Aluminum alloy materials and aluminum alloy clad materials

Abstract

To provide an aluminum alloy material with excellent brazing properties that can be manufactured using raw materials such as waste materials generated during the manufacturing process of many clad materials, waste materials from aluminum alloy heat exchangers, and recycled materials collected from the market, thereby reducing the amount of new metal used and significantly reducing CO2 emissions. [Solution] The aluminum alloy material contains, relative to the total mass of the aluminum alloy material, Si: 1.1% by mass to 1.6% by mass, Fe: 0.1% by mass to 0.8% by mass, Mn: 0.8% by mass to 2.0% by mass, Cu: 0.3% by mass to 0.8% by mass, Zn: 0.2% by mass to 0.5% by mass, Cr: 0.6% by mass or less, Mg: 0.5% by mass or less, Ti: 0.5% by mass or less, and the balance consisting of Al and unavoidable impurities. Also, the average cross-sectional area of ​​elemental Si is 8.2 μm 2 The following is the result.

Description

[Technical Field]

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

[0002] In recent years, achieving carbon neutrality has become a challenge for society as a whole, and various methods for solving this problem are being considered. For example, in light of resource depletion, recycling of various materials has progressed, and recycling of metals, which are consumed in large quantities, has been carried out for some time. Furthermore, with growing global interest in the environment, and in consideration of responding to the ELV Directive (End-of-Life Vehicles Directive), there is a demand for the reuse of waste materials such as those from automotive heat exchangers. In particular, aluminum consumes a large amount of electricity and emits CO2 during the production of virgin aluminum. Therefore, reducing the amount of virgin aluminum used through recycling can significantly reduce CO2 emissions during the production of aluminum alloy materials.

[0003] However, because automotive heat exchangers are made of clad materials, which are made of aluminum alloy cores and laminated with sacrificial anode materials that impart corrosion resistance to the surface and brazing filler metals that impart brazing properties to the surface, recycling clad materials to produce core materials can sometimes result in a deterioration of the core material's properties. For this reason, recycling clad materials used in heat exchangers is more difficult than recycling single-layer aluminum alloy materials.

[0004] Patent Document 1 discloses a method for producing an aluminum alloy material using a casting raw material containing a predetermined content of scrap from automotive heat exchangers using clad materials and / or scrap from aluminum alloy clad materials used in automotive heat exchangers. The production method described in Patent Document 1 includes a casting step of casting an aluminum alloy ingot A having a predetermined composition using the casting raw material, and the natural electrode potential of the resulting aluminum alloy part A is specified. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7275336 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the aluminum alloy material produced by the manufacturing method described in Patent Document 1 does not have sufficiently excellent recyclability and brazability. For example, when producing a core material by recycling scrap from end-of-life vehicles, increasing the scrap content increases the Si concentration in the core material and significantly reduces the solidus temperature. In other words, while increasing the Si concentration is necessary to improve the recycling rate, an increase in the Si concentration in the core material leads to melting of the core material during brazing, resulting in a decrease in brazability.

[0007] The present invention has been made in consideration of the above problems, and aims to provide an aluminum alloy material and an aluminum alloy clad material that can be manufactured using as raw materials a large amount of waste materials generated during the manufacturing process of clad materials, waste materials from aluminum alloy heat exchangers, and recycled materials collected from the market, and that have excellent brazing properties, thereby reducing the amount of virgin metal used and significantly reducing CO2 emissions. [Means for solving the problem]

[0008] The above object can be achieved by the aluminum alloy material according to the present invention described below in [1].

[0009] [1] Based on the total mass of the aluminum alloy material, Si: 1.1% by mass or more and 1.6% by mass or less, Fe: 0.1% by mass or more and 0.8% by mass or less, Mn: 0.8% by mass or more and 2.0% by mass or less, Cu: 0.3% by mass or more and 0.8% by mass or less, Zn: 0.2% by mass or more and 0.5% by mass or less, Cr: 0.6% by mass or less, Mg: 0.5% by mass or less, Ti: 0.5% by mass or less; the balance being Al and unavoidable impurities, The average cross-sectional area of ​​elemental Si is 8.2 μm 2 An aluminum alloy material characterized by the following:

[0010] Moreover, the aluminum alloy material of the present invention is preferably the following [2].

[0011] [2] Furthermore, Zr: 0.30 mass% or less, V: 0.30% by mass or less, Ca: 0.10% by mass or less, and The aluminum alloy material according to [1], characterized in that it contains at least one selected from the following: Sr: 0.10 mass % or less.

[0012] The above object can also be achieved by the aluminum alloy clad material according to the present invention described below in [3].

[0013] [3] A core material made of the aluminum alloy material according to [1] or [2]; and a skin material laminated on at least a portion of the surface of the core material. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an aluminum alloy material and an aluminum alloy clad material having excellent brazing properties, which can be manufactured using raw materials such as waste materials generated during the manufacturing process of a larger number of clad materials, waste materials from aluminum alloy heat exchangers, and recycled materials collected from the market, thereby reducing the amount of virgin metal used and significantly reducing CO2 emissions. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a graph showing a differential thermal analysis curve of aluminum alloy test material A, with the vertical axis representing differential thermal analysis (DTA) and the horizontal axis representing measurement temperature. [Figure 2] FIG. 2 is a graph in which the scale of the vertical axis of FIG. 1 is enlarged. [Figure 3] FIG. 3 is a graph showing a differential thermal analysis curve of aluminum alloy test material B, with the vertical axis representing differential thermal analysis (DTA) and the horizontal axis representing measurement temperature, with the vertical axis scale enlarged. [Figure 4] FIG. 4 is a graph showing the relationship between the heat of fusion and the average cross-sectional area of ​​simple substance Si. [Figure 5] FIG. 5 is a photograph, substituted for a drawing, showing an image obtained by performing a mapping analysis using an EPMA on the aluminum alloy material of Example No. 4. [Figure 6] FIG. 6 is a photograph, substituted for a drawing, showing an image obtained by carrying out a mapping analysis by EPMA on the aluminum alloy material of Comparative Example No. 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present inventors conducted extensive research into the effect of the blending of waste and recovered materials on brazing properties. While core materials typically do not melt at brazing temperatures, they found that core materials containing a large amount of recycled material locally melt below the brazing temperature. Specifically, an increase in the Si content in the aluminum alloy material constituting the core material increases the melting peak area below 600°C in the differential thermal analysis curve. This melting peak below 600°C rises at 577°C or 559°C, which is thought to represent melting of the elemental Si or Mg2Si phase.

[0017] Furthermore, the inventors of the present invention have found that as the amount of local melting of the core material increases, the amount of fluid brazing material decreases, resulting in a deterioration in brazeability. This is thought to be because the amount of Si diffused from the brazing material increases due to the local melting of the core material, reducing the liquid phase fraction of the brazing material. Therefore, they considered that there is a correlation between the average cross-sectional area (size) of elemental Si in an aluminum alloy material and the heat of fusion. As a result of further investigation, they found that the smaller the size of elemental Si, the smaller the heat of fusion.

[0018] In the aluminum alloy material according to this embodiment, the amount of Al-Mn-Si(-Fe-Cr) compounds with high melting points is increased, and the elemental Si is finely dispersed, and the average cross-sectional area of ​​the elemental Si is controlled to a predetermined value or less, thereby reducing the heat of fusion, thereby suppressing local melting of the aluminum alloy material as the core material and improving brazability.

[0019] Hereinafter, an aluminum alloy material according to an embodiment of the present invention will be described in detail.

[0020] [Aluminum alloy material] Hereinafter, the chemical components contained in the aluminum alloy material according to the embodiment of the present invention and the reasons for limiting the contents thereof will be described in detail.

[0021] (Si: 1.1 mass% or more and 1.6 mass% or less) Si is an element that improves the strength of aluminum alloy materials. However, as described above, when an aluminum alloy material is used as a core material, an increase in the Si content in the aluminum alloy material increases the amount of local melting of the core material, causing the core material to melt below the brazing temperature, while reducing the amount of melting of the brazing material at the desired temperature. Specifically, if the Si content in the aluminum alloy material is less than 1.1 mass%, the amount of recycled material used in the market cannot be increased, resulting in a decrease in the recycling rate. Therefore, the Si content in the aluminum alloy material is set to 1.1 mass% or more, preferably 1.2 mass% or more, and more preferably 1.3 mass% or more, relative to the total mass of the aluminum alloy material. On the other hand, if the Si content in the aluminum alloy material exceeds 1.6 mass%, the amount of elemental Si and Mg-Si compounds produced significantly increases, resulting in a decrease in brazability. Therefore, the Si content in the aluminum alloy material is set to 1.6 mass% or less, preferably 1.58 mass% or less, and more preferably 1.55 mass% or less, relative to the total mass of the aluminum alloy material.

[0022] (Fe: 0.1 mass% or more and 0.8 mass% or less) The inclusion of Fe in the aluminum alloy material allows Si to precipitate as an Al-Mn-Si-Fe compound, further suppressing local melting of the aluminum alloy material used as the core material and further improving brazability. Furthermore, since commercially available recycled materials generally contain Fe, in order to reduce the Fe content in the aluminum alloy material to less than 0.1% by mass, high-purity aluminum ingots must be used, increasing production costs. Therefore, the Fe content in the aluminum alloy material is set to 0.1% by mass or more, preferably 0.2% by mass or more, and more preferably 0.3% by mass or more, based on the total mass of the aluminum alloy material. On the other hand, if the Fe content in the aluminum alloy material exceeds 0.8% by mass, large intermetallic compounds are likely to form during casting, reducing plastic workability. Therefore, the Fe content in the aluminum alloy material is set to 0.8% by mass or less, preferably 0.7% by mass or less, and more preferably 0.6% by mass or less, based on the total mass of the aluminum alloy material.

[0023] (Mn: 0.8 mass% or more and 2.0 mass% or less) As described above, Mn is an element that precipitates Si as an Al-Mn-Si compound, thereby refining the size of elemental Si in the aluminum alloy material and reducing the amount of Mg-Si compounds. By incorporating an appropriate amount of Mn into the aluminum alloy material, local melting of the aluminum alloy material used as the core material can be suppressed, thereby improving brazability. If the Mn content in the aluminum alloy material is less than 0.8% by mass, the effect of improving brazability cannot be fully achieved. Therefore, the Mn content in the aluminum alloy material is set to 0.8% by mass or more, preferably 1.0% by mass or more, and more preferably 1.1% by mass or more, relative to the total mass of the aluminum alloy material. On the other hand, if the Mn content in the aluminum alloy material exceeds 2.0% by mass, large intermetallic compounds are likely to be formed during casting, which reduces plastic workability. Therefore, the Mn content in the aluminum alloy material is set to 2.0% by mass or less, preferably 1.9% by mass or less, and more preferably 1.8% by mass or less, relative to the total mass of the aluminum alloy material.

[0024] (Cu: 0.3 mass% or more and 0.8 mass% or less) Waste materials and recovered materials generally contain Cu. Therefore, in order to make the Cu content in the aluminum alloy material less than 0.3% by mass, it is necessary to use high-purity aluminum ingots, which increases production costs. Furthermore, if the Cu content in the aluminum alloy material is less than 0.3% by mass, the corrosion resistance of the core material decreases. Therefore, the Cu content in the aluminum alloy material is set to 0.3% by mass or more, preferably 0.32% by mass or more, and more preferably 0.35% by mass or more, relative to the total mass of the aluminum alloy material. On the other hand, if the Cu content in the aluminum alloy material exceeds 0.8% by mass, the solidus temperature decreases, making it more likely to melt during brazing. Therefore, the Cu content in the aluminum alloy material is set to 0.8% by mass or less, preferably 0.7% by mass or less, and more preferably 0.65% by mass or less, relative to the total mass of the aluminum alloy material.

[0025] (Zn: 0.2 mass% or more and 0.5 mass% or less) Waste materials and recovered materials generally contain Zn, a component derived from sacrificial anode materials. Therefore, in order to keep the Zn content in the aluminum alloy material below 0.2% by mass, it is necessary to use high-purity aluminum bullion, which increases production costs. Therefore, the Zn content in the aluminum alloy material is set to 0.2% by mass or more, preferably 0.21% by mass or more, and more preferably 0.22% by mass or more, relative to the total mass of the aluminum alloy material. On the other hand, if the Zn content in the aluminum alloy material exceeds 0.5% by mass, the solidus temperature decreases, making it more likely to melt during brazing. Therefore, the Zn content in the aluminum alloy material is set to 0.5% by mass or less, preferably 0.48% by mass or less, and more preferably 0.45% by mass or less, relative to the total mass of the aluminum alloy material.

[0026] (Cr: 0.6% by mass or less) Cr is an element that can precipitate Si as an Al-Mn-Si-Fe-Cr compound, suppresses local melting of the aluminum alloy material used as the core material, and has the effect of improving brazability. Therefore, the aluminum alloy material may contain Cr as needed, but it may also contain 0% by mass. In this embodiment, the lower limit of the Cr content in the aluminum alloy material is not particularly limited, but when the Cr content in the aluminum alloy material is 0.02% by mass or more, the brazability can be further improved. Therefore, the Cr content in the aluminum alloy material is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and particularly preferably 0.15% by mass or more, based on the total mass of the aluminum alloy material. On the other hand, when the Cr content in the aluminum alloy material exceeds 0.6% by mass, giant intermetallic compounds are likely to be formed, which may deteriorate the plastic workability. Therefore, the Cr content in the aluminum alloy material is set to 0.6 mass % or less, preferably 0.55 mass % or less, and more preferably 0.5 mass % or less, relative to the total mass of the aluminum alloy material.

[0027] (Mg: 0.5% by mass or less) Since Mg is an element that reacts with flux during brazing and reduces brazability, a small Mg content in the aluminum alloy material is preferable. If the Mg content in the aluminum alloy material exceeds 0.5 mass%, the brazability will decrease. Therefore, the Mg content in the aluminum alloy material is set to 0.5 mass% or less, preferably 0.4 mass% or less, more preferably 0.3 mass% or less, and even more preferably 0 mass% with respect to the total mass of the aluminum alloy material.

[0028] (Ti: 0.5% by mass or less) Ti is an element that has the effect of improving the strength of an aluminum alloy material through solid-solution strengthening. Furthermore, the inclusion of Ti in an aluminum alloy material has the effect of slightly increasing the solidus temperature, thereby suppressing local melting of the aluminum alloy material and improving brazability. Therefore, the aluminum alloy material may contain Ti, if necessary, but it may contain 0 mass% Ti. In this embodiment, the lower limit of the Ti content in the aluminum alloy material is not particularly limited. However, when the Ti content in the aluminum alloy material is 0.05 mass% or more, the effect of improving the strength and brazability of the aluminum alloy material can be obtained. Therefore, the Ti content in the aluminum alloy material is preferably 0.05 mass% or more, and more preferably 0.10 mass% or more, relative to the total mass of the aluminum alloy material. On the other hand, when the Ti content in the aluminum alloy material exceeds 0.5 mass%, large intermetallic compounds are likely to be formed, which may result in a decrease in plastic workability. Therefore, the Ti content in the aluminum alloy material is 0.5 mass% or less, preferably 0.4 mass% or less, and more preferably 0.3 mass% or less, relative to the total mass of the aluminum alloy material.

[0029] The aluminum alloy material according to this embodiment has the specified contents of the above elements, but may further contain Zr, V, Ca, and Sr in appropriate contents. The effects and preferred contents of Zr, V, Ca, and Sr will be described below.

[0030] (Zr: 0.30% by mass or less) Zr in the aluminum alloy material improves strength through solid solution strengthening and also precipitates Al-Zr-based intermetallic compounds, which act to coarsen crystal grains after brazing. Therefore, the aluminum alloy material may contain Zr as needed, but it may also contain 0 mass% Zr. In this embodiment, when the Zr content in the aluminum alloy material is 0.30 mass% or less, the formation of giant intermetallic compounds can be suppressed and a decrease in plastic workability can be prevented. Therefore, the Zr content in the aluminum alloy material is preferably 0.30 mass% or less, more preferably 0.20 mass% or less, and even more preferably 0.10 mass% or less, relative to the total mass of the aluminum alloy material.

[0031] (V: 0.30% by mass or less) V in an aluminum alloy material has the effect of improving strength through solid solution strengthening. Therefore, the aluminum alloy material may contain V as necessary, but may contain 0 mass% V. In this embodiment, when the V content in the aluminum alloy material is 0.30 mass% or less, the formation of giant intermetallic compounds can be suppressed, and a decrease in plastic workability can be prevented. Therefore, the V content in the aluminum alloy material is preferably 0.30 mass% or less, more preferably 0.20 mass% or less, and even more preferably 0.10 mass% or less, relative to the total mass of the aluminum alloy material.

[0032] (Ca: 0.10% by mass or less) Ca in the aluminum alloy material increases the pH upon dissolution, suppressing the decrease in pH due to the hydrolysis reaction at the local anode where Al dissolution occurs and thereby suppressing the corrosion reaction, which is effective in improving corrosion resistance. Therefore, the aluminum alloy material may contain Ca as needed, but it may contain 0% by mass. In this embodiment, when the Ca content in the aluminum alloy material is 0.10% by mass or less, deterioration of brazing properties can be suppressed in brazing using a fluoride flux. Therefore, the Ca content in the aluminum alloy material is preferably 0.10% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less, based on the total mass of the aluminum alloy material.

[0033] (Sr: 0.10% by mass or less) Sr in the aluminum alloy material has the effect of refining elemental Si. Furthermore, since waste materials and recovered materials may contain Sr, the Sr content in the aluminum alloy material may be 0% by mass in order to use the waste materials and recovered materials as raw materials for the aluminum alloy material. However, Sr may be contained as necessary. When the Sr content in the aluminum alloy material is 0.10% by mass or less, the formation of giant Sr-based compounds can be suppressed, and a decrease in plastic workability can be prevented. Therefore, the Sr content in the aluminum alloy material is preferably 0.10% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less, based on the total mass of the aluminum alloy material.

[0034] (Remainder: Al and inevitable impurities) The balance of the aluminum alloy material according to this embodiment is Al and unavoidable impurities. Examples of the unavoidable impurities include B, Sc, Ni, Mo, Na, In, and Bi. Each of these unavoidable impurities may be contained in an amount of less than 0.05% by mass. The total amount of the unavoidable impurities in the aluminum alloy material is preferably 0.2% by mass or less, and more preferably 0.1% by mass or less, based on the total mass of the aluminum alloy material.

[0035] <Average cross-sectional area of ​​simple silicon: 8.2 μm 2 Below> In an aluminum alloy material serving as a core material, if the amount of local melting increases in a temperature range below the brazing temperature, the amount of Si diffusing from the brazing material increases, resulting in a deterioration in brazability. Therefore, in this embodiment, the average cross-sectional area (i.e., average cross-sectional area) of simple substance Si is specified based on a differential thermal analysis (DTA) curve of the aluminum alloy material in order to make the amount of heat of fusion calculated from an endothermic peak in a temperature range below the brazing temperature a predetermined value or less. First, the amount of heat of fusion will be described in more detail below.

[0036] Fig. 1 is a graph showing a differential thermal analysis curve of aluminum alloy test material A, with the vertical axis representing differential thermal analysis (DTA) and the horizontal axis representing measurement temperature, and Fig. 2 is a graph with the vertical axis of Fig. 1 scaled up. Fig. 3 is a graph with the vertical axis representing differential thermal analysis (DTA) and the horizontal axis representing measurement temperature, with the vertical axis scaled up. The differential thermal analysis curves shown in Figs. 1 to 3 were measured at a heating rate of 40°C / min.

[0037] The degree of melting of the core material during brazing heating can be evaluated, for example, using a DTA curve. DTA analysis analyzes the flow of heat, and can measure not only the amount of heat involved in the temperature rise, but also the change in the state of the aluminum alloy between the liquid and solid phases. As shown in Figure 1, for example, when the temperature of aluminum alloy test material A is increased, an endothermic peak protruding downward appears. If this endothermic peak appears at a temperature lower than 600°C, it can be determined that the aluminum alloy material used as the core material is locally melting below the brazing temperature, which may affect brazability.

[0038] The content of each component in aluminum alloy test material A shown in FIGS. 1 and 2 and aluminum alloy test material B shown in FIG. 3 is shown below in mass % relative to the total mass of the test material. (Aluminum alloy test material A) Si:1.26%, Fe:0.27%, Cu:0.29%, Mn:0.93%, Mg:0.02%, Zn:0.28% (Aluminum alloy test material B) Si:1.66%, Fe:0.27%, Cu:0.26%, Mn:0.86%, Mg:0.65%, Zn:0.30%

[0039] Specifically, the components that significantly differ between test material A and test material B are Si and Mg. As mentioned above, when aluminum alloy materials are produced using waste or recovered materials, the Si content is, for example, 1.1 mass% or more. For aluminum alloy materials with high Si content, an endothermic peak appears between 577°C and 600°C, as shown in Figure 2. Furthermore, for aluminum alloy materials with even higher Si and Mg contents, a larger endothermic peak appears than that shown in Figure 2, as shown in Figure 3. The heat of fusion of the aluminum alloy can be calculated by integrating the magnitude of this endothermic peak over time and converting it to a weight value. Furthermore, since the heat of fusion of pure Al is 397 μV·s / mg, the melting fraction can be roughly estimated from the heat of fusion calculated from the endothermic peak in the differential thermal analysis curve. For example, if the heat of fusion in the temperature range from 550°C to 600°C is 4.0 μV·s / mg, the melting fraction in that temperature range can be estimated as 4.0 / 397 = 1.01%.

[0040] Furthermore, although not shown, a cross-sectional photograph of the aluminum alloy test material A after brazing shows a uniform distribution of elements, whereas a cross-sectional photograph of the aluminum alloy test material B shows a non-uniform distribution of elements. The presence of non-uniform elements indicates the presence of a structure that solidified after melting. Furthermore, in a clad material in which a brazing filler metal is layered on the surface of an aluminum alloy material, it has been confirmed that the flow coefficient of the brazing filler metal decreases as the Si content in the aluminum alloy material increases and the heat of fusion increases. Therefore, in this embodiment, the heat of fusion in the range of 550°C to 600°C is used as an index for determining the range of the average cross-sectional area of ​​elemental Si.

[0041] A method for calculating the heat of fusion will be specifically described using FIG. 2. In FIG. 2, the endothermic reaction begins at approximately 577°C, and the endothermic reaction is considered to start at 550°C or higher regardless of the composition. Therefore, the area of ​​the endothermic peak appearing in the temperature range of 550°C to 600°C is calculated. First, an auxiliary line L1 is drawn along a substantially linear DTA curve in the temperature range below the endothermic reaction start temperature. Next, an auxiliary line L2 parallel to the vertical axis is drawn at 600°C. The area of ​​the region surrounded by the auxiliary line L1, the auxiliary line L2, and the DTA curve is calculated by time integration, and the obtained value is converted to a value per weight, which is used as the heat of fusion.

[0042] Specifically, the heat of fusion of aluminum alloy test material A was 1.6 μV·s / mg, and the heat of fusion of aluminum alloy test material B was 6.6 μV·s / mg. This shows that as the Si content and Mg content in the aluminum alloy material increase, elemental Si and Mg-Si compounds are formed, increasing the heat of fusion. In this embodiment, the average cross-sectional area of ​​elemental Si is specified so that the heat of fusion is 2.5 μV·s / mg or less. Note that it is preferable to adjust each component so that the heat of fusion is 2.0 μV·s / mg or less, and more preferably 1.6 μV·s / mg or less.

[0043] Figure 4 is a graph showing the relationship between the heat of fusion and the average cross-sectional area of ​​elemental Si. As mentioned above, the smaller the size of elemental Si, the smaller the heat of fusion. As shown in Figure 4, when the average cross-sectional area of ​​elemental Si is 8.2 μm 2 If the heat of fusion exceeds 2.5 μV·s / mg, the brazing property will decrease. Therefore, the average cross-sectional area of ​​simple Si in aluminum alloy material is 8.2 μm 2 Less than 8.0μm 2 Preferably, it is 7.0 μm or less. 2 The smaller the average cross-sectional area of ​​the simple substance Si, the better. Although the lower limit of the average cross-sectional area of ​​the simple substance Si is not particularly set, a practical value is 0.5 μm2 The average cross-sectional area of ​​simple substance Si in the aluminum alloy material is preferably 8.2 μm or more in any cross section. 2 It is preferable that:

[0044] The average cross-sectional area of ​​elemental Si can be measured by mapping analysis using an electron probe microanalyzer (EPMA). The method of mapping analysis using EPMA involves elemental mapping of Al, Si, and Mn, and extracting regions where the concentrations of Al and Mn are low and the concentration of Si is particularly high compared to the matrix, thereby identifying these regions as elemental Si. The areas of the identified elemental Si are then individually measured, and the average value calculated, thereby obtaining the average cross-sectional area. The magnification is preferably about 500 times, and the measurement area is about 0.05 mm2 in total. 2 The measurement field may be one field or multiple fields, for example, five fields or ten fields.

[0045] The average cross-sectional area of ​​simple silicon is 8.2 μm 2 In order to achieve the following, for example, a method of controlling the value obtained by a specific formula using the contents of predetermined elements in the aluminum alloy material can be mentioned. The specific formula will be described below.

[0046] (α calculated by formula (1): 1.60 or more) By setting the value α calculated by the following formula (1) to 1.60 or more, the average cross-sectional area of ​​simple silicon can be reduced to 8.2 μm 2 Therefore, the value α is preferably 1.60 or more, more preferably 1.75 or more, and even more preferably 1.85 or more. There is no particular upper limit to the value α, but it is preferably 3.50 or less, for example.

[0047] α={2.4-4.4×exp(-1.1×[Mn])}+{0.70-0.7×exp(-4.0×[Cr])}+[Fe]+0.5×[Ti]...Equation (1) In the above formula (1), [Mn] is the Mn content in the aluminum alloy material expressed as a mass% relative to the total mass of the aluminum alloy material, [Cr] is the Cr content in the aluminum alloy material expressed as a mass% relative to the total mass of the aluminum alloy material, [Fe] is the Fe content in the aluminum alloy material expressed as a mass% relative to the total mass of the aluminum alloy material, and [Ti] is the Ti content in the aluminum alloy material expressed as a mass% relative to the total mass of the aluminum alloy material.

[0048] (Recycling rate: 40% or more) In this embodiment, in order to produce an aluminum alloy material with a high recycling rate using waste materials and recovered materials, the contents of each component in the aluminum alloy material and the heat of fusion calculated from the DTA curve are specified so that excellent brazing properties can be obtained even with a high Si content. The recycling rate R is a value expressed as a percentage of the mass of waste materials and recovered materials relative to the total mass of the aluminum alloy material. By setting the recycling rate R to 40% or more, the effect of reducing CO2 emissions resulting from the use of virgin metal can be sufficiently obtained. Therefore, the recycling rate R is preferably 40% or more, more preferably 45% or more, and even more preferably 50% or more. Furthermore, by setting the recycling rate R to 95% or less, the contents of chemical components such as Si, Mn, Cr, and Fe in the aluminum alloy material can be controlled within appropriate ranges. Therefore, the recycling rate R is preferably 95% or less, more preferably 90% or less, and even more preferably 85% or less.

[0049] [Method of manufacturing aluminum alloy materials] The method for producing the aluminum alloy material according to the embodiment of the present invention is not particularly limited, and the material can be produced by a known production method.

[0050] Next, an aluminum alloy clad material according to an embodiment of the present invention will be described in detail. In this specification, the aluminum alloy clad material may be simply referred to as a "clad material."

[0051] [Aluminum alloy clad material] The clad material according to this embodiment includes a core material made of the aluminum alloy material according to this embodiment and a skin material laminated on at least a portion of the surface of the core material. Examples of the skin material include brazing filler metal and sacrificial anode material. Examples of the clad material include a clad material having a brazing filler metal laminated on at least a portion of the surface of the aluminum alloy material, and a clad material including a sacrificial anode material between the brazing filler metal and the core material. Furthermore, the clad material may include an intermediate layer between the core material and the brazing filler metal.

[0052] The contents of the components contained in the aluminum alloy material for brazing filler metal, the aluminum alloy material for sacrificial anode material, and the intermediate layer, as well as the reasons for limiting the numerical values ​​thereof, will be explained below.

[0053] <Aluminum alloy for brazing filler metal> (Si: 2.50 mass% or more and 13.00 mass% or less) Si in the aluminum alloy material for brazing filler metal improves the liquid phase ratio at the brazing heating temperature, thereby ensuring the amount of molten brazing filler metal. If the Si content in the aluminum alloy material for brazing filler metal is 2.50% by mass or more, a sufficient amount of molten brazing filler metal can be ensured, and the fluidity of the molten brazing filler metal can be maintained appropriately, resulting in excellent brazing properties. Therefore, the Si content in the aluminum alloy material for brazing filler metal is preferably 2.50% by mass or more, more preferably 3.00% by mass or more, and even more preferably 3.50% by mass or more, based on the total mass of the aluminum alloy material for brazing filler metal. Furthermore, if the Si content in the aluminum alloy material for brazing filler metal is 13.00% by mass or less, the fluidity of the molten brazing filler metal can be prevented from becoming too high, and the occurrence of erosion due to the molten brazing filler metal can be suppressed. Therefore, the Si content in the aluminum alloy material for brazing filler metal is preferably 13.00% by mass or less, more preferably 12.50% by mass or less, and even more preferably 12.00% by mass or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0054] (Fe: 0.05 mass% or more and 1.00 mass% or less) Fe in aluminum alloy brazing filler metals tends to form Al-Fe and Al-Fe-Si compounds, which reduces the effective Si content of the brazing filler metal. Furthermore, the formation of Al-Fe and Al-Fe-Si compounds may reduce the fluidity of the brazing filler metal during brazing, potentially impairing brazing performance. Since commonly used aluminum alloy brazing filler metals contain Fe, if the Fe content in the aluminum alloy brazing filler metal is 0.05% by mass or more, it is not necessary to use high-purity metal as a raw material for producing the aluminum alloy brazing filler metal. Therefore, the Fe content in the aluminum alloy brazing filler metal is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.12% by mass or more, based on the total mass of the aluminum alloy brazing filler metal. On the other hand, if the Fe content in the aluminum alloy brazing filler metal is 1.00% by mass or less, good brazing performance can be achieved. Therefore, the Fe content in the aluminum alloy material for brazing filler metal is preferably 1.00 mass% or less, more preferably 0.80 mass% or less, and even more preferably 0.60 mass% or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0055] (Zn: 5.50% by mass or less) Zn is an alloying element that makes the potential of an aluminum alloy less noble. Therefore, when the aluminum alloy material for brazing filler metal contains Zn, it acts as a sacrificial anode material and provides the effect of sacrificial corrosion protection. However, in this embodiment, the Zn content in the aluminum alloy material for brazing filler metal may be 0% by mass. Furthermore, when the Zn content in the aluminum alloy material for brazing filler metal is 5.50% by mass or less, it is possible to prevent a decrease in workability and suppress the occurrence of cracks during cold rolling. Therefore, the Zn content in the aluminum alloy material for brazing filler metal is preferably 5.50% by mass or less, more preferably 5.00% by mass or less, and even more preferably 4.50% by mass or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0056] (Mn: 1.00% by mass or less) Mn in the aluminum alloy material for brazing filler metal improves the viscosity of the molten brazing filler metal and suppresses the flow of the molten brazing filler metal, but in this embodiment, the Mn content in the aluminum alloy material for brazing filler metal may be 0% by mass. Furthermore, if the Mn content in the aluminum alloy material for brazing filler metal is 1.00% by mass or less, the generation of Al-Mn(-Fe-Si)-based compounds with a high specific gravity in the molten brazing filler metal can be suppressed, and the amount of molten brazing filler metal can be kept appropriate. Therefore, the Mn content in the aluminum alloy material for brazing filler metal is preferably 1.00% by mass or less, more preferably 0.95% by mass or less, and even more preferably 0.90% by mass or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0057] (Cu: 1.00% by mass or less) Cu in the aluminum alloy material for brazing filler metal has the effect of improving the corrosion resistance of the region formed when brazing heat is applied, but in this embodiment, the Cu content in the aluminum alloy material for brazing filler metal may be 0 mass%. Furthermore, when the Cu content in the aluminum alloy material for brazing filler metal is 1.00 mass% or less, the noble potential of the brazing filler metal can be suppressed and corrosion of the core material can be prevented. Therefore, the Cu content in the aluminum alloy material for brazing filler metal is preferably 1.00 mass% or less, more preferably 0.95 mass% or less, and even more preferably 0.90 mass% or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0058] (Cr: 0.30 mass% or less) Cr in the aluminum alloy for brazing filler metal improves strength through solid solution strengthening and also precipitates Al-Cr intermetallic compounds, which act to coarsen crystal grains after brazing. In this embodiment, the Cr content in the aluminum alloy for brazing filler metal may be 0% by mass. Furthermore, if the Cr content in the aluminum alloy for brazing filler metal is 0.30% by mass or less, the formation of large intermetallic compounds can be suppressed, and good plastic workability can be obtained. Therefore, the Cr content in the aluminum alloy for brazing filler metal is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for brazing filler metal.

[0059] (Ti: 0.30% by mass or less) Although Ti in the aluminum alloy material for brazing filler metal improves the viscosity of the molten brazing filler metal and suppresses the flow of the molten brazing filler metal, in this embodiment, the Ti content in the aluminum alloy material for brazing filler metal may be 0% by mass. Furthermore, if the Ti content in the aluminum alloy material for brazing filler metal is 0.30% by mass or less, the generation of Al-Ti compounds with a high specific gravity in the molten brazing filler metal can be suppressed, and an excessive amount of molten brazing filler metal flowing downward in the vertical direction can be prevented. Therefore, the Ti content in the aluminum alloy material for brazing filler metal is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0060] (Zr: 0.30% by mass or less) Zr in the aluminum alloy for brazing filler metal improves strength through solid solution strengthening and also precipitates Al-Zr-based intermetallic compounds, which act to coarsen crystal grains after brazing. In this embodiment, the Zr content in the aluminum alloy for brazing filler metal may be 0% by mass. Furthermore, if the Zr content in the aluminum alloy for brazing filler metal is 0.30% by mass or less, the formation of large intermetallic compounds can be suppressed, and a decrease in plastic workability can be prevented. Therefore, the Zr content in the aluminum alloy for brazing filler metal is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for brazing filler metal.

[0061] (V: 0.30% by mass or less) V in the aluminum alloy for brazing filler metal is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the V content in the aluminum alloy for brazing filler metal may be 0 mass%. Furthermore, if the V content in the aluminum alloy for brazing filler metal is 0.30 mass% or less, the formation of large intermetallic compounds can be suppressed, and a decrease in plastic workability can be prevented. Therefore, the V content in the aluminum alloy for brazing filler metal is preferably 0.30 mass% or less, more preferably 0.20 mass% or less, and even more preferably 0.10 mass% or less, based on the total mass of the aluminum alloy for brazing filler metal.

[0062] (Sr: 0.10% by mass or less) Sr in the aluminum alloy material for brazing filler metal is an element that has the effect of refining Si particles and improving brazing properties, but in this embodiment, the Sr content in the aluminum alloy material for brazing filler metal may be 0% by mass. Furthermore, if the Sr content in the aluminum alloy material for brazing filler metal is 0.10% by mass or less, oxidation of Sr during casting can be prevented. Therefore, the Sr content in the aluminum alloy material for brazing filler metal is preferably 0.10% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.02% by mass or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0063] (Na: 0.10% by mass or less) Na in the aluminum alloy material for brazing filler metal is an element that has the effect of refining Si particles and improving brazing properties, but in this embodiment, the Na content in the aluminum alloy material for brazing filler metal may be 0 mass%. Furthermore, if the Na content in the aluminum alloy material for brazing filler metal is 0.10 mass% or less, oxidation of Na during casting can be prevented. Therefore, the Na content in the aluminum alloy material for brazing filler metal is preferably 0.10 mass% or less, more preferably 0.05 mass% or less, and even more preferably 0.02 mass% or less, based on the total mass of the aluminum alloy material for brazing filler metal.

[0064] (Remainder: Al and inevitable impurities) The remainder of the aluminum alloy material for brazing filler metal in the clad material is Al and unavoidable impurities. Examples of the unavoidable impurities include Ca, Be, Sb, rare earth elements, and Li. Specifically, the aluminum alloy material for brazing filler metal may contain up to 0.05% by mass of Ca, up to 0.01% by mass of Be, and less than 0.01% by mass of other elements. The total amount of unavoidable impurities in the aluminum alloy material for brazing filler metal is preferably up to 0.05% by mass of the total mass of the aluminum alloy material for brazing filler metal.

[0065] <Aluminum alloy for sacrificial anodes> (Zn: 0.50 mass% or more and 6.00 mass% or less) Zn in the aluminum alloy material for sacrificial anode material is an element that has the effect of preventing pitting corrosion and crevice corrosion by making the potential of the base material less noble and enhancing the sacrificial corrosion protection effect for the aluminum alloy material for the core material and the intermediate layer. If the Zn content in the aluminum alloy material for sacrificial anode material is 0.50% by mass or more, sufficient sacrificial corrosion protection effect can be obtained. Therefore, the Zn content in the aluminum alloy material for sacrificial anode material is preferably 0.50% by mass or more, more preferably 0.60% by mass or more, and even more preferably 0.70% by mass or more, based on the total mass of the aluminum alloy material for sacrificial anode material. Furthermore, if the Zn content in the aluminum alloy material for sacrificial anode material is 6.00% by mass or less, excessive increase in the self-corrosion of the sacrificial anode material can be prevented, and a decrease in the corrosion resistance of the clad material can be suppressed. Therefore, the Zn content in the aluminum alloy material for sacrificial anode material is preferably 6.00 mass% or less, more preferably 5.70 mass% or less, and even more preferably 5.50 mass% or less, based on the total mass of the aluminum alloy material for sacrificial anode material.

[0066] (Si: 0.05 mass% or more and 1.50 mass% or less) Si in the aluminum alloy material for sacrificial anodes is an element that has the effect of improving the strength of the aluminum alloy material for sacrificial anodes. If the Si content in the aluminum alloy material for sacrificial anodes is 0.05% by mass or more, the effect of improving the strength can be obtained. Therefore, the Si content in the aluminum alloy material for sacrificial anodes is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.15% by mass or more, based on the total mass of the aluminum alloy material for sacrificial anodes. Furthermore, if the Si content in the aluminum alloy material for sacrificial anodes is 1.50% by mass or less, a decrease in the solidus temperature can be suppressed, and melting during brazing can be prevented. Therefore, the Si content in the aluminum alloy material for sacrificial anodes is preferably 1.50% by mass or less, more preferably 1.45% by mass or less, and even more preferably 1.40% by mass or less, based on the total mass of the aluminum alloy material for sacrificial anodes.

[0067] (Fe: 0.05 mass% or more and 2.00 mass% or less), Fe in the aluminum alloy for sacrificial anodes is an element that forms an Al-Fe-Mn-Si compound with Si and Mn, and has the effect of improving strength through dispersion strengthening. When the Fe content in the aluminum alloy for sacrificial anodes is 0.05% by mass or more, the effect of improving strength can be obtained. Therefore, the Fe content in the aluminum alloy for sacrificial anodes is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.12% by mass or more, based on the total mass of the aluminum alloy for sacrificial anodes. Furthermore, when the Fe content in the aluminum alloy for sacrificial anodes is 2.00% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Fe content in the aluminum alloy for sacrificial anodes is preferably 2.00% by mass or less, more preferably 1.80% by mass or less, and even more preferably 1.60% by mass or less, based on the total mass of the aluminum alloy for sacrificial anodes.

[0068] (Mg: 3.00% by mass or less) Mg in the aluminum alloy material for sacrificial anode material is an element that not only improves the strength of the aluminum alloy material for sacrificial anode material itself by precipitating Mg2Si, but also has the effect of diffusing Mg into the core material by brazing heat, thereby improving the strength of the core material. However, in this embodiment, the Mg content in the aluminum alloy material for sacrificial anode material may be 0% by mass. Furthermore, if the Mg content in the aluminum alloy material for sacrificial anode material is 3.00% by mass or less, it can be easily pressure-bonded during hot clad rolling. Therefore, the Mg content in the aluminum alloy material for sacrificial anode material is preferably 3.00% by mass or less, more preferably 2.80% by mass or less, and even more preferably 2.60% by mass or less, based on the total mass of the aluminum alloy material for sacrificial anode material.

[0069] (Mn: 1.80% by mass or less) Mn in the aluminum alloy material for sacrificial anode material is an element that has the effect of improving strength after brazing by dissolving in the base metal and forming an Al-Mn-Si intermetallic compound with Si. However, in this embodiment, the Mn content in the aluminum alloy material for sacrificial anode material may be 0% by mass. Furthermore, if the Mn content in the aluminum alloy material for sacrificial anode material is 1.80% by mass or less, the fluidity of the molten brazing filler metal on the surface of the aluminum alloy material for sacrificial anode material side during brazing is increased, thereby improving brazing properties. Therefore, the Mn content in the aluminum alloy material for sacrificial anode material is preferably 1.80% by mass or less, more preferably 1.60% by mass or less, and even more preferably 1.40% by mass or less, based on the total mass of the aluminum alloy material for sacrificial anode material.

[0070] (Cu: 0.50% by mass or less) When the Cu content in the aluminum alloy material for sacrificial anode material is 0.50 mass% or less, the pitting corrosion potential of the sacrificial anode material is prevented from becoming nobler, and the effect of sacrificial corrosion protection can be sufficiently obtained. Therefore, the Cu content in the aluminum alloy material for sacrificial anode material is preferably 0.50 mass% or less, more preferably 0.40 mass% or less, and even more preferably 0.30 mass% or less, based on the total mass of the aluminum alloy material for sacrificial anode material.

[0071] (Cr: 0.30 mass% or less) Cr in the aluminum alloy for sacrificial anode material is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Cr content in the aluminum alloy for sacrificial anode material may be 0% by mass. Furthermore, if the Cr content in the aluminum alloy for sacrificial anode material is 0.30% by mass or less, it is possible to prevent the formation of large intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the Cr content in the aluminum alloy for sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for sacrificial anode material.

[0072] (Ti: 0.30% by mass or less) Ti in the aluminum alloy for sacrificial anode material is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Ti content in the aluminum alloy for sacrificial anode material may be 0% by mass. Furthermore, if the Ti content in the aluminum alloy for sacrificial anode material is 0.30% by mass or less, it is possible to prevent the formation of large intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the Ti content in the aluminum alloy for sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for sacrificial anode material.

[0073] (Zr: 0.30% by mass or less) Zr in the aluminum alloy for sacrificial anode material is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Zr content in the aluminum alloy for sacrificial anode material may be 0% by mass. Furthermore, if the Zr content in the aluminum alloy for sacrificial anode material is 0.30% by mass or less, it is possible to prevent the formation of giant intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the Zr content in the aluminum alloy for sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for sacrificial anode material.

[0074] (V: 0.30% by mass or less) V in the aluminum alloy for sacrificial anode material is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the V content in the aluminum alloy for sacrificial anode material may be 0% by mass. Furthermore, if the V content in the aluminum alloy for sacrificial anode material is 0.30% by mass or less, it is possible to prevent the formation of large intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the V content in the aluminum alloy for sacrificial anode material is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the aluminum alloy for sacrificial anode material.

[0075] (Remainder: Al and inevitable impurities) The remainder of the aluminum alloy material for sacrificial anode materials in the clad material is Al and unavoidable impurities. Examples of the unavoidable impurities include Ca, Be, Sb, rare earth elements, and Li. Specifically, the aluminum alloy material for sacrificial anode materials may contain 0.05% by mass or less of Ca, 0.01% by mass or less of Be, and less than 0.01% by mass of other elements. The total amount of unavoidable impurities in the aluminum alloy material for sacrificial anode materials is preferably 0.05% by mass or less of the total mass of the aluminum alloy material for sacrificial anode materials.

[0076] <Middle class> (Si: 0.05 mass% or more and 1.50 mass% or less) Si in the intermediate layer is an element that improves strength after brazing by dissolving in the base material and forming an Al-Mn-Si intermetallic compound with Mn. When the Si content in the intermediate layer is 0.05% by mass or more, the strength improvement effect can be sufficiently obtained. Therefore, the Si content in the intermediate layer is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.15% by mass or more, based on the total mass of the intermediate layer. Furthermore, when the Si content in the intermediate layer is 1.50% by mass or less, a decrease in the solidus temperature can be suppressed, and melting during brazing can be prevented. Therefore, the Si content in the intermediate layer is preferably 1.50% by mass or less, more preferably 1.40% by mass or less, and even more preferably 1.30% by mass or less, based on the total mass of the intermediate layer.

[0077] (Fe: 0.05 mass% or more and 2.00 mass% or less) The Fe in the intermediate layer is an element that forms an Al-Fe-Mn-Si compound with Si and Mn, and has the effect of improving strength through dispersion strengthening. When the Fe content in the intermediate layer is 0.05% by mass or more, the effect of improving strength can be sufficiently obtained. Therefore, the Fe content in the intermediate layer is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.12% by mass or more, based on the total mass of the intermediate layer. Furthermore, when the Fe content in the intermediate layer is 2.00% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Fe content in the intermediate layer is preferably 2.00% by mass or less, more preferably 1.80% by mass or less, and even more preferably 1.60% by mass or less, based on the total mass of the intermediate layer.

[0078] (Zn: 6.00% by mass or less) Zn in the intermediate layer is an element that has the effect of lowering the potential of the intermediate layer and improving corrosion resistance, but in this embodiment, the Zn content in the intermediate layer may be 0% by mass. Furthermore, if the Zn content in the intermediate layer is 6.00% by mass or less, a decrease in the solidus temperature of the intermediate layer can be suppressed, and melting of the intermediate layer during brazing can be prevented. Therefore, the Zn content in the intermediate layer is preferably 6.00% by mass or less, more preferably 5.80% by mass or less, and even more preferably 5.60% by mass or less, relative to the total mass of the intermediate layer.

[0079] (Mn: 1.80% by mass or less) Mn in the intermediate layer is an element that has the effect of improving strength after brazing by dissolving in the base material and forming an Al-Mn-Si intermetallic compound together with Si. However, in this embodiment, the Mn content in the intermediate layer may be 0% by mass. Furthermore, if the Mn content in the intermediate layer is 1.80% by mass or less, the precipitation of coarse intermetallic compounds can be prevented and a decrease in rollability can be suppressed. Therefore, the Mn content in the intermediate layer is preferably 1.80% by mass or less, more preferably 1.70% by mass or less, and even more preferably 1.60% by mass or less, relative to the total mass of the intermediate layer.

[0080] (Cu: 1.00% by mass or less) Cu in the intermediate layer is an element that dissolves in the base material after brazing and has the effect of improving the strength after brazing. However, in this embodiment, the Cu content in the intermediate layer may be 0% by mass. Furthermore, if the Cu content in the intermediate layer is 1.00% by mass or less, a decrease in the solidus temperature can be suppressed and melting of the intermediate layer during brazing can be prevented. Therefore, the Cu content in the intermediate layer is preferably 1.00% by mass or less, more preferably 0.90% by mass or less, and even more preferably 0.80% by mass or less, relative to the total mass of the intermediate layer.

[0081] (Cr: 0.30 mass% or less) Cr in the intermediate layer is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Cr content in the intermediate layer may be 0% by mass. Furthermore, if the Cr content in the intermediate layer is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Cr content in the intermediate layer is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the intermediate layer.

[0082] (Ti: 0.30% by mass or less) Ti in the intermediate layer is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Ti content in the intermediate layer may be 0% by mass. Furthermore, if the Ti content in the intermediate layer is 0.30% by mass or less, the formation of large intermetallic compounds during casting can be prevented, and a decrease in plastic workability can be suppressed. Therefore, the Ti content in the intermediate layer is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the intermediate layer.

[0083] (Zr: 0.30% by mass or less) Zr in the intermediate layer is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the Zr content in the intermediate layer may be 0% by mass. Furthermore, if the Zr content in the intermediate layer is 0.30% by mass or less, it is possible to prevent the formation of large intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the Zr content in the intermediate layer is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the intermediate layer.

[0084] (V: 0.30% by mass or less) V in the intermediate layer is an element that has the effect of improving strength through solid solution strengthening, but in this embodiment, the V content in the intermediate layer may be 0% by mass. Furthermore, if the V content in the intermediate layer is 0.30% by mass or less, it is possible to prevent the formation of large intermetallic compounds during casting and suppress a decrease in plastic workability. Therefore, the V content in the intermediate layer is preferably 0.30% by mass or less, more preferably 0.20% by mass or less, and even more preferably 0.10% by mass or less, based on the total mass of the intermediate layer.

[0085] (Remainder: Al and inevitable impurities) The remainder of the intermediate layer in the clad material is Al and unavoidable impurities. Examples of unavoidable impurities include Mg, Ca, Be, Sb, rare earth elements, and Li. Specifically, the intermediate layer may contain up to 0.05% by mass of Mg, up to 0.05% by mass of Ca, up to 0.01% by mass of Be, and less than 0.01% by mass of other elements. The total amount of unavoidable impurities in the intermediate layer is preferably 0.05% by mass or less of the total mass of the intermediate layer. [Example]

[0086] The present embodiment will be described in more detail below with reference to examples, but the present invention is not limited to these examples, and modifications can be made within the scope of the spirit of the present invention, and all such modifications are included in the technical scope of the present invention.

[0087] <Aluminum alloy manufacturing> Aluminum alloy materials having various chemical compositions shown in Table 1 below were manufactured. Specifically, the aluminum alloy materials were manufactured by melting and casting the aluminum alloys having the chemical compositions shown in Table 1, subjecting them to homogenization heat treatment and facing, followed by hot rolling, cold rolling, and final annealing. In this example, it is assumed that the aluminum alloy materials are manufactured using waste materials and recovered materials with a recycling rate R of, for example, 50% or more. For this reason, the Si content in the aluminum alloy materials is set to about 1.5% by mass.

[0088] (Measurement of heat of fusion) For each aluminum alloy material, DTA analysis was performed under an argon atmosphere using a TG / DTA6300 manufactured by SII (Seiko Instruments Inc.) at a heating rate of 40°C / min and using alumina as a standard substance, and the heat of fusion was calculated based on the obtained DTA curve.

[0089] (Calculation of the value α calculated by formula (1)) The value α was calculated using the following formula (1) based on the contents of Mn, Cr, Fe, and Ti in each aluminum alloy material. Formula (1): α={2.4-4.4×exp(-1.1×[Mn])} +{0.70-0.7×exp(-4.0×[Cr])}+[Fe]+0.5×[Ti] Here, [Mn] is a value that represents the Mn content in the aluminum alloy material in mass%, [Cr] is a value that represents the Cr content in the aluminum alloy material in mass%, [Fe] is a value that represents the Fe content in the aluminum alloy material in mass%, and [Ti] is a value that represents the Ti content in the aluminum alloy material in mass%.

[0090] (Measurement of average cross-sectional area of ​​elemental Si) For each aluminum alloy material, the average cross-sectional area of ​​elemental Si was measured by mapping analysis using EPMA. Specifically, elemental mapping of Al, Si, and Mn was performed using EPMA, and regions where the concentrations of Al and Mn were low and the concentration of Si was particularly high compared to the parent phase were extracted, and these regions were identified as elemental Si. The areas of the identified elemental Si were then measured individually, and their average value was calculated as the average cross-sectional area. In this example, the magnification was 500 times, and the measurement area was approximately 0.05 mm in total. 2 The measurement field was set to one field.

[0091] <Evaluation of test materials> (Evaluation of brazing properties) Brazability was evaluated based on the measurement results of the heat of fusion. The evaluation criteria for brazability were that the heat of fusion was 2.5 μV·s / mg or less was considered to have good brazability, while that of the heat of fusion exceeding 2.5 μV·s / mg was considered to have poor brazability.

[0092] The measurement results of the heat of fusion, the value α calculated by formula (1), and the average cross-sectional area of ​​simple substance Si are shown in Table 1 below. In the column for the content of each component in Table 1, "-" indicates that the element is not contained or the content is below the measurement limit. The balance of each component in the aluminum alloy material shown in Table 1 is Al and unavoidable impurities.

[0093] [Table 1]

[0094] As shown in Table 1 above, in Invention Examples 1 to 10, the contents of each component in the aluminum alloy material and the average cross-sectional area of ​​elemental Si were within the ranges specified in the present invention, so the heat of fusion was 2.5 μV·s / mg or less, and excellent brazability was obtained. FIG. 5 is a photograph, substitute for a drawing, showing an image obtained by performing EPMA mapping analysis on the aluminum alloy material of Invention Example 4. FIG. 6 is a photograph, substitute for a drawing, showing an image obtained by performing EPMA mapping analysis on the aluminum alloy material of Comparative Example 1. In the images shown in FIGS. 5 and 6, the white areas indicate elemental Si. As shown in FIGS. 5 and 6, the cross-sectional area of ​​elemental Si in Invention Example 4 is smaller than the cross-sectional area of ​​elemental Si in Comparative Example 1.

[0095] On the other hand, in Comparative Examples Nos. 1 to 3, the average cross-sectional area of ​​elemental Si exceeded the upper limit specified in the present invention, and therefore the heat of fusion exceeded 2.5 μV·s / mg, resulting in poor brazability compared to the invention examples.

[0096] As described above, according to the present invention, it is possible to obtain an aluminum alloy material with excellent brazability at a high recycling rate by utilizing waste materials and recovered materials. In addition, it is possible to reduce the amount of virgin metal used and to significantly reduce CO2 emissions.

Claims

1. For the total mass of aluminum alloy materials, Si: 1.1% by mass or more and 1.6% by mass or less, Fe: 0.1% by mass or more and 0.8% by mass or less, Mn: 0.8% by mass or more and 2.0% by mass or less, Cu: 0.3% by mass or more and 0.8% by mass or less, Zn: 0.2% by mass or more and 0.48% by mass or less; Cr: 0.6% by mass or less, Mg: 0.5% by mass or less, Ti: 0.5% by mass or less (excluding 0%); the balance being Al and unavoidable impurities; The average cross-sectional area of ​​simple silicon is 8.2 μm ２ An aluminum alloy material characterized by the following:

2. Furthermore, Zr: 0.30 mass% or less, V: 0.30% by mass or less, Ca: 0.10% by mass or less, and 2. The aluminum alloy material according to claim 1, further comprising at least one selected from the group consisting of Sr: 0.10 mass % or less, and Sr: 0.10 mass % or less.

3. An aluminum alloy material as described in claim 1 or 2, characterized in that the Ti content is 0.01 mass% or more.

4. A core material made of the aluminum alloy material according to claim 1 or 2; and a skin material laminated on at least a portion of the surface of the core material.

5. A core material made of the aluminum alloy material according to claim 3; and a skin material laminated on at least a portion of the surface of the core material.

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