JP2020076124A - Method for producing metal composite material and metal composite material - Google Patents

Abstract

To provide a metal composite material which is prevented from deforming due to its own weight and also has high strength.SOLUTION: A method for producing a metal composite material is provided that is comprised of: a bound body formation step of forming layers of metal particles, supplying an organic binder to the layers of the metal particles to bind the metal particles, sequentially laminating the layers of the bound metal particles, thereby forming a bound body; a porous body fabrication step of drying the bound body thereby fabricating a porous body having a vacancy part; and a step of heating copper or a copper alloy containing Ti in reduction atmosphere and infiltrating the copper or copper alloy in the porous body, reacting carbon of the binder and Ti in the copper or copper alloy, thereby forming a TiC phase on the interface of the metal particles and the copper or copper alloy.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a shaped body manufactured by infiltration treatment using a metal.

A new modeling technique for forming a three-dimensional model (hereinafter referred to as a model) from material particles based on three-dimensional drawing data is drawing attention. One of them is a binder injection method (hereinafter referred to as a binder injection method), in which metal particles, which are material particles, are thinly laid, and an organic binder is injected onto the metal particles so that the binder is The metal particles in the sprayed portion are solidified, and the solidified layers are sequentially laminated to produce a binder having a complicated shape. The produced bound body is heated to bond the metal particles to each other to form a porous shaped body having pores.
With this method, it is possible to flexibly create various shapes based on three-dimensional drawing data, but since the porosity of the shaped body is high, the strength is inferior to the cast body using the mold, and there is a risk of deformation due to its own weight during heating. was there.
Therefore, a process of improving strength by infiltration of a metal, for example, a process of melting a metal or an alloy having a lower melting point than that of the shaped body, filling the void portion of the shaped body and re-solidifying is performed (for example, patents Reference 1).

Japanese Patent Publication No. 2018-510267

  However, there is a problem that it is necessary to remove the binder at the time of forming the binder before infiltration of the metal, and if this remains, sufficient strength cannot be secured.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a metal composite that improves the strength of a shaped article produced by the binder injection method.

  The method for producing a metal composite according to the present invention comprises forming a layer of metal particles, supplying an organic binder to the layer of metal particles to bind the metal particles to each other, and binding the metal particles to each other. A binder forming step of sequentially laminating layers of metal particles to form a binder; a porous body preparing step of drying the binder to prepare a porous body having pores; The body is infiltrated by heating copper or a copper alloy containing Ti under a reducing atmosphere, reacting carbon of the binder with Ti in the copper or the copper alloy, the metal particles and the copper or the copper And a step of forming a TiC phase at the interface with the copper alloy.

  Further, the metal composite according to the present invention is a core portion in which a plurality of metal particles are formed in contact with each other, and copper or copper containing Ti filled between the plurality of metal particles while covering the outer periphery of the core portion. A base portion made of an alloy and an interface portion in which a TiC phase is formed on at least a part of the interface between the core portion and the base portion are provided.

  According to the present invention, by infiltrating a porous body with copper or a copper alloy containing Ti, carbon and Ti remaining on the surface of the metal particles constituting the porous body react with each other, and the metal particles and copper or By forming a TiC phase at the interface with the copper alloy, it is possible to suppress carbon residue and significantly improve the strength of the produced metal composite.

It is a schematic block diagram of the three-dimensional modeling apparatus concerning Embodiment 1 of this invention. FIG. 3 is a schematic configuration diagram of a porous body according to the first exemplary embodiment of the present invention. It is a schematic block diagram which shows the state of the infiltration process of the porous body concerning Embodiment 1 of this invention. It is a schematic diagram which shows the modeling method of the metal composite piece concerning Embodiment 1 of this invention. It is a schematic diagram which shows the metal complex concerning Embodiment 1 of this invention. FIG. 6 is a relationship diagram showing a tensile strength ratio of the metal composite body according to the second embodiment of the present invention.

Embodiment 1.
The inventors have paid attention to the fact that one of the causes of the insufficient strength of the molded body manufactured by the conventional infiltration treatment is the residual organic component of the binder, and wondered whether the organic component could be denatured. As a result of diligent studies, it was found that it is possible to react carbon in the organic component with a metal and leave the metal compound in the shaped body as a metal compound.
Then, in particular, titanium and carbon are reacted with each other to form TiC, and a metal composite is left as a TiC phase between the metal particles forming the shaped body or at the interface between the metal particles and the infiltrant. I confirmed that I could secure it. Hereinafter, a method for producing a metal composite and a metal composite according to the present invention will be described.

FIG. 1 is a schematic configuration diagram of a three-dimensional modeling apparatus according to the first embodiment of the present invention. The three-dimensional modeling apparatus 4 has a modeling chamber 7 that is surrounded by a modeling chamber wall 5 and includes a table 6 that moves up and down. Metal particles 10 (for example, stainless steel particles) are supplied into the modeling chamber 7 from the metal particle supply unit 9 provided in the tank 8 to the table 6. The supplied metal particles 10 are spread on the table 6 by a squeegee 11 and pressed to form a metal particle layer 12 having a thickness t _D.
An organic binder 14 dissolved or mixed in a solvent is jetted from the nozzle 13 to the formed metal particle layer 12, and the binder 14 is moved to an arbitrary position on the metal particle layer 12 as the nozzle 13 moves. Is supplied. As a result, the plurality of metal particles 10 are bound by the binder 14, and the bound metal particle layers 12 are sequentially stacked to form the three-dimensional bound body 1. In FIG. 1, the shape of a fan of a ventilation fan is shown as an example of the binder 1.

  Next, the obtained binder 1 is taken out from the modeling room 7 and dried. Since the solvent component of the binder 14 remains in the binder 1, the solvent component is removed by drying to promote the binding and prevent the binder 1 from being deformed. The drying temperature and the drying time for removing the remaining solvent components are, for example, 200 ° C. and about 8 hours.

  Next, the dried binder 1 is cooled at room temperature. As shown in FIG. 2, the binder 1 is composed of a plurality of metal particles 10 and a binder 14 that binds them to each other, and becomes a porous body 2 having pores. Since there are metal particles not bound by the binder 14 around the porous body 2, these are removed.

  Next, as shown in FIG. 3, the dried and cooled porous body 2 is brought into contact with copper containing Ti or a copper alloy containing Ti as an infiltrant 15 in a hydrogen atmosphere, and heated by a heater 16. Here, the infiltrant 15 is in the form of powder, and the porous body 2 is dipped therein. Block-shaped or strip-shaped ones may be supplied.

By this infiltration treatment, the pores 17 of the porous body 2 shown in FIG. 4A are filled with copper or copper alloy containing Ti, and the porous body 2 is formed by a plurality of metal particles 10 contacting each other. The metal composite 3 is formed by the core portion 18 and the base portion 19 that covers the outer periphery of the core portion 18 and that is composed of the infiltrant 15 filled between the plurality of metal particles 10 (FIG. 4). (B)).
Further, as shown in FIG. 5, the metal composite 3 further has an interface portion 21 in which the TiC phase 20 is formed on at least a part of the interface between the core portion 18 and the base portion 19.

  The TiC phase 20 has a different shape depending on the Ti content in the infiltrant 15 and the amount of the binder 14 in the porous body 2. In addition to the TiC phase 20 formed so as to be scattered or cover the interface portion 21, the TiC phase 20 also exists in the base portion 19. It may exist between the metal particles 10. Further, as shown in FIG. 5, carbon 22 may remain in the metal composite body 3.

  By such infiltration treatment, that is, copper or copper alloy containing Ti is brought into contact with the porous body 2 and heated and held, carbon 22 and Ti remaining on the surface of the metal particles 10 constituting the porous body 2 And the TiC phase 20 is formed at the interface between the metal particles 10 and copper or copper alloy, the carbon 22 can be prevented from remaining, and the strength of the produced metal composite 3 can be remarkably improved.

  Further, the surplus organic component may be degreased, but in the present invention, the carbon 22 of the organic component reacts with Ti, so the degreasing treatment can be omitted. In a normal degreasing process, after the porous body 2 is manufactured, a heating process is performed at about 500 ° C. in a vacuum atmosphere for about 1 to 24 hours. Therefore, when the degreasing process is omitted, work efficiency is improved.

  Here, if the average particle diameter of the metal particles 10 constituting the metal particles 10 is about 1 μm or more and 50 μm or less, the metal particles 10 have high fluidity, and therefore a uniform metal particle layer is obtained in the binder injection method. 12 can be formed, and the highly accurate porous body 2 can be obtained.

  In order to increase the packing density of the metal particles 10 and obtain a uniform metal particle layer 12, the metal particles 10 are preferably spherical with an aspect ratio of 1.0, but the aspect ratio is 1.0 or more.2. It may be a flat shape such as a spherical shape of 0 or less, an elliptical shape, or a polyhedral shape.

  Further, since the metal particles 10 having an average particle diameter of less than 1 μm are difficult to form a uniform metal particle layer 12 having low fluidity as they are, the metal particles 10 are mixed with a resin or an organic solvent in advance, The composite particles or dispersions having an average particle size of 1 μm or more and 50 μm or less can be used by improving the fluidity.

  Further, in the present embodiment, SUS316L powder having an average particle size of 10 μm is used as the stainless steel powder which is the metal particles 10, but it is applicable to other metal particles having the same fluidity.

  Further, the infiltration treatment can be performed under a hydrogen atmosphere, but it is preferably under a reducing atmosphere so as not to oxidize carbon. The heating temperature and heating time for the infiltration treatment are, for example, 1100 ° C. and 30 minutes.

  Further, the binder 1 may have a hollow structure. At this time, a hole for removal may be provided in advance when the binder 1 is formed so that the unbound metal particles 10 in the hollow structure can be removed. The removed metal particles 10 can be reused in the three-dimensional modeling apparatus 4.

  Also, an example of manufacturing a fan of a ventilation fan as the metal composite 3 has been shown, but since the strength of the metal composite 3 can be improved by forming the TiC phase 20, the stress of automobile parts, aircraft drive parts, etc. It can also be applied to metal parts where it is necessary to secure strength.

  After the infiltration treatment, the metal composite 3 may be subjected to a cutting process or the like to change its shape.

In the present invention, the step of supplying the organic binder 14 to the layer of the metal particles 10 and binding the metal particles 10 to each other is repeated to form the three-dimensionally-shaped binder 1. Body formation process). The binder 1 becomes a porous body 2 having pores 17 by being dried (a porous body producing step), the porous body 2 is infiltrated with copper or copper alloy containing Ti, and the porous body 2 is subjected to a reducing atmosphere. By heating, the carbon 22 of the binder 14 and the Ti in the copper or copper alloy are reacted.
Accordingly, the core portion 18 formed by the plurality of metal particles 10 in contact with each other, and the base made of copper or copper alloy containing Ti filled between the plurality of metal particles 10 and covering the outer periphery of the core portion 18. The part 19 and the interface part 21 in which the TiC phase 20 is formed on at least a part of the interface between the core part 18 and the base part 19 are obtained.

  Then, the carbon 22 remaining on the surface of the metal particles 10 constituting the porous body 2 and Ti are reacted with each other to form a TiC phase 20 at the interface between the metal particles 10 and copper or a copper alloy, thereby performing a simple treatment. Thus, the metal composite body 3 having secured strength can be obtained.

Embodiment 2.
The strength of the metal composite body 3 described in the first embodiment will be described. In order to confirm the strength of the metal composite 3, a metal composite piece having a width of 20 mm, a length of 100 mm and a thickness of 5 mm was prepared in the same manner as in the first embodiment. For comparison, a sample piece infiltrated with copper containing no Ti was prepared.

FIG. 6 is a diagram showing the relationship between the tensile strength ratio of the metal composite piece and the Ti content in the infiltrant material 15. The tensile strength of the sample piece infiltrated with copper containing no Ti is 1 and the infiltration The tensile strength ratio of the metal composite piece when changing the Ti content of the material 15 is shown.
As shown in FIG. 6, it can be seen that when the Ti content exceeds 0.01% by weight, the tensile strength becomes larger than the tensile strength when copper containing no Ti is used. When 0.1% by weight of Ti was contained in the infiltrant 15, the tensile strength ratio became 1.5 times. When the Ti content was further increased, it became about 2.5 times at 0.3% by weight, and no further increase in tensile strength was observed. Further, when it exceeded 0.5% by weight, a gradual decrease was observed. When the Ti content was 2.0% by weight or more, the difference with the case of using copper containing no Ti was not observed.
It is speculated that this is because Ti formed, for example, titanium hydride and remained on the surface of the metal particles 10 to inhibit the formation of the TiC phase 20. Further, when the Ti content is 2.0% by weight or more, the TiC phase is unlikely to be formed in the interface portion 21.

  That is, when the Ti content in the infiltrant 15 is less than 0.01% by weight, the amount of the TiC phase 20 formed in the obtained metal composite piece is insufficient and the Ti content is 2.0% by weight or more. In this case, since the TiC phase 20 to be formed is hard to be formed, the Ti content is preferably 0.01% by weight or more and less than 2.0% by weight. Furthermore, 0.01% by weight or more and 0.5% by weight or less, 0.1% by weight or more and 0.5% by weight or less, and 0.3% by weight or more and 0.5% by weight or less are preferable.

  In this way, by infiltrating the copper or copper alloy containing Ti into the porous body 2, the carbon 22 remaining on the surface of the metal particles 10 constituting the porous body 2 reacts with Ti, and the metal particles 10 By forming the TiC phase 20 at the interface between the copper and the copper or copper alloy, the carbon 22 can be suppressed from remaining, and the strength of the produced metal composite 3 can be significantly improved.

  It should be noted that, in the present invention, the respective embodiments can be freely combined, or the respective embodiments can be appropriately modified or omitted within the scope of the invention.

1 binder, 2 porous body, 3 metal composite, 4 three-dimensional modeling device, 5 modeling chamber wall,
6 table, 7 modeling room, 8 tank, 9 metal particle supply section, 10 metal particle,
11 squeegee, 12 metal particle layer, 13 nozzle, 14 binder, 15 infiltrant,
16 heaters, 17 holes, 18 cores, 19 substrate, 20 TiC phase,
21 interface, 22 carbon.

Claims (6)

A layer of metal particles is formed, an organic binder is supplied to the layer of metal particles to bind the metal particles together, and the layers of the bound metal particles are sequentially laminated to form a binder. A binder forming step for forming
A porous body producing step of producing a porous body having pores by drying the binder,
The porous body is heated to infiltrate copper or copper alloy containing Ti under a reducing atmosphere, carbon of the binder is reacted with Ti in the copper or the copper alloy, and the metal particles and the Forming a TiC phase at the interface with copper or the copper alloy;
A method for producing a metal composite, comprising:   The method for producing a metal composite according to claim 1, wherein the Ti content of the copper or copper alloy containing Ti is 0.01% by weight or more and less than 2.0% by weight.   The method for producing a metal composite according to claim 1 or 2, wherein the reducing atmosphere is a hydrogen atmosphere.   The method for producing a metal composite according to any one of claims 1 to 3, wherein the average particle diameter of the metal particles is 1 µm or more and 50 µm or less.   The method for producing a metal composite according to any one of claims 1 to 4, wherein the metal particles are stainless steel particles. A core portion formed by a plurality of metal particles in contact with each other,
A base portion made of copper or a copper alloy containing Ti filled between the plurality of metal particles while covering the outer periphery of the core portion,
An interface part in which a TiC phase is formed on at least a part of the interface between the core part and the base part,
A metal composite having.

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