JP4643319B2 - COMPOSITE MATERIAL, ITS MANUFACTURING METHOD, AND COMPOSITE MATERIAL MANUFACTURING DEVICE - Google Patents

Description

  The present invention relates to a composite material, a manufacturing method thereof, and a composite material manufacturing apparatus, and particularly capable of bonding at a low temperature, without forming a brittle layer at a bonding interface, and effectively preventing generation of residual stress and oxidation. The present invention relates to a composite material, a manufacturing method thereof, and a composite material manufacturing apparatus.

  Naturally, materials that make up mechanical structures such as power plants, chemical plants, aircraft, and automobiles must have sufficient structural strength that does not break down, and in addition to corrosion resistance and wear resistance corresponding to the usage environment. Various characteristic functions, such as sexiness, are required. As one of the methods for satisfying the characteristic function corresponding to each use environment, a method of combining a plurality of materials having different characteristic functions is adopted. Conventionally, many studies have been made on a joining structure in which a plurality of materials are combined and a manufacturing technique for realizing the joining structure.

  As an example of a method of manufacturing a composite material by combining the above-mentioned plurality of materials, compounding by joining different materials has been tried in various fields. For example, taking a chemical plant as an example, in addition to the basic strength as a structure, corrosion resistance and durability against corrosive liquids and gases are required. It is known that an active metal such as Ti or Zr is effective as a material for improving the corrosion resistance. All of these metals are called active metals because of their high reactivity, and are components that exhibit excellent corrosion resistance by forming a chemically stable passive film on the surface of these metal materials. Here, as one method for realizing a material that satisfies both the structural strength and the corrosion resistance at the same time, a skeleton is made of a mechanical structural material represented by a superalloy such as a steel material, a Ni-based alloy, or a Co-based alloy, In general, a method of joining and integrating a coating material containing an active metal such as Ti or Zr on the surface of a mechanical structural material in contact with a corrosive liquid or gas is widely used.

However, when the active metal is joined and integrated with the mechanical structural material, the following disadvantageous events are likely to occur if a general fusion welding method for once melting the constituent materials such as arc welding is employed.
(1) An intermetallic compound having high brittleness is generated at the joint interface between the mechanical structural material and the active metal material, the joint strength is weakened, and the structural strength and toughness value of the composite material are easily lowered.
(2) Since a great amount of thermal stress is generated due to the difference in thermal expansion between the mechanical structural material and the active metal material, cracking due to residual stress, peeling and deformation at the joint interface are likely to occur, and the fatigue strength and durability of the composite material are increased. It becomes easy to deteriorate. The number of man-hours and equipment costs in the post-treatment process increase, such as the need for an annealing operation to remove the residual stress generated in the joint.
(3) In a high temperature environment due to heat of fusion, the active metal tends to generate oxides by reaction with oxygen, resulting in poor bonding and material properties.

  In addition, as a result of the disadvantageous events as described above occurring in combination, cracks and significant oxidation of the active metal occur at the material interface during bonding, and the required corrosion resistance cannot be maintained.

  As joining methods of different materials that solve the above problems, solid phase joining methods such as a friction joining method and a diffusion joining method that do not form a melt phase have been developed. Here, the friction welding method is a method in which two members are brought into contact with each other and pressed to generate frictional heat by relative movement of the contact surface, and the members are integrated by pressure welding at a high temperature.

  The diffusion bonding method is a method in which the temperature and pressure are increased in the solid phase region, and the material is bonded by atomic diffusion. In this method, the components are diffused and penetrated to join the two metal members together.

  In these solid-phase joining methods, it is possible to suppress a rise in the temperature of the active metal to a low level because no high-temperature molten phase is formed, and the occurrence of adverse events (1) to (3) described above can be prevented. Can be reduced. However, while the former friction welding method has a drawback that it can only be applied to small parts, the latter diffusion bonding method has a problem that the diffusion time of atoms is long and it takes a lot of time for the bonding process, so it is widely applied. The current situation is that it has not been achieved.

  On the other hand, in recent years, a friction stir welding method has been developed as a kind of solid phase bonding method and has begun to be widely put into practical use. In the friction stir welding method, a soft material such as an aluminum alloy material is abutted and constrained on a backing made of a hard material, and press-fitting is performed while rotating the press-fit pin of a friction welding tool harder than the soft material into the abutting part. -It is a method of moving and softly joining soft materials together.

  This friction stir welding method is a bonding method under a low temperature condition in which a melt phase is not formed, and at the same time, has an advantage that the bonding operation is quicker and the bonding efficiency is higher than the conventional solid phase bonding method. Furthermore, since local construction is possible and a heat treatment process is unnecessary, it can be applied to large parts and structures.

Examples in which such a friction stir welding method is applied to a soft material having a low melting point mainly composed of Al, Cu, or the like are disclosed in the following Patent Documents 1, 2, and 3. An example applied to a hard material with a relatively high melting point such as a steel material is described in Patent Document 4 below. Furthermore, the following patent documents 5 and 6 describe an example applied to the joining of dissimilar metals combining a steel material and an Al alloy or Ti alloy. Moreover, the example applied to joining of active metals, such as Mg and Ti, is described in the following patent document 7.
JP 2000-170280 A JP 2001-259863 A JP 2003-94177 A JP 2002-273579 A JP 2003-170280 A JP 2003-305586 A JP 2000-301363 A

  However, in the joining method shown in Japanese Patent Application Laid-Open No. 2003-170280 (Patent Document 5) for dissimilar metal joining in which a steel material and an Al alloy or Ti alloy are combined, a joining tool is inserted into the material having a lower melting point. It is characterized by friction stir. In this case, in the combination of carbon steel and Ti alloy, a tool is inserted into the carbon steel side having a low melting point. In general, while carbon steel is required to have strength, Ti alloy is often required to have corrosion resistance, and carbon steel as a high-strength member is thick and Ti alloy as a corrosion-resistant member is thin. There are many cases. However, if the thickness of the material on the low melting point side where the welding tool is inserted becomes large, the joining operation becomes difficult, and there are limits to the material system and structure to which this joining method can be applied, and the use of the joining material is limited. There was a difficulty in reducing the degree of freedom.

  Further, in the joining method described in Japanese Patent Application Laid-Open No. 2003-305586 (Patent Document 6) for joining dissimilar metals such as a combination of a steel material and Al or Ti alloy, a brazing material is inserted into the dissimilar metal interface. In addition, the friction stir welding is performed at the same time as brazing with the frictional heat generated at that time, and the brazing portion supplements the joint strength of the friction stir welding. In this case, it is necessary to strictly control the amount of generated frictional heat so that the temperature of the brazing material becomes optimum. Furthermore, softening of the material into which a tool for joining by frictional heat is inserted is also an important factor in friction stir welding. However, since the frictional heat is limited by the brazing temperature, the material into which the joining tool is inserted may not be softened. As a result, there is a problem that the applicable material system and structure are restricted from the life of the joining tool. It was.

  On the other hand, the joining method described in Japanese Patent Application Laid-Open No. 2000-301363 (Patent Document 7) for joining active metals such as Mg and Ti butt-joins active metals. It is not a composite material in which an active metal is formed on the surface of a metal or ceramic substrate, but does not belong to a structure or material system that adds a function such as corrosion resistance to a strength member, and is used as a component of a structure with excellent corrosion resistance There was a problem that could not be done.

  The present invention has been made to solve the above-described conventional problems, and can be bonded at a low temperature, and a brittle layer is not formed at the bonding interface, effectively preventing the occurrence of residual stress and oxidation. An object of the present invention is to provide a composite material, a method for manufacturing the composite material, and a composite material manufacturing apparatus.

Composite material according to the present invention in order to achieve the above object, on the substrate surface made of a metal or ceramics, the composite material obtained by bonding a cladding material consisting of active metal or active metal alloy, wherein the active metal is Zr In addition, the base material and the bonding material are integrally friction-bonded at a portion of the friction stir layer formed by generating frictional heat in the bonding material to soften the bonding material and stirring.

  As the base material used in the composite material according to the present invention, a metal material responsible for the basic structural strength of the composite material and ceramics responsible for corrosion resistance, heat resistance, and the like are used. Further, a metal material made of an active metal or an active metal alloy is used as the bonding material.

  Here, the active metal is a metal rich in reactivity, and a friction stir layer can be formed at a low temperature even with a small amount of frictional heat, so that the base material and the laminated material can be easily joined. As specific examples of the active metal, Zr, Mg, Ti, etc., which can easily form a compound at a relatively low temperature, can be suitably used. As the above-mentioned laminated material, an active metal simple substance, an alloy material containing a plurality of active metals, or an alloy material of one or more active metals and other metal elements can be used.

  In the present invention, the basic structural strength is borne by the metal material as the base material, while the structural strength is borne by the metal material as the laminated material as well as the structure in which the laminated material is borne by the wear resistance and corrosion resistance. On the other hand, it is good also as a structure which makes a ceramic base material bear abrasion resistance and corrosion resistance.

  According to the composite material, since the component member does not need to be melted at the time of manufacture, an increase in temperature at the time of joining is suppressed, and diffusion of constituent elements of the joining target material can be effectively reduced. As a result, formation of a brittle intermetallic compound at the bonding interface is suppressed, bonding having high bonding strength is possible, and a composite material having excellent durability can be provided. Further, since the constituent members are not melted, the temperature rise at the time of joining is suppressed, and the residual stress due to the difference in the linear expansion coefficients of the constituent materials can be effectively reduced. As a result, cracking due to residual stress, separation and deformation of the member at the bonding interface are suppressed, high-reliability bonding without deformation becomes possible, and a highly reliable composite material can be provided.

  In the composite material, it is preferable that the friction stir layer is formed in a spot shape on the laminated material, and the base material and the laminated material are friction-bonded by point bonding. In the case where a predetermined bonding strength can be obtained only by point bonding, a composite material can be rapidly produced only by this point bonding structure.

  Furthermore, in the composite material, it is preferable that the friction stir layer is linearly formed on the laminated material, and the base material and the laminated material are friction bonded by wire bonding. If a predetermined bonding strength can be obtained only by this wire bonding, a composite material can be quickly produced only by this wire bonding structure.

  In the composite material, it is preferable that the friction stir layer is formed in a planar shape on the laminated material, and the base material and the laminated material are friction bonded by surface bonding. According to this surface bonding structure, the length of the bonding target portion is increased as compared with the point bonding structure and the line bonding structure, but the bonding strength of the composite material can be further increased.

  Furthermore, in the composite material, it is preferable that the thickness of the bonding material to be joined is in the range of 0.1 mm to 10 mm. When the thickness of the laminated material is less than 0.1 mm, the reaction activity of the active metal is insufficient, and a sufficient corrosion-resistant layer and friction stir layer are not formed, resulting in a decrease in bonding strength of the constituent members. On the other hand, even if the thickness of the laminated material is set excessively so as to exceed 10 mm, the effect of improving the bonding strength is saturated, and the volume ratio of the friction stir layer occupying the volume of the bonded portion as described later is relatively It may decrease and the joint strength may decrease instead. Therefore, the thickness of the laminated material is set in the range of 0.1 mm to 10 mm, and more preferably in the range of 1 mm to 8 mm.

  Moreover, in the composite material, it is preferable that the volume ratio of the friction stir layer to the volume of the joint portion of the laminated material is 20% or more. When the volume ratio of the friction stir layer is less than 20%, a sufficient friction stir layer is not formed and the bonding strength of the constituent members is lowered.

Here, the volume ratio Vx of the friction stir layer is obtained by integrating the product of each width and thickness (height) of the friction stir zone 3 of the laminated material 2 over the entire width as shown by the oblique lines in the schematic diagram of FIG. If the volume obtained in this way is Va and the volume of the joint, which is the product of the surface area of the friction stir zone 3 and the thickness of the laminated material, is Vb, the following equation (1) is given. The volume Va of the friction stir zone 3 may be calculated as a rotating body volume having a cross-sectional shape of the friction stir zone 3 by a cross-sectional structure photograph obtained by cutting along a cut surface passing through the center of the joint.
[Equation 1]
Vx (%) = Va / Vb × 100 (1)

  Further, in the composite material, the active metals are Ti, Zr, Hf that are Group 4A elements, Sc, Y that are Group 3A elements, lanthanoid rare earth elements having element numbers 57 to 71, and Group 5A elements. It is preferably at least one selected from the group consisting of V, Nb and Ta. The active metal element is a highly reactive metal, and a friction stir layer can be formed at a low temperature even with a small amount of frictional heat, thus speeding up the joining operation between the base material and the laminated material.

In the method for producing a composite material according to the present invention, a laminated material made of Zr which is an active metal or a Zr alloy thereof is superposed on the surface of a base material made of metal or ceramics, and a pressure bar is pressed against the surface of the laminated material. By rotating and generating frictional heat, the laminated material is softened and stirred to form a friction stirring layer, and the base material and the bonding material are integrally friction-bonded at the site where the friction stirring layer is formed. Features.

In the method for producing a composite material, it is preferable to adjust the oxygen partial pressure of the atmosphere on the surface of the laminated material heated by the frictional heat to 10 ⁴ Pa or less (about 0.1 atm or less). The partial pressure of oxygen in the atmosphere of cladding material surface by adjusting below 10 4 ^Pa, it is possible to prevent the deterioration due to oxidation of the components effectively. The specific oxygen concentration is 5% by volume or less, more preferably 1% by volume or less.

An apparatus for producing a composite material according to the present invention includes a moving mechanism for moving a laminated body in which a base material as a material to be joined and a laminated material made of Zr which is an active metal or its Zr alloy are laminated, and lamination from the surface of the laminated material. A pressure bar that pressurizes the body and is rotated by a motor; a travel mechanism that causes the pressure bar to travel along the surface of the laminate; and a blocking mechanism that blocks an atmosphere of the pressurization portion of the laminate by the pressure bar; And an oxygen reduction mechanism for reducing the oxygen partial pressure in the atmosphere of the pressurizing unit, and a control mechanism for controlling the operation of each mechanism, and the atmosphere of the pressurizing unit of the laminate by the pressurizing rod interruption mechanism for interrupting, wherein the gas curtain der Rukoto locally shielding atmosphere around pressing.

  In the manufacturing apparatus, a pressing force is applied to the pressure bar by the load cell, and at the same time, a rotational force is applied to the pressure bar by the motor, and the pressure is applied from the surface of the laminated material in which the base material and the laminated material are stacked. Is done. The laminated material pressed by the pressure bar generates frictional heat at the contact portion, and is stirred while the portion is softened to form a friction stir layer. The laminated material is integrally friction bonded.

  When providing multiple point joints, forming line joints, or forming surface joints, drive the travel mechanism to drive the pressure rod along the surface of the laminate or drive the moving mechanism. The relative position between the laminate and the pressure rod is adjusted by moving the laminate at least.

  According to the composite material manufacturing apparatus, since melting of the constituent members is not required at the time of manufacturing, the temperature rise at the time of joining is suppressed, and the diffusion of constituent elements of the joining target material can be effectively reduced. As a result, formation of a brittle intermetallic compound at the bonding interface is suppressed, bonding having high bonding strength is possible, and a composite material having excellent durability can be provided.

  In addition, there is no need for a heating furnace to soften the joining member, and if there is a place where a pressure rod can be installed, it can be easily used for joining operations. Operation becomes possible. Furthermore, by changing the size (diameter) of the pressure rod or relatively moving the object to be joined, it is possible to cope with all joining forms from point joining to line joining and further to surface joining.

  In addition, since it includes a shut-off mechanism that shuts off the atmosphere of the pressurizing part of the laminate by the pressurizing rod and an oxygen reduction mechanism that reduces the oxygen partial pressure in the atmosphere of the pressurizing part, Degradation due to oxidation can be effectively prevented.

Furthermore, in the composite material manufacturing apparatus, the main components of the pressure rod for pressing the laminated body from the surface of the laminated material are hard refractory metals W, Mo, Nb, Ta and hard refractory carbide ceramics. SiC, B ₄ C and diamond, Si ₃ N ₄ and c-BN (cubic boron nitride) which are hard high melting point nitride ceramics, and Al ₂ O ₃ which is hard high melting point oxide ceramics , Preferably at least one selected from the group consisting of SiO ₂ .

  The hard refractory metal and the hard refractory ceramic are both high in hardness and excellent in heat resistance. When these materials are used as the main component of the pressure rod, pressure is applied without causing deformation of the joint. The rod can be used in a stable state for a long time.

  In the composite material manufacturing apparatus, it is preferable that the pressure bar has a round bar shape. By forming the pressure bar in a round bar shape, the rotational force is transmitted smoothly compared to a pressure bar having a non-circular cross section such as a square bar shape. Moreover, the movement mechanism of moving a laminated body and the movement operation | movement of the pressurization rod for pressurizing a laminated body from the surface of a laminated material can be implemented smoothly.

  Further, in the composite material manufacturing apparatus, the tip of the pressure bar that is in the shape of the round bar is formed in a curved surface shape, or is formed so as to have a protrusion having a diameter smaller than the diameter of the round bar. preferable. By forming the tip of the pressure rod into a curved surface, the pressure (surface pressure) at the axial center of the pressure rod can be increased, and the friction stirring operation can be performed from the center of the joint to the periphery. You can proceed sequentially. Further, the friction stir force can be increased by providing a protrusion having a diameter smaller than the diameter of the round bar at the tip of the pressure bar.

  In the composite material manufacturing apparatus, it is preferable that the shut-off mechanism for shutting off the atmosphere of the pressurizing portion of the laminate by the pressurizing rod is a gas curtain that locally shields the atmosphere around the pressurizing portion. By the non-oxidizing gas ejection effect by the gas curtain, the atmosphere around the pressurizing part can be shielded locally, and the deterioration of the joint part by the oxidizing gas (oxygen) in the atmospheric gas (air) is effective. Can be prevented.

  Furthermore, when the composite material manufactured by the composite material manufacturing apparatus is used as a constituent material of a radioactive waste container for containing radioactive waste, a radioactive waste container excellent in structural strength, corrosion resistance and durability is used. Can be provided.

  According to the composite material, the manufacturing method thereof, and the composite material manufacturing apparatus according to the present invention, it is not necessary to melt the constituent members at the time of manufacturing the composite material. Can be effectively reduced. As a result, formation of a brittle intermetallic compound at the bonding interface is suppressed, bonding having high bonding strength is possible, and a composite material having excellent durability can be provided. Further, since the constituent members are not melted, the temperature rise at the time of joining is suppressed, and the residual stress due to the difference in the linear expansion coefficients of the constituent materials can be effectively reduced. As a result, cracking due to residual stress, separation and deformation of the member at the bonding interface are suppressed, high-reliability bonding without deformation becomes possible, and a highly reliable composite material can be provided.

  Next, embodiments of a composite material, a manufacturing method thereof, and a composite material manufacturing apparatus according to the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a configuration of an apparatus for producing a composite material according to the present embodiment. That is, the composite material manufacturing apparatus according to the present embodiment includes a moving mechanism 11 that moves a laminated body 20 in which a base material (carbon steel) 1 and a bonding material (Zr alloy) 2 as bonded materials are stacked, and a bonding material. under pressure laminate 20 from the second surface, and a W-made pushing rods 5 which is rotated by a motor 9, a driving mechanism 15 for running along the upper Symbol pressure rod 5 to the laminate surface, the pushing rod 5 The shut-off mechanism 12 that shuts off the atmosphere of the pressurizing part of the laminate 20 by the above, the oxygen reducing mechanism 13 that reduces the oxygen partial pressure in the atmosphere of the pressurizing part, and the control mechanism for controlling the operation of each of the mechanisms 14. The oxygen reduction mechanism 13 includes, for example, a vacuum pump that discharges an oxidizing atmosphere from an airtight container that constitutes the atmosphere blocking mechanism 12 or a gas supply device that supplies a nonoxidizing gas such as an inert gas to the airtight container. . The carbon steel base material 1 and the Zr alloy 2 as the materials to be joined are placed in an airtight container (cover) that blocks oxygen. The pressure applied to the pressure bar 5 is detected by the load cell 10.

  When the manufacturing apparatus is operated, as shown in FIGS. 1 and 2, the load cell 10 is driven based on the control signal from the control mechanism 14 to apply the pressure 6 to the pressure bar 5, and at the same time, the motor 9. As a result, a rotational force in the direction of arrow 7 is applied to the pressure bar 5 and pressed from the Zr alloy (lamination material) 2 side surface of the laminate 20 in which the carbon steel base material 1 and the Zr alloy as the lamination material 2 are overlapped. . The Zr alloy 2 pressed by the pressure bar 5 generates frictional heat at the contact portion, and is agitated while being softened. As a result, the friction stirrer layer 3 is formed in the press stirrer as shown in FIG. Then, the carbon steel substrate 1 and the Zr alloy as the laminated material 2 are integrally friction-bonded at the portion where the friction stir layer 3 is formed to prepare a composite material. And in order to manufacture the composite material of point joining, as shown in FIG. 2, the pressurizing rod 5 is pressed and rotated at a predetermined position, and the friction stir processing is performed, so that the joining structure as shown in FIG. Can be produced.

  1 is driven to move the laminated body in the direction of arrow 8 (FIG. 2), or the traveling mechanism 15 is driven to press and rotate the pressure bar 5 to rotate the surface of the laminated body. , The friction stir layer 3 can be formed in a linear shape or a planar shape.

  The following embodiments will be described with respect to a bonding form in which the shape of the friction stir layer is specifically changed.

[Example 1]
FIG. 3 is a cross-sectional view showing the structure of a composite material in which a Zr alloy containing Zr as an active metal is friction bonded to the surface of the carbon steel substrate 1. More specifically, an active metal Zr alloy 2 is friction bonded to the carbon steel base material 1 via a friction stir zone 3 by point bonding. FIG. 4 is a plan view of the composite material shown in FIG. 3 viewed from the Zr alloy 2 side. As shown in FIG. 4, the Zr alloy 2 has a plurality of friction stir zones 3 on the arc, and the carbon steel base material 1 and the Zr alloy 2 are spot-bonded at this portion. Yes.

[Example 2]
Next, FIG. 5 is a plan view showing the friction bonding structure of the composite material according to the second embodiment. Specifically, in Example 2, the Zr alloy 2 containing Zr as the active metal on the carbon steel substrate 1 is integrated with the carbon steel and the Zr alloy through the friction stir zone 3 by wire bonding. Make up composite material. In this line joining, the moving mechanism 11 shown in FIG. 1 is driven to move the laminate in the direction of arrow 4 (FIG. 5), or the traveling mechanism 15 is driven to press and rotate the pressure rod 5. The point joint of Example 1 is linearly continued by running in the direction of arrow 4 (FIG. 5) along the surface of the laminate, and the Zr alloy 2 has a plurality of linear frictions. Stirring regions 3 and 3 exist, and the carbon steel base material and the Zr alloy 2 are wire-bonded through these region portions.

[Example 3]
FIG. 6 is a plan view showing a composite material friction bonding structure according to the third embodiment. This composite material was manufactured by the following procedure. That is, as shown in FIG. 2, after a Zr alloy 2 is laminated on a carbon steel base material 1 to form a laminate, a round bar-shaped W pressure rod 5 with a circular arc at the tip is formed on the Zr alloy 2 surface of the laminate. Press and simultaneously rotate in the direction of arrow 7 while applying pressure 6. The moving mechanism 11 shown in FIG. 1 is driven to move the laminated body in the direction of arrow 4 (FIG. 6), or the traveling mechanism 15 is driven to press and rotate the pressure bar 5 to rotate the surface of the laminated body. The point joining in Example 1 is continued in a planar shape by running in the direction of the arrow 4 (FIG. 6) along the line. A planar friction stir zone 3 is formed in the Zr alloy 2. In this surface joining, the point joining in Example 1 was continued, and then this line joining was further continued. A friction stir zone 3 was formed over the entire surface of the Zr alloy 2. Thus, the carbon steel substrate and the Zr alloy 2 are surface-bonded.

[Example 4]
In the manufacturing method of the composite material of Example 1 in which the carbon steel base material 1 and the Zr alloy 2 as a laminated material are integrally joined by spot joining, the pressure applied to the pressure rod, the rotation speed of the pressure rod, and the friction A number of composite materials according to Example 4 were prepared by varying the agitation time and varying the volume ratio of the friction agitation region at the joint.

  About the composite material which concerns on each Example 4, the cross-sectional structure | tissue of the composite material was observed in the cut surface which passes along the center of each junction part, and the volume ratio which occupies for the junction part was measured from the cross-sectional shape of the friction stirring area | region (layer). . Specifically, as shown in the graph of FIG. 7, the volume ratio Vx of the friction stir zone 3 is the product of each width and thickness (height) of the friction stir zone 3 of the Zr alloy over the entire width. Assuming that the volume obtained by integration is Va, and the volume of the joint, which is the product of the surface area of the friction stir zone 3 and the thickness of the laminated material, is Vb, the above equation (1) {Vx (%) = Va / Vb × 100}.

  Moreover, the joint strength of the joint portion of each composite material according to Example 4 was measured. This bonding strength was calculated as a ratio to the tensile strength of the Zr alloy. FIG. 7 shows the relationship between the volume ratio Vx of the friction stir zone and the bonding strength (relative value). As is clear from the graph shown in FIG. 7, qualitatively, the bonding strength between the carbon steel substrate 1 and the Zr alloy 2 is increased by increasing the volume ratio Vx of the friction stir zone 3 formed in the Zr alloy 2. It turned out to increase. Specifically, when the volume ratio Vx of the friction stir zone 3 increases to about 20%, the joining of the Zr alloy 2 to the carbon steel substrate 1 starts, and when the volume ratio Vx exceeds 50%, the Zr alloy 2 is almost It was confirmed that the joint strength was comparable to the tensile strength.

  FIG. 3 is a cross-sectional view showing the structure of the joint portion of the composite material according to Example 4 in the same manner as in Example 1. After the Zr alloy 2 was stacked on the carbon steel base material 1, The cross-sectional structure is shown after the surface is moved while rotating at high speed while pressing a round bar-shaped pressure bar whose tip is an arc. As is apparent from FIG. 3, a friction stir zone 3 is formed in the Zr alloy 2, and it can be confirmed that the carbon steel substrate 1 and the Zr alloy 2 are well bonded through this zone. .

Also, a method for producing a composite material based on friction stir welding according to the present embodiment, in which a Zr alloy is friction bonded on a carbon steel substrate via a friction stir zone, a conventional laser welding method, a TIG welding method, The composite material manufacturing method based on the HIP (high temperature isotropic pressure) bonding method has advantages from the viewpoint of temperature rise of the composite material, deformation, bonding speed, part size constraints, and compatibility with small parts The results of comparing and evaluating the disadvantages are shown in Table 1 below.

  As summarized in Table 1 above, by using the composite material manufacturing apparatus (joining system) according to this example, the friction joining structure and the friction joining method as shown in FIGS. 7 and 3 can be easily realized. The Zr alloy 2 can be firmly integrated on the carbon steel substrate 1. In particular, as a feature of the method of the present embodiment, the temperature rise at the time of joining is small, the amount of deformation is small, the joining construction speed is relatively fast, and the construction method is highly efficient. Moreover, since a heating furnace for heating and softening the bonding material is not required, application to a large object is easy. Furthermore, there is an advantage that it can be applied to a small object by appropriately changing the size (outer diameter) of the pressure rod to a small size. That is, when compared with the conventional laser welding method, TIG welding method, and HIP (high temperature isotropic pressurization) bonding method, the present embodiment method and apparatus is a friction bonding method of an active metal-containing material on a substrate. As a device, it is excellent overall.

As described above, according to the composite material, the manufacturing method, and the manufacturing apparatus according to the present embodiment, the following effects can be obtained.
(1) Since there is no melting of the bonding material at the time of bonding, the temperature rise at the time of bonding is suppressed, and the diffusion of constituent elements of the carbon steel base material 1 and the Zr alloy 2 as the object can be reduced. As a result, formation of a brittle intermetallic compound such as an Fe—Zr system at the bonding interface is effectively suppressed, and a composite material having high bonding strength can be obtained.
(2) Since it is not necessary to melt the bonding material, the temperature rise during bonding is suppressed, and the residual stress due to the difference in the coefficient of linear expansion of the constituent materials can be reduced. As a result, cracking due to residual stress, separation and deformation at the bonding interface are suppressed, and highly reliable bonding is possible.
(3) By containing the bonding material in a closed container such as an oxygen barrier cover and bonding in a state where the oxygen partial pressure is low, oxidation of Zr or the like which is a highly reactive active metal can be effectively suppressed, A highly reliable bonding with less oxidation of Zr or the like becomes possible.
(4) A manufacturing furnace can be reduced in size without requiring a heating furnace or the like for heating and softening the bonding material. In particular, since a joining system can be constructed if there is a space in which the pressure rod 5 can be installed, it is possible to join carbon steel and a Zr alloy in a wide range of applications from large structures to small parts.
(5) By changing the size of the pressure rod 5 as appropriate, or by moving the object (laminated body) relative to the pressure rod 5, from point joining to line joining, and further to surface joining. It is possible to correspond to any bonding form. In addition, by increasing the diameter of the pressure rod 5, increasing the moving speed of the object, and simultaneously joining with a plurality of pressure rods, the construction method is devised so that even a large joint area can be efficiently obtained in a short time. Industrially superior effects such as being able to be joined can be exhibited.

In each of the above embodiments, a composite material using carbon steel as the base material 1 is shown. However, as the base material, carbide ceramics such as SiC, oxide ceramics such as Al ₂ O ₃ , AlN, Si3N4, etc. Even when nitride ceramics are used and bonded materials containing active metals on their surfaces are bonded by friction stir welding, composite materials having high bonding strength and excellent durability have been obtained.

The perspective view which shows the structure of the manufacturing apparatus for manufacturing the composite material which concerns on this invention. Sectional drawing which shows the state which friction-joins Zr alloy on a carbon steel base material when manufacturing the composite material which concerns on this invention. Sectional drawing which shows the cross-sectional structure | tissue of the composite material produced with the joining method which friction-joins a Zr alloy on a carbon steel base material via a friction stirring area | region. The top view which is one Example of the composite material which concerns on this invention, and shows the friction joining structure which formed the several friction stirring area | region and joined the Zr alloy on the carbon steel base material by point joining. The top view which shows the friction joining structure which is another Example of the composite material which concerns on this invention, and formed the some strip | belt-shaped friction stirring area | region, and joined Zr alloy integrally on the carbon steel base material by wire joining. The top view which shows the friction joining structure which is another Example of the composite material which concerns on this invention, formed the planar friction stirring area | region, and joined Zr alloy integrally on the carbon steel base material by surface joining. The graph which shows the relationship between the volume ratio of the friction stirring area | region and joining strength in the junction part of the composite material which frictionally joined the Zr alloy on the carbon steel base material through the friction stirring area | region formed in Zr alloy.

Explanation of symbols

1 Base material (Carbon steel base material)
2 Laminate (Zr alloy)
3 Friction stir zone (friction stir layer)
4 Moving direction of pressure bar 5 Pressure bar (W pressure bar)
6 Pressurizing force 7 Rotating direction 8 Moving direction 9 Motor 10 Load cell 11 Bonding material moving mechanism 12 Blocking mechanism (airtight container, oxygen blocking cover)
13 Oxygen reduction mechanism 14 Control mechanism (PC for control)
15 Pressure rod travel mechanism 20 Laminate

Claims (13)

In a composite material in which a laminated material made of an active metal or an active metal alloy is bonded on the surface of a base material made of metal or ceramics,
The active metal is Zr, and the base material and the composite material are integrally friction-bonded at a portion of the friction stir layer formed by generating friction heat in the composite material to soften the composite material and stirring. A composite material characterized by that. 2. The composite material according to claim 1, wherein the friction stir layer is formed in a spot shape on the laminated material, and the base material and the laminated material are friction bonded by point bonding. 2. The composite material according to claim 1, wherein the friction stir layer is linearly formed on the laminated material, and the base material and the laminated material are friction bonded by wire bonding. 2. The composite material according to claim 1, wherein the friction stir layer is formed in a planar shape on a laminated material, and the base material and the laminated material are friction bonded by surface bonding. The composite material according to claim 1, wherein a thickness of the joining material to be joined is in a range of 0.1 mm to 10 mm. The composite material according to claim 1, wherein the volume ratio of the friction stir layer to the volume of the joint portion of the laminated material is 20% or more. A laminated material made of Zr, which is an active metal, or a Zr alloy thereof is superimposed on the surface of a base material made of metal or ceramics, and frictional heat is generated by rotating while pressing a pressure bar on the surface of the laminated material. A method for producing a composite material comprising: softening and stirring a material to form a friction stir layer, and integrally friction-bonding the base material and the laminated material at a portion where the friction stir layer is formed. The method for producing a composite material according to claim 7, wherein the oxygen partial pressure of the atmosphere on the surface of the laminated material heated by the frictional heat is adjusted to 10 ⁴ Pa or less. A moving mechanism for moving a laminate in which a base material as a material to be joined and a laminated material made of Zr which is an active metal or a Zr alloy thereof are stacked;
A pressure bar that pressurizes the laminate from the surface of the laminated material and rotates by a motor;
A traveling mechanism for traveling the pressure rod along the surface of the laminate;
A shut-off mechanism that shuts off the atmosphere of the pressurizing portion of the laminate by the pressurizing rod;
An oxygen reduction mechanism for reducing the oxygen partial pressure in the atmosphere of the pressurizing unit;
A control mechanism for controlling the operation of each mechanism ,
Blocking mechanism for blocking the atmosphere of the pressure of the stack by the pushing rods are, apparatus for producing a composite material characterized in the gas curtain der Rukoto locally shielding atmosphere around pressing. The main components of the pressure rod for pressing the laminate from the surface of the laminated material are W, Mo, Nb, Ta, which are hard refractory metals, and SiC, B ₄ C, diamond, which are hard refractory carbide ceramics. Selected from the group consisting of Si ₃ N ₄ and c-BN (cubic boron nitride) which are hard high melting point nitride ceramics, and Al ₂ O ₃ and SiO ₂ which are hard high melting point oxide ceramics The composite material manufacturing apparatus according to claim 9, wherein the composite material manufacturing apparatus is at least one selected from the group described above.
10. The composite material manufacturing apparatus according to claim 9, wherein the pressure bar has a round bar shape. 12. The composite according to claim 11, wherein a tip of the pressure bar in the shape of a round bar is formed in a curved surface or is provided with a protrusion having a diameter smaller than the diameter of the round bar. Material production equipment. The composite material according to claim 1, wherein the composite material is a radioactive waste container for containing radioactive waste.

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