Classifications

• • 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
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/02—Compacting only
• • 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
  • C22C1/1084—Alloys containing non-metals by mechanical alloying (blending, milling)
• • 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
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/24—After-treatment of workpieces or articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82B—NANOSTRUCTURES FORMED BY MANIPULATION OF INDIVIDUAL ATOMS, MOLECULES, OR LIMITED COLLECTIONS OF ATOMS OR MOLECULES AS DISCRETE UNITS; MANUFACTURE OR TREATMENT THEREOF
  • B82B3/00—Manufacture or treatment of nanostructures by manipulation of individual atoms or molecules, or limited collections of atoms or molecules as discrete units
• • 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
  • C22C1/1005—Pretreatment of the non-metallic additives
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/0047—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents
  • C22C32/0052—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only carbides
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/0047—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents
  • C22C32/0052—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only carbides
  • C22C32/0057—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only carbides based on B4C
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/0084—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ carbon or graphite as the main non-metallic 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
  • B22F2998/10—Processes characterised by the sequence of their steps
• • 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
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

• the present invention relates to a metal base composite and a method for manufacturing the same, and more particularly to a metal base composite having a structure that can significantly improve the mechanical properties such as strength by using carbon nanomaterials and powder method will be.
• fullerene molecule is a very fine particle, about 1 nm in size, but initially fullered particles are combined in a face-centered cubic (fee), present in the form of a powder of several tens of micrometers. Since fullerene particles in their original form were dispersed in a metal base, fullerenes could not be dispersed as nanoparticles but exist as particles of several tens of micrometers. In addition, when the powder method is used, fullerene particles having a size of several tens of micrometers are not inserted into the metal powder, but exist on the surface, which impedes the bonding between the powders during integration, making it difficult to manufacture high-quality bulk materials and possible industrial utility. This is incomplete.
• the present invention has been made to solve the above-mentioned problems in the prior art, and one object thereof is to pulverize a carbon material in powder form, which exists in a micrometer size, into a nano-size carbon material by a powder method, and disperse it into a metal base. It is to provide a metal matrix composite and a method for producing the same by improving the properties of the material.
• Another object of the present invention is to separate carbonaceous materials, such as fullerenes, which are initially arranged in face-centered cubic (fee), in powder form of several micrometers to several tens of micrometers or more, in nanometer size, and are separated from the metal matrix. It is to provide a metal matrix composite uniformly dispersed therein and a method for producing the same.
• Another object of the present invention is a metal-based composite having a new phase or structure that can be manufactured in large quantities in large quantities using a simple mechanical process and has excellent material properties. It is to provide a manufacturing method and a composite material thereof.
• a method for producing a metal matrix composite comprising: 1) grinding a solid carbon material to micrometer size; 2) dispersing the pulverized carbon material into the metal matrix powder in nanometer size while plastically deforming the metal matrix powder; 3) integrating the composite powder of the metal / carbon nanomaterial obtained in 2) using a hot forming process; 4)
• the integrated bulk material is heat-treated at a predetermined temperature, and has a metal-carbon nanophase, a metal-carbon nanoband on which these metal-carbon nanophases are grown, or a metal-carbon nanonetwork structure in which these nanobands self-bond. Characterized in that it comprises the step of forming a composite.
• the carbon atoms penetrate between the metal matrix lattice by the heat treatment in the step 4), and the metal matrix lattice is deformed or enlarged so that the metal-carbon nanophase, metal-carbon nanoband or metal-carbon nano A network structure can be formed.
• the heat treatment in step 4) may be carried out at a temperature range in which each carbon atom is short enough to infiltrate between the metal matrix lattice but does not produce carbon compounds. , Preferably at a temperature of 0.5 to 1 Tm (Tm: melting point of the metal matrix).
• the metal matrix powder may be a pure metal of aluminum, copper, iron, titanium, or magnesium, or an alloy capable of plastic deformation based on a double selected one
• the carbon material may be fullerene, carbon nanoleuube. , Graphite, carbon black or amorphous carbon.
• the metal matrix powder is aluminum powder
• the carbon material is fullerene
• the composite in step 4) is Al 1 C x (0 ⁇ x ⁇ 3) represented by A1-.
• the carbon material may be ground using a mechanical milling process in 1) and 2).
• a metal matrix composite prepared by using a metal matrix powder and a carbon material, wherein the carbon-carbon bonds of the carbon material are dissociated to produce a short range of diffusion of each carbon atom.
• Metal-carbon nanophase particles that form while deforming or enlarging the metal matrix lattice, which are formed between these matrix lattice, metal-carbon nanobands formed by the growth of these nanophase particles, or metal-carbon in which the nanobands are self-bonded. It comprises a nano network structure, characterized in that it does not contain the carbon compound by carbon.
• the dislocation stones are fixed around the metal-carbon nanophase particles, or the metal matrix grains may be miniaturized by the metal-carbon nanoband or metal-carbon network structure, or growth thereof may be suppressed.
• the metal matrix powder is aluminum powder
• the carbon material is fullerene, in which case the composite may exhibit a mechanical strength in excess of 500 MPa.
• a method for preparing a metal matrix composite is provided by a) mechanically milling a fullerene, which is initially arranged in a face-centered cubic (fee), present in the form of micrometer-sized powder. B) dispersing the pulverized fullerene in nanometer size into the metal matrix powder while plastically deforming the metal matrix powder by mechanical milling process; and c) hot forming the composite powder of metal matrix / fullerene. And d) heat-treating the integrated material at a predetermined temperature so that the metal-carbon nanophase, the metal-carbon nanobands on which these metal-carbon nanophases are grown, or the nanobands self-bond. Forming a composite having a metal-carbon nanonetwork structure.
• a metal-based composite prepared using aluminum powder and fullerene, in which the carbon-carbon bonds of the fullerene are dissociated to produce a short range of carbon atoms.
• A1-C nanophase particles that penetrate between aluminum matrix lattice and form while deforming or enlarging the aluminum matrix lattice, A1-C nanobands formed by the growth of these nanophase particles, or A1-C self-bonded A1-C nanobands.
• C nano network structure is included, and the carbon compound (A1 4 C 3 ) based on carbon is not included.
• the composite exhibits mechanical strength in excess of 500 MPa.
• a method for producing a metal matrix composite comprises the steps of: 1) milling a solid compound comprising a penetrating element of nitrogen or boron to a micrometer size; 2) dispersing the pulverized solid compound in the nanometer size into the metal matrix powder while plastically deforming the metal matrix powder to obtain a composite powder; 3) preparing a bulk material by integrating the composite powder; 4) The bulk material is heat-treated at a predetermined temperature, and the metal-nitrogen or boron nanobands or nanobands in which the metal-nanoparticles of nitrogen or boron, the idol metal-nitrogen or nanophase particles of boron are grown.
• step 4 Forming a composite having a nano-network structure of bonded metal-nitrogen or boron.
• nitrogen or boron atoms penetrate between the metal matrix lattice, and the metal matrix lattice is deformed or enlarged to form nano-particles of the metal-nitrogen or boron, Can form nano-network structures of metal-nitrogen or boron nanobands or metal-nitrogen or boron ⁇
• the heat treatment in the step 4) may be carried out at a temperature of 0.5 ⁇ 1 Tm (Tm: melting point of the metal matrix).
• the metal matrix powder may be a pure metal of aluminum, copper, iron, titanium or magnesium, or an alloy capable of plastic deformation based on a dual selected one.
• the solid compound may be boron carbide (B 4 C) or boron nitride (BN), and in certain embodiments, the solid compound is boron carbide (B 4 C), and the metal matrix
• the powder may be magnesium.
• a metal matrix composite prepared using a metal matrix powder and a solid compound containing an invasive element of nitrogen or boron, wherein the composite is formed by dissolving the bond of the solid compound.
• Metal-nitrogen or boron nanophase particles formed by deforming or enlarging the metal matrix lattice in which nitrogen atoms or boron atoms are diffused in a short range and enter the metal matrix lattice, and the metals formed by the growth of these nanoparticles -Nitrogen or boron nanobands, or these nanobands are characterized in that they comprise a nano-network structure of self-bonded metal-nitrogen or boron.
• dislocations are fixed around the nanophase particles of metal-nitrogen or boron, or the metal matrix is formed by the nano-band structure of the metal-nitrogen or boron or the nano-network structure of metal-nitrogen or boron. It is characterized by the fact that a grain is refine
• the metal matrix powder may be a pure metal of aluminum, copper, iron, titanium or magnesium, or an alloy capable of plastic deformation based on a double selected one
• the solid compound may be boron carbide (B 4 C) or boron nitride (BN), and in certain embodiments, the solid compound is boron carbide (B 4 C), and the metal matrix powder may be magnesium.
• nano-sized carbon material is uniformly added inside the metal base powder to form a strong interfacial bond with the surrounding metal atoms, so as to provide a good quality bulk material in the hot processing of the powder. Not only can it be integrated, but also high strength and ductile mechanical properties can be realized at the same time, greatly extending the industrial scope.
• Bon even if the prepared bulk-type composite material is heat-treated at a temperature of 0.5 ⁇ lT m (melting point of the base metal), the metal-carbon nanophase precipitates in the form of particles or grows into nanobands without degrading mechanical properties. Or, they combine with each other to form a network structure, rather the mechanical properties are improved.
• the manufacturing method according to the present invention is very simple and easy to automate, the process cost is low and the industrial utility is excellent.
• FIG 3 is a photograph of the microstructure after heat treatment of the A1 / C6Q composite for 12 hours, showing that the composite includes a novel A1-C nanophase (indicated by dashed lines).
• FIG. 5 is an enlarged photograph of an A1-C nanophase generated after heat treatment of an Al / Ceo composite material for 12 hours.
• FIG. 6 is a photograph of the microstructure after the 24-hour heat treatment of the AVCeo composite material, showing that the A1-C nanophase self-bonded to include the network-type A1-C nanoband structure.
• FIG. 7 is an enlarged photograph of an Al—C nanoband structure in a network form after heat treatment of an Al / Ceo composite material for 24 hours.
• FIG 9 is a graph showing the hardness change according to the heat treatment time during the 500 ° C heat treatment of the aluminum matrix composite according to the invention in more detail.
• FIG. 10 is a X-ray diffraction analysis of the aluminum matrix composite according to the present invention according to the heat treatment time during the 500 ° C heat treatment, showing the change of grains.
• FIG. 11 is a photograph taken using a transmission electron microscope of the microstructure after heat treatment of the aluminum matrix composite according to the present invention at 520 ° C for 2 hours.
• FIG. 13 is a transmission electron micrograph showing a Mg—C nanophase in which a lattice is deformed by forcing carbon atoms in a lattice of magnesium by heat-treating the magnesium matrix composite according to the present invention at 425 ° C.
• FIG. 13 is a transmission electron micrograph showing a Mg—C nanophase in which a lattice is deformed by forcing carbon atoms in a lattice of magnesium by heat-treating the magnesium matrix composite according to the present invention at 425 ° C.
• FIG. 14 shows the results of X-ray diffraction analysis of the lattice constants of the pure magnesium specimens and the sample obtained by heat-treating the Mg-Ceo composite at 425 ° C. for 12 hours, showing that the lattice constant was increased compared to pure magnesium.
• 15 is a view showing the hardness change according to the heat treatment time when the magnesium matrix composite according to the present invention heat-treated at 425 ° C.
• 16 is a photograph taken with a transmission electron microscope of the microstructure of the magnesium -B 4 C composite according to the present invention.
• FIG. 17 is a photograph of a magnesium-B 4 C composite according to the present invention after heat treatment at 550 ° C. for 3 hours, followed by transmission electron microscopy. -B shows that the nanophase is formed.
• FIG. 18 is a view showing the hardness change according to the heat treatment time when the magnesium-B 4 C composite according to the present invention heat-treated at 550 ° C.
• the inventors conducted a study on how to uniformly disperse the carbon material in the metal matrix. To this end, fullerene among various solid carbon materials, among them, Ceo was selected as a carbon material, aluminum was selected as a metal base, and a composite powder was prepared according to the following procedure.
• the metal-based material is generally a material capable of elasticity and plastic deformation for smooth insertion and dispersion of carbon nanomaterials such as fullerene.
• a pure metal such as aluminum, copper, iron, titanium, or an alloy capable of plastic deformation based on one or more selected.
• Ceo a kind of fullerene, is initially arranged in a face-centered cubic structure and exists in powder form of several micrometers to several tens of micrometers or more.
• the present inventors first pulverized the micrometer-sized Ceo using a planetary mill. That is, after charging 2 g of Ceo powder and a stainless steel ball (about 800 g) having a diameter of 5 mm in a stainless steel container, the container was rotated at a speed of 200 rpm to apply physical energy, that is, kinetic energy, to the Ceo powder. In order to prevent excessive heat generation, a total of 2 hours of milling was performed by repeating the process of air cooling for 30 minutes and 8 times for 30 minutes.
• FIG. 1 (b) A photograph of the crushed Ceo particles after milling with a scanning electron microscope is shown in Figure 1 (b). After milling, the Ceo particles were crushed to a size of 100 nm ⁇ 1 / ⁇ , and the pulverized particles were weakly agglomerated by the Vantterbal force.
• the mechanical milling as described above may be performed by various milling methods capable of applying energy to a milling medium such as a ball such as a spex mill or an attrition mill as well as a planetary mill.
• a milling medium such as a ball such as a spex mill or an attrition mill as well as a planetary mill.
• An attrition mill was used to disperse the pulverized Ceo particles (2 vol.%) In aluminum powder (average particle size 150 / dl).
• 100 g of aluminum and ground Ceo mixed powder and 5 mm diameter stainless steel balls (approximately 1.5 kg) were loaded into a stainless steel container, and the blade was rotated at a speed of 500 rpm to provide energy for the materials in the container to collide.
• the temperature of the container was prevented from rising by pouring cooling water on the outside of the container while the materials collided with each other.
• the powder and the balls were separated using a sieve, and the composite powder was collected.
• the collected powder was photographed using HREM (High-resolution TEM), and the photograph is shown in FIG. 2.
• Ceo particles are inserted into the relatively soft aluminum powder during the milling process, and Ceo particles are crushed to smaller size, ie nano size, during the plastic deformation, crushing and cold welding. It can be uniformly dispersed into the powder. Most of the C60 particles appear to have been inserted into the aluminum powder in the milling process, so Ceo will not interfere with the bonding between the metals in the hot forming process . Judging. That is, according to the present invention, the Ceo particles may be pulverized into nano-sized particles of less than 1 / m or less through the first milling process, the metal powder is plastically deformed during the second milling process into the metal powder Evenly distributed in nano size.
• the Ceo nanoparticles are uniformly dispersed in the metal powder through the first and second milling processes, thereby preventing the diffusion of metal atoms to stabilize the microstructure.
• C60 does not exist on the surface of the powder, metal atoms diffuse smoothly on the surface, so that the combination of the powder and the powder is not hindered in a later hot working process, thereby producing a high quality bulk material.
• Metal / C 60 composite according to the present invention In the powder, the Ceo nanoparticles are uniformly dispersed in the metal base, and a metal base composite powder having strong interfacial bonds with the matrix is obtained. By using the same, a good bulk material can be produced by the following procedure. ,
• impact energy is imparted through a medium, such as a ball, to a mixed powder in a container through a single milling process such as ball milling or hand milling under predetermined conditions determined experimentally.
• a medium such as a ball
• C 60 nanoparticles can be inserted into the metal powder and dispersed.
• Ceo and metal powders have strong interfacial bonding properties due to the mechanical interlocking of carbon and metal atoms, and Ceo is uniformly dispersed in the powder. It does not inhibit the binding between the powders.
• the above steps can be accomplished through a simple process compared to the conventional method of dispersing carbon nanoleuver inside a metal base through various steps such as dispersion and calcination using a dispersion solvent.
• the mechanical energy used in the ball milling or hand milling method may vary depending on the type and microstructure of the metal matrix, the type / size / weight of the milling medium, milling speed, milling vessel It can be controlled by the size round.
• Ceo may be dispersed in the metal powder by applying various methods such as simple mixing, ultrasonic method, and hand milling.
• the inventors have found that Ceo can be uniformly dispersed in the metal base through the process as described above, and the final composite is manufactured by using the composite powder prepared through such a process through a simplified process. We studied how to do it.
• the present inventors apply only pressure or powder to the powder primarily to prevent the powder from being damaged when the Ceo-dispersed metal-based composite powder is directly processed at a high temperature and high pressure. If an intermediate (compact molded body) is produced by applying a pressure at a temperature in a range that is not damaged, that is, a range in which oxidation does not occur, and the intermediate is hot worked to produce a final bulk material, the metal base is in the hot process.
• the present invention was completed, focusing on the technical problem, anticipating that the characteristics of the composite powder can be prevented.
• the present inventors adopted a normal temperature pressing method as a method for producing an intermediate by applying pressure to the aluminum -Ceo (2 vol.%) Composite powder prepared in the above-described milling process. After loading the composite powder into the copper ribs and applying a pressure of 500 MPa to produce a thickener, the compacted powder showed a porosity of 20% or less and prevented the oxidation of the powder and the damage of Ceo in the subsequent hot working process.
• a normal temperature pressing method as a method for producing an intermediate by applying pressure to the aluminum -Ceo (2 vol.%) Composite powder prepared in the above-described milling process. After loading the composite powder into the copper ribs and applying a pressure of 500 MPa to produce a thickener, the compacted powder showed a porosity of 20% or less and prevented the oxidation of the powder and the damage of Ceo in the subsequent hot working process.
• a normal temperature pressing method as a method for producing an intermediate by applying pressure to the aluminum -Ceo (2 vol.%) Composite powder
• the present inventors were hot rolled at 480 ° C to hot work the intermediate produced according to the above process, and carried out 27 times with 12% reduction to reduce the thickness of the final plate 97% compared to the thickness of the initial intermediate It was.
• a hot forming process not only hot rolling, but also various hot forming processes capable of integrating the powder by applying heat and pressure such as hot extrusion and hot pressing may be used.
• the heat treatment at a temperature of 500 ° C. for the cotton, aluminum / Ceo composite is only one exemplary heat treatment temperature, and the present invention is not limited to the heat treatment at this temperature.
• the heat treatment was carried out by charging the aluminum / Ceo composite material in a furnace (furnace) that is maintained at 500 ° C in the air, and maintained for a predetermined time and then air-cooled, and the present invention is the same as the heat treatment temperature It should be understood that it is not limited to the heat treatment method.
• the microstructure according to the heat treatment is shown in FIG. 3. 3 shows a microstructure photographed using HREM after heat treatment at 500 ° C. for Al / Ceo composite according to the above procedure, and the inventors found that unexpected microstructure was obtained through such heat treatment. Confirmed.
• FIG. 4 shows a state diagram of A1-C.
• A1-C a state diagram of A1-C.
• a carbon compound such as A1 4 C 3 is formed when carbon is contained within a predetermined range.
• these A1 4 C 3 carbon compounds are known to continuously grow at high temperatures, which greatly degrades the mechanical properties of A1-C alloys.
• the A1-C nanophase included in the composite according to the present invention may be represented by a composition in a range different from that of the conventional chemical stoichiometric coefficient, that is, Al 4 C x (0 ⁇ x ⁇ 3).
• Phase is a novel nanophase that has not been reported in existing A1-C alloys. That is, referring to FIG. 5, in which the Al—C nanophase generated after heat treatment of the Al / Ceo composite material for 12 hours is enlarged, the lattice constant of the newly generated A1-C nanophase is about 3 A. It can be seen that the increase is greater than the constant of about 2.8A.
• FIG. 5 shows the microstructure after the Al / Ceo composite is heat treated for 24 hours The photograph taken was shown.
• the Al—C nanophases shown in FIG. 5 are anisotropically grown in the form of nano bands to minimize lattice strain energy, or these nano bands.
• Self-assembly formed an A1-C nano-network structure of about 5 ⁇ 0 nm thick around the grains, indicating that the composite was very stable at high temperatures.
• An enlarged photograph of the nano-network structure is shown in FIG.
• the metal matrix composite according to the present invention is a carbon nanomaterial, such as fuller Ceo, is pulverized into a nano-sized form to be uniformly dispersed into the metal powder, and then the metal matrix-carbon Not only do not interfere with powder-to-powder bonding upon the integration of the composite powder of nanomaterials, but also the integrated composite material has greatly improved material properties such as its mechanical strength. Furthermore, when the integrated composite is heat treated at a lower temperature than the melting point of the metal matrix, the carbon constituting the carbon nanomaterial is broken, and each of these carbon atoms is short-range diffused, depending on the heat treatment time.
• Metal matrix-carbon nanophase these metal matrix-carbon nanophases are anisotropically grown metal matrix-carbon nanobands, and these nanobands self-bond to form a metal matrix-carbon nanonetwork structure. All of these tissues are new phases or structures that have not been reported previously, resulting in remarkable results of inhibiting the growth of metal matrix grains and improving the mechanical properties such as strength even after prolonged heat treatment. This mechanical property improvement will be described in more detail below.
• FIG. 8 is a graph showing the hardness according to the retention time after maintaining the composite prepared according to the above process at a temperature of 500 ° C. Up to 6 hours, the hardness decreases due to grain growth and recovery of residual stress. However, it can be observed that as the heat treatment is performed for 12 hours or more, the hardness of the composite is improved as the heat treatment time increases. For more accurate strength measurements, heat treatments of 1 hour, 24 hours and 7 days were carried out on the composite and then subjected to a compression test with a strain of ⁇ — 1 , and the results are shown in FIG. 9.
• the one-hour heat treatment is an annealing treatment to remove residual stress generated in the rolling process for manufacturing the composite material.
• the annealing treatment for one hour, the inherent mechanical properties of the material can be evaluated. .
• the aluminum matrix composite according to the present invention all exhibited a high strength of at least 500 MPa.
• a mechanical strength of about 500 MPa even if only 1 hour annealing treatment showed a mechanical strength of about 500 MPa.
• fullerene appears to maintain its carbon bond in the metal base, and the fullerene is uniformly inserted in the metal base, thereby improving mechanical strength. This is the strength achieved with the addition of only 2 vol% of loosening, which can be considered a surprising result.
• the composite according to the present invention Mechanical strength can be increased significantly.
• the mechanical strength is remarkably improved using only 2 vol% (l wt%) ⁇ 1 small amount of fullerene.
• the work hardening index (n) representing the strength increase (tilt) according to the strain change increases as the heat treatment time increases.
• the work hardening index is high, even materials with the same yield strength show better properties after plastic deformation, and in general, necking also occurs late, and thus is evaluated as a material having good ductility.
• Figs. 8 and 9 show aspects different from the existing precipitation hardening. That is, according to the existing precipitation hardening theory, the mechanical strength decreases due to coarsening of grains as the heat treatment time increases. In other words, there is a limit to increasing the strength by using precipitation hardening.
• the mechanical strength increases as the heat treatment time increases, which is described above as the heat treatment time increases.
• the metal—C nanophases are anisotropically grown to form metal-C nanobands, or these metal ⁇ C nanobands self-bond to form metal-C nanonetwork structures, which hinder the growth of the parent metal grains. This seems to be due to the continuous improvement of strength.
• This test result is a new phenomenon that does not appear in existing materials. This will be described in more detail with reference to FIG. 10.
• the composite material according to the present invention not only uniformly disperses fullerene nanoparticles, exhibits excellent mechanical properties such as high strength, but also does not decrease in strength even after heat treatment at high temperature, and carbons derived from fullerene are combined with aluminum.
• the A1-C nanophases which were not seen on the surface, form anisotropically grown A1-C nanobands or self-bonded A1-C nanonetwork structures, resulting in higher strength and very stable properties in silver.
• the composite manufacturing method according to the present invention is a simple method that can be used in the general industry, and enables excellent productivity.
• the final work material is very high in density and maintains the properties of the powder as it can exhibit excellent mechanical properties.
• FIG. 11 is a photograph taken using a transmission electron microscope of the microstructure of the composite after heat treatment of the Al-Ceo composite at 520 ° C for 2 hours.
• the Al-C nanophase in which the lattice was deformed by the forced solid solution of carbon was also produced by the heat treatment at 520 ° C., and the fraction of the nanophase was 70% or more even after only 2 hours of heat treatment. This means that when the heat treatment temperature is increased according to the present invention, the nanophase can be generated at a higher speed.
• FIG. 12 is a view showing the results of measuring the change in the lattice constant of the specimen after the heat treatment at 520 ° C through 2 X-ray diffraction analysis. From the X-ray diffraction analysis shown, it can be seen that the peak has shifted to the left so that it can be observed with the naked eye. At this time, when calculating the lattice constant, the lattice constant of pure aluminum (about 0.405 nm) In comparison, the lattice constant (about 0.422 nm) of the specimen nanophase heat treated at 52 CTC for 2 hours was increased by about 5%.
• the composite lattice according to the present invention can extend the volume of the unit lattice by about 15% or more, thereby saving energy and the like. It can be expected to be useful as a related material.
• the manufacturing method of the composite material proposed in the present invention is very simple compared to the conventional atomic doping method and low manufacturing cost, it is expected that the industrial utility is high.
• fullerene especially C60
• C60 fullerene
• fullerenes having a bucky ball structure such as C 17 and C 120 can also be applied to the present invention.
• carbon materials that can be ground to nanometer sizes by mechanical methods such as carbon nanotubes, graphite, carbon black, amorphous carbon, etc. It is important to understand that it is applicable to the invention, which also falls within the scope of the invention.
• aluminum has been described as an example of the base metal, but the present invention It should be understood that it is not limited to aluminum. That is, in addition to aluminum, as described above, a carbon material such as copper, iron, titanium, magnesium, or a metal capable of smoothly invading and dispersing such as an alloy capable of plastic deformation based on one or more selected ones may be easily infiltrated and dispersed. It should be understood that the method of the present invention can be applied to produce metal-based composites having novel metal-carbon nanophase, metal-carbon nasothi, and metal-carbon nanonetwork structures.
• the present inventors carried out experiments in accordance with the same process as described above, using magnesium in addition to aluminum as a metal base, by heat-treating the Mg-Ceo composite at 425 ° C, carbon atoms of magnesium It was confirmed that a phenomenon in which the solid solution is forced into the lattice, the lattice is modified Mg-C nano phase is formed, which is shown in FIG.
• Figure 14 is a graph showing the results of X-ray diffraction analysis of the lattice constants of the specimen and pure magnesium specimens heat-treated Mg-Ceo composite material at 425 ° C for 12 hours.
• the X-ray diffraction peak shifted to the left, indicating an increase in the magnesium lattice constant.
• 15 is a graph measuring the hardness change according to the heat treatment time when the Mg-Ceo composite material and the pure magnesium specimen was heat-treated at 425 ° C.
• the Mg-C60 composite shows good hardness.
• the pure magnesium maintains the value after the hardness decreases due to the initial heat treatment of the heat treatment, but the Mg-Ceo composite material according to the present invention after the hardness decreases due to the annealing phenomenon, the hardness again due to the Mg-C nanophase You can see the increase.
• carbon is described as an element that deforms the metal lattice by forcibly penetrating into the metal lattice, but it should be understood that the present invention is not limited to carbon. That is, carbon is one of the elements capable of forming an intermetallic compound, and thus an element capable of forming an intermetallic compound, that is, boron or a nitrogen atom, may also exhibit the effects of the present invention.
• FIG. 16 is a photograph taken using a transmission electron microscope of the microstructure of the composite material in which B 4 C (boron carbide, boron carbide) is dispersed in the magnesium base. Through the mechanical milling process, it can be seen that boron clusters of 2 to 3 nm size are dispersed.
• the composite material was heat-treated at 550 ° C., and the microstructure of the heat-treated composite material was shown in FIG. 17 using a transmission electron microscope. As shown in FIG. 17, it can be seen that boron atoms penetrated into the magnesium lattice to form the Mg-B nanophase while deforming the magnesium lattice.
• Figure 18 shows the change in hardness according to the heat treatment of the Mg-B composite material formed as described above, it can be seen that the hardness increases with the heat treatment time as in the previous embodiment. That is, even after heat treatment at a relatively high temperature (approximately 0.9Tm, Tm: magnesium melting point) of 550 ° C, it can be seen that the hardness increases rather than decreases, because Mg-B nanophase is produced.
• the mechanical properties are improved. Like the above-described embodiment, this also appears to be caused by the effect of the dislocations around the nano-phase particles, etc. Also, the nano-phase particles are formed according to the same mechanism as the above embodiment to form a nano-band or nano network structure
• carbon in boron carbide like boron, forms nanophases such as Mg C.
• Mg-C because of the ratio of one carbon per four boron, the effect of Mg-C appears to be relatively small compared to Mg-B.
• Mg-C also appears to contribute to some improvement in mechanical properties.
• the present embodiment is not only carbon but also compounds of boron and nitrogen atoms which are forcibly dissolved in the metal lattice to deform the metal lattice (eg, B4C: boron carbide, BN: boron nitride). It is shown that the present invention can be applied to the manufacture of metal-based composites having nanophase, nanoband or nanonetwork structures. While the present invention has been described with reference to various embodiments, it should be understood that the present invention is not limited to the above embodiments. For example, the heat treatment temperature, time, etc. may vary depending on the type of metal matrix used, the carbon material used, the amount of intermetallic compound forming elements (nitrogen, boron), and these methods may vary depending on the application. It should be understood. That is, the present invention can be variously modified and modified within the scope of the following claims, all of which fall within the scope of the present invention. Accordingly, the invention is limited only by the claims and the equivalents thereof.

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• 2010
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