Metal matrix composite and its manufacturing process

Abstract

The object of the invention is to provide a composite material comprising a fibrous reinforcement embedded in a metallic glass matrix exhibiting improved flexural strength and elongation at break, compared to metallic glass without fiber reinforcement. To this end, the invention relates to a composite material comprising a carbon fiber-based fibrous reinforcement embedded in a metallic glass matrix characterized in that: (1.1) the matrix is ​​amorphous; (1.2) the matrix is ​​obtained from metallic glass particles whose size is given by their D50, designated by the reference Dpvm50; (1.3) the fibrous reinforcement comprises carbon fibers with an average length Lfc* less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; (1.4) the fiber reinforcement ratio is between 0.1 and 50%v, preferably 15 and 45%v; and even more preferably between 20%v and 40%v.The invention also relates to a method for manufacturing this composite material. Figure 3.

Description

Title of the invention: Metal matrix composite and its manufacturing process. Field of the invention

[0001] The invention relates to the field of metallic glass-based composite materials and their manufacturing technologies.

[0002] In particular, the invention relates to a composite material comprising a fibrous reinforcement included in a metallic glass matrix.

[0003] The invention also relates to methods for manufacturing the composite material.

[0004] The invention also relates to objects made from this composite material, and intended for fields of application such as watchmaking, in particular luxury watchmaking, leather goods, sports, consumer electronics, the railway industry... Technological background of the invention

[0005] Many amorphous metallic alloys with good glass-forming capacity have been developed in recent years.

[0006] These are bulk metallic glasses (MMGs) which possess very interesting mechanical, magnetic, thermophysical and structural properties.

[0007] They exhibit, for example, up to twice the breaking strength and four times the elasticity of their crystalline counterparts and therefore have a very high potential for use as structural materials.

[0008] Unfortunately, these properties cannot be fully exploited due to the brittle fracture behavior of these alloys.

[0009] In the absence of a crystalline structure, deformation by dislocation displacement is impossible, but occurs in one or a few highly localized shear bands. Even though VMMs may exhibit a certain type of "ductile" fracture mechanism at the microscopic scale, metallic glasses are generally brittle because the fracture energy is concentrated in a very small volume of the sample. A drastic improvement in the plasticity of VMMs would lead to a revolutionary new material for structural applications.

[0010] Work presented in the literature (see ia §

[008] below) reports the introduction of carbon fibers into a metallic glass matrix. More specifically, it concerns woven carbon fiber structures associated with a zirconium-based metallic glass matrix known as Vitreloy 1. The results attributed to this work are the development of a method for preserving the amorphous state of the matrix in the composite by infiltration. The resulting composites are layered and possess heterogeneous mechanical properties such as tensile strength, Young's modulus, and compressive strength. In other words, the mechanical properties of these composites are anisotropic. This means that, for a composite whose fiber reinforcement is a fabric and whose matrix is ​​a VMM, the mechanical properties are higher in the X / Y plane than those of the composite material in the Z direction (see attached [Fig. 1]).

[0011] Furthermore, the process for obtaining these composites requires very high processing temperatures to bring the VMM matrix to a viscosity low enough for the fiber reinforcement to infiltrate during composite manufacturing. This manufacturing constraint makes the process inconvenient and energy-intensive.

[0012] “Kim, CP, Busch, R., Masuhr, A., Choi-Yim, H. & Johnson, W. L _[ Processing of Carbon-Fiber-Reinforced Zr41.2Til 3.8Cul2.5Nil0.0Be22.5 Bulk Metallic Glass Composites”. Appl. Phys. Lett. 79, 1456-1458 (2001) ]». Objectives of the invention

[0013] In this context, the invention aims to satisfy at least one of the following objectives - to provide a composite material comprising a fibrous reinforcement included in a metallic glass matrix exhibiting improved flexural strength and elongation at break, compared to the same metallic glass without fibrous reinforcement; - to provide a composite material comprising a fibrous reinforcement included in a metallic glass matrix, resistant to abrasion; - to provide a composite material comprising a fibrous reinforcement included in a metallic glass matrix, having mechanical properties, such as tensile strength, Young's modulus, compressive strength, which are homogeneous and isotropic; - to provide a composite material comprising a fibrous reinforcement included in a metallic glass matrix, which is easy and economical to manufacture; - to provide a manufacturing process for a composite material comprising a fibrous reinforcement included in a metallic glass matrix, this composite material satisfying at least one of the objectives stated above; - to provide an object made from a metallic glass-based composite material that meets at least one of the above objectives. Brief description of the invention

[0014] The invention satisfies at least one of the above objectives and relates, according to a first aspect, to a composite material comprising a fibrous reinforcement based on carbon fibers included in a metallic glass matrix characterized in that: (1.1) the matrix is ​​amorphous; (1.2) the matrix is ​​obtained from metallic glass particles whose size is given by their D50 designated by the reference Dpvm50; (1.3) the fibrous reinforcement comprises carbon fibres of length Lfc less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; (1.4) the fiber reinforcement rate is between 0.1 and 50%v, preferably 15 and 45%v; and even more preferably between 20% and 40%v.

[0015] The advantages of this VMM matrix composite include the following: - improved mechanical properties (flexural strength, elongation at break, etc.), particularly compared to a control consisting of the same metallic glass without fibrous reinforcement; - weight reduction without compromising mechanical properties; - Facilitation and application of manufacturing.

[0016] The composite material according to the invention also has at least one of the following advantageous and high-performance characteristics.

[0017] (i) the matrix is ​​a metallic glass alloy consisting of a Zr or Pd or Fe base or Pt or Cu or Au or Ti or Ni.

[0018] (ü) the metallic particles used to obtain the matrix have a Dpvm50, is such that, in microns and in increasing order of preference: 5 < Dpvm50 < 500; 5 < Dpvm50 < 250; 20 < Dpvm50 < 250 ; 20 < Dpvm50 < 100.

[0019] (iü) the average length Lfc * of the carbon fibers of the fibrous reinforcement, is such that, in microns and in increasing order of preference: 10 < Lfc * < 1000; 10 < Lfc * < 500; 30 < Lfc * < 500; 30 < Lfc * < 300.

[0020] (iv) the carbon fibers of the fibrous reinforcement come from carbon fibers free from one another and whose average length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50.

[0021] (v) the carbon fibers of the fibrous reinforcement come from free carbon fibers relative to each other and whose average length Lfc is such that, in microns and in increasing order of preference: 10 < Lfc < 1000; 10 < Lfc < 500; 30 < Lfc < 500; 30 < Lfc < 300.

[0022] (vi) The composite material according to the invention is obtained • by hot sintering / pressing; • by injection / molding • or by 3D printing from a mixture comprising: —> a powder of metallic glass particles whose size, given by their D50 designated by the reference Dpvm50; —> carbon fibers of length Lfc.

[0023] According to a second aspect of it, the invention relates to a method for manufacturing a composite material comprising a fibrous reinforcement included in a metallic glass matrix, this composite material being in particular that defined by at least one of the characteristics (i) to (vi) above.

[0024] In a first embodiment, this process essentially consists of: - A - to implement a device including a mold; - B - mix a powder of metallic glass particles whose size is given by their D50 designated by the reference Dpvm50, with carbon fibers free from each other and whose length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; according to a volume percentage of fibers relative to the whole particles / fibers between 0.1 and 50 %v, preferably 15 and 45 %v; between 20 % and 40 %v; - C - place in the mold the mixture obtained in step -B-; - D - on the one hand, bring the mixture to be sintered contained in the mold to a temperature between the glass transition temperature and the crystallization temperature, preferably by increasing the temperature of the mold in stages; and, on the other hand, by applying a pressure of between 50 and 150 MPa to the mixture contained in the mold; - E - recover the composite material obtained, shaped in the mold, and consisting of ♦ an amorphous matrix; ♦ and a fibrous reinforcement comprising carbon fibers of length Lfc * less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50 and present with a fibrous reinforcement rate between 0.1 and 50 %v, preferably 15 and 45 %v; and even more preferably between 20 % and 40 %v.

[0025] According to a first possibility "(PI)* of the first mode of implementation of this process: • The mold is an integral part of a Spark Plasma Sintering (SPS) sintering device, this device comprising: 3 at least one component for exerting pressure on the mixture to be sintered contained in the mold, 3 and means of electrically energizing the mold and, possibly, the mixture to be sintered contained in the mold; the latter possibly being subjected to an electrical voltage generating a plasma.

[0026] According to a 2nd possibility '(P2)' of the first implementation of this process: • The mold is an integral part of an injection / molding device.

[0027] In a second embodiment *(P3)', this method essentially consists of: - to implement by 3D printing a mixture of a powder of metallic glass particles whose size is given by their D50 designated by the reference Dpvm50, with carbon fibers free from each other and whose length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; according to a volume percentage of fibers relative to the whole particles / fibers between 0.1 and 50 %v, preferably 15 and 45 %v; between 20 % and 40 %v; - and to recover the resulting composite material, consisting of: an amorphous matrix, and by a fibrous reinforcement comprising carbon fibers of length Lfc * less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50 and present according to a fibrous reinforcement rate between 0.1 and 50 %v, preferably 15 and 45 %v; and even more preferably between 20 % and 40 %v.

[0028] According to a third aspect, the invention relates to an object made of composite material according to the invention, or obtained by a process according to the invention.

[0029] Preferably, this object is chosen from the following items: watch components; jewelry items; fashion accessories; sports and leisure items; telephony items; HIFI items; devices and tools for the medical sector; items for the aeronautical and space industry. Brief description of the drawings

[0030] This description is made with reference to the attached figures illustrating non-limiting examples of embodiments, and in which: Fig. 1

[0031] [Fig.1]

[0032] The [Fig.1] is a perspective view of a composite material, carbon fibers metallic glass matrix, according to the prior art mentioned in § 6, 7 & 8 above in an orthonormal XYZ spatial reference frame. Fig. 2

[0033] [Fig.2]

[0034] Fig. 2 is a scanning electron microscope ("SEM") image of a sample of carbon fibers free or mobile relative to each other, used as raw material in the manufacture of the composite material according to the invention. Fig. 3

[0035] [Fig.3]

[0036] Fig. 3 is a scanning electron microscope ("SEM") image of a sample of amorphous metallic glass particles, used as raw material in the manufacture of the composite material according to the invention. Fig. 4

[0037] [Fig.4]

[0038] Fig. 4 represents a photograph of a part of the composite material after consolidation, directly from the mold, as obtained in Example 1. Fig. 5

[0039] [Fig.5]

[0040] Fig. 5 is an optical microscope image with a 500x zoom of the surface of the part in Fig. 4. Fig. 6

[0041] [Fig.6]

[0042] [Fig.6] is an X-ray diffractogram of the part shown in [Fig.4]. Fig. 7

[0043] [Fig.7]

[0044] Figure 7 shows an optical microscopy image with a 200x zoom of a composite material part according to the invention, as obtained in Example 1 after post-processing. Fig. 8

[0045] [Fig.8]

[0046] Fig. 8 presents an optical microscopy image of the part in Fig. 7, with a zoom of x 500. Detailed description of the invention

[0047] • Definitions Throughout this entire exposition, any singular refers indifferently to a singular or a plural. By convention, the symbol "*" assigned as a superscript to parameters will signify that these are characteristics of the finished composite material, as contrasted with the same parameters relating to the raw materials used to manufacture the composite material. The definitions given below, as examples, may be used to interpret this presentation: - "composite material": heterogeneous material consisting of at least two components and whose properties are different from those of each constituent taken independently - "amorphous": free from or comprising at most 50%m (by mass), preferably at most 10%m, and, even more preferably at most 5%m of crystalline phase in relation to all the phases present in the composite material. - "metallic glass": amorphous metal or metallic alloy. - "particles": corpuscles with a small aspect ratio, preferably less than 5, and more preferably close to 1. The aspect ratio is a dimensionless number related to the shape of an object. It is the ratio between two perpendicular dimensions of the object, the longer one divided by the shorter one. - "Fibers": elementary formations, plant or animal, with a filamentous appearance, generally occurring in bundles. This term is also used more broadly to refer to certain mineral or synthetic materials having the same appearance. Several fibers are generally used to make a yarn. The shape factor for these elements is quite high, preferably greater than 5, and even more preferably greater than 1000 for so-called long fibers (L>lm). - "base of a metallic alloy": Major element of the metallic alloy - "%v": volume percentage of a component relative to the total volume of the material. - "approximately"; "in the order of"; "about": within + or - 10%, preferably within 5%.

[0048] Composite:

[0049] This invention relates to composites whose matrix is ​​composed of metallic glass particles (also called solid metallic glass: SML) and whose fibrous reinforcement is formed of short carbon fibers, i.e. carbon fibers whose length is judiciously selected according to the size of the SML particles.

[0050] A metallic glass is an amorphous metallic alloy or an amorphous metal is a solid with an amorphous rather than crystalline structure. As shown in [Fig.5], the composite material 1 according to the invention comprises a matrix 20 formed by aggregation of metallic glass particles 2 (starting particles) and in which are included the carbon fibers 3 forming the fibrous reinforcement of the composite 1.

[0051] The metallic glass particles 2 from which the matrix of the composite material according to the invention is derived have a size given by their D50, denoted Dpvm50, and corresponding to the following definition: it is the particle size distribution, also known as the median diameter or average value of the particle size distribution; it is the particle diameter value at 50% in the cumulative distribution. The D50 particle size distribution is one of the important parameters characterizing particle size. For example, if D50 = 5.8 pm, then 50% of the particles in the sample are larger than 5.8 pm, and 50% are smaller than 5.8 pm. D50 is generally used to represent the size of a particle group. Within the framework of the invention, Dpvm50 is measured via a particle size analysis by laser granulometry according to the ISO 13320 standard.

[0052] These particles can therefore have any type of morphology. The particles designated by reference 2 in [Fig.3] are substantially spherical, while those designated by reference 21 have elongated, non-spherical shapes. The starting particles shown in [Fig.3], as an example, have a Dpvm50= 63 pm. These starting particles 2 can also have any type of morphology.

[0053] The composition of these VMM particles is specific and allows them to remain amorphous, in particular when the manufacture of the composite material 1 is carried out under the conditions defined below for the implementation of the process according to the invention. Preferably, these materials are, among others, metallic alloys from three main families: -1- Palladium-based VMM. This type of alloy produces a metallic glass with good resistance to deterioration (corrosion, scratches, etc.) and recognized aesthetic qualities. Such a composite material can therefore serve as a raw material for the manufacture of medical devices. Palladium can be alloyed in particular with elements chosen from the group comprising - advantageously constituted by - one or more of the following elements without limitation: silver; gold; platinum; aluminium; iron; copper; titanium; nickel; tungsten; chromium; iron; manganese; zirconium; hafnium; vanadium; niobium; molybdenum; tin; bismuth; antimony; lead; cadmium; beryllium; or selenium and their combinations. -2- Zirconium-based VMM. This type of alloy produces a glass-metal composite material with excellent mechanical properties, such as compressive strength and elasticity. This composite material can therefore be used as a raw material for the production of springs, elastic fastening mechanisms, watches, and even surgical instruments. Zirconium can be alloyed in particular with elements chosen from the group comprising - advantageously consisting of - one or more of the following elements without limitation: silver; gold; platinum; palladium; aluminium; iron; copper; titanium; nickel; tungsten; chromium; iron; manganese; hafnium; vanadium; niobium; molybdenum; tin; bismuth; antimony; lead; cadmium; beryllium; or selenium and their combinations. -3- Iron-based VMM (magnetic alloy): This type of alloy allows the production of metallic glass, which has high wear resistance and very high hardness (by (example of the order of 950HV). Such a composite material can thus serve as a raw material for the production of catalytic equipment and objects for sport (baseball bat, tennis racket, ...). Iron can be alloyed in particular with elements chosen from the group comprising - advantageously consisting of one or more of the following without limitation: silver; gold; platinum; palladium; aluminium; copper; titanium; nickel; tungsten; chromium; iron; manganese; zirconium; hafnium; vanadium; niobium; molybdenum; tin; bismuth; antimony; lead; cadmium; beryllium; or selenium and their combinations.

[0054] According to variations of the invention, VMM alloys based on platinum, copper, gold, nickel, or titanium can be considered. Examples include: Au65.2Cu22.4Ag12.4, Pt57.5Cul4.7Ni5.3P22.5, Cu60Zr30TiL0, Ni70PdL0P16B4, or Ti62Zr5V10Cu4Be9

[0055] In other embodiments of the invention, the metallic glass particles of the composite material 1 may be a mixture of particles of different alloys and / or a mixture of particles of different sizes Dpvm50.

[0056] Fibrous reinforcement According to the invention, the fibers 3* of the fibrous reinforcement included in the matrix resulting from the aggregation of VMM particles 2, are made up of short fibers 3, whose average length Lfc * does not exceed a ceiling value equal to 3 x Dpvm50 of the VMM particles. This average length Lfc * is determined after dissolution of the composite in strong acids such as HCl-H2SO4-HNO3-HF.

[0057] The protocol implemented is as follows: 1- Taking a sample of 0.5 to 2 g of composite material. 2- Total dissolution (greater than or equal to 95%w) of the VMM matrix, at high temperature (ambient temperature - 200°C) in an acid bath judiciously chosen according to the VMM; 3- Filtration on ceramic filter (pore size less than or equal to 5 pm); 4- Rinse with demineralized water; 5- Measurement of fiber length, on optical images (taken by optical microscopy magnification x500) using Matlab® software, for a sample taken randomly.

[0058] Lfc * is for example between 35 and 500 microns. In the example of composite material 1 shown in Figures 4 & 5, Lfc* = 60 pm.

[0059] The carbon fibers 3* included in the matrix 20 are derived from carbon fibers 3 (starting fibers) as shown in the attached [Fig. 2]. These starting fibers 3 have an average length Lfc, and correspond to the same definition as that given above for the average length Lfc * of the carbon fibers 3* of the composite material 1 shown in [Fig.4]. According to the invention, the average length Lfc of the starting fibers 3 does not exceed a ceiling value equal to 3 x Dpvm50 of the VMM particles 2. This average length Lfc can be determined by statistical measurement on optical images (taken by optical microscopy magnification x500) using Matlab® software, for a sample taken randomly. Advantageously, Lfc = Lfc *, with a tolerance of + / - 15% In the example shown in [Fig.2], the average Lfc length of the starting carbon fibers 3* is on the order of 60 pm

[0060] According to a remarkable feature of the invention, the starting fibers 3 intended to constitute the fibrous reinforcement are free or mobile relative to each other, in order to facilitate their flow and mixing with the VMM particles 2, during the manufacture of the composite material 1 according to the invention. This means that the 3 fibers are independent of each other and retain their own mobility. To this end, it is advantageous that they not be sizing. If they are, they should be desizing by any known and appropriate means.

[0061] The fibers used as starting fibers 3 to constitute the fibrous reinforcement of the composite material 1 with a 20 VMM matrix are advantageously fibers that do not degrade and that retain their chemical, physical and / or mechanical integrity up to temperatures of at least 600°C, preferably at least 700°C, and, even more preferably, on the order of 800°C. Fibers with non-nucleating and / or VMM crystallization retarding properties are preferred in the context of the invention. In this context, carbon fibers are prime candidates for the composite according to the invention. These are even more preferentially carbon fibers comprising one or more fiber categories among which: High Strength, Intermediate Modulus, High Modulus and Ultra High Modulus as defined by E. Fitzer, KH Kôchling, HP Boehm, and H. Marsh, “Recommended terminology for the description of carbon as a solid” Pure Appl. Chem., vol. 67, no. 3, pp. 473-506, 1995.

[0062] Carbon fibers can be generated, without limitation, from precursors such as rayon, polyacrylonitrile (PAN), and pitch. Rayon precursors are cellulosic materials. PAN-based precursors are derived from petrochemicals and have excellent tensile strength, thanks to a minimum of surface defects. Pitch precursors based on petroleum bitumen, coal tar and polyvinyl chloride can also be used to produce carbon fibers.

[0063] Surprisingly and unexpectedly, the starting fibers 3*, particularly the carbon 3* fibers, do not behave, as one might have expected, as a nucleating agent to promote crystallization, contrary to the desired amorphous character of the composite material. On the contrary, these starting fibers 3* act as a stabilizer for the composite material in its amorphous state.

[0064] One of the essential characteristics of the composite material 1 [matrix 20 VMM / fibrous reinforcement with short carbon fibers 3*] is indeed the preservation of the amorphous character proper to the starting VMM particles 2 ([Fig.3]), after manufacture of the composite 1 and, more particularly, after consolidation (densification / sintering) of the composite 1. This is reflected in an X-ray diffractogram ([Fig.6]), on the one hand, of the starting VMM particle powder 2, and, on the other hand, of the composite material 1 [matrix 20 VMM / fibrous reinforcement 3 *], by an amorphous bump BAcomp for the starting VMM particle powder 2 and by an amorphous bump BAinv for the composite material 1 [matrix 20 VMM / fibrous reinforcement 3 *]; BA“mp & B Ainv being preferably centered, substantially, on the same angle value 2Theta = 37°. The reference method for producing the X-ray diffractogram is as follows: NF EN 1330-11.

[0065] The composite material 1 according to the invention has improved compressive strength compared to unreinforced metallic glass. By "improved", we advantageously mean a percentage increase of at least 5%, preferably at least 10%. Comparative measurements of these improved properties are carried out with test specimens of the same shape and dimensions for the composite material 1 according to the invention and for the control material consisting of the metallic glass matrix without fibrous reinforcement.

[0066] Process

[0067] Several methods are possible for manufacturing the composite material 1 [20 VMM matrix / fibrous reinforcement 3*] according to the invention. In accordance with the latter, the following 3 paths are particularly favored: •(PI)* hot sintering / pressing; •(P2)“injection / molding; •(P3)« or 3D printing; using a mixture comprising: —> a powder of 2 metallic glass particles whose size, given by their D50 designated by the reference Dpvm50; —> carbon fibers of length Lfc *.

[0068] Step A: Implementation of a device comprising a mold. •(P !)• The mold is an integral part of a sintering device using the Spark Plasma Sintering (SPS) technique. This device includes at least one element for applying pressure to the material to be sintered contained in the mold, means for electrically energizing the mold and, optionally, the mixture, obtained in step -B-, to be sintered and contained in the mold; the latter being optionally subjected to an electrical voltage generating a plasma. This could be, for example, an SPS device of the HP D25 type from FCT®. *(P2)* The mold is an integral part of an injection / molding device This could be, for example, an injection / molding device of the ENGEL e-motion 110 type.

[0069] Step -B-: Carbon fibers 3 and metal-glass alloy powder are mixed using a powder mixer. The powder consists of metal-glass particles 2 whose size is given by their D50 designated by the reference Dpvm50, with carbon fibers 3 free or mobile relative to each other and whose length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; with a %v of fibers relative to the total particles / fibers of between 0.1 and 50% v / v, preferably 15 and 45% v; even more preferably between 20% v and 40% v. This step allows for obtaining a homogeneous mixture useful for producing a composite material 1 with isotropic properties. This mixing step is one of the key steps, facilitating the densification step with a regular distribution of carbon fibers 3 and alloy particles 2.

[0070] Step -C-: •(P!)•: The powder mixture of [particles 2 / fibers 3] from step -B- is placed in a mold lined with a carbon release system, allowing the densified part to be extracted under the influence of temperature (250-800°C) and pressure (50-300 MPa). This release system is adapted to the densification method called Spark Plasma Sintering (SPS). The amount of material added is calculated to fill the chamber once this material is completely densified. •(P 2 )• : The previously prepared mixture is introduced into a crucible of the desired geometry, then it is melted and cooled to obtain an ingot, a bar, or a ball. depending on what is needed as input to the injection machine. The components are then introduced into the injection machine. •(P 3 ) • : The mixture is introduced into the storage chamber of the 3D printer.

[0071] Step-D-: •£ P il*: On the one hand, the mixture contained in the mold is heated to a temperature between the glass transition temperature and the crystallization temperature of the metallic glass alloy; and, on the other hand, a pressure of between 50 and 1000 MPa is applied to the mixture in the mold. The densification of the mixture is achieved using the SPS (Selective Pressure System) manufacturing technique. The parameters are adjusted to control the densification of the parts while preventing crystallization of the metallic glass matrix. These parameters are specific to each composition: type of alloy and volumetric content of carbon fibers. The important parameters concern the thermal cycle (specific to each alloy and the pressure parameter) and the pressure applied to the material (50–1000 MPa).In this embodiment, the homogeneous mixture is heated to a temperature exceeding the glass transition temperature of the metal-glass alloy using a pulsed electric current. Applying high pressures under these conditions allows the matrix to form sintering necks, and the appropriate holding time leads to complete densification of the material. The densified part is then cooled to allow for demolding. •£P 2 )• : The demolded part is melted again and then injected at high speed, with or without vacuum assistance, into a cold mold whose temperature is controlled depending on the nature of the VMM (5 - 100°C) •£P 3 )• : Depending on the printer technology chosen, the part is printed in successive layers to obtain the part.

[0072] Step -E-: The resulting composite material is recovered, shaped, and made up of - a metallic glass matrix, - and by a fibrous reinforcement. The part is removed from the mold and finishing steps can be carried out. EXAMPLES

[0073] EXAMPLE 1: Manufacture via SPS •æH*

[0074] Raw materials

[0075] The metal alloy used is supplied by Heraeus. It is referenced under the name AMLOY ZrOl. This composition is a standard metal-glass alloy composition since it is a Zr70Cu24Al14Nb2 alloy. The particle size parameters of this powder are as follows: Di0 = 42.76 µm, Dpvm50 = 62.99 µm and D9o = 97.06 pm. These parameters are measured by laser particle size analysis according to ISO 13320.

[0076] The carbon fibers used in this example are recycled ex-PAN carbon fibers from the supplier ELG Carbon. Their average length Lfc* is 60 pm. These coated fibers undergo a pre-use heat treatment to clean the surface. They are placed in a Soxhlet extractor setup where the boiling solvent is acetone. The fibers are washed for 24 hours. A drying step is then performed: the fibers are placed in a vacuum oven at 400 °C for 12 hours.

[0077] Equipment

[0078] - A reference oven M346 modified to withstand 400°C from France Etuves.

[0079] - Biconical mixer

[0080] - SPS of type HP D25 from FCT®

[0081] Methodology j. 1. De-seminate the carbon fibers using the method described above. This step is carried out with 1 kg of fibers. 2. Mix the carbon fibers, at 20% by volume, in the metallic glass using the biconical mixer for 6 hours at 30-40 rpm. A total mixture of 2 kg is produced. 3. Introduce the required amount of mixture into the pellet mold (Diameter 15mm Thickness 10mm) 4. Place the mold in the SPS and the following cycle is started: 5 min, 410°C and 100 MPa. 5. Demold the resulting part. This cylindrical part, 15 mm in diameter and 10 mm thick, is shown in [Fig. 4].

[0082] Evaluation tests

[0083] A first evaluation is carried out as soon as it comes out of the mold, which consists of stressing the part and dropping it from a height of one meter without momentum onto a hard surface, such as concrete, verifying that the part does not break or crumble.

[0084] An XRD evaluation of Bruker D8 - Advanced was carried out (see [Fig. 6]). It indicates that the material remains amorphous according to EN NF 1330-11: no crystalline peak and an amorphous peak aligned with that of VMM alone.

[0085] A hydrostatic weighing allows us to conclude that the porosity rate is standard for this type of application: 3.5% according to ISO 1183-1.

[0086] Post-processing is performed on the part to enable optical microscopy of the material. This post-processing consists of manually polishing the part with 6000 grit sandpaper for 20 minutes, with the paper being changed every few minutes. 2 minutes. Several shots (Figures 5, 7 & 8) are taken with a Keyence VHX-7000 type microscope with various objectives.

[0087] EXAMPLE 2: Selective laser sintering

[0088] Raw materials:

[0089] Metal: The metal alloy used is supplied by Heraeus. It is referenced under the name AMLOY ZrO2. This composition is a standard metal-glass alloy composition, as it is a ZrCul6Nil2Al14Ti3 alloy. The particle size parameters of this 2-particle powder are as follows: D10 = 21.35 µm, Dpvm50 = 40.02 µm, and D90 = 61.86 µm. These parameters are determined by laser granulometry according to ISO 13320.

[0090] Fiber reinforcement: The carbon fibers used in this example are recycled and desiccated ex-PAN carbon fibers from the supplier ELG Carbon. Their average length (Lfc) is 80 µm. To bring the fiber size closer to that of the metal, they were reground between two steel plates with a force of 180 tonnes to produce a powder surface area of ​​100 cm² per 30 g batch.

[0091] Apparatus j.

[0092] - Biconical mixer

[0093] - Trumpf TruPrint 1000 type 3D-SLS printer.

[0094] Methodology:

[0095] The method used to produce this composite takes up the method described in patent WO2019179680A1 by substituting the VMM / Copper with the VMM / Carbon mixture described above.

[0096] The mixture used for this example was made in a biconical mixer for 5 hours at 30-40 rpm, in order to mix 10%v of reground carbon fibers whose Lfc was brought back to 30 pm in 90%v of VMM.

[0097] The 5kg thus prepared were introduced into the Trumpf TruPrint 1000 type SLS machine, in order to produce 5 cubes of 10 mm on each side.

Claims

Demands

1. Composite material comprising a fibrous reinforcement based on carbon fibers included in a metallic glass matrix characterized in that: (1.1) the matrix is ​​amorphous; (1.2) the matrix is ​​obtained from metallic glass particles whose size is given by their D50 designated by the reference Dpvm50; (1.3) the fibrous reinforcement comprises carbon fibers of average length Lfc* less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; the fiber reinforcement ratio is between 0.1 and 50%v, preferably 15 and 45%v; and even more preferably between 20 and 40%v.

2. Composite material according to claim 1 characterized in that the matrix is ​​a metal glass alloy consisting of a base of Zr or Pd or Fe or Pt or Cu or Au or Ti or Ni.

3. Composite material according to any one of the preceding claims characterized in that Dpvm50, is such that, in microns and in an increasing order of preference: 5 < Dpvm50 < 500; 5 < Dpvm50 < 250; 20 < Dpvm50 < 250; 20 < Dpvm50 < 100.

4. Composite material according to any one of the preceding claims characterized in that the average length Lfc* of the carbon fibers of the fibrous reinforcement is such that, in microns and in an increasing order of preference: 10 < Lfc* < 1000; 10 < Lfc* < 500; 30 < Lfc* < 500; 30 < Lfc* < 300.

5. Composite material according to any one of the preceding claims characterized in that the carbon fibers of the fibrous reinforcement are derived from carbon fibers free from one another and whose average length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50.

6. Composite material according to any one of the preceding claims, characterized in that the carbon fibers of the fibrous reinforcement originate from carbon fibers free from each other with respect to the others and whose average length Lfc is such that, in microns and in increasing order of preference: 10 < Lfc < 1000; 10 < Lfc < 500; 30 < Lfc < 500; 30 < Lfc < 300.

7. A method for manufacturing a composite material according to any one of the preceding claims, the latter comprising a fibrous reinforcement included in a metallic glass matrix characterized in that this material is obtained • by hot sintering / pressing; • by injection / molding; • or by 3D printing from a mixture comprising: —> a powder of metallic glass particles whose size, given by their D50 designated by the reference Dpvm50; —> medium length carbon fibers Lfc.

8. The method according to claim 7, characterized in that it essentially consists of: - A - implementing a device comprising a mold; - B - mixing a powder of metallic glass particles whose size is given by their D50, designated by the reference Dpvm50, with carbon fibers free from one another and whose average length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; according to a volume percentage of fibers relative to the total particles / fibers between 0.1 and 50%v, preferably 15 and 45%v; between 20 and 40%v; - C - placing the mixture obtained in step B into the mold; - D - firstly, heating the mixture to be sintered contained in the mold to a temperature between the glass transition temperature and the crystallization temperature, preferably by increasing the mold temperature in steps;and, on the other hand, by applying a pressure of between 50 and 150 MPa to the mixture contained in the mold; - E - recover the composite material obtained, shaped in the mold and consisting of ♦ an amorphous matrix; ♦ and a fibrous reinforcement comprising carbon fibers of average length Lfc * less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50 and present according to a fibrous reinforcement rate included; between 0.1 and 50 %v, preferably 15 and 45 %v; and even more preferably between 20 and 40 %v.

9. The method according to claim 8 characterized in that: • the mold is an integral part of a sintering device using the spark plasma sintering (SPS) technique, this device comprising: 3 at least one element for exerting pressure on the mixture to be sintered contained in the mold, 3 and means for electrically energizing the mold and, optionally, the mixture to be sintered contained in the mold; the latter being optionally subjected to an electrical voltage generating a plasma; or • the mold is an integral part of an injection / molding device.

10. A method for manufacturing a composite material, in particular according to any one of the preceding claims 1 to 6, the latter comprising a fibrous reinforcement included in a metallic glass matrix, characterized in that it essentially consists of carrying out 3D printing, from a mixture of a powder of metallic glass particles whose size is given by their D50 designated by the reference Dpvm50, with carbon fibers free from one another and whose average length Lfc is less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50; according to a volume percentage of fibers relative to the whole particles / fibers of between 0.1 and 50 %v, preferably 15 and 45 %v; between 20 and 40 %v; and of recovering the composite material obtained, consisting of: ♦ an amorphous matrix;♦ and a fibrous reinforcement comprising carbon fibers of average length Lfc * less than or equal to 3 times Dpvm50, preferably 1.5 times Dpvm50 and present with a fibrous reinforcement rate between 0.1 and 50 %v, preferably 15 and 45 %v; and even more preferably between 20 and 40 %v.;

11. Object made of composite material according to any one of the preceding claims 1 to 6, or obtained by a process according to any one of claims 7 to 10. 19

12. Subject matter of claim 11 selected from the following articles: watch components; jewelry articles; fashion accessories; sports and leisure articles; telephony articles; HIFI articles; devices and tools for the medical sector; articles for the aeronautical and space industry.

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