Aluminum alloy material and aluminum alloy clad material

Abstract

To prevent erosion and so on at brazing, by suppressing decrease in melting point of a material due to Si inclusion.SOLUTION: An aluminum alloy has a composition containing 0.05 to 2.0% of element X (excluding Mn and Fe) that contains 1.1 to 2.5% of Si and produces intermetallic compounds containing Si, the remainder being Al and unavoidable impurities. X has an outer most shell electron configuration with two electrons in the 4s orbital and none in the 3d orbital, has one or more electrons in the 3d orbital and one or more vacancies in the 3d orbital, has an outer most shell electron configuration with two electrons in the 5s orbital and none in the 4d orbital, or has one or more electrons in the 4d orbital and one or more vacancies in the 4d orbital. The intermetallic compound containing Si and X has more than 10 particles per 10,000 μm2 with a circular equivalent diameter of 1 μm or more, and a melting point of 590°C or higher.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aluminum alloy material and an aluminum alloy clad material. [Background technology]

[0002] Automotive heat exchangers using aluminum materials are manufactured by brazing, which is a multi-point batch joining technique. For example, Patent Document 1 proposes a fin material that contains Mn, Si, and Zn and is used for brazing. By the way, recently CO 2 There is a growing need for materials with low emissions. Aluminum emits no CO during the manufacturing process after casting. 2 Although the amount of CO emissions is not that large, the refining of bullion requires a huge amount of electricity and indirectly emits a large amount of CO. 2 Therefore, low CO 2 In order to be a material that can be recycled, it is desirable to reduce the rate of use of virgin metal, i.e., to have a high recycling rate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-178170 A Summary of the Invention [Problem to be solved by the invention]

[0004] In brazing, the objects are exposed to a high-temperature environment of approximately 600°C, and if any components other than the brazing material that contributes to the joining melt, manufacturing becomes impossible, so the components other than the brazing material must have a relatively high melting point compared to the brazing material. On the other hand, increasing the recycling rate of materials affects the lowering of the melting point due to an increase in impurity elements, etc. There are several elements that contribute to lowering the melting point, but Si, which is generally contained in aluminum alloy materials, has the effect of lowering the melting point, so Si-containing materials have a significant impact on reducing the recycling rate, and achieving both high Si-containing materials and brazing has become an issue.

[0005] The present invention has been made against the background of the above circumstances, and has an object to provide an aluminum alloy material and an aluminum alloy clad material that enable brazing by preventing a decrease in the melting point of the aluminum alloy material. [Means for solving the problem]

[0006] In response to the above-mentioned problems, the present invention selects an element X that forms an intermetallic compound with a Si content of 15% or more by atomic weight and that has a high stability of its electronic state, and further controls the dispersion state of the intermetallic compound to produce an aluminum alloy material with a high melting point, thereby successfully developing a high Si-containing material that can be brazed.

[0007] That is, among the aluminum alloy materials of the present invention, a first embodiment is an aluminum alloy material having a composition containing 1.1 to 2.5% by mass of Si, 0.05 to 2.0% by mass of an element (excluding Mn and Fe, hereinafter referred to as X) that forms an intermetallic compound containing Si, and the remainder being Al and unavoidable impurities, in which X has an outermost shell electron configuration in which two electrons are arranged in the 4s orbital and no electron in the 3d orbital, or has one or more electrons in the 3d orbital and one or more vacancies in the 3d orbital, or has an outermost shell electron configuration in which two electrons are arranged in the 5s orbital and no electron in the 4d orbital, or has one or more electrons in the 4d orbital and one or more vacancies in the 4d orbital, and the intermetallic compounds containing Si and X have a circle equivalent diameter of 1 μm or more in an observation in the surface layer surface (RD-TD plane) direction. 2 It is characterized by having more than 10 per unit mass and a melting point (solidus temperature) of 590°C or higher.

[0008] In another aspect of the invention, the aluminum alloy material of the above-mentioned aspect further contains, in mass %, one or more of Mn: 0.1-2.0%, Fe: 0.05-0.7%, and Cu: 0.01-1.5%.

[0009] In another aspect of the invention, the aluminum alloy material of the above-mentioned aspect further comprises, in the composition, 0.35% by mass or less of one or more of Ti, V, Co, Ni, Zr and Nb.

[0010] In another aspect of the invention, the aluminum alloy material of the above-mentioned aspect further comprises, in the composition, one or both of Zn: 0.01-8.0% and Mg: 0.01-1.5%, by mass %.

[0011] The first embodiment of the aluminum alloy clad material of the present invention comprises an aluminum alloy material according to the above-mentioned invention as a core material, and one or more layers of a different aluminum alloy material are bonded to one or both sides of the core material.

[0012] In another embodiment of the invention of an aluminum alloy clad material, the aluminum alloy material of the above-described embodiment is used as a skin material, and another type of aluminum alloy is used as a core material, with the skin material bonded to one or both sides of the core material.

[0013] The contents stipulated in the present invention will be explained below. Silicon: 1.1 to 2.5% Silicon is included because it contributes to improving strength. However, if the silicon content is below the lower limit, the alloy cannot be considered suitable for recycling. On the other hand, if the silicon content exceeds the upper limit, the melting point of the material will decrease even if element X is included. For this reason, the silicon content is specified. For the same reason, it is preferable to set the lower limit at 1.2% and the upper limit at 2.0%.

[0014] Element X:0.05~2.0% Element X (excluding Mn and Fe) reduces the solid solubility of Si in the base material by forming an intermetallic compound containing Si (in addition to binary intermetallic compounds of Si-X, ternary or higher intermetallic compounds including other elements are also acceptable), thereby suppressing the decrease in the melting point of the base material. If the content is below the lower limit, the effect is insufficient, and if it exceeds the upper limit, the intermetallic compound grows coarsely and the rollability decreases.

[0015] Element X has an outermost shell electron configuration of two electrons in the 4s orbital and no electrons in the 3d orbital, or one or more electrons in the 3d orbital and one or more vacancies in the 3d orbital, or two or more electrons in the 5s orbital and no electrons in the 4d orbital, or one or more electrons in the 4d orbital and one or more vacancies in the 4d orbital. Element X forms an intermetallic compound containing Si, but the purpose of this is to reduce the solubility of Si in the base material and suppress the drop in the melting point of the base material; in other words, this intermetallic compound must not dissolve during brazing heat treatment and the constituent elements must not redissolve in aluminum. To meet this condition, a strong bond must be formed, and at least one of the elements that make up the intermetallic compound must have a wide orbital spread. Here, the orbital of Si that is not a closed shell is the 3p orbital, but the spread of the p orbital is insufficient. In order to meet the above condition, element X must have a d orbital with a large orbital spread that participates in the bond. For an element with two electrons in the 4s orbital and no electrons in the 3d orbital, even if there is no electron in the 3d orbital, if there are two electrons in the 4s orbital, the energy difference between the 4s orbital and the 3d orbital is small, and the electron in the 4s orbital can transition to the 3d orbital, and the 3d orbital can contribute to the bond. If there is one electron in the 4s orbital and all the 3d orbitals are vacant, the energy difference between the 4s orbital and the 3d orbital is large, so transition is not possible. When an element has an electron in the 3d orbital, the 3d orbital can contribute to bonding, but if the 3d orbital becomes a closed shell, it cannot receive electrons and cannot contribute to bonding. The same is true for the 5s and 4d orbitals. Note that, unlike the elements mentioned above, elements that have electrons in the 6s or 5d orbital have a 4f orbital involved in the arrangement of electrons, but if the f orbital has an electron, lanthanide contraction will occur and the bond will be weakened, making it inappropriate. The same applies below.

[0016] Specific examples of the element X include Ca, Sc, Cr, Sr, Y, and Mo. More preferred elements include Ca, Sr, and Cr.

[0017] Mn: 0.1-2.0% Mn is added as desired to improve material strength by precipitating as intermetallic compounds such as Al-Mn, Al-Mn-Si, Al-Mn-Fe, and Al-Mn-Si-Fe. If the content is below the lower limit, the effect is insufficient, and if the content is above the upper limit, coarse intermetallic compounds (crystallized products) are generated during casting, and rollability is reduced. Note that Mn may be contained in an amount of 0.03% or less as an inevitable impurity.

[0018] Fe: 0.05-0.7 Fe is optionally contained in order to improve the strength of the material by precipitating as an intermetallic compound such as Al-Mn-Fe or Al-Mn-Si-Fe. If the content is less than the lower limit, the cost increases, and if it exceeds the upper limit, coarse intermetallic compounds (crystallized products) are generated during casting, and rollability decreases. Fe may be contained in an amount of less than 0.05% as an inevitable impurity.

[0019] Cu: 0.01 to 1.5% Cu is optionally added to improve the strength of the material by dissolving in solid solution. If the content is below the lower limit, the effect is insufficient, whereas if the content is above the upper limit, the material strength becomes too high, making it difficult to manufacture the material. The content of Cu may be less than 0.01% as an unavoidable impurity.

[0020] One or more of Ti, V, Co, Ni, Zr, and Nb: 0.35% or less These elements are optionally added in order to form intermetallic compounds and improve the strength of the material. If the content exceeds the upper limit, coarse intermetallic compounds are formed during casting, and rollability is reduced.

[0021] Zn: 0.01-8.0%, Mg: 0.01-1.5% (type 1 or type 2) Zn is optionally contained in order to make the natural potential of the material lower than that of other members by dissolving in solid solution and to improve the pitting corrosion resistance by its sacrificial anticorrosive effect, which is particularly effective when the aluminum material of the present invention is used as a constituent material of a clad material. If the content is below the lower limit, the effect is insufficient, whereas if the content is above the upper limit, the potential becomes excessively noble, increasing the rate of self-corrosion. Mg improves the strength of the material through solid solution. 2 It is optionally contained in order to improve the strength of the material by precipitating as an intermetallic compound with Si, etc. If the content is below the lower limit, the effect is insufficient, and if it exceeds the upper limit, the material strength becomes too high, making it difficult to manufacture the material. Zn may be contained as an unavoidable impurity in an amount of less than 0.01%, and Mg may be contained as an unavoidable impurity in an amount of less than 0.01%.

[0022] Dispersion amount of intermetallic compounds Observation of the surface layer (RD-TD) direction of intermetallic compounds containing Si and X showed that 10,000 μm2 of the intermetallic compounds had a circle equivalent diameter of 1 μm or more. 2 More than 10 per If the particles are too fine, they will redissolve during the brazing heat treatment, and if a predetermined distribution number is not obtained, the effect of suppressing the melting point decrease cannot be obtained sufficiently. The intermetallic compounds containing Si and X can be distributed in a predetermined size and number by controlling the cooling rate in casting, the homogenization treatment conditions, the temperature and time in hot rolling, and the reduction rate per pass in cold rolling.

[0023] Melting point (solidus temperature) of 590°C or higher The melting point (solidus temperature) of the base material, which is mainly composed of aluminum, is 590°C or higher. If the melting point is less than 590°C, the base material will melt during the brazing heat treatment, making it impossible to manufacture heat exchangers, etc.

[0024] Aluminum alloy clad material The aluminum alloy material of the present invention can be used alone, but can also be used as a constituent material of an aluminum alloy clad material bonded with other materials. In one embodiment, the aluminum alloy material of the present invention is used as a core material, and a skin material can be used on one or both sides of the core material. The skin material may be either a single layer or multiple layers. When used as a core material, the material may be a single layer, or the material may be multi-layered, or the material may be multi-layered with another material. In another embodiment, the aluminum alloy material of the present invention can be used as a skin material of an aluminum alloy clad material. Various aluminum materials or aluminum alloy materials can be used as the core material, and the present invention is not limited to a specific material for the core material. The aluminum alloy material of the present invention can be laminated to one or both sides of the core material. The aluminum alloy material can be a single layer or multiple layers.

[0025] The aluminum alloy material and aluminum alloy clad material of the present embodiment are preferably used by being subjected to brazing, although the use of the present embodiment is not limited thereto. Effect of the Invention

[0026] According to the present invention, the element X supplements Si, suppressing a drop in the melting point of the material and preventing erosion during brazing, thereby enabling good brazing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] An embodiment of the present invention will be described below. The aluminum alloy material of the present invention can be manufactured through the steps of casting, homogenization treatment, facing, soaking, hot rolling, and cold rolling after being adjusted to have a composition as specified in the present application, and can be subjected to intermediate annealing and final annealing as necessary. There are no particular requirements for facing, soaking, intermediate annealing, or final annealing.

[0028] Casting and cooling rate Casting can be performed using semi-continuous casting or the like. There is no particular limitation on the casting method. The cooling rate during casting is preferably 0.1°C / s or more and less than 25°C / s. If the cooling rate during casting is below the lower limit, the intermetallic compounds containing Si and X will grow coarsely and the rollability will decrease. If it exceeds the upper limit, it will be impossible to generate a sufficient amount and size of intermetallic compounds. For the same reason, it is preferable to set the cooling rate to 0.5°C / s or more and less than 15°C / s.

[0029] Homogenization After casting, it is desirable to carry out homogenization treatment. The homogenization treatment is desirably carried out at a temperature of 400°C or higher and lower than 620°C for 1 to 10 hours. By carrying out homogenization treatment under the above-mentioned specified conditions, the precipitation and growth of intermetallic compounds containing Si and X is promoted. If the temperature is lower than the lower limit, sufficient effect cannot be obtained, and if the temperature exceeds the upper limit, the material will melt. For the same reason, it is desirably 470°C or higher and lower than 600°C. The time is desirably 3 hours or more.

[0030] Temperature and time in hot rolling The rolling time at a material temperature of 400 to 500°C is preferably 3 minutes or more. By satisfying the above-mentioned predetermined rolling time in which dynamic strain is introduced in the predetermined high temperature range, the precipitation of intermetallic compounds containing Si and X of a predetermined size defined in the present invention is promoted. If the predetermined time is not met, sufficient effect cannot be obtained. For the same reason, 5 minutes or more is preferable.

[0031] Reduction per pass in cold rolling In cold rolling, the reduction rate per pass is preferably less than 60%. If it exceeds the upper limit, the intermetallic compounds containing Si and X are crushed finely, and the size of the intermetallic compounds cannot be satisfied. For the same reason, it is preferably less than 45%.

[0032] When the aluminum alloy material of the present embodiment is used as a constituent material of a clad material, the manufacturing process of the clad material is as follows: the skin material is cast, and if necessary, homogenized, surface-cut, and hot-rolled, and the core material and the skin material are assembled, and then the clad material is manufactured through soaking, hot rolling, and cold rolling. At this time, intermediate annealing and final annealing are performed if necessary. The manufacturing conditions of the clad rolling are the same as those described above.

[0033] In the aluminum alloy material obtained in this embodiment, when the intermetallic compounds containing Si and X were observed in the surface layer (RD-TD plane) direction, the number of those having a circle equivalent diameter of 1 μm or more was 10,000 μm. 2 There are more than 10 per unit area. In addition, the base material of aluminum alloys, which is mainly composed of aluminum, has a melting point (solidus temperature) of 590°C or higher.

[0034] Although the present invention has been described based on the above embodiment, appropriate modifications can be made to the above embodiment without departing from the scope of the present invention. EXAMPLES

[0035] Aluminum alloys with the composition shown in Table 1 (the balance being Al and unavoidable impurities) were prepared, and then cast under the conditions shown in Table 2, followed by the steps of casting → homogenization → facing → soaking → hot rolling → cold rolling, to produce bare materials with a thickness of 1 mm and temper O. These were used as test materials (excluding materials for evaluating corrosion resistance).

[0036] Distribution of intermetallic compounds containing Si and elements with the above electron configuration (element X: excluding Mn and Fe) The obtained test materials were evaluated for the distribution of intermetallic compounds containing Si and an element having the above-mentioned electron configuration (element X: excluding Mn and Fe). In the evaluation, the material cross section (RD-ND surface) was exposed by cross-section polishing, and a FE-EPMA (field emission electron probe microanalyzer) was used to perform fully automated particle analysis from the material cross section (RD-ND surface) direction to measure 10,000 μm 2 In the observation field, the number of intermetallic compounds containing Si and an element having the above-mentioned electron configuration (element X: excluding Mn and Fe) having a circle equivalent diameter of 1 μm or more was counted. The results are shown in Tables 3 to 6.

[0037] Melting Point Determination The melting point (solidus temperature) of each test material was measured using differential thermal analysis. The melting point of each test material was evaluated into three levels: A, B, and C. A: 600℃ or higher is good B: 590℃ to less than 600℃ is slightly better C: Less than 590℃ is defective

[0038] Material Strength After heat treatment equivalent to brazing, samples were cut out parallel to the rolling direction to prepare JIS No. 13 B test pieces, and tensile tests were performed. The brazing conditions were heating to 600°C at an average heating rate of 100°C / min, holding at 600°C for 3 minutes, and then cooling to 150°C at a cooling rate of 100°C / min. The material strength of each test material was evaluated on the following three levels: A, B, and C. A: 190MPa or more is good B: 170MPa or more but less than 190MPa is considered to be somewhat good. C: Less than 170MPa is defective

[0039] Corrosion resistance The aluminum alloy material of the Zn-containing alloy corresponding to the present invention was manufactured under the conditions shown in Table 2 as a sacrificial material, and A3003 was used as a core material to prepare a clad material by bonding them together. At this time, the plate thickness of the clad material was 0.2 mm, and the clad ratio of the sacrificial material was 20%. The surfaces other than the sacrificial material were masked, and the SWAAT test was performed for 40 days, and the corrosion resistance was evaluated based on the corrosion depth of the sacrificial material. The corrosion resistance of each test material was evaluated in two stages, A and C, as follows. A: Maximum corrosion depth of less than 80μm is good. C: 80μm or more is defective

[0040] [Table 1]

[0041] [Table 2]

[0042] [Table 3]

[0043] [Table 4]

[0044] [Table 5]

[0045]

Table 6

Claims

1. An aluminum alloy material having a composition containing 1.1 to 2.5% by mass of Si, 0.05 to 2.0% by mass of an element (excluding Mn and Fe, hereinafter referred to as X) that forms an intermetallic compound containing Si, and the remainder being Al and unavoidable impurities, wherein X has an outermost shell electron configuration in which two electrons are arranged in the 4s orbital and no electron in the 3d orbital, or has one or more electrons in the 3d orbital and one or more vacancies in the 3d orbital, or has an outermost shell electron configuration in which two electrons are arranged in the 5s orbital and no electron in the 4d orbital, or has one or more electrons in the 4d orbital and one or more vacancies in the 4d orbital, and the intermetallic compound containing Si and X has a circle equivalent diameter of 1 μm or more when observed in the surface layer surface (RD-TD surface) direction, and the number of intermetallic compounds containing Si and X that have a circle equivalent diameter of 1 μm or more is 10,000 μm or more. ２ and a melting point (solidus temperature) of 590°C or higher.

2. 2. The aluminum alloy material according to claim 1, wherein the composition contains, in mass%, one or more of Mn: 0.1 to 2.0%, Fe: 0.05 to 0.7%, and Cu: 0.01 to 1.5%.

3. 3. The aluminum alloy material according to claim 1, wherein the composition contains one or more of Ti, V, Co, Ni, Zr and Nb in an amount of 0.35% by mass or less.

4. 3. The aluminum alloy material according to claim 1, further comprising, in mass %, one or both of Zn: 0.01 to 8.0% and Mg: 0.01 to 1.5%.

5. The aluminum alloy material according to claim 3, wherein the composition contains, in mass %, one or both of Zn: 0.01 to 8.0% and Mg: 0.01 to 1.5%.

6. 3. An aluminum alloy clad material comprising the aluminum alloy material according to claim 1 or 2 as a core material, and one or more layers of a different type of aluminum alloy material bonded to one or both sides of the core material.

7. 4. An aluminum alloy clad material comprising the aluminum alloy material according to claim 3 as a core material, and one or more layers of a different type of aluminum alloy material bonded to one or both sides of the core material.

8. 5. An aluminum alloy clad material comprising the aluminum alloy material according to claim 4 as a core material, and one or more layers of a different aluminum alloy material bonded to one or both sides of the core material.

9. 6. An aluminum alloy clad material comprising the aluminum alloy material according to claim 5 as a core material, and one or more layers of a different aluminum alloy material bonded to one or both sides of the core material.

10. 3. An aluminum alloy clad material, comprising the aluminum alloy material according to claim 1 or 2 as a skin material, a different aluminum alloy as a core material, and the skin material bonded to one or both sides of the core material.

11. 4. An aluminum alloy clad material, comprising the aluminum alloy material according to claim 3 as a skin material, a different aluminum alloy as a core material, and the skin material bonded to one or both sides of the core material.

12. 5. An aluminum alloy clad material, comprising the aluminum alloy material according to claim 4 as a skin material, a different aluminum alloy as a core material, and the skin material bonded to one or both sides of the core material.

13. 6. An aluminum alloy clad material, comprising the aluminum alloy material according to claim 5 as a skin material and another aluminum alloy as a core material, the skin material being bonded to one or both sides of the core material.

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