JP2007083242A - Joining method and joined body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining method which can reduce the waste of material and can reduce a tool cost due to the damage of a tool in cutting; and further to provide a joined body. <P>SOLUTION: In the method for joining a metallic composite material 10 and a soft metal 20, the metallic composite material and the soft metal are joined by a plastic flow caused by carrying out a friction stir operation to the soft metal. In this case, the joining is performed by causing the plastic flow on a boundary surface by carrying out the friction stir operation to the soft metal by inserting the pin of a joining tool into the metal side. By this method, a structure can be easily manufactured without cutting it out from a bulky material. As a result, a large casting mold becomes unnecessary, and the waste of material can be reduced. Further, the tool cost due to the damage of the tool in cutting can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a joining method in which butt joining is performed by friction stirring and a joined body joined by the joining method.

  Metal matrix composite materials (MMC) are used as brake disks and stages. On the other hand, there is a document indicating that aluminum MMCs can be bonded to each other by friction stir welding (FSW) which is solid phase bonding (see, for example, Patent Document 1 and Patent Document 2).

The friction stir welding tool described in Patent Document 1 or the like is a tool for friction stir welding of MMCs, iron alloys, non-ferrous alloys, and superalloys in the same manner as non-ferrous alloys. The tool includes a shaft portion, a shoulder portion and a pin disposed on the shaft portion via the shoulder portion, the pin and the shoulder portion being coated with at least a high wear-resistant material and designed to reduce stress risers. . In addition, the friction stir welding tool shoulder has a collar disposed around the shoulder and a portion of the shaft so as to prevent movement relative to the shaft, and between the shoulder and the shaft and between the collar and the tool. Provide heat flow barrier to manage heat. In this way, a tool for friction stir welding with improved wear resistance is provided.
Special table 2003-532542 gazette Special Table 2003-532543

  Metal matrix composite materials (MMC) are used as brake disks and stages. However, MMC is difficult to melt weld because of significant changes in its composition. Mainly, it could only be joined by brazing, cast-bowl joining, or cut out from a bulk material. It has been shown that aluminum MMCs can be joined by friction stir welding (FSW), which is solid phase joining (Japanese Patent Publication No. 2003-532542, Japanese Patent Publication No. 2003-532543), but the welding tool is damaged. There are serious problems such as mixing of the welding tool material into the bonding site. For this reason, there are no examples yet in practical use.

  Metal matrix composite (MMC) is difficult to join by fusion welding. Solid-phase bonding is possible by non-melting friction stir welding, but the center of the welding tool is inserted and rotated at the bonding interface between metal matrix composites, which requires a special tool and damages the welding tool However, there is a problem that mixing into the joint is observed.

  As described above, the size of precision parts by MMC has been increasing in recent years. As a method to cope with the increase in size, a technique for dividing and joining products is necessary. MMC is a material that is difficult to weld, and application of friction stir welding, which is a non-melting solid phase bonding, is being sought, but there are many problems such as severe tool wear.

  This invention is made in view of such a situation, and it aims at providing the joining method and joined body which can reduce the waste of a material and the tool cost resulting from the damage at the time of cutting. And

  (1) In order to achieve the above object, the joining method according to the present invention is a method of joining a metal matrix composite material and a metal, and the metal matrix composite material is obtained by plastic flow generated by friction stirring of a soft metal. And soft metal.

  Thus, in the joining method of the present invention, when joining a metal matrix composite material (MMC) and a soft metal, a plastic flow is caused at the interface by inserting a pin of a joining tool on the metal side and frictionally stirring the soft metal. Cause the joining. This facilitates the production of the structure and eliminates the need to cut out from the bulk material. As a result, a large mold is not necessary, and material waste can be reduced. Moreover, the tool cost resulting from the damage at the time of cutting can be reduced.

  (2) Moreover, the joining method according to the present invention is a method of joining metal matrix composite materials by interposing a soft metal as an intermediate material between the butt surfaces of the metal matrix composite material, and friction-stirring the soft metal. It is characterized in that the metal matrix composite materials are connected to each other by bonding by plastic flow at the bonding interface portion.

  In this way, metal matrix composites that are difficult to melt weld are joined via soft metals, so it can be applied to products that could not be produced without cutting them out from bulk materials, which increases material costs and manufacturing costs. Can be reduced.

  (3) Moreover, the joining method according to the present invention is characterized in that the metal matrix composite material is an aluminum matrix composite material and the soft metal is aluminum.

  As described above, since aluminum is bonded to the aluminum-based composite material, pretreatment such as removal of the oxide layer is not required, and good bonding can be realized without leaving a bonding interface.

  (4) Moreover, the joined body which concerns on this invention is formed with the metal matrix composite material member formed with the metal base material and the reinforcement material disperse | distributed in the said metal base material, and a soft metal, The said metal matrix composite material And a metal member to be joined to the member, wherein the reinforcing material is diffused to the metal member side by plastic flow at the joint portion of both members.

  Thereby, it can replace with the structure cut out and formed from the bulk material, and can use the joined body of this invention for various structures. As a result, a large mold is not required, waste of materials can be reduced, and tool costs resulting from damage during cutting can be reduced. Also, unlike the joined body joined by welding, the joined body of the present invention is joined by plastic flow, and the reinforcing material is dispersed on the metal member side to improve the joining, so the strength of the joint is necessary. It can be used for various members.

  (5) Further, the joined body according to the present invention is characterized in that the region where the reinforcing material diffuses extends over 100 μm from the joint surface of both members.

  Thus, since the joined body of the present invention is joined by plastic flow and the reinforcing material is dispersed over 100 μm or more on the metal member side, it can be used for a member that requires strength of the joint.

  (6) In the joined body according to the present invention, the metal member is a metal material of the same type as the metal base material of the metal matrix composite material member.

  In this way, a metal member of the same type as the metal base material of the metal matrix composite material member is used to join the metal matrix composite material member and the metal member, so a pretreatment such as removing the oxide layer is required. Therefore, good bonding can be realized without leaving a bonding interface.

  (7) Moreover, the joined body according to the present invention is formed of a metal base material and a plurality of metal matrix composite members formed of a reinforcing material dispersed in the metal base material, and a plurality of the soft metal. A metal member that joins the plurality of metal matrix composite members by being joined to the metal matrix composite material member, and the reinforcing material diffuses to the metal member side by plastic flow at each joint portion. It is characterized by that.

  In this way, metal matrix composite materials that are difficult to melt weld are connected by joining soft metals, so it can be applied to products that could not be produced unless they were cut out from bulk materials until now. Manufacturing costs can be greatly reduced.

  (8) Moreover, the joining method according to the present invention is a joining method in which two members are friction stir welded using a rotary tool having a pin portion, and a metal base material and a reinforcing material dispersed in the metal base material. A butting step of abutting a metal matrix composite material member formed by a soft metal and a metal member formed by a soft metal, aligning the center axis of the pin portion to the metal member side, and the pin from the butting surface of both members A pin insertion step of inserting the pin portion such that the offset to the portion is ± 1 mm or less, and a friction agitation step of rotating the pin portion and performing friction agitation while maintaining the offset It is characterized by that.

  Thus, in the joining method of the present invention, when joining the metal matrix composite material and the soft metal, the pins of the joining tool are inserted on the metal side and friction stir is performed to cause plastic flow at the interface and join. Since most of the pin portions are not inserted into the metal matrix composite member, they can be joined regardless of the direction of rotation of the rotary tool. As a result, the metal matrix composite material members can be joined simultaneously on both sides of the metal member, and the metal matrix composite material members can be connected to each other.

  As described above, a pin of a welding tool is inserted into a soft metal and friction stirs to cause plastic flow at the bonding interface with the metal matrix composite material, thereby enabling bonding. By not inserting or slightly inserting the pins of the joining tool into the metal matrix composite, plastic flow can be caused at the joining interface, so that damage to the joining tool can be suppressed. In the friction stir welding of MMC, a special welding tool such as super steel or PCBN is used. However, according to this method, it is possible to carry out using normal tool steel by adjusting the offset amount of the pin. However, when particles are dispersed to soft metal by offsetting to the metal matrix composite material side, there is a lot of damage to the tool, so it is necessary to use a material with high hardness such as super steel as the joining tool. .

  According to the joining method of the present invention, it is easy to produce a structure, and it is not necessary to cut out and form from a bulk material. As a result, a large mold is not necessary, and material waste can be reduced. Moreover, the tool cost resulting from the damage at the time of cutting can be reduced.

  In addition, according to the joining method of the present invention, since the metal matrix composite material that is difficult to be melt welded is joined through a soft metal, it can be applied to products that could not be produced unless cut from a bulk material until now. Material costs and manufacturing costs can be greatly reduced.

  Further, according to the joined body of the present invention, the joined body of the present invention can be used for various structures in place of the structure cut out and formed from the bulk material. As a result, a large mold is not required, waste of materials can be reduced, and tool costs resulting from damage during cutting can be reduced. Also, unlike the joined body joined by welding, the joined body of the present invention is joined by plastic flow, and the reinforcing material is dispersed on the metal member side to improve the joining, so the strength of the joint is necessary. It can be used for various members.

  Further, according to the joining method of the present invention, when joining the metal matrix composite material and the soft metal, the pins of the joining tool are inserted into the metal side and friction stirring is performed to cause plastic flow at the interface and join. Since most of the pin portions are not inserted into the metal matrix composite member, they can be joined regardless of the direction of rotation of the rotary tool. As a result, the metal matrix composite material members can be joined simultaneously on both sides of the metal member, and the metal matrix composite material members can be connected to each other.

  As described above, since the metal matrix composite material is difficult to be melt-welded, when a structure is produced, the metal matrix composite material is often cut out from a bulk material. For this reason, there are many problems such as requiring a large mold, wasteful material, and damage to the tool at the time of cutting, resulting in increased tool cost. Since this invention enables joining of metal matrix composite materials through an aluminum material, those faults are eliminated. Since it can be performed with general-purpose machine tools, the ripple effect is considered to be large. Further, since the reinforcing material can be dispersed in the stirrer region of the soft metal by the friction stir action, it is also important as a new particle dispersion method that has never existed.

  In the method of the present invention, when joining a metal matrix composite material (MMC) and a soft metal, a pin of a joining tool is inserted on the metal side and friction stirring is performed to cause plastic flow at the interface and join. Because there are few or few pins in the metal matrix composite, there is little damage to the pins. When joining composite materials, a soft metal is interposed between the surfaces of the two butting surfaces, and a pin of a welding tool is inserted into this metal and frictionally stirred, thereby causing plastic flow at the interface and Join the composite material. By offsetting the pin to the metal matrix composite and adjusting the joining speed and rotation speed, it is possible to change the plastic flow state and disperse the reinforcing material in the metal matrix composite into the soft metal by plastic flow. It is.

  Because metal matrix composites (MMC) that are difficult to melt weld can be joined via soft metals, it can be applied to products that could only be produced by cutting out from bulk materials so far, and material costs and manufacturing costs can be greatly reduced. It has great industrial utility value.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, in order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

(Embodiment 1)
FIG. 1 is a perspective view of a joined body 1 in which an aluminum-based MMC member and an aluminum member are joined by friction stir welding. As shown in FIG. 1, the joined body 1 is configured by joining an MMC member 10 (metal-based composite material member) and an aluminum member 20 (metal member) at a joint portion 25. The MMC member 10 has a plate shape and is formed of an aluminum base material and a SiC ceramic reinforcing material dispersed in the base material. The proportion of reinforcing material in the base material is 30 vf%. The MMC member 10 may be made of alumina instead of SiC as a reinforcing material. In that case, for example, the ratio of the reinforcing material in the base material is set to 37 vf%.

  Note that the materials of the base material and the reinforcing material are not particularly limited to those described above. The ratio of the reinforcing material in the base material is preferably 30 vf% to 70 vf%. For example, if the MMC member 10 of 30 vf% to 50 vf% is used, it can be applied to a member that requires easy joining. If the MMC member 10 of 55 vf% to 70 vf% is used, it can be applied to a member having high strength. The aluminum member 20 is formed in a plate shape from aluminum. It is preferable to use a soft metal such as aluminum for the metal member. By performing friction stir welding using a soft metal, bonding is improved by plastic flow. Soft metals include magnesium and copper, and are not particularly limited to aluminum.

  Since it is necessary to plastically flow both the base material and the metal member of the metal matrix composite material member, it is desirable that the base material and the metal member are the same material. When different types of materials are bonded, the bonding interface tends to remain, and in some cases, it is necessary to remove the oxide layer on the surface. The joint surface 30 is an interface formed by joining both members. If plastic flow of the base material occurs at least in the vicinity of the joining surface 30, joining is possible regardless of the material. However, it is considered that the hardness distribution varies depending on the dispersion region of the reinforcing material. Further, the bonding strength depends on the strength of the agitated aluminum part and the change of the agitating region by the tool.

  FIG. 2 is an electron microscope (SEM) photograph of a cross section obtained by cutting the vicinity of the joint portion 25 perpendicularly to the joint surface 30. FIG. 2 shows a state in which the MMC member 10 and the aluminum member 20 are joined using the joining surface 30 as an interface. The particles visible on the aluminum member 20 side are the reinforcing material 31 diffused from the MMC member 10. In the vicinity of the joint portion 25, the reinforcing material 31 is diffused over 100 μm toward the aluminum member 20 due to plastic flow during frictional stirring.

  Next, the manufacturing method of said joined body 1 is demonstrated. The joined body 1 is manufactured by a joining method in which friction stir welding is performed using a rotary tool having a pin portion. FIG. 3 is a cross-sectional view showing a state where the pin portion of the rotary tool is inserted into the member. FIG. 4 is a plan view showing a step of performing frictional stirring by rotating and moving the pin portion. The rotary tool 40 does not need to be made of a high hardness material such as super steel, and may be a normal tool steel capable of friction stirring of aluminum. Since it is sufficient that the base material of the metal matrix composite material and the material of the metal member plastically flow, the shape of the pin portion 42 of the rotary tool 40 can be either straight or threaded. The shape of the pin portion 42 may be a shape in which a depression is formed in the central portion of the straight pin in order to promote plastic flow in the vertical direction.

  First, the side surface of the MMC member 10 and the side surface of the aluminum member 20 are butted together. Next, as shown in FIG. 3A, the center axis of the pin portion 42 is set on the aluminum member 20 side, and the offset D from the butting surface 35 of both members to the pin portion 42 is ± 1 mm or less. The pin part 42 is inserted in the A direction so as to be. The offset refers to the distance from the abutting surface 35 to the outer peripheral surface of the pin portion 42. When the pin portion 42 enters from the abutting surface 35 to the MMC member 10 side, the pin portion 42 is accommodated in the aluminum member 20. When it is, it becomes negative. The offset D is preferably within ± 1 mm.

  In the manufacturing method of the present invention, even when the pin portion 42 of the rotary tool 40 is inserted only on one side of the member (−offset), the plastic flow of the counterpart material is caused by the plastic flow on the one side, thereby enabling the joining. . If the + offset amount is large, the amount of heat generated on the MMC member 10 side increases, and a large defect may occur. For this reason, it is preferable to reduce the + offset amount as much as possible or to set it to −offset. In addition, when the material of the metal member is different from the material of the base material of the metal matrix composite material member, the bonding is better when offset to the metal matrix composite material member side. As shown in FIG. 3B, the pin portion 42 is inserted until the shoulder portion 43 of the rotary tool 40 leaves a gap of 0.5 mm or less on the aluminum member 20 or comes into contact therewith.

  When the pin part 42 is inserted, as shown in FIG. 4, the offset when the pin part 42 is inserted is maintained, and the pin part 42 is moved in the C direction while rotating in the B direction to perform friction stirring. In the vicinity of the friction-stirred joint 25, plastic flow occurs, and both members are joined. The rotation direction is preferably the same direction (B direction) as the C direction on the MMC member 10 side, but it may be the reverse direction.

(Embodiment 2)
In the above embodiment, the joined body 1 is formed by joining the MMC member 10 and the aluminum member 20. However, the joined body 1 may be joined to a plurality of MMC members using the aluminum member as an intermediate material, and the MMC members are connected to each other. Good.

  FIG. 5 is a perspective view of a joined body 51 in which two MMC members are connected using an aluminum member as an intermediate material. As shown in FIG. 5, the two plate-like MMC members 61 and 62 are joined to the aluminum member 70 by a joining surface 81 and a joining surface 82, respectively.

  Next, a method for manufacturing the joined body 51 will be described. The joined body 51 is manufactured by a joining method in which friction stir welding is performed using a rotary tool having a pin portion. FIG. 6 is a cross-sectional view showing a state where the pin portion of the rotary tool is inserted into the member. FIG. 7 is a plan view showing a step of performing frictional stirring by rotating and moving the pin portion.

  First, the side surfaces of the MMC members 61 and 62 and the side surface of the aluminum member 70 are abutted from both sides of the aluminum member 70 with the aluminum member 70 interposed therebetween. Next, the aluminum member 70 is set so that the central axis of the pin part 42 enters, and the offsets D1 and D2 from the butted surfaces 91 and 92 of both members to the pin part 42 are ± 1 mm or less, respectively. 42 is inserted. The offset is preferably within ± 1 mm. The pin portion 42 is inserted until the shoulder portion 43 of the rotary tool 40 leaves a gap of 0.5 mm or less in the aluminum member 70 or comes into contact therewith.

  When the pin portion 42 is inserted, as shown in FIG. 7, the offset when the pin portion 42 is inserted is maintained, and the pin portion 42 is moved in the F direction while rotating in the E direction to perform friction stirring. In the vicinity of the friction-stirred joint 75, plastic flow occurs, and the MMC member and the aluminum member are joined. The rotation direction may be the E direction or the opposite direction. In the manufacturing method of the present invention, even when the pin portion 42 of the rotary tool 40 is inserted only into the aluminum member 70 (-offset), the plastic flow of the counterpart material is caused by the plastic flow on one side thereof, thereby enabling the joining. . For this reason, it can join without depending on the rotation direction of the rotary tool 40. In the conventional dissimilar material joining, since it was necessary to insert the pin portion 42 to the high hardness material side (+ offset), there were cases where the joining could not be performed depending on the rotation direction. However, in the joining method of the present invention, the joining is performed on both sides of the aluminum member 70 that is being agitated without depending on the rotating direction. As a result, the MMC members 61 and 62 can be joined with the aluminum member 70 interposed therebetween.

  In addition, in said embodiment, although the plate-shaped thing is used for a member, application to other shapes is also possible.

  Aluminum (A6063) and aluminum MMC (30% SiC + Al-10Si) plate materials (both 190x20xt5mm) are installed in the machining center in the state where the long direction is put together, and the joining tool ( A shoulder diameter of 20 mm and a pin diameter of 4 mm and a length of 4.5 mm are inserted while being rotated and moved along the joining interface (see FIG. 8). Rotating speed 3000rpm, joining speed 500mm / min, offset 0.1mm on aluminum side (no pin inserted in MMC) confirmed. As a result, it has been clarified that aluminum MMCs can be joined together by interposing aluminum as an intermediate material. Further, even when the offset was 0, 0.1 mm on the MMC side, bonding was confirmed, and at that time, it was confirmed that the reinforcing material in the aluminum MMC was dispersed in the aluminum.

  Moreover, the offset was set in a range of −0.1 mm to +0.1 mm and bonding was performed (+ represents a case where a pin is inserted on the MMC side). In forward rotation (MMC side and tool direction coincide with the welding direction), any offset could be joined, but in reverse rotation (MMC side and tool direction and welding direction are opposite) + offset Occasionally, defects occurred at the bonding interface, and good bonding could not be obtained. When the offset is -0.1 mm, both forward rotation and reverse rotation are (1) rotational speed 3000 rpm, joining speed 500 mm / min, (2) rotational speed 3000 rpm, joining speed 200 mm / min, (3) rotational speed 4000 rpm, joining speed 500 mm / min. Bonding was confirmed under the conditions of FIG. 9 is an electron micrograph showing a cross section near the joint when the joint is confirmed.

  As shown in FIG. 10, in the joining between MMC members, in the experiment in which the aluminum member was sandwiched between the MMC members by a vise and fixed (MMC-Al-MMC), the aluminum member slips between the MMCs during joining. It was necessary to fix the member with a jig.

  For both MMC members, the offset was -1.0 mm or less (1) Rotating speed 3000 rpm, Joining speed 200 mm / min (2) Rotating speed 4000 rpm, Joining speed 500 mm / min. It was done.

It is a perspective view of the joined body concerning the present invention. (Embodiment 1) It is an electron microscope (SEM) photograph of the section which cut the junction part neighborhood. It is sectional drawing which shows the process of inserting a pin part in a member. (Embodiment 1) It is a top view which shows the process of rotating and moving a pin part and performing friction stirring. (Embodiment 1) It is a perspective view of the joined body concerning the present invention. (Embodiment 2) It is sectional drawing which shows the process which has inserted the pin part in the member. (Embodiment 2) It is a top view which shows the process of rotating and moving a pin part and performing friction stirring. (Embodiment 2) 1 is a diagram illustrating Example 1. FIG. 1 is a diagram illustrating Example 1. FIG. FIG. 6 is a diagram showing Example 2.

Explanation of symbols

1, 51 Joint 10, 61, 62 MMC member (metal-based composite material member)
20, 70 Aluminum member (metal member)
25, 75 Joint part 30, 81, 82 Joint surface 31 Reinforcement material 35, 91, 92 Butt face 40 Rotating tool 42 Pin part 43 Shoulder part D, D1, D2 Offset

Claims (8)

  In the method for joining a metal matrix composite material and a metal, a joining method for joining the metal matrix composite material and the soft metal by plastic flow generated by friction stirring of the soft metal.   In a method of connecting metal matrix composite materials, a metal is bonded by plastic flow at the joint interface by interposing a soft metal as an intermediate material between the butt surfaces of the metal matrix composite material and frictionally stirring the soft metal. A method for joining metal matrix composite materials, characterized in that the matrix composite materials are connected to each other.   The joining method according to claim 1, wherein the metal matrix composite material is an aluminum matrix composite material, and the soft metal is aluminum. A metal matrix composite material member formed of a metal matrix and a reinforcing material dispersed in the metal matrix;
A metal member formed of a soft metal and bonded to the metal matrix composite material member,
In the joined portion of both members, the reinforcing material is diffused to the metal member side by plastic flow.   5. The joined body according to claim 4, wherein the region where the reinforcing material diffuses extends over 100 [mu] m from the joint surface of both members.   6. The joined body according to claim 4, wherein the metal member is a metal material of the same type as the metal base material of the metal matrix composite material member. A plurality of metal matrix composite members formed of a metal matrix and a reinforcing material dispersed in the metal matrix;
A metal member that is formed of a soft metal and is joined to the plurality of metal matrix composite members to connect the plurality of metal matrix composite members;
In each joined portion, the reinforcing material is diffused to the metal member side by plastic flow. In a joining method in which two members are friction stir welded using a rotary tool having a pin portion,
A butting step of abutting a metal base material and a metal matrix composite material member formed of a reinforcing material dispersed in the metal base material and a metal member formed of a soft metal;
A pin insertion step of inserting the pin portion so that the center axis of the pin portion is aligned with the metal member side, and the offset from the butting surface of both members to the pin portion is ± 1 mm or less,
And a friction stir step in which the pin portion is rotationally moved to perform friction stir while maintaining the offset.

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