JP2005264277A - Method for producing metal member having void - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a metal member provided with a fine void at the inside without depending on the ductility of the kinds of metal, and in which the cross-sectional shape of the void can be made into the complicated one. <P>SOLUTION: A first compact 1 composed of a first mixture comprising first metal powder and a first binder is formed. The compact 1 is buried into a second mixture comprising second metal powder having a melting point higher than that of the first metal and a second binder to form a second compact 3. Both the first and second binders are removed from the compact 3. The compact 3 is heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal to melt the first metal, and a void 6 is formed on the region which has been occupied by the compact 1. The first metal is Cu, and the second metal is Fe or stainless steel. Both the binders can be removed by being heated at a temperature lower than the melting point of the first metal or being extracted with a solvent at a temperature lower than the melting point of the first metal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a metal member having a void such as a fine hole inside.

  2. Description of the Related Art Some molds used for plastic injection molding, metal casting, and the like include a conduit through which a medium for cooling or heating flows.

  A metal member having a gap such as the pipe line inside thereof, such as the mold, has conventionally been formed by subjecting a metal molded body to a cutting process using a drill, an end mill, or the like, or a metal powder injection molding method. It is manufactured by directly forming a metal member having the gap by (Metal Injection Molding) or precision casting. However, in cutting with a drill, end mill, etc., depending on the shape and size of the tool, and the methods such as the metal powder injection molding method and precision casting method are themselves methods using a mold, There are also restrictions on the shape and size of the voids that can be formed. For this reason, in the conventional method, there is a problem that it is difficult to form a gap having a complicated shape or a minute gap as the conduit.

  On the other hand, a first metal material is disposed on the base metal, and a second metal material having a melting point higher than that of the first metal material is sprayed on the base metal and the first metal material, thereby spraying. After forming the metal layer, the first metal material is melted by heating to a temperature higher than the melting point of the first metal material and lower than the melting point of the second metal material, corresponding to the shape of the first metal There is known a method of manufacturing a composite metal body having a space portion (see, for example, Patent Document 1).

  However, in the above method, the layer of the second metal material formed on the first metal material is formed by thermal spraying. Therefore, it takes a great amount of energy and time to form a layer having a desired thickness. There is a problem that it requires.

  In order to solve the above problem, the present inventors have already filed a patent application for a method for producing a metal member having a minute gap inside. In the manufacturing method, a molded body made of a first metal such as Al is embedded in a powder of a second metal having a melting point higher than that of the first metal such as Ni, Fe, Ti, etc. A powder compact to be included is formed, and the powder compact is heated at a temperature higher than the melting point of the first metal and lower than the melting point of the second metal. In this way, the first metal is melted, the melted first metal moves to the gap between the powders of the second metal, and a void is formed in the region occupied by the compact made of the first metal. On the other hand, the molten first metal powder and second metal powder are sintered and solidified, so that a metal member having a minute void inside can be easily formed (Japanese Patent Application No. 2003-78240). See the description).

  According to such a method, by forming the first metal molded body in a curved shape or a meandering shape that is meandering, a void having a shape corresponding to the first metal molded body is formed inside the metal molded body. Therefore, the gap can be used as a conduit through which the refrigerant or the heat medium flows. When Al is used as the first metal and Ni is used as the second metal, a coating layer made of nickel aluminide, which is an intermetallic compound of Al and Ni, can be formed on the surface of the gap. .

  However, in the above method, since it is necessary to form a molded body from the first metal in advance, the size, particularly the diameter, of the molded body is limited, and it is difficult to form fine voids.

  Therefore, the present inventors further put a wire made of a first metal having a low melting point such as Zn into a formed body made of a second metal such as Al having a melting point higher than that of the first metal. A preform is formed by penetrating along the length direction, and after the preform is stretched along the length direction, the melting point of the second metal is higher than the melting point of the first metal. A patent application has already been filed for a method for producing a metal member that is heated at a lower temperature (see Japanese Patent Application No. 2003-389683).

  According to the manufacturing method, the preform is stretched along the length direction by drawing, rolling, or the like, so that the wire made of the first metal is included and cut in a direction perpendicular to the length. A long member having a reduced area can be formed. Therefore, by heating the elongate member to the temperature, melting the wire rod and dissolving the first metal in the second metal, forming a void in the region occupied by the wire rod, A metal member having fine voids inside can be formed. In the manufacturing method, the metal member is further formed into a complicated shape such as a coil shape by bending or the like, and then cast into a light metal such as Al or Mg, so that the metal member is made of Al, Mg or the like and has a fine inside. It is possible to easily form a cast-shaped article having a gap.

However, in the production method described in the specification of Japanese Patent Application No. 2003-389683, the metal species that can be used are not limited to those having excellent ductility, and the cross-sectional shape of the gap formed is a wire made of the first metal. Since the cross-sectional shape is reduced in a similar manner, it is difficult to form a void having a complicated cross-sectional shape.
JP 11-279742 A JP-A-10-219474

  The present invention eliminates such inconvenience, and can manufacture a metal member having a fine void inside regardless of the ductility of the metal species, and can make the cross-sectional shape of the void into a complicated shape. It aims at providing the manufacturing method of a member.

  In order to achieve this object, the production method of the present invention includes a first mixture comprising a first metal powder and a first binder that can be removed at a temperature lower than the melting point of the first metal. A step of forming the molded body, a second metal powder having a melting point higher than that of the first metal, and a second binder capable of being removed at a temperature lower than the melting point of the first metal. A step of forming a second molded body embedded in the second mixture containing the first molded body and a step of removing both the first and second binders from the second molded body. The second molded body from which both the first and second binders are removed is heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal to melt the first metal. The molten first metal is moved into the gap between the powders of the second metal, and the area occupied by the first molded body While forming the gap, characterized in that it comprises a step of allowed to solidify by sintering the first metal and molten powder of the second metal.

  In the production method of the present invention, first, a first metal powder is mixed with a first binder, and a first molded body is formed from the obtained first mixture. Since the first mixture has appropriate viscosity and fluidity by mixing the first metal powder with the first binder, the first molded body has a fine cross-sectional area and A complicated cross-sectional shape can be provided.

  Next, in the manufacturing method of the present invention, a first molded body is embedded in a second mixture obtained by mixing a second metal powder with a second binder, and the first molding is performed. A second molded body containing the body is formed. At this time, the second mixture has appropriate viscosity and fluidity by mixing the second metal powder with the second binder, and follows the shape of the first molded body. The first molded body can be embedded without impairing its shape.

  In the production method of the present invention, next, both the first and second binders are removed from the second molded body. Then, the second molded body from which both the first and second binders are removed is heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal. In this way, the first metal is melted, and the melted first metal moves to the gap between the powders of the second metal, and a void is formed in the region occupied by the first molded body. . Then, the metal member provided with the said space | gap inside can be obtained by sintering and solidifying the fuse | melted 1st metal and 2nd metal powder.

  Therefore, according to the manufacturing method of the present invention, even when the first and second metals are poor in ductility, it is possible to manufacture a metal member having fine voids inside, and the cross-sectional shape of the voids is complicated. It can be a shape.

  Further, according to the manufacturing method of the present invention, the region formed by the first molded body is formed by an alloy or an intermetallic compound formed by dissolving the molten first metal in the second metal. A peripheral wall of the formed gap can be formed.

  Conventionally, a mixed metal powder that forms an intermetallic compound by reaction is applied to the surface of a metal material and heated to form a coating layer made of the intermetallic compound generated from the mixed metal powder on the surface of the metal material. A method is known (see, for example, Patent Document 2). However, in such a method, it is difficult to form a peripheral wall made of the intermetallic compound on the surface of the void formed inside the metal member.

  In this regard, according to the manufacturing method of the present invention, the first metal is dissolved in the second metal by melting the first molded body disposed in the second molded body. Can do. Therefore, by forming an alloy or intermetallic compound from the first metal and the second metal, the alloy or intermetallic compound is formed on the surface of the void formed in the region occupied by the first molded body. A peripheral wall made of can be easily formed.

  In the production method of the present invention, the first metal can be one or more metals selected from Al and Si, and the second metal can be Ti, V, Cr, Mn, Fe, Co. One or more metals selected from Ni, Cu, Zr, Nb, Mo, Hf, Ta, and W can be used. When the first metal is Al, a transition metal aluminide with the second metal is generated as an intermetallic compound that forms the peripheral wall. Some of the transition metal aluminides are excellent in heat resistance and corrosion resistance, such as NiAl. Further, when the first metal is Si, a transition metal silicide with the second metal is generated as an intermetallic compound that forms the peripheral wall.

  When Zn is used as the first metal, Al can be used as the second metal, and when Cu is used as the first metal, Fe or stainless steel is used as the second metal. Steel can be used.

  In the production method of the present invention, both the first and second binders can be removed by heating to a temperature lower than the melting point of the first metal. As a result, both the first and second binders are removed by heating to a temperature lower than the melting point of the first metal, melting, evaporating, or pyrolyzing.

  At this time, in the production method of the present invention, the second molded body is first heated to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders, and both binders are removed. Next, heating is performed at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal. When the second molded body is heated to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders, the second molded body including the embedded first molded body is also included. Thus, the binder is removed, and the molded body made of the first metal is embedded in the molded body made of the second metal. Therefore, next, the formed body made of the second metal is heated together with the embedded formed body made of the first metal at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal. As a result, the first metal is melted, and a metal member having the voids therein can be obtained.

  In the production method of the present invention, both the first and second binders may be removed by extraction with a solvent at a temperature lower than the melting point of the first metal.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing the manufacturing method of the present embodiment, and FIG. 2 is a sectional view taken along the line II-II in FIG. 3 is a perspective view showing a metal member obtained by the manufacturing method of the present embodiment, and FIG. 4 is a sectional view taken along line IV-IV in FIG.

  In the manufacturing method of the present embodiment, first, a first metal powder is mixed with a first binder to form a first mixture. As the first metal, one or more metals selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Hf, Ta, and W are used as the second metal described later. In this case, one or more metals selected from Al and Si can be used. As the first metal, Zn can be used when the second metal described later is Al, and Cu can be used when the second metal described later is Fe or stainless steel. .

  The first binder can be removed by heating to a temperature lower than the melting point of the first metal or by extraction with a solvent at a temperature lower than the melting point of the first metal. For example, an inorganic binder may be used, and an organic binder such as polyethylene glycol, polyethylene, polypropylene, polystyrene, paraffin, a mixture of beeswax and turpentine oil may be used. A mixture with turpentine oil can be preferably used.

  When the first metal powder is mixed with the first binder, it becomes a first mixture having an appropriate viscosity and fluidity, and the mixture is formed into an arbitrary shape as shown in FIG. 1 can be obtained. The molding can be performed, for example, by extruding the first mixture from the tip of the nozzle, and the first molded body 1 having a cross-sectional shape that matches the shape of the nozzle can be formed.

  Next, the second metal powder is mixed with the second binder to form a second mixture. As the second metal, when the first metal is one or more metals selected from Al and Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, and Nb are used. One or more metals selected from Mo, Hf, Ta, and W can be used. As the second metal, Al can be used when the first metal is Zn, and Fe or stainless steel can be used when the first metal is Cu.

  The second binder can be removed by heating to a temperature lower than the melting point of the first metal or by extraction with a solvent at a temperature lower than the melting point of the first metal. For example, an inorganic binder may be used, and an organic binder such as polyethylene glycol, polyethylene, polypropylene, polystyrene, paraffin, a mixture of beeswax and turpentine oil may be used. A mixture with turpentine oil can be preferably used.

  The second metal powder is mixed with the second binder to form a second mixture having an appropriate viscosity and fluidity. As shown in FIGS. Can be formed in the second mixture 2 without impairing the shape of the molded body 1.

  At this time, since the second molded body 3 has plasticity together with the embedded first molded body 1, it is stretched in the length direction to reduce the cross-sectional area, or further deformed after stretching. Can be easily performed. By doing in this way, while using the 1st molded object as a wire, the elongate member which includes this wire and the cross-sectional area of the direction perpendicular | vertical to length is reduced can be formed easily. . In addition, a plurality of other molded bodies formed in the same manner as the second molded body 3 may be combined into one and then stretched as described above, and a long member having a complicated cross-sectional shape Can be easily formed.

  In the manufacturing method of the present embodiment, the second molded body 3 is then heated to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders. In this way, both binders are removed by melting, evaporation or thermal decomposition, the first molded body 1 becomes a molded body 4 made of only the first metal powder, and the second molded body 3 becomes the second molded body 4. It becomes the molded object 5 which consists only of metal powder of this.

  Therefore, after forming the powder compact by press molding the compact 5 together with the embedded compact 4, the powder compact is lower than the melting point of the second metal and the melting point of the first metal. Heat at a higher temperature. As a result, the first metal is melted, and the melted first metal moves into the gap between the powders of the second metal, and as shown in FIGS. A gap 6 is formed in the occupied area. And the metal member 7 provided with the space | gap 6 inside can be obtained by sintering and solidifying the fuse | melted 1st metal and the powder of the 2nd metal. At this time, the peripheral wall 6a of the gap 6 is formed of an alloy or an intermetallic compound generated by dissolving the first metal in the second metal.

  In the present embodiment, after the second molded body 3 is heated to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders, both the first and second binders are The removed molded body 5 is pressure-molded together with the molded body 4 to form a powder molded body, and the powder molded body is heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal. However, the second molded body 3 may be directly heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal. In this way, the same result can be obtained. .

  In the present embodiment, both the first and second bodies 3 are heated by heating the second molded body 3 to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders. The binder is removed. However, by extracting the second molded body 3 by dissolving it in a solvent at a temperature lower than the melting point of the first metal and removing both the first and second binders, the first and second Both binders may be removed.

  Furthermore, in the present embodiment, the first metal powder and the first binder are mixed to form the first mixture. However, a third metal powder may be further added. Good. If it does in this way, the compounding of the metal in the 1st molded object 1 can be changed in gradient, or it can be set as a locally different mixing | blending.

  For example, when the first metal is Al and the second metal is Ni, Si powder as a third metal powder is further added to the Al powder to form the first mixture. As a result, the peripheral wall 6a of the gap 6 can be made of Ni—Al—Si ternary intermetallic compound.

  Next, examples of the present invention will be described.

  In this example, first, Cu powder having a diameter of 50 μm, beeswax and turpentine oil were mixed at a mass ratio of 65:19:16, and then a part of the turpentine oil was volatilized to obtain viscosity and fluidity. A first mixture comprising was formed. Next, a linear body having a diameter of 700 μm and a length of 10 mm was formed as the first molded body 1 shown in FIGS.

  Next, powder of stainless steel (SUS304) having a diameter of 10 μm or less, beeswax and turpentine oil are mixed at a mass ratio of 65:19:16, and then a part of the turpentine oil is volatilized to obtain viscosity and fluidity. A second mixture comprising was formed. Next, the molded body 1 was embedded in the second mixture 2 to form a second molded body 3.

  Next, the molded body 3 is heated to 573 K at a rate of 0.2 K / second in an argon gas stream, and held at this temperature for 3600 seconds to remove beeswax and turpentine oil. Obtained. Next, the compact 5 was pressure-molded at a pressure of 624 MPa to obtain a powder compact with a diameter of 20 mm and a length of 15 mm.

  Next, the powder compact was heated to 1473 K at a rate of 0.2 K / sec and then cooled to room temperature at a rate of 0.4 K / sec. As a result, as shown in FIGS. 3 and 4, a metal member 7 having a gap 6 in the region occupied by the first molded body 1 was obtained. The gap 6 had an elliptical cross-sectional shape with a major axis of 920 μm and a minor axis of 460 μm, and had a length of 10 mm.

The perspective view which shows an example of the manufacturing method of this invention. II-II sectional view taken on the line of FIG. The perspective view which shows an example of the metal member obtained by the manufacturing method of this invention. IV-IV sectional view taken on the line of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st molded object, 2 ... 2nd mixture, 3 ... 2nd molded object, 6 ... Air gap, 7 ... Metal member.

Claims (7)

Forming a first molded body comprising a first mixture comprising a first metal powder and a first binder that can be removed at a temperature lower than the melting point of the first metal;
The first molded body is embedded in a second mixture containing a second metal powder having a higher melting point than the first metal and a second binder that can be removed at a temperature lower than the melting point of the first metal. A step of forming a second molded body containing the first molded body;
Removing both the first and second binders from the second molded body;
The second molded body from which both the first and second binders have been removed is heated at a temperature lower than the melting point of the second metal and higher than the melting point of the first metal, and the first metal is melted, The molten first metal is moved to the gap between the second metal powders to form voids in the area occupied by the first molded body, while the second metal powder and the molten first metal A method for producing a metal member having voids, comprising the step of sintering and solidifying the material.   The first metal is one or more metals selected from Al and Si, and the second metal is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Hf. 2. The method for producing a metal member having voids according to claim 1, wherein the metal member is at least one metal selected from Ta, W.   2. The method for manufacturing a metal member having voids according to claim 1, wherein the first metal is Zn, and the second metal is Al.   2. The method for manufacturing a metal member having voids according to claim 1, wherein the first metal is Cu, and the second metal is Fe or stainless steel.   5. The void according to any one of claims 1 to 4, wherein both the first and second binders can be removed by heating to a temperature lower than the melting point of the first metal. The manufacturing method of the metal member which has.   After the second molded body is heated to a temperature lower than the melting point of the first metal and capable of removing both the first and second binders to remove both binders, the second molded body is lower than the melting point of the second metal, The method for producing a metal member having voids according to claim 5, wherein heating is performed at a temperature higher than the melting point of the metal of 1.   5. The first and second binders can be removed by extraction with a solvent at a temperature lower than the melting point of the first metal. 6. The manufacturing method of the metal member which has the space | gap of this.

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