produced with a ferritic iron-aluminum-chromium matrix in which the matrix is thus predominantly in the structure of the cubic body-centered ferrite, can be used in particular for disks and blisks in high-pressure compressors, low-pressure and high-pressure turbines of gas turbines and for other components in gas turbines be used at temperatures above 700 ° C.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)

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Citations (4)

• 2013
  • 2013-08-21 EP EP13181162.2A patent/EP2840158A1/fr not_active Withdrawn

Patent Citations (5)

Non-Patent Citations (2)

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