Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C14/00—Alloys based on titanium
• • 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
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/045—Alloys based on refractory metals
  • C22C1/0458—Alloys based on titanium, zirconium or hafnium
• • 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
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/047—Making non-ferrous alloys by powder metallurgy comprising intermetallic compounds
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C30/00—Alloys containing less than 50% by weight of each constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
  • C22F1/18—High-melting or refractory metals or alloys based thereon
  • C22F1/183—High-melting or refractory metals or alloys based thereon of titanium or alloys based thereon
• • 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 invention relates to titanium-based intermetallic alloys.
• Titanium-based titanium-based intermetallic alloys of the Ti 2 AINb type are known from application FR 9716057. Such alloys have a high yield strength up to 650 ° C., high creep resistance at 550 ° C. and good ductility. at room temperature. However, these alloys may have creep and high temperature oxidation resistance (650 ° C. and beyond) insufficient for certain applications in turbomachines, such as downstream discs or high pressure compressor wheels. These parts are the hottest rotating parts of the compressor and are usually made of nickel alloy density greater than 8 which can be detrimental to the weight of the machine.
• the invention proposes, according to a first aspect, a titanium-based intermetallic alloy comprising, in atomic percentages, 16% to 26% of Al, 18% to 28% of Nb, 0% to 3% of titanium.
• a metal M selected from Mo, W, Hf, and V, 0% to 0.8% Si or 0.1% to 2% Si, 0% to 2% Ta, 0% to 4% Zr with the condition Fe + Ni ⁇ 400 ppm, the remainder being Ti.
• the alloy according to the invention advantageously has improved high temperature creep resistance.
• Such an alloy may advantageously have a yield strength greater than 850 MPa at a temperature of 550 ° C., a high creep resistance between 550 ° C. and 650 ° C., and a ductility greater than 3.5% and a limit. of elasticity greater than 1000 MPa at room temperature.
• ambient temperature it is necessary to understand the temperature of 20 ° C.
• the alloy Unless otherwise stated, if several metals M selected from Mo, W, Hf and V are present in the alloy, it should be understood that the sum of the percent atomic percentages of each of the metals present is within the indicated range of values. For example, if Mo and W are present in the alloy, the sum of the atomic percentage content in Mo and the atomic percentage content in W is between 0% and 3%.
• Tantalum present in atomic contents of between 0 and 2% advantageously makes it possible to reduce the kinetics of oxidation and to increase the creep resistance of the alloy.
• the alloy can verify, in atomic percentage, the following condition: Fe + Ni ⁇ 350 ppm, for example Fe + Ni 300 300 ppm.
• the alloy can verify, in atomic percentage, the following condition: Fe + Ni + Cr ⁇ 350 ppm, for example Fe + Ni + Cr ⁇ 300 ppm.
• the alloy can verify, in atomic percentage, the following condition: Fe ⁇ 200 ppm, for example Fe ⁇ 150 ppm, for example Fe ⁇ 100 ppm.
• the atomic percentage ratio Al / Nb may be between 1 and 1.3, for example between 1 and 1.2.
• Such an Al / Nb ratio advantageously makes it possible to improve the resistance to hot oxidation of the alloy.
• the atomic percentage ratio Al / Nb is between 1.05 and 1.15.
• Such an Al / Nb ratio makes it possible to give the alloy optimum resistance to hot oxidation.
• the alloy may comprise, in atomic percentage, 20% to 22% of Nb.
• Nb contents advantageously make it possible to give the alloy improved oxidation resistance, ductility and mechanical strength.
• the alloy may comprise, in atomic percentage, 22% to 25% of Al. Such contents advantageously make it possible to give the alloy creep resistance and improved oxidation.
• the alloy may comprise, in atomic percentage, 23% to 24% of Al.
• Such contents advantageously make it possible to confer on the alloy an improved ductility as well as creep resistance and improved oxidation.
• the alloy may comprise, in atomic percentage, 0.1% to 2% Si, for example 0.1% to 0.8% Si.
• the alloy may comprise, atomic percentage, 0.1% to 0.5% Si.
• Such Si contents advantageously make it possible to improve the creep resistance of the alloy while giving it good resistance to oxidation.
• the alloy may comprise, in atomic percentage, 0.8% to 3% of M.
• the alloy may comprise, in atomic percentage, 0.8% to 2.5% of M preferably 1% to 2% of M.
• Such metal contents M advantageously make it possible to improve the heat resistance of the alloy.
• the alloy may comprise, in atomic percentage, 1% to 3% of Zr.
• the alloy may comprise, in atomic percentage, from 1 to 2% of Zr.
• Such Zr contents advantageously make it possible to improve the creep strength, the mechanical strength above 400 ° C and the oxidation resistance of the alloy.
• the alloy may be such that the following condition is satisfied as an atomic percentage: M + Si + Zr + Ta ⁇ 0.4%, for example M + Si + Zr + Ta ⁇ 1%.
• the alloy may be such that: the content, as an atomic percentage, of Al is between 20% and 25%, preferably between 21% and 24%; the content, in atomic percentage, of Nb is between 20% and 22%, preferably between 21% and 22%, the atomic percentage ratio Al / Nb being between 1 and 1.3, preferably between 1 and 1.2, more preferably between 1.05 and 1.15,
• the content, in atomic percentage, in M is between 0.8% and 3%, preferably between 0.8% and 2.5%, more preferably between 1% and 2%, and
• the alloy being optionally such that the content, in atomic percentage, of Si is between 0.1% and 2%, for example between 0.1% and 0.8%, preferably between 0.1% and 0%, 5%.
• Table 1 gives the compositions of examples of alloys S1 to S12 according to the invention. All these compositions satisfy, as an atomic percentage, the following condition Fe + Ni ⁇ 400 ppm.
• the invention also relates to a turbomachine equipped with a part comprising a particular formed of an alloy as defined above.
• the part can, for example, be a housing or a rotating part.
• the invention also relates to an engine comprising a turbomachine as defined above.
• the invention also relates to an aircraft comprising a motor as defined above.
• FIG. 1 represents the evolution of the creep resistance of various alloys at 650 ° C. under a stress of 310 MPa
• FIG. 2 represents the influence of the Al / Nb ratio on the resistance to hot oxidation
• FIGS. 3A to 3D illustrate the results obtained in terms of mechanical properties for a preferred alloy according to the invention. Examples
• EXAMPLE 1 Manufacture of an Alloy According to the Invention From raw materials consisting of titanium sponges and master alloy granules, a mixture was produced to obtain the chemical composition S12 described in Table 1 above. This mixture of powders was then homogenized and compressed to form a compact constituting an electrode. This electrode was then remelted under vacuum by creating an electric arc between the consumable electrode and the bottom of the water-cooled crucible (vacuum arc remelting process or "VAR" for "Vacuum Arc Remelting”). ). The ingot obtained is then reduced to a bar by high speed deformation (by forging or extrusion) to reduce the grain size. The last step is an isothermal forging of slices cut in the bar at a temperature just below the ⁇ transus temperature and at a low rate of deformation (some 10 "3 ).
• Such an alloy of composition S12 which contains 1.3% of zirconium has a very good resistance to hot oxidation. Indeed, this alloy does not peel after exposure of 1500 hours at 700 ° C in air, a thin layer of very adherent and therefore protective oxide, composed of alumina and zirconia being formed. Alloys containing no zirconium may have a lower resistance to hot oxidation.
• Example 2 Improvement of the resistance to hot creep by implementing a limited Fe + Ni content
• Table 2 These alloys comprise trace elements Fe and Ni which are present in the form of impurities, and result naturally from the manufacturing process.
• Fe and Ni elements are impurities from the stainless steel container used to make titanium powders. It is thus preferable to use a high purity titanium powder taken from the center of the volume delimited by the container where the pollution coming from the walls is negligible in order to ensure that the Fe + Ni condition ⁇ 400 ppm is obtained.
• FIG. 1 an improvement in the creep resistance at 650 ° C. under a stress of 310 MPa is observed when the trace element contents are reduced in order to satisfy the Fe + Ni ⁇ 400 ppm relationship.
• creep reaches 1% after 250 hours with an alloy according to the invention (P3) whereas this creep value is reached only after 40 hours with an alloy according to the invention. prior art (PI).
• composition S12 has both good results in tension and in creep. More particularly:
• FIG. 3A shows, for different alloys, the evolution of the elastic limit (R 0 , 2 ) as a function of the temperature
• FIG. 3B shows, for different alloys, the evolution of elongation at break (ductility) as a function of temperature
• FIG. 3C compares the creep (time for creep 1%) of different alloys at temperatures of 600 and 650 ° C.
• FIG. 3D compares the creep rupture time of different alloys at temperatures of 600 and 650 ° C.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Powder Metallurgy (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

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• 2014
  • 2014-12-22 FR FR1463066A patent/FR3030577B1/fr active Active
• 2015
  • 2015-12-14 CN CN201580069975.2A patent/CN107109540B/zh active Active
  • 2015-12-14 EP EP15823349.4A patent/EP3237646B1/de active Active
  • 2015-12-14 US US15/538,119 patent/US10119180B2/en active Active
  • 2015-12-14 RU RU2017126060A patent/RU2730348C2/ru active
  • 2015-12-14 JP JP2017551367A patent/JP6805163B2/ja active Active
  • 2015-12-14 BR BR112017013328-8A patent/BR112017013328B1/pt active IP Right Grant
  • 2015-12-14 WO PCT/FR2015/053481 patent/WO2016102806A1/fr active Application Filing
  • 2015-12-14 CA CA2971092A patent/CA2971092C/fr active Active

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