JP2003293060A - Aluminum alloy composite material for brazing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy composite material which has high strength, improves the corrosion resistance of a coolant side when being used as a radiator tube, and is made thin in thickness. <P>SOLUTION: An Al-Si based brazing filler metal 3 is formed on one side of a core material 1. A surface material 2 is formed on the other side at a clad ratio of 6 to 30% of the whole sheet thickness. The core material 1 contains, by mass, ≤0.2% Mg, ≤0.3% Cr, ≤0.2% Fe, 0.2 to 1.0% Cu, 0.05 to 1.3% Si, 0.3 to 1.8% Mn and 0.02 to 0.3% Ti, and satisfying ≤2.0% Cu+Si. A surface material 2 has a composition containing 2 to 9% Zn, and further containing at least one kind of metal selected from the group consisting of 0.3 to 1.8% Mn and 0.04 to 1.2% Si, and also, precipitated products or crystallized products with a means particle diameter of <0.1 μm are contained in ≥5.0×10<SP>8</SP>pieces/mm<SP>3</SP>. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy composite material suitable as a brazing sheet used for tubes and plates of a radiator of an automobile, and in particular, has high strength. Also, the present invention relates to a brazing aluminum alloy composite material having excellent corrosion resistance on the inner surface side (coolant side) when used as a tube plate of a radiator and capable of being thinned. [0002] In a brazing aluminum alloy composite material in which a brazing material is clad on one surface of a core material and a cladding material is clad on the other surface of the core material, the strength of the core material is improved by adding Mg to the core material. Let me. However, when the Mg content of the core material exceeds 0.2% by mass, the brazing property is extremely reduced. For this reason, it is not preferable to add Mg to the core material. [0003] Further, there has been proposed an aluminum alloy composite material which is reduced in thickness without impairing corrosion resistance and brazing properties. In the aluminum alloy composite material described in JP-A-8-283891, the skin material contains 0.3 to 3% by mass of Mg and 2.2 to 5% by mass of Zn.
By adding g, the strength of the skin material is improved. Further, Japanese Patent Application Laid-Open No. 11-61306 discloses that instead of adding Mg to a skin material, Mn and S are added to the skin material.
An aluminum alloy composite material having improved strength by adding i has also been proposed. [0005] However, each of the above-mentioned prior arts has the following disadvantages. First, the aluminum alloy composite material described in Japanese Patent Application Laid-Open No. 8-283891 attempts to improve the strength by adding Mg to the skin material. However, when the thickness is reduced, Mg is diffused by heat diffusion during brazing. Reaches the brazing material surface via the core material and impairs the brazing property. For this reason, in order to maintain a predetermined brazing property, the thickness of the core material must be increased, and there is a limit to thinning. In addition, the conventional aluminum alloy composite material has a problem that it cannot be used as a tube material having a structure in which the skin material is brazed because the brazing property of the skin material is inferior. On the other hand, the aluminum alloy described in Japanese Patent Application Laid-Open No. 11-61306 attempts to improve the strength by adding Mn and Si to the skin material, but only by adding the Mn and Si components to the skin material. There is a limit to thinning while maintaining corrosion resistance. The present invention has been made in view of the above problems, and has high strength, excellent corrosion resistance on the inner surface side (coolant side) when used as a radiator tube, and can be made thinner. It is an object of the present invention to provide a brazing aluminum alloy composite material. In the aluminum alloy composite for brazing according to the present invention, a brazing material made of an Al-Si based aluminum alloy is formed on one surface of a core material, and the other surface of the core material is formed on the other surface of the core material. In an aluminum alloy composite material in which a cladding material is formed with a cladding ratio of 6 to 30% of the total thickness, the core material includes Mg: 0.2% by mass or less, Cr: 0.3% by mass or less, and Fe: 0. 2% by mass or less, Cu: 0.2 to 1.0
% By mass, Si: 0.05 to 1.3% by mass, Mn: 0.1% by mass.
3 to 1.8% by mass, Ti: 0.02 to 0.3% by mass
And the balance is composed of Al and unavoidable impurities. The skin material is Zn: 2 to 9% by mass, Mn: 0.3 to 1.8% by mass, and Si: 0.04%. Having a composition containing at least one member selected from the group consisting of -1.2 mass% and having an average particle size of less than 0.1 µm of 5.0 x 10 ⁸ precipitates / crystals / mm It is characterized by containing ³ or more. DETAILED DESCRIPTION OF THE INVENTION As a result of various experiments and studies conducted by the present inventors to solve the above problems, Mn and Si are contained in a skin material in a predetermined range, and the thickness of the skin material is further reduced to a predetermined value. By limiting the distribution of precipitates or crystallized substances to the skin material, it is possible to significantly reduce the thickness of the aluminum alloy composite material while maintaining brazing properties, corrosion resistance and strength. Was. The reasons for adding components and limiting the composition of the core material, skin material and brazing material of the aluminum alloy composite material for brazing of the present invention will be described below. First, the composition of the core material will be described. Mg (magnesium): 0.2% by mass or less Mg is an element that improves the strength of the core material. However, if added in excess of 0.2% by mass, the brazing property is reduced. In particular, in the brazing by the Nocolok method, the decrease is extremely large. Therefore, the content of Mg is limited to 0.2% by mass or less. In order to further suppress the decrease in brazing properties, the content of Mg is preferably set to 0.1% by mass or less. Cu (copper): 0.2 to 1.0% by mass Cu is an element that improves the strength of the core material, and also improves the corrosion resistance on the brazing material side. However, when Cu is added to the core material, the intergranular corrosion susceptibility is increased, so that the corrosion resistance on the skin material surface side is reduced. Therefore, by adding Zn in an amount of 2% by mass or more to the skin material, the potential of the skin material can be set to be lower than the grain boundary, and grain boundary corrosion can be prevented. In other words, by increasing the amount of Zn added to the skin material, the potential of the skin material with respect to the core material can be set not only to the matrix of the core material, but also to the grain boundaries, thereby preventing grain boundary corrosion. Can be.
If the added amount of Cu is less than 0.2% by mass, it is insufficient to improve the strength of the core material. On the other hand, when Cu is added in excess of 1.0% by mass, the melting point of the core material is reduced, so that the core material is melted during brazing. Therefore, the content of Cu is set to 0.2 to 1.0% by mass. Si (silicon): 0.05 to 1.3 quality
% Si is an element that improves the strength of the core material.
The strength of the core material is improved by the Si-based precipitate. But S
If the amount of i is less than 0.05% by mass, it is insufficient to improve the strength of the core material. On the other hand, Si is 1.3% by mass.
If added in excess of the above, the melting point of the core material is lowered, and the core material is melted during brazing due to the increase in the low melting point phase. Therefore, the content of Si is set to 0.05 to 1.3% by mass. Mn (manganese): 0.3 to 1.8 mass
% Mn is an element that improves the corrosion resistance, brazeability and strength of the core material. When the added amount of Mn is less than 0.3% by mass,
The strength cannot be improved. However, when the added amount of Mn exceeds 1.8% by mass, a compound in which the crystal grains are coarsened is generated, so that the workability is reduced. Therefore,
The content of Mn is set to 0.3 to 1.8% by mass. [0015] Ti (titanium): 0.02 to 0.3 mass
% Ti is an element that further improves the corrosion resistance of the core material.
If the added amount of Ti is less than 0.02% by mass, the corrosion resistance of the core material cannot be sufficiently improved. On the other hand, even if Ti is added in an amount exceeding 0.3% by mass, the corrosion resistance of the core material cannot be improved any more, and instead, a compound in which the crystal grains are coarsened is generated, so that the workability is reduced. I will. Therefore, the content of Ti is 0.02 to 0.3% by mass.
And As described above, Ti is an indispensable element for improving the corrosion resistance of the core material, and when Ti is added, it precipitates in a layer form in the core material, thereby suppressing the progress of pitting corrosion in the depth direction, and Can be used to shift the core material potential noble. In addition, since Ti has a low diffusion rate in an aluminum alloy and moves little during brazing, the addition of Ti maintains the potential difference between the core material and the brazing material or the core material and the skin material, and electrochemically reduces the core material. It is effective in preventing corrosion. Cr (chromium): 0.3% by mass or less Cr is an element that improves the corrosion resistance, strength and brazing properties of the core material. Even if Cr is added in excess of 0.3% by mass,
Above that, the corrosion resistance, strength and brazing properties of the core material cannot be improved, but rather the workability is reduced due to the coarsening of the crystal of the compound. Therefore, the content of Cr is 0.1.
3% by mass or less. In addition, a more preferable addition amount of Cr is 0.02 to 0.3% by mass. Fe (iron): 0.2% by mass or less Fe is an element that refines crystal grains in the core material and improves the strength and weldability of the core material. If the added amount of Fe exceeds 0.2% by mass, the corrosion resistance of the core material is reduced. Therefore, the content of Fe is set to 0.2% by mass or less. In addition, a more preferable addition amount of Fe is 0.02 to 0.2% by mass. Next, the composition of the skin material will be described. Mn (manganese): 0.3 to 1.8 mass
% Mn is an element that improves the strength of the skin material. That is, Mn
Is dissolved in the skin material, thereby improving the material strength. M
If the addition amount of n is less than 0.3% by mass, a sufficient Mn solid solution amount cannot be obtained, and the strength cannot be secured. On the other hand, if the added amount of Mn is more than 1.8% by mass, the amount of the compound increases, thereby reducing the workability of the skin material and serving as a starting point of cracks, thereby reducing the workability of the entire clad material. Therefore, when Mn is added to the skin material, the Mn content of the skin material is 0.1.
3 to 1.8% by mass. Si (silicon): 0.04 to 1.2 quality
By adding the amount% Si to the skin material as in the case of Mn, the strength is improved. If the amount of Si is less than 0.04% by mass, the effect of improving the strength is not sufficient. When the amount of Si added is 1.
If it is more than 2% by mass, the intergranular corrosion susceptibility increases, and the corrosion resistance decreases. Therefore, when Si is added to the skin material, S
The range of the i content is 0.04 to 1.2% by mass. Note that Mn and Si have the same effect, and at least one of them may be added. Zn (zinc): 2 to 9% by mass Zn is added to the skin material in order to make the potential of the skin material low.
In this case, when the addition amount of Cu in the core material is 0.2% by mass or less, a sufficient sacrificial anode effect can be obtained when the addition amount of Zn in the skin material is less than 2% by mass, and corrosion resistance is maintained. Can be. However, as mentioned above,
When the addition amount of Cu in the core material exceeds 0.2% by mass,
When the content is 1.0% by mass or less, the amount of Zn added to the skin material needs to be 2 to 9% by mass. This is because if the amount of Zn added to the skin material is less than 2% by mass, the potential of the skin material cannot take a sufficient potential difference with respect to the grain boundary, and grain boundary corrosion occurs, and the skin material side On the other hand, if Zn is added to the skin material in an amount exceeding 9% by mass, the self-corrosion rate of the skin material itself increases, so that the skin material is quickly consumed and the sacrificial anode effect is reduced. Is shortened, and the corrosion resistance deteriorates. Note that, in order to obtain a balance between strength and corrosion resistance in a state where the amount of Si is increased, the amount of Zn is preferably set to 3% by mass or more. In addition to adding at least one selected from the group consisting of Mn and Si, Fe, C
By adding at least one selected from the group consisting of r, Mg, and Cu together, the strength of the skin material can be further improved, and it is effective in improving the strength of the entire plate thickness. Is preferred. Fe: 0.02 to 0.25% by mass Fe is an element for improving the strength of the skin material by making crystal grains of the skin material fine and by dissolving Fe in solid solution. If the Fe content is less than 0.02% by mass, the effects of refining crystal grains and improving strength are insufficient. If the amount of Fe exceeds 0.25% by mass, the amount of Fe-containing precipitates or crystallization in the skin material increases, so that the number of cathode sites increases. For this reason, the corrosion rate of the skin material itself increases, and the corrosion resistance decreases. Therefore, when adding Fe, the content of Fe is set to 0.25% by mass or less. In addition,
A more preferable addition amount of Fe is 0.02 to 0.2% by mass. Cr: 0.01 to 0.30% by mass Cr is an element that improves corrosion resistance and strength in a skin material. Even if Cr is added in excess of 0.3% by mass, the corrosion resistance and strength of the skin material cannot be improved beyond that,
In addition, the increase in the amount of crystallization containing Cr increases the number of cathode sites, so that the corrosion rate of the skin material itself increases, and the corrosion resistance decreases. Therefore, the content of Cr is 0.1.
3% by mass or less. On the other hand, when Cr is 0.01 or less, the effect of improving strength and corrosion resistance cannot be obtained. Therefore, when Cr is added, the content of Cr is 0.0
1 to 0.30% by mass. Mg: 0.005 to 0.15% by mass Mg improves the strength of the skin material by forming a solid solution in the skin material. Furthermore, when Si coexists, the strength can be further improved by the effect of the dispersion of the precipitate of Mg ₂ Si. If the Mg content exceeds 0.15% by mass, the brazing property at the portion where the skin material side is joined is deteriorated, so the content of Mg is set to 0.15% or less.
If the Mg content is less than 0.005%, the effect of improving the strength is small. Therefore, when adding Mg, the addition amount is set to 0.005 to 0.15% by mass. Cu: 0.001 to 0.15% by mass Cu improves the strength of the skin material by forming a solid solution in the skin material. When Cu in the skin material exceeds 0.15% by mass, since the potential of the skin material is noble, the Cu of the core material is 0.2 to
Even when Zn of the skin material is controlled to 2 to 7% at 1% by mass,
Since the sacrificial anode effect on the core material is reduced, the corrosion resistance on the skin material side is deteriorated. If the Cu content is less than 0.001% by mass, the effect of increasing the strength is small, and a sufficient effect of increasing the strength on the skin material side cannot be obtained. Clad rate of skin material: aluminum alloy composite
6 to 30% of the total thickness of the material By setting the cladding rate of the skin material having the composition of the present invention to 6% or more, sufficient strength can be obtained while maintaining corrosion resistance even when the thickness is significantly reduced. Can be Cladding rate is 6%
If it is smaller, the sacrificial anode effect of the skin material will be insufficient, and the corrosion resistance will decrease. Therefore, the cladding rate of the skin material having the composition of the present invention is set to 6% or more of the total thickness. When the cladding rate is increased to 30% or more, the thickness of the core material is relatively decreased, and the corrosion resistance on the outer surface side is deteriorated. Therefore, the upper limit of the cladding rate is set to 30%.
Therefore, the cladding ratio of the skin material is set to 6 to 30%. Precipitates or crystals having an average particle size of less than 0.1 μm
The intermetallic compound mainly composed of Al-Mn in the skin material having a particle size of 5.0 × 10 ⁸ particles / mm ³ or more is required to distribute a precipitate or a crystallized material having a size specified in the present invention by a certain amount or more. Thereby, the crystal grains of the skin material after brazing become coarse, and the corrosion resistance is improved. The cladding material is cold-worked to a predetermined thickness after being clad-rolled with the core material or the like, but when a precipitate or a crystal having a size specified in the present invention is present in the cladding material, it is difficult to be processed. A so-called pinning effect that suppresses the movement of dislocations introduced into the semiconductor device. Dislocations are released from this pinning by the heat of brazing, but if only coarse precipitates or crystals are present in the cladding,
The dislocation movement is not suppressed by the pinning effect, and recrystallization with coarse crystal precipitates as the nucleus takes precedence. It will be easier. As in the present invention, when the precipitates or crystallized substances are controlled to be minute, dislocations are released after being pinned at the time of heating by brazing, thereby delaying the occurrence of recrystallization. As a result, the grain of the skin material is coarse. Therefore, intergranular corrosion hardly occurs and high corrosion resistance can be obtained. Further, when deformation is applied by press working, precipitates or crystallized substances are less likely to fall off due to coarse crystal grains, and as a result, there is also an effect that corrosion resistance does not deteriorate. The size of the precipitate or crystallization is 0.0
If the diameter is smaller than 1 μm, the pinning effect does not work sufficiently. Therefore, the number of precipitates having a size of 0.01 μm or more and 0.1 μm or less should be substantially equal to or more than the number specified in the present invention. The size of the precipitates or crystallized substances in the skin material can be appropriately adjusted by the components in the skin material, the soaking treatment before rolling, and the heating temperature during clad rolling. Next, the brazing material will be described. As the brazing material, an Al-Si based alloy similar to a conventionally used brazing material, for example, an A4045 alloy or the like can be used.
Further, by adding Zn to the brazing material, the brazing material can be positively operated as a sacrificial anode. In this case, the amount of Zn added is preferably the same as the amount of Zn added to the skin material, that is, 2 to 5% by mass. Also,
In order to ensure the corrosion resistance of the brazing material surface, it is necessary to secure a potential difference between the fin material and the outer surface.
A trace amount of a metal element such as u for raising the potential may be added. The composition of the above-mentioned core material, skin material and brazing material may be individually adjusted as the composition of each member before clad, or heating and cooling during brazing and the like. By controlling the conditions, it is also possible to adjust the components by diffusing from one member to the other. EXAMPLES The effects of the examples of the present invention will be specifically described below in comparison with comparative examples that fall outside the scope of the present invention. Table 1 below shows the composition of the core material, and Table 2 shows the composition of the skin material. The core material No. shown in Table 1 was used. Nos. 1 to 7 are examples of the present invention. 8 to 17 are comparative examples of the present invention. Moreover, the skin material No. shown in Table 2 was used. Nos. 1 to 7 are examples of the present invention. Nos. 8 to 13 are comparative examples out of the claims of the present invention. [Table 1] [Table 2] Each core material and skin material shown in Tables 1 and 2 above,
Brazing material (JIS 4045 alloy; Si: 10.5 mass%,
Fe: 0.05% by mass, Cu: 0.05% by mass, Ti:
Aluminum alloy composite material for brazing as shown in FIG. 1 was produced using 0.02% by mass and the balance being Al and inevitable impurities. FIG. 1 is a sectional view showing an aluminum alloy composite for brazing according to an embodiment of the present invention. As shown in FIG. 1, this aluminum alloy composite material 4
Is formed by laminating a skin material 2 and a brazing material 3 on both surfaces of a core material 1 respectively. Tables 3 and 4 below show combinations of the core material and the skin material in this composite material, their thickness, the thickness of the brazing material, and the thickness of the composite material. [Table 3] [Table 4] Each of the composite materials shown in Tables 3 and 4 was subjected to a brazing property test, a tensile strength measurement, and a corrosion resistance test. The test method is as follows. That is, in the brazing property test, the flux for Nokoloc was 5 g / m2 on the brazing material side of the aluminum alloy composite material for brazing.
^After applying ² and drying, it was heated in a nitrogen atmosphere having a dew point of −40 ° C. under conditions of an ultimate temperature of 600 ° C. and a holding time of 2 minutes at 600 ° C. FIG. 2 is a sectional view showing a part of the tube of the radiator. As shown in FIG. 2, in the actual manufacture of the radiator, the core material 31, the skin material 32 and the brazing material 3
The brazing is performed in a state in which the tube 34 made of No. 3, the fin 35 for releasing heat, and the header 36 connecting the tube 34 are combined. In consideration of simplification and quantification of brazing evaluation, The brazing property was evaluated by the flow coefficient by drop test (aluminum brazing handbook (issued in January 1992), the method of “drop type fluidity test” described on P126 of Japan Institute of Light Metal Structure Welding). The evaluation results of the brazing properties are shown in Tables 5 and 6 below. In the columns of brazing properties in Tables 5 and 6,
流動 when the fluidity is 65% or more, × when the fluidity is less than 65%
It is. The precipitate or crystallized substance in the skin material was observed with a transmission electron microscope, the thickness was measured by equal thickness interference fringes, and the number in a unit volume was measured. [Table 5] [Table 6] In order to determine the strength after brazing, a tensile test (JIS Z224) was performed on the aluminum alloy composite for brazing that had been subjected to the same heat treatment as the above-mentioned brazeability test.
1) was performed. The results are shown in Table 4 above. The strength after brazing is ○ when the tensile strength exceeds 158 MPa, and x when the tensile strength is 158 MPa or less. In the brazing material side corrosion test, as in the brazing property test, the CASS test (5 of JIS H8681) was continuously performed on the heated aluminum alloy composite material for brazing.
Tested for 50 hours. The results are shown in Table 4 above. In the brazing material side corrosion depth column of Table 4, the brazing material side erosion depth is 70.
場合 indicates the case of not more than μm, and × indicates that the erosion depth on the brazing material side exceeds 70 μm. In order to determine the corrosion resistance on the skin material side, a corrosion test on the skin material side was performed. In the skin material side corrosion test, as in the brazeability test, artificial water (Cl: 300 mass ppm, SO ₄ : 10) was used for the heated aluminum alloy composite for brazing.
0 ppm by mass and Cu: 5 ppm by mass). The aluminum alloy composite material is immersed in artificial water for 8 hours at 88 ° C (including the heating time from room temperature to 88 ° C), and at room temperature for 16 hours (including the cooling time from 88 ° C to room temperature), a cycle test of 30 days Carried out. The results are shown in Table 4 above. In the skin material corrosion depth column of Table 4, the case where the skin material side depth is 30 μm or less is ○, and the skin material side depth is 30 μm.
Is greater than x. As shown in Table 4, Example 1 of the present invention
No. 10 to 10 were all excellent in brazing properties, tensile strength, corrosion depth on the brazing material side and corrosion depth on the skin material side. In Comparative Example 11, since the amount of Cr in the core material was less than the lower limit, the strength was slightly inferior. In Comparative Example 12, since the Cr content of the core material exceeded the upper limit, the workability was slightly reduced.
On the other hand, in Comparative Example 13, the strength after brazing was insufficient because the amount of Si in the core material was less than the lower limit. In Comparative Example 14, since the Cu content of the core material was less than the lower limit, the strength after brazing was insufficient. In Comparative Example 15, since the Mn content of the core material was less than the lower limit, the strength after brazing was insufficient. In Comparative Example 16, the amount of Mg in the core material exceeded the upper limit, so that the brazing property was poor. In Comparative Example 17, since the Ti content of the core was less than the lower limit, the corrosion resistance of the core deteriorated. In Comparative Example 18, since the amount of Si in the core exceeded the upper limit, the core was melted. In Comparative Example 19, since the Fe content of the core exceeded the upper limit, the corrosion resistance of the core deteriorated. In Comparative Example 20, since the Cu content of the core material exceeded the upper limit,
Melting of the core material occurred. In Comparative Example 21, since the Mn of the core material exceeded the upper limit, the workability was deteriorated. In Comparative Example 22, the workability was deteriorated because the amount of Ti in the core material exceeded the upper limit. In Comparative Example 23, the strength after brazing was insufficient because Si in the skin material was less than the lower limit. In Comparative Example 24, since the Si of the skin material exceeded the upper limit, the corrosion resistance on the skin material side was deteriorated. In Comparative Example 25, since the Mn of the skin material was less than the lower limit, the strength after brazing was insufficient. In Comparative Example 26, since the Mn of the skin material exceeded the upper limit, the workability was reduced. In Comparative Example 27, since the Zn of the skin material was less than the lower limit, the corrosion resistance on the skin material side was deteriorated. Comparative Example 28 shows the Z of the skin material.
Since n exceeded the upper limit, the corrosion resistance on the skin material side deteriorated.
In Comparative Example 29, since the cladding ratio of the skin material was less than the lower limit, the corrosion resistance on the skin material side was deteriorated. In Comparative Example 30, since the cladding ratio of the skin material exceeded the upper limit, the corrosion resistance on the brazing material side deteriorated. In Comparative Example 31, the corrosion resistance on the skin material side was deteriorated because the precipitate or crystallized substance of a predetermined size in the skin material was below the lower limit. As described above, according to the present invention,
An aluminum alloy composite material for brazing having high strength and high corrosion resistance and capable of thinning can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an aluminum alloy composite for brazing according to an embodiment of the present invention. FIG. 2 is a perspective view showing a part of a tube of a radiator. FIG. 3 is a sectional view showing a laminated structure of an aluminum alloy composite material constituting a tube. [Description of Signs] 1, 31: core material 2, 32: skin material 3, 33: brazing material 4: aluminum alloy composite material 34: tube 35: fin 36: header

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Fumihiro Sato             15 Kinuigaoka, Moka-shi, Tochigi             Toka Steel Works Moka Works

Claims (1)

Claims 1. A brazing material made of an Al-Si based aluminum alloy is formed on one surface of a core material, and a cladding material having a cladding ratio of 6 to 30% of the total thickness on the other surface of the core material. In the aluminum alloy composite material formed by the above, the core material is Mg:
0.2 mass% or less, Cr: 0.3 mass% or less, Fe:
0.2 mass% or less, Cu: 0.2 to 1.0 mass%, S
i: 0.05 to 1.3% by mass, Mn: 0.3 to 1.
8% by mass, Ti: 0.02 to 0.3% by mass,
The remainder has a composition consisting of Al and unavoidable impurities, and the skin material has a Zn content of 2 to 9% by mass and a Mn content of 0.2 to 9% by mass.
A precipitate having a composition containing at least one selected from the group consisting of 3 to 1.8% by mass and Si: 0.04 to 1.2% by mass, and having an average particle size of less than 0.1 μm or An aluminum alloy composite material for brazing, comprising at least 5.0 × 10 ⁸ crystallites / mm ³ .