JP2007245219A - Joining method of aluminum radical composite material and joined body of aluminum radical composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of firmly joining an Al radical composite material with an Al radical composite material or an Al alloy, and also to provide an Al radical composite material joined body manufactured by this joining method. <P>SOLUTION: The Al radical composite material joined body 10 is obtained by applying a prescribed pressure in the joining direction of a first and a second member 12, 14 and by heating the weld zone of these materials 12, 14 to a diffusion temperature of Mg, wherein the first member 12 is composed of an Al radical composite material while the second member 14 is composed of an Al radical composite material or an Al alloy, and wherein Al or an Al alloy containing 0.2-3 mass% of Mg is interposed between the two members as an intermediate material 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for joining an aluminum matrix composite material and an aluminum matrix composite material or an aluminum alloy, and an aluminum matrix composite material joined body produced by the method.

  Metal Matrix Composites (MMC), which is a composite of metal and ceramics, has excellent properties such as lightness, high rigidity, low thermal expansion, and high thermal conductivity. Application to pistons, cylinder blocks, brake disks, electronic circuit boards, heat sinks, etc. is under consideration.

  MMC is easy to manufacture in a relatively simple shape, but it is not always easy to manufacture a complex shape. Therefore, it is urgently necessary to establish a technology for joining simple-shaped MMC parts to other metal parts and other MMC parts, and a joining method using a metal brazing material, a joining method using an FSW method, and the like have been proposed. (For example, see Patent Documents 1 and 2).

In the joining of aluminum-based composite materials, aluminum forms an oxide film on its surface. Therefore, in the joining method using a metal brazing material, sufficient joining strength cannot be obtained due to the presence of this oxide film, Moreover, since the temperature of the brazing material that can be used is considerably lower than the heat resistance temperature of the aluminum-based composite material, the thermal characteristics of the aluminum-based composite material cannot be exhibited sufficiently. In addition, the joining method by the FSW method has a large composition dependency of the aluminum-based composite material, and is not suitable for a material having a particularly high ceramic content.
JP 2002-263881 A (paragraph [0009] etc.) JP 2002-35965 A (paragraphs [0008], [0009], etc.)

  The present invention has been made in view of such circumstances, and provides a method for firmly joining an aluminum-based composite material and an aluminum-based composite material or an aluminum alloy, and an aluminum-based composite material joined body produced by this joining method. For the purpose.

  According to the present invention, there is provided a method for joining a first member made of an aluminum-based composite material and a second member made of an aluminum-based composite material or an aluminum alloy, between the first member and the second member A predetermined pressure is applied to the first member and the second member by interposing an aluminum or aluminum alloy containing 0.2 to 3% by mass of magnesium as an intermediate material, and the first member and There is provided a joining method of an aluminum-based composite material, wherein the joining portion of the second member is heated to a diffusion temperature of magnesium.

  As the intermediate material, a powder or a plate material is preferably used. In addition, for heating the joint between the first member and the second member, an electric heating method or a high frequency induction heating method is preferably used.

  According to the invention, a joined body produced by this joining method, that is, a first member made of an aluminum-based composite material, and an aluminum-based composite material or an aluminum alloy joined to the first member via an intermediate layer. And the intermediate layer is made of aluminum or aluminum alloy containing 0.2 to 3% by mass of magnesium.

  The present invention has an effect that the aluminum-based composite material can be firmly bonded to the aluminum-based composite material or the aluminum alloy. Moreover, since the aluminum matrix composite material joined body of the present invention can be produced by energization heating, it is possible to obtain the effect that on-site assembly, joining, repair and the like using the joined body are possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic structure of an aluminum matrix composite material joined body (hereinafter referred to as “joined body”).

  The joined body 10 includes a first member 12 made of an aluminum-based composite material (hereinafter referred to as “Al-based composite material”), and a second member made of an Al-based composite material or an Al alloy joined via the intermediate layer 16. 14.

Examples of the Al-based composite material used for the first member 12 include Al—SiC, Al—Al ₂ O ₃ , and Al—AlN, and those having a ceramic content such as SiC of 5% by volume to 80% by volume. Is preferred. The same applies to the case where the second member 14 is an Al-based composite material. When the second member 14 is an Al alloy, all aluminum alloys except for an aluminum alloy containing 3% by mass or more of Mg can be used. One example is an AC4C material (Al-7Si-0.3Mg).

  The intermediate layer 16 is made of Al containing 0.2 to 3% by mass of magnesium (Mg) (that is, Al containing no metal element other than this predetermined amount of Mg and inevitable impurities) or Al alloy (that is, this predetermined amount). In addition to Mg, Al) further contains a certain amount of metal components other than Mg. As the Al alloy containing a predetermined amount of Mg, all aluminum alloys except for an aluminum alloy containing 3% by mass or more of Mg can be used. As an example, a 2024 alloy (Al-4.38Cu-0.63Mn- 1.48 Mg).

  FIG. 2 schematically shows a method for manufacturing the joined body 10. In this joined body 10, Al or an Al alloy containing 0.2 to 3 mass% of Mg is interposed as an intermediate material 18 between the first member 12 and the second member 14, It can be produced by applying a predetermined pressure in the joining direction of the two members 14 and heating the intermediate member 18 and the vicinity thereof, which are the joining portions of the first member 12 and the second member 14, to the Mg diffusion temperature. .

  As the intermediate material 18, a powder or a plate material is preferably used. Since the intermediate material 18 is a material that becomes the intermediate layer 16 shown in FIG. 1 by this pressure heating, when a powder material is used as the intermediate material 18, it has a microstructure in which the powders are combined by pressure and heating. It is necessary. When using a powder as the intermediate member 18, for example, a molded body produced by a method of press molding the powder in advance or a method of molding the powder with a resin is disposed between the first member 12 and the second member 14, The method of pressurizing and heating, or holding the powder in a liquid and spraying it on both surfaces or one surface of the joining surface of the first member 12 and the second member 14, evaporating the liquid to dry, and abutting the joining surfaces , A method of pressurizing and heating, and forming a uniform thickness layer by dropping powder with a sieve etc. on the upper surface of the lower member of the first member 12 and the second member 14, It is possible to use a method of sandwiching, pressurizing, and heating by a member located at the position.

  For heating the joint between the first member 12 and the second member 14, an electric heating method capable of local heating (DC electric heating method, pulse electric heating method) or a high frequency induction heating method is preferably used. In the electric heating method, for example, a direct current or a pulse current is applied to a jig used to apply pressure to the first member 12 and the second member 14. As a result, large Joule heat is generated at the joint surface having a large resistance, and the joint surface is joined. In the high-frequency induction heating method, a coil is wound around a joint portion, and a current having a constant frequency is passed through the joint portion, thereby joining the joint surfaces with Joule heat generated by an eddy current generated in the vicinity of the joint surface. Such local heating can suppress deformation of the first member 12 and the second member 14 due to heat. Moreover, according to such a joining method, assembly, joining, repair, etc. at the installation site of the joined body 10 become possible.

Before the bonding process, the first member 12 and the second member 14 have metal Al as a main component, so that an oxide film (Al ₂ O ₃ film) is naturally formed on the surface. Since this oxide film inhibits bonding, it is necessary to remove this oxide film during bonding in order to increase the bonding strength. When the first member 12 and the second member 14 are joined via the intermediate member 18, “heating to the Mg diffusion temperature” means that the joined portion is heated to a temperature at which the reduction reaction of the oxide film by Mg occurs. More specifically, it means heating to 400 ° C. or higher.

More specifically, the removal reaction of the oxide film with Mg is performed by reacting the Al ₂ O ₃ present on the joint surfaces of the first member 12 and the second member 14 and the intermediate material 18 with Mg contained in the intermediate material 18. In this reaction, MgO and MgAl ₂ O ₃ agglomerate, thereby increasing the number of metallic joints and increasing the joint strength.

  Therefore, when the Mg content of the intermediate material 18 is less than 0.2% by mass, the reduction reaction of the oxide film becomes insufficient, and reliable bonding cannot be performed. Further, if the Mg content of the intermediate material 18 is more than 3% by mass, an MgO oxide film is likely to be formed on the intermediate material 18, so that the reduction reaction of magnesium at the joint surface due to Mg does not occur. As a result, reliable bonding cannot be performed.

  The temperature and pressure when joining the first member 12 and the second member 14 via the intermediate member 18 are appropriately set within a range in which the mechanical characteristics of the first member 12 and the second member 14 do not deteriorate. . The bonding treatment atmosphere is preferably a reduced pressure (vacuum) atmosphere or an inert gas atmosphere so that the constituent material of the bonded body 10 is not oxidized during heating.

  In addition, when the 1st member 12 and the 2nd member 14 contain much Mg, the thing with little Mg amount is used as the intermediate material 18, and conversely, the Mg content of the 1st member 12 and the 2nd member 14 is small. In this case, it is preferable to use a material having a large amount of Mg as the intermediate material 18. In addition, when an Al alloy containing a predetermined amount of Mg is used as the intermediate member 18 for joining the first member 12 and the second member 14, some of the components are transferred to the first member 12 and the second member 14. Strictly speaking, the composition of the intermediate layer 16 formed by the intermediate material 18 may deviate from the composition of the intermediate material 18, but such a diffusion amount is extremely small relative to the total amount. It can be considered that the Mg content of the intermediate layer 16 is approximately the same as the Mg content of the intermediate material 18.

  Next, examples of the present invention will be described.

(Joint test of Al-based composite material and Al alloy with Mg-containing Al)
A first member having a metal part composition of Al-10Si-2Mg (mass%) and made of an Al-based composite material containing SiC (particle size: 10 μm) of 30% by volume and having a shape of φ30 mm × 30 mm; A second member having a shape of φ30 mm × 30 mm made of AC4C material (Al-7Si-0.3Mg), which is a kind of Al alloy, was prepared. Further, Al, Al-0.2Mg, Al-0.4Mg, Al-1.0Mg, Al-1 are used as intermediate materials to be inserted into these joining surfaces in order to join these first and second members. .5Mg, Al-3.0Mg, Al-4.0Mg (composition is mass%) powder and plate material were prepared.

  When these powders were used as an intermediate material, the powder was uniformly distributed on the joint surface with a sieve, and the thickness was 40 μm. Moreover, when using a board | plate material as an intermediate material, the thickness was 3) mm.

  The intermediate member was placed between the first member and the second member, and the first member and the second member were pressurized at a pressure of 5 MPa in a vacuum atmosphere, and a bonding process was performed at 500 ° C. for 5 minutes. As a heating method at this time, a high frequency induction heating method was used. In addition, a hole was made at a position 5 mm away from the bonding surface of the second member (Al alloy), a thermocouple was inserted therein, and the temperature measured thereby was defined as the bonding temperature.

  For the sample obtained after the bonding treatment, the ratio of the tensile strength of the sample and the tensile strength of the Al alloy that is the base material is calculated. If it was less than that, it was judged as “not joined”.

  The tensile strength is obtained by cutting a test piece (10 mm × 10 mm × about 60 mm) for a tensile test from the obtained joined body and measuring the tensile strength at a tensile speed of 2 mm / min based on “JIS Z2241”. Asked.

The results are shown in Table 1. When Al containing no Mg and Al-4.0Mg were used as the intermediate material, the Al-based composite material and the Al alloy were not joined via the intermediate material, but Al-0.2 to 3.0 Mg It was confirmed that these materials can be bonded satisfactorily by using.

(Joint test of Al-based composite material and Al-based composite material with Mg-containing Al)
A member having a metal part composition of Al-10Si-2Mg (mass%) and made of an Al-based composite material containing SiC (particle diameter: 10 μm) of 30% by volume and having a shape of φ30 mm × 30 mm is a first member. And as a 2nd member, the joining test and evaluation of the obtained joined body were performed like the joining test of Al group composite material and Al alloy which were mentioned above.

The results are shown in Table 2. As shown in Table 2, when Al not containing Mg and Al-4.0Mg were used as the intermediate material, the Al-based composite materials could not be joined together via the intermediate material. It was confirmed that by using -0.2 to 3.0 Mg, the Al-based composite materials can be joined well.

(Joint test of Al-based composite material and Al alloy with Mg-containing Al alloy)
A first member having a metal part composition of Al-10Si-2Mg (mass%) and made of an Al-based composite material containing 30% SiC (particle size: 10 μm) by volume, and having a shape of φ30 mm × 5 mm; A second member having a shape of φ30 mm × 30 mm made of AC4C material (Al-7Si-0.3Mg), which is a kind of Al alloy, was prepared.

  As an intermediate material to be inserted into these joining surfaces in order to join these first and second members, a powder of 2024 alloy (Al-4.38Cu-0.63Mn-1.48Mg) having a particle size of 40 μm is used. Using.

  The joining form of the first member and the second member is a structure in which the first member is sandwiched by the second member, and 0.8 g (thickness of 40 μm) is provided on the joining surface at the location between the two first members and the second member. ) Were inserted, and the joining temperature was changed by a direct current heating method to produce various joined bodies. At this time, the treatment atmosphere was a vacuum atmosphere or a nitrogen atmosphere, the pressure applied between the second members was 7 MPa, and the joining treatment time was 5 minutes.

  The degree of deformation of the obtained joined body was determined from the change ratio (%) of the length before and after joining. Similarly, the degree of deformation of only the first member was also measured. Further, a tensile test specimen (10 mm × 10 mm × about 65 mm) was cut out from the obtained joined body to obtain a tensile strength of the obtained joined body, and the tensile strength was determined based on “JIS Z2241” at a tensile speed of 2 mm / Determined by measuring in minutes.

  Further, for comparison, the intermediate member is not inserted between the first member and the second member, and the joining process is performed under the same conditions, the degree of deformation of the obtained joined body is measured, and the tensile test piece is cut out from the joined body. The tensile strength was determined.

  FIG. 3 shows the relationship between the bonding temperature of the bonded body and the tensile strength when the processing atmosphere is a vacuum atmosphere. For comparison, FIG. 3 also shows the tensile strength of the second member (AC4C) alone treated at the same temperature for the same time.

  When the intermediate material was not used, the first member and the second member were not joined at 500 ° C. or lower. It turns out that these can be joined at 500 degreeC by using an intermediate material. Further, as shown in the results at 525 ° C. and 550 ° C., it was confirmed that the tensile strength of the joined body was improved by using the intermediate material.

  As a result of the tensile test, the joined body obtained by performing the joining treatment at 525 ° C. using the intermediate material was broken at the joining surface of the first member and the second member. On the other hand, the joined body obtained by the joining treatment at 550 ° C. was broken at the intermediate portion of the first member as a result of the tensile test. This was considered to be because the bonding temperature was high and the Al-based composite material as the first member deteriorated during the bonding process due to pressurization.

  The tensile strength of the joined body obtained by the joining treatment at 550 ° C. is extremely lower than the original tensile strength (material characteristics) of the first member. For this reason, when the fracture surface of the joined body produced on the same conditions was observed, it was confirmed that the crack has generate | occur | produced in the thickness direction of the 1st member. Furthermore, when this crack portion was observed with a scanning electron microscope (SEM) and composition analysis was performed with an energy dispersive X-ray analyzer (EDX), Cu contained in the 2024 alloy was segregated near the crack at the joint interface. And it was confirmed that Cu concentration became high, so that it was near the interface of the 1st member and the 2nd member. From this, it was considered that the diffusion of Cu into the first member caused the first member to have a low melting point, cracks were generated by the pressurization during the bonding process, and extended.

  From this result, it is considered desirable to reduce the bonding pressure. Further, as the intermediate material, it is considered more preferable to use an Mg-containing Al alloy made of an element that does not diffuse into the Al-based composite material to be joined and lower the melting point of the Al-based composite material.

  FIG. 4 shows the relationship between the joining temperature and the degree of deformation of the joined body. It can be determined that deformation of the joined body due to the insertion of the intermediate material does not occur as compared with the case where the joining is performed without using the intermediate material.

  FIG. 5 shows the degree of deformation of only the first member (Al-based composite material) in relation to the bonding temperature. Also in this case, there is no substantial difference between the case where the intermediate material is used and the case where the intermediate material is not used, and it can be determined that the difference shown in FIG.

  FIG. 6 shows the relationship between the bonding temperature and the tensile strength of the bonded body when the processing atmosphere is a nitrogen gas atmosphere. For comparison, FIG. 6 also shows the tensile strength of the second member (AC4C) alone processed at the same temperature for the same time. As shown in FIG. 6, it was confirmed that the tensile strength was improved by using the intermediate material even when the joining process was performed in a nitrogen gas atmosphere. The joined body obtained by processing at 525 ° C. using the intermediate material and the joined body obtained by processing at 550 ° C. without using the intermediate material show equivalent tensile strength, and by using the intermediate material, It can be seen that the first member and the second member can be strongly bonded at a low temperature.

Sectional drawing which shows schematic structure of Al group composite material conjugate | zygote. The figure which shows typically the preparation methods of Al group composite material conjugate | zygote. The graph which shows the relationship between the joining temperature and tensile strength of Al group composite material joining body at the time of processing atmosphere made into vacuum atmosphere. The graph which shows the relationship between the joining temperature and deformation degree of a joined body. The graph which shows the deformation degree of only a 1st member (Al group composite material) by relationship with joining temperature. The graph which shows the relationship between the joining temperature and tensile strength of a joined body at the time of setting process atmosphere as nitrogen gas atmosphere.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Bonded body, 12 ... 1st member (Al group composite material), 14 ... 2nd member (Al group composite material or Al alloy), 16 ... Intermediate | middle layer, 18 ... Intermediate material.

Claims (4)

A method of joining a first member made of an aluminum matrix composite material and a second member made of an aluminum matrix composite material or an aluminum alloy,
Between the first member and the second member, an aluminum or aluminum alloy containing 0.2 to 3 mass% magnesium as an intermediate material is interposed,
A predetermined pressure is applied to the first member and the second member, and a bonding portion between the first member and the second member is heated to a diffusion temperature of magnesium. Method.   The said intermediate material is a powder or a board | plate material, The joining method of the aluminum-based composite material of Claim 1 characterized by the above-mentioned.   The method for bonding an aluminum-based composite material according to claim 1 or 2, wherein heating of the bonding portion between the first member and the second member is performed by energization heating or high-frequency induction heating. A first member made of an aluminum-based composite material;
A second member made of an aluminum-based composite material or an aluminum alloy joined to the first member via an intermediate layer;
The said intermediate | middle layer consists of aluminum or aluminum alloy containing 0.2-3 mass% magnesium, The aluminum group composite material joined body characterized by the above-mentioned.

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