Aluminum alloy materials and aluminum alloy clad materials

Abstract

To provide an aluminum alloy material having excellent brazing properties, which can be manufactured using raw materials such as waste materials generated during the manufacturing process of clad materials, waste materials from aluminum alloy heat exchangers, and recycled materials collected from the market. [Solution] The aluminum alloy material contains, relative to the total mass of the aluminum alloy material, 1.1 to 1.6 mass% Si, 0.1 to 0.8 mass% Fe, 0.8 to 2.0 mass% Mn, 0.3 to 0.8 mass% Cu, 0.2 to 0.5 mass% Zn, 0.5 mass% or less Mg, 0.5 mass% or less Ti, and the balance being Al and unavoidable impurities. The aluminum alloy material also has a heat of fusion of 3.0 μV·s / mg or less, calculated from an endothermic peak occurring in the range of 550 to 600°C based on a differential thermal analysis curve with a heating rate of 40°C / min.

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 mass% or more and 0.5 mass% or less, Mg: 0.5% by mass or less, Ti: 0.5% by mass or less; the balance being Al and unavoidable impurities, An aluminum alloy material characterized in that the heat of fusion calculated from the endothermic peak occurring in the range of 550°C to 600°C based on a differential thermal analysis curve with a heating rate of 40°C / min is 3.0 μV·s / mg or less.

[0010] Moreover, the aluminum alloy material of the present invention preferably satisfies the following [2] to [4].

[0011] [2] The aluminum alloy material according to [1], further comprising 0.6 mass % or less of Cr.

[0012] [3] When the content of Mn is [Mn] in mass%, the content of Cr is [Cr] in mass%, the content of Fe is [Fe] in mass%, and the content of Ti is [Ti] in mass%, The aluminum alloy material according to [2], characterized in that the value α calculated by the following formula (1) is 1.5 or more. α={2.4-4.4×exp(-1.1×[Mn])}+{0.70-0.7×exp(-4.0×[Cr])}+[Fe]+0.5×[Ti]...Equation (1)

[0013] [4] 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 any one of [1] to [3], characterized in that it contains at least one selected from the following: Sr: 0.10 mass % or less.

[0014] The above object can also be achieved by the aluminum alloy clad material according to the present invention described below in [5].

[0015] [5] A core material made of the aluminum alloy material according to any one of [1] to [4]; and a skin material laminated on at least a portion of the surface of the core material. [Effects of the Invention]

[0016] 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]

[0017] [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 heat and the horizontal axis representing 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 the differential thermal analysis curve of aluminum alloy test material B, with the vertical axis representing differential heat and the horizontal axis representing temperature, with the vertical axis scale enlarged. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present inventors have 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 have 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. Further research by the present inventors has revealed that the melting peak below 600°C begins at 577°C or 559°C, which is near the eutectic temperature of Al-Si and Al-Mg-Si.

[0019] Furthermore, the inventors 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 diffusing from the brazing material increases due to the local melting of the core material, resulting in a decrease in the liquid phase fraction of the brazing material. In addition, the local melting temperature of the core material is around 577°C or 559°C, which corresponds to the eutectic temperature of Al-Si or Al-Mg-Si. From this, it is thought that when an aluminum alloy material containing more than a predetermined amount of Si is heated, local melting is likely to occur starting from elemental Si or Mg-Si compounds.

[0020] In the aluminum alloy material according to this embodiment, Si is precipitated as an Al-Mn-Si compound, thereby reducing the amount of elemental Si and Mg-Si compounds, thereby suppressing local melting of the aluminum alloy material used as the core material and improving brazability.

[0021] Hereinafter, an aluminum alloy material according to an embodiment of the present invention will be described in detail.

[0022] [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.

[0023] (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.

[0024] (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.

[0025] (Mn: 0.8 mass% or more and 2.0 mass% or less) As described above, Mn is an element that has the effect of precipitating Si as an Al-Mn-Si compound and reducing the amount of elemental Si and Mg-Si compounds in the aluminum alloy material. 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.

[0026] (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 0.1% 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.

[0027] (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.

[0028] (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.

[0029] (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.

[0030] The aluminum alloy material according to this embodiment contains the above-mentioned elements in predetermined contents, and preferably also contains an appropriate amount of Cr. The effects of Cr and the preferred amount of Cr will be described below.

[0031] (Cr: 0.6% by mass or less) By further containing Cr in the aluminum alloy material, Si can be precipitated as an Al-Mn-Si-Fe-Cr compound, which further suppresses local melting of the aluminum alloy material used as a core material and further improves brazability. Therefore, the aluminum alloy material may contain Cr as needed, but it may also contain 0 mass% Cr. 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 mass% or more, the brazability can be further improved. Therefore, the Cr content in the aluminum alloy material is preferably 0.02 mass% or more, more preferably 0.05 mass% or more, even more preferably 0.1 mass% or more, and particularly preferably 0.15 mass% or more, relative to the total mass of the aluminum alloy material. On the other hand, when the Cr content in the aluminum alloy material exceeds 0.6 mass%, large 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.

[0032] The aluminum alloy material according to this embodiment contains the above-mentioned elements in predetermined contents, and 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.

[0033] (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.

[0034] (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.

[0035] (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.

[0036] (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.

[0037] (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.

[0038] (Heat of fusion calculated based on the differential thermal analysis curve in the specified temperature range: 3.0 μV·s / mg or less) In the aluminum alloy material serving as the core material, if the amount of local melting increases in the temperature range below the brazing temperature, the amount of Si diffusing from the brazing material increases, resulting in a decrease in brazability. Therefore, in this embodiment, the heat of fusion calculated from the endothermic peak in the temperature range below the brazing temperature based on the differential thermal analysis (DTA) curve of the aluminum alloy material is specified. The heat of fusion specified in this embodiment will be described in more detail below.

[0039] Fig. 1 is a graph showing a differential thermal analysis curve of aluminum alloy test material A, with the vertical axis representing differential heating and the horizontal axis representing 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 heating and the horizontal axis representing 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.

[0040] In this embodiment, a DTA curve is used as a method for evaluating the degree of melting of the core material during brazing heating. DTA analysis analyzes the flow of heat, and can measure not only the amount of heat related to temperature rise but also the state change between the liquid phase and the solid phase of the aluminum alloy. As shown in FIG. 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 may locally melt below the brazing temperature, affecting brazability.

[0041] 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%

[0042] 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%.

[0043] 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-uniformly distributed elements indicates the presence of a structure that solidified after being melted once. 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 is specified to be in the range of 550°C or higher and 600°C or lower.

[0044] The method for calculating the heat of fusion will be specifically explained using Figure 2. In Figure 2, the endothermic reaction begins around 577°C, and it is believed that the endothermic reaction starts at 550°C or higher regardless of the composition. Therefore, the area of ​​the endothermic peak appearing in the 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 auxiliary line L1, auxiliary line L2, and the DTA curve is then calculated by time integration and converted to a value per weight, which is the heat of fusion.

[0045] Specifically, the heat of fusion of aluminum alloy test material A is 1.6 μV·s / mg, and the heat of fusion of aluminum alloy test material B is 6.6 μV·s / mg. This shows that as the Si content and Mg content in aluminum alloys increase, elemental Si and Mg-Si compounds are formed, increasing the heat of fusion.

[0046] When a DTA analysis is performed under the above conditions and the heat of fusion calculated using the obtained DTA curve exceeds 3.0 μV·s / mg, this means that approximately 0.75 mass% of the entire aluminum alloy material is melted, and when this is used as a core material, brazability will decrease. Therefore, the heat of fusion should be 3.0 μV·s / mg or less, preferably 2.0 μV·s / mg or less, and more preferably 1.0 μV·s / mg or less.

[0047] (The value α calculated by formula (1): 1.5 or more) The present inventors have conducted extensive research into conditions under which the heat of fusion of an aluminum alloy material can be reduced in the temperature range of 550°C or higher and 600°C or lower, and have found that the value α calculated by the following formula (1) shows a clear correlation with the heat of fusion. When the value α is 1.5 or higher, the brazeability can be further improved. Therefore, the value α is preferably 1.5 or higher, more preferably 1.6 or higher, even more preferably 1.7 or higher, and particularly preferably 1.8 or higher.

[0048] 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.

[0049] (Value β calculated by formula (2): 1.90 or less) As described above, in this embodiment, excellent brazability can be obtained by adjusting the contents of specific elements contained in the aluminum alloy material and specifying the amount of heat of fusion generated within a predetermined temperature range. Furthermore, the inventors have found that the value β calculated by the following formula (2) correlates with the formation of giant intermetallic compounds. When the value β is 1.90 or less, the formation of giant intermetallic compounds can be suppressed and a decrease in plastic workability can be prevented. Therefore, the value β is preferably 1.90 or less, more preferably 1.88 or less, and even more preferably 1.86 or less.

[0050] β = [Mn] + [Mg] × 0.8 + [Cr] × 1.7 In the above formula (1), [Mn] is the Mn content in the aluminum alloy material expressed as mass% relative to the total mass of the aluminum alloy material. Also, [Mg] is the Mg content in the aluminum alloy material expressed as mass% relative to the total mass of the aluminum alloy material, and [Cr] is the Cr content in the aluminum alloy material expressed as mass% relative to the total mass of the aluminum alloy material. When the Mg content or Cr content in the aluminum alloy material according to this embodiment is 0 mass%, [Mg] and [Cr] are each set to 0.

[0051] (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.

[0052] 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."

[0053] [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.

[0054] 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.

[0055] <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.

[0056] (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.

[0057] (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.

[0058] (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.

[0059] (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.

[0060] (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.

[0061] (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.

[0062] (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.

[0063] (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.

[0064] (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.

[0065] (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.

[0066] (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.

[0067] <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.

[0068] (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.

[0069] (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.

[0070] (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.

[0071] (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.

[0072] (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.

[0073] (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.

[0074] (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.

[0075] (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.

[0076] (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.

[0077] (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.

[0078] <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.

[0079] (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.

[0080] (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.

[0081] (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.

[0082] (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.

[0083] (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.

[0084] (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.

[0085] (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.

[0086] (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.

[0087] (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]

[0088] 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.

[0089] <Aluminum alloy manufacturing> Aluminum alloy materials having various chemical compositions shown in Table 1 below were manufactured. In this embodiment, it is assumed that the aluminum alloy materials are manufactured using waste materials and recovered materials at 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 mass%.

[0090] (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.

[0091] (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%.

[0092] <Evaluation of test materials> (Evaluation of brazing properties) Clad materials were fabricated having a core material made of each aluminum alloy material and a brazing filler metal laminated on one side of the core material. The brazing filler metal contained 10 mass% Si, and the clad material had a plate thickness of 1.0 mm. A drop-type fluidity test was then performed on the fabricated clad materials, and the flow coefficient was calculated using a gravimetric method. Specifically, the clad materials were first cut into pieces measuring 30 mm x 80 mm, and the weights (W0) of the cut pieces were measured. The clad materials, with the longitudinal direction of their main surfaces oriented vertically, were then brazed at 600°C for 3 minutes, and the weights (Wb) of the lower 1 / 4 (30 mm x 20 mm) of the 80 mm length in the vertical direction were measured. The flow coefficient (K3) was then calculated using the following equation (3) and used as an index of fluidity. K3 = (4Wb - W0) / (3W0 × brazing filler metal cladding ratio) Equation (3) The brazeability was evaluated based on the following criteria: when the flow coefficient K3 calculated by the above formula (3) was 0.45 or more, the brazeability was judged to be "good," when the flow coefficient K3 was 0.46 or more, the brazeability was judged to be "better," when the flow coefficient K3 was 0.47 or more, the brazeability was judged to be "excellent," and when the flow coefficient K3 was less than 0.45, the brazeability was judged to be "poor."

[0093] (Observation of giant intermetallic compounds) For each aluminum alloy material, a cross section perpendicular to the rolling direction was polished and observed at 200x magnification using an optical microscope to determine whether or not there was a giant intermetallic compound. 2 (i.e., 5,000,000 μm 2 ) area, and the area is 1000 μm 2 When one or more of the above compounds are present, it is judged that a giant intermetallic compound exists (indicated as "occurrence" in Table 1), and when the area is 1000 μm 2 When the above compounds were not present, it was determined that no giant intermetallic compounds were present (indicated as "none" in Table 1).

[0094] The measurement results of the heat of fusion, the value α calculated by formula (1), the evaluation results of brazability, and the presence or absence of macro intermetallic compounds are all 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.

[0095] [Table 1]

[0096] As shown in Table 1 above, in Examples 1 to 10, the content and heat of fusion of each component in the aluminum alloy material were within the ranges specified in the present invention, and therefore the flow coefficient K3 was 0.45 or more, indicating that the aluminum alloy material had excellent brazability. In particular, in Examples 3, 5, 7, 8, and 9, the aluminum alloy material contained Cr within a preferred range, which further enhanced the suppression effect of elemental Si and significantly reduced the heat of fusion. For example, Examples 3 and 7 had lower heats of fusion than Example 4, which had similar contents of Si, Fe, Cu, Mn, and Zn other than Cr. In addition, Example 5 had lower heats of fusion than Example 1, which had similar contents of the above elements other than Cr. In Example 9, the heat of fusion was lower than Example 2, which had similar contents of the above elements other than Cr.

[0097] Furthermore, in Examples 1 to 5 and 8, the value β calculated by formula (2) was within the preferred range defined in the present invention, so that the generation of macro intermetallic compounds could be suppressed and aluminum alloy materials with good plastic workability could be obtained.

[0098] 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.

[0099] On the other hand, in Comparative Examples Nos. 1 and 2, the heat of fusion exceeded the upper limit of the range defined in the present invention, and therefore the brazing properties were poor compared to the invention examples.

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 mass% or more and 0.48 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; An aluminum alloy material characterized in that a heat of fusion calculated from an endothermic peak occurring in a temperature range of 550°C or higher and 600°C or lower based on a differential thermal analysis curve at a heating rate of 40°C / min is 3.0 μV·s / mg or lower.

2. The aluminum alloy material according to claim 1, further comprising 0.6 mass % or less of Cr.

3. When the Mn content is [Mn] in mass%, the Cr content is [Cr] in mass%, the Fe content is [Fe] in mass%, and the Ti content is [Ti] in mass%, The aluminum alloy material according to claim 2, wherein a value α calculated by the following formula (1) is 1.5 or more: α={2.4-4.4×exp(-1.1×[Mn])}+{0.70-0.7×exp(-4.0×[Cr])}+[Fe]+0.5×[Ti]...Formula (1)

4. 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.

5. An aluminum alloy material according to any one of claims 1 to 4, characterized in that the Ti content is 0.01 mass% or more.

6. A core material made of the aluminum alloy material according to any one of claims 1 to 4; and a skin material laminated on at least a portion of the surface of the core material.

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

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