Classifications

• • 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
  • C22C1/02—Making non-ferrous alloys by melting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D19/00—Casting in, on, or around objects which form part of the product
  • B22D19/14—Casting in, on, or around objects which form part of the product the objects being filamentary or particulate in form
• • 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
• • 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
  • C22C1/0425—Copper-based alloys
• • 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
  • C22C1/10—Alloys containing non-metals
  • C22C1/1036—Alloys containing non-metals starting from a melt
• • 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
  • C22C30/02—Alloys containing less than 50% by weight of each constituent containing copper
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
  • C22C9/01—Alloys based on copper with aluminium as the next major constituent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

• the invention relates to the area of Material Science and Technology as far as the design and production of the materials are concerned, and to the area of Physical Technology with regard to the properties of high damping.
• the sectors of industrial activity in which the invention can apply are: domestic appliances and domotics, machine-tools and machinery in general, electronic packaging, transport including aeronautics, aerospace, construction.
• SMA Shape Memory Alloys
• beta high temperature phase
• martensite low temperature phase
• the interphases of martensite are mobile both during the transformation and in the martensite phase, and under the effect of a vibration or external mechanical stress they are liable to undergo movement, absorbing mechanical energy and giving rise to the powerful damping displayed by SMAs [2].
• Copper-based SMAs are known to display a coefficient of damping higher than those of Ti—Ni which are the SMAs that are commercially used in practically all applications.
• a). Composite materials formed directly by various sheets or pieces of SMA, whether this be of Ti—Ni or of copper base. In this case, as well as a great many publications, U.S. Pat. No. 4,808,246 can be highlighted.
• b). Composite materials with a soft metal matrix, responsible for the damping, and rigid particles (W, SiC) in a variable percentage, the sole aim of which is to increase the E modulus of the material [6]. c).
• the technical problem that is raised and which has led to the present invention is to achieve a material with a high coefficient of damping tan( ⁇ ), whose maximum can be adjusted to a particular temperature range, depending on the application it is intended for. Moreover, in the majority of applications, the elastic modulus E is required to be as high as possible in order to optimise the relation tan( ⁇ ) ⁇ E.
• the SMA powder particles constitute the majority element with a percentage between 45% and 70%, being responsible for the powerful damping of the composite material.
• the powder particles are of copper base SMA and display the proper martensite transformation in an adjustable temperature range. *).
• the temperature range of the damping maximum of the composite material is very wide (>50° C.) and can be adjusted by controlling the composition of the SMA powder particles. *).
• the matrix has to be a low melting point metal matrix, and be ductile at the martensite transformation temperature of the SMA particles. *).
• the matrix contributes to the damping background and generates an amplifying effect of the damping of the particles, never described so far. *).
• the composite materials thus obtained can display a tan( ⁇ ) ⁇ E relation that can be optimised in a wide temperature range, better than any other material presently specified.
• the present invention relates to a metal matrix composite material characterised in that it is based on particles of shape-memory alloy powder, having a copper base with a concentration of between 45% and 70% by volume in relation to the total volume of the material, said powder particles being supported by a metal matrix.
• the copper base is present in the material at a concentration of between 50% and 60% by volume in relation to the total volume of the composite material.
• the inventive material displays a thermoelastic martensitic transformation at between ⁇ 150° C. and +250° C.
• the copper base is selected from among Cu—Al—Ni, Cu—Zn—Al and Cu—Al—Mn.
• Said metal matrix of metals or alloys surrounds the powder particles and acts as a binder for the composite material.
• the metal matrix can, according to embodiments of the invention, comprise:
• alloys of said metals with a solidifying point below 330° C.
• Said metal, or metals (or their alloys), of low melting point must be ductile at the temperature of the adjusted maximum damping.
• metals that can constitute the metal matrix can be selected, among others, In, Sn, Pb, Cd, TI and their alloys.
• the metal matrix can be selected from among:
• preferred metals are Zn or Mg.
• the alloy powder particles will be able to have the same single concentration of copper base, or the composite material will be able to include particles of different concentrations of base copper.
• the composite material will be able to include particles of different concentrations of base copper.
• the percentage of particles with a different concentration of copper base can be equal to or less than 15% in relation to the entire composite material.
• particles of different composition will also be able to be included in the composite material, being able to be rigid, metallic or ceramic, and having the sole purpose of increasing the modulus of the composite material.
• Said powder particles of different composition can be present in the material in a percentage equal to or less than 15% of the composite material. Moreover, these particles can be chosen from among Rhenium, Tungsten, Molybdenum, Silicon Carbide and Boron Carbide.
• the present invention furthermore relates to a method for obtaining a metal matrix composite material as defined above, which comprises:
• the shape-memory alloy powder particles can be obtained by means of spraying with gas or by any other method permitting powder particles to be obtained which display the thermoelastic martensite transformation proper to shape-memory alloys.
• Said method can furthermore comprise a stage of adjusting the temperature range of the damping maximum of the composite material via the direct or inverse martensite transformation temperatures of the powder particles, varying the composition of the constituent elements of the shape-memory alloy.
• said method can comprise the inclusion in the composite material of particles of different concentrations of copper base, which can be included in the composite material by means of heat treatment.
• said method can comprise the inclusion in the composite material of particles with a concentration gradient in the composite material by means of mechanical alloying.
• the metal matrix comprises metals with a melting point below 330° C., or alloys of said metals with a solidifying temperature of below 330° C.
• said method comprises:
• degasifying in vacuo preferably at a temperature of between 120° C. and 300° C.
• the infiltration is carried out under pressure which can be achieved by means of centrifugation or by means of applying gas pressure to the melt.
• the metal matrix comprises one or more metals with a melting point above 330° C., or alloys of those metals
• the properties of the martensite transformation of the shape-memory alloy powder particles will have to be preserved, due to which said method can be a powder metallurgy method, which comprises:
• the compaction can be carried out using sinterisation with uniaxial stressing at a temperature below 300° C. or the compaction can also be done by means of previous encapsulating in vacuo and subsequent isostatic compacting at high pressure at a temperature below 300° C.
• This method can also possibly be used in the case of metal matrices with lower melting point, such as those mentioned above in the embodiment described in the method.
• the method can alternatively be an infiltration method at high temperature, which can comprise:
• tempering the composite material in a rapid cooling medium can be water.
• the choice of the metal matrix will serve to optimise the binder properties of the composite material, as will the relation tan( ⁇ ) ⁇ E, and will be chosen according to the type of SMA used and the range of temperatures at which the composite material is going to find itself under service conditions in the various applications.
• the shape-memory alloy powder particles contribute a high coefficient of damping for the composite material, owing to the movement of the martensite interphases, especially in the proximity of the martensite transformation temperature (direct or inverse).
• the matrix permits absorption of the deformation which the particles undergo when the martensite interphases move, whether this be in the martensite phase or when undergoing the transformation induced by temperature or stress. In this way, the matrix absorbs the deformation of the particles preventing the composite material from degrading.
• the matrix also contributes to the continual damping background and generates an amplifying effect for the damping of the particles.
• the temperature range of the damping maximum can be adjusted between ⁇ 150° C. and +250° C., via the martensite transformation temperatures (direct or inverse) of the powder particles, which are in turn controlled by means of the composition of the elements constituting the alloy with shape-memory.
• the present invention also refers to the use of the composite material defined earlier for the absorption of vibrations.
• Said vibrations can be acoustic or mechanical.
• the solution contributed by the present invention to the problem raised is therefore a novel concept of composite material based on shape-memory alloy (SMA) powder particles with copper base, as the main damping elements with a percentage ⁇ 40% embedded in a ductile metal matrix, of low melting point.
• SMA shape-memory alloy
• copper base SMA powders are in response to the fact that said alloys display a coefficient of damping higher than Titanium-Nickel base SMAs. Furthermore, via the control of the composition of these powder particles, the temperature of the damping maximum can be adjusted. The low melting point metal matrix, as well as providing support for the particles, also generates an amplifying effect on the damping, never before described.
• Alloy powders of Cu—Al—Ni have been used with a concentration by weight: 13.1% Al, 3.1% Ni, 83.8% Cu.
• the powders were produced by means of spraying by gas. And powders have been used that were passed through a sieve of sizes between 25 and 50 microns.
• Indium of purity 99.99% was used as matrix metal.
• the powders introduced into a teflon mould were degasified at 130° C. for 6 hours in a vacuum of 0.01 mbar.
• the infiltration was performed at 190° C., by means of applying a helium gas pressure of 3 bars on the melt.
• the composite material contained 60% by volume of Cu—Al—Ni particles and 40% indium.
• the damping coefficient tan( ⁇ ) has been measured in torsion with a mechanical electroscopy equipment which permits one to work at different frequencies and according to temperature, since, as is well known, the coefficient of damping of a material depends on these two parameters.
• the composite material displays two damping maxima at 65° C. and 100° C. corresponding to the direct and inverse martensite transformation respectively. Stated below are the values of the coefficient of damping for different frequencies:

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)

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• 2005
  • 2005-08-31 ES ES200502129A patent/ES2276605B1/es not_active Expired - Fee Related
• 2006
  • 2006-08-30 ES ES06807938T patent/ES2725078T3/es active Active
  • 2006-08-30 WO PCT/ES2006/000493 patent/WO2007026039A1/es not_active Ceased
  • 2006-08-30 JP JP2008528542A patent/JP2009506217A/ja active Pending
  • 2006-08-30 US US11/991,262 patent/US20090123329A1/en not_active Abandoned
  • 2006-08-30 EP EP06807938.3A patent/EP1930452B1/en active Active

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