HIGH-STRENGTH SOLDER-PLATED AL-MG-SI ALUMINUM MATERIAL

Abstract

The present disclosure provides an aluminium material for the manufacture of high-strength, soldered components, including an aluminium alloy. After soldering, the aluminium material is in materially-bonded contact with at least one solder layer. The object of providing an aluminium material is to provide not only good soldering properties and formability, but also high strength. This is achieved because the aluminium alloy of the aluminium material has a solidus temperature, and the aluminium material has an increase in yield strength compared to the state after soldering and cooling.

Claims

1. An aluminium material for the manufacture of high-strength, soldered components comprising an aluminium alloy of the type AA6xxx, wherein the aluminium material is preferably at least in some areas directly or indirectly in materially-bonded contact with at least one solder layer comprising an aluminium solder alloy after soldering, wherein the aluminium alloy has a solidus temperature Tsol of at least 595° C. and the aluminium material has an increase in the yield strength R.sub.p0.2 compared to the state after soldering of at least 90 MPa, at least 110 MPa or preferably at least 120 MPa after soldering at at least 595° C. and cooling at an average cooling rate of at least 0.5° C./s from 595° C. to 200° C. and an artificial ageing at 205° C. for 45 minutes after soldering.

2. The aluminium material of claim 1, wherein the aluminium material has a yield strength R.sub.p0.2 of at least 160 MPa, preferably at least 180 MPa, particularly preferably more than 200 MPa after soldering at at least 595° C. and cooling at an average cooling rate of at least 0.5° C./s from 595° C. to 200° C. and artificial ageing at 205° C. for 45 minutes.

3. The aluminium material according of claim 1, wherein the aluminium alloy of the type AA6xxx, has the following composition in wt.-%: 0.5%≤Si≤0.9%, preferably 0.50%≤Si≤0.65% or 0.60%≤Si≤0.75%, Fe≤0.5%, preferably 0.05%≤Fe≤0.5%, particularly preferably 0.05%≤Fe≤0.3%, Cu≤0.5%, preferably 0.05%≤Cu≤0.3% or 0.1%≤Cu≤0.3%, Mn≤0.5%, preferably Mn≤0.2%, particularly preferably 0.01%≤Mn≤0.15%, 0.4%≤Mg≤0.8%, preferably 0.45%≤Mg≤0.8%, particularly preferably 0.45%≤Mg≤0.75%, Cr≤0.3%, preferably Cr≤0.1%, particularly preferably Cr≤0.05%, Zn≤0.3%, preferably ≤0.05%, Ti≤0.3%, Zr≤0.1%, particularly preferably Zr≤0.05%, the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%.

4. The aluminium material according to claim 1, wherein the aluminium solder alloy, with which the aluminium material is directly or indirectly in materially-bonded contact, has the following composition in wt.-%: 7.0%≤Si≤13.0%, Fe≤0.8%, Cu≤2.5%, Mn≤0.1%, Mg≤0.1%, Cr≤0.1%, Zn≤2.5%, Ti≤0.3%, Zr≤0.1%, the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%.

5. The aluminium material of claim 1, wherein the aluminium material is designed as a core alloy layer of an aluminium composite material and the aluminium composite material comprises at least one one-sided or two-sided outer cladding layer.

6. The aluminium material of claim 1, wherein the aluminium material is designed as a core alloy layer of an aluminium composite material and the aluminium composite material comprises at least one one-sided or two-sided outer solder layer comprising an aluminium solder alloy.

7. The aluminium material of claim 6, wherein the thickness of the at least one solder layer is 3% to 15% of the aluminium composite material.

8. The aluminium material of claim 5, wherein the aluminium composite material comprises at least one cladding layer provided on one or both sides of the core layer, wherein the cladding layer has an aluminium alloy with an Mg content of <0.1 wt.-%, preferably <0.05 wt.-%.

9. The aluminium material of claim 5, wherein the aluminium alloy of the cladding layer has the following composition in wt.-%: Si≤1.0%, Fe≤2.0%, preferably 0.1%≤Fe≤2.0%, Cu≤0.3%, Mn≤0.3%, Mg≤0.1%, preferably ≤0.05%, Cr≤0.1%, Zn≤2.0%, Ti≤0.3%, Zr≤0.20%, the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%.

10. The aluminium composite material of claim 5, wherein the corrosion potential of the cladding layer after soldering is less noble than the corrosion potential of the aluminium core alloy layer, preferably the potential difference between the cladding layer and the aluminium core alloy layer after soldering is >10 mV.

11. The aluminium composite material of claim 5, wherein the cladding layer has 3% to 15% of the thickness of the entire aluminium composite material.

12. A method for the thermal joining of components made of an aluminium alloy claim 1, in which soldering, preferably CAB or vacuum soldering, is carried out at a soldering temperature of at least 585° C., wherein after heating to and holding at soldering temperature, the components are cooled from the soldering temperature to 200° C. at an average cooling rate of at least 0.5° C./s, at least 0.66° C./s or at least 0.75° C./s and the thermally joined components are artificially aged after soldering.

13. The method of claim 12, wherein the artificial ageing of the soldered components is carried out at temperatures of between 100° C. and 280° C., preferably of between 140° C. and 250° C., preferably at 180 to 230° C., wherein the duration of the artificial ageing is 10 minutes, preferably at least 30 minutes or at least 45 minutes.

14. The method of claim 12, wherein a battery cooling plate, a heat exchanger or a structural component of a motor vehicle is soldered.

15. Use of an aluminium material of claim 1 for manufacturing a battery cooling plate, a heat exchanger or a structural component of a motor vehicle.

16. A soldered component, wherein the component is designed as a battery cooling plate, as a structural component of a motor vehicle or as a heat exchanger, comprising an aluminium material of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] The present invention will now be described in more detail in connection with the drawing, in which is shown:

[0092] FIG. 1a to 1g show schematic representations of possible exemplary embodiments of the aluminium composite material and aluminium material in a sectional view;

[0093] FIG. 2 shows, in a perspective representation, the test arrangement for carrying out the bending test;

[0094] FIG. 3 shows, in a perspective schematic representation, the arrangement of the bending punch in relation to the rolling direction when carrying out the bending test;

[0095] FIG. 4 shows schematically the measurement of the bending angle on a curved sample according to an exemplary embodiment; and

[0096] FIG. 5 shows, in a schematic representation, exemplary embodiments for a heat exchanger, a battery cooling plate and a structural component of a motor vehicle.

DETAILED DESCRIPTION

[0097] FIG. 1a shows a two-layer aluminium composite material, while FIG. 1b a three-layer variant and FIGS. 1c and 1d a four-layer variant of the aluminium composite material according to the invention. FIG. 1a shows a sectional view of an exemplary embodiment of an aluminium material according to the invention in the form of an aluminium composite material 1a with a core layer 2 and a solder layer 3. According to a further exemplary embodiment, the solder layer 3 can also be provided by a soldering foil F or a component K with a solder layer such that the aluminium material is at least in some areas directly in materially-bonded contact with at least one solder layer 3 after soldering. FIG. 1e to FIG. 1g show these exemplary embodiments.

[0098] The exemplary embodiment in FIG. 1b shows an aluminium composite material 1b with an aluminium material according to the invention as core layer 2, a solder layer 3 and an additional cladding layer 4. FIG. 1c illustrates a further exemplary embodiment of the aluminium material according to the invention in the form of a four-layer composite material 1c with a core layer 2 with a two-sided cladding layer 4 and an outer solder layer 3. If the solder layer 3 according to one exemplary embodiment is provided by a soldering foil or a further component with a solder layer, the aluminium material of the core layer 2 can be in indirect materially-bonded contact with the solder layer after soldering. In the present case, indirect materially-bonded contact is the contact of the core layer 2 with the solder layer 3 via the cladding layer 4. The four-layer composite material 1c can also be provided by an aluminium material 2a with cladding layers 4 by providing the solder layer 3 via at least one separate component K after soldering.

[0099] FIG. 1d shows a four-layer variant of the composite material 1d with a core layer 2, a cladding layer 4 arranged on the core layer 2 and two outer solder layers 3. Here too, an indirect materially-bonded contact can be designed between the aluminium material 2, here as a core layer of an aluminium composite material, and the solder layer 3 after soldering. Nevertheless, the properties according to the invention after soldering can also be achieved after soldering in such an exemplary embodiment, in which the solder layer is provided by a soldering foil or a further part or a further component. All aluminium composite materials 1a, 1b, 1c and 1d shown can for example be used for the manufacture of heat exchangers, structural components of motor vehicles or battery cooling plates.

[0100] FIG. 1e to FIG. 1g show by way of example exemplary embodiments in a sectional view in which the aluminium material 2a according to the invention has in sections direct materially-bonded contact after soldering. In FIG. 1e, the solder layer is provided by a soldering foil F. In FIG. 1f, the solder layer is provided by a further component K.

[0101] FIG. 1g shows an aluminium material 2a with a two-sided cladding layer, for example made of an AA8079 alloy, which is at least in some areas in indirect contact with a solder layer provided as a soldering foil F after soldering.

[0102] The properties of the aluminium material according to the invention are represented and described below on the basis of the embodiment as an aluminium composite material. However, it is apparent that in particular the measured strength properties are provided by the core alloy and thus by the aluminium material of the exemplary embodiments according to the invention. This means that the results can also be transferred to a single-layer aluminium material, which is in sections in direct or indirect materially-bonded contact with the solder layers after a soldering process. All information on the composition of the aluminium alloys refers to the state of the materials before soldering.

[0103] The aluminium composite materials 1a, 1b, 1c, 1d shown in FIG. 1a to 1d and the aluminium material 2a are usually present as strips, which were manufactured, for example, by hot rolling or roll cladding, wherein the total thickness can be 0.1 mm to 5 mm. Other manufacturing processes such as “simultaneous casting” with subsequent rolling are also conceivable for manufacturing the strips. The core layer 2 or the aluminium material 2a consists of an aluminium alloy of the type AlMgSi and has a solidus temperature Tsol of at least 595° C., wherein the aluminium composite material has an increase in the yield strength R.sub.p0.2 compared to the state after soldering of at least 90 MPa, at least 110 MPa or preferably at least 120 MPa after soldering at at least 595° C. at an average cooling rate of at least 0.5° C./s from 595° C. to 200° C. and an artificial ageing at 205° C. for 45 minutes. In the case of the aluminium composite material 1a, 1b, 1c, 1d and the aluminium material 2a, the increase in the yield strength values can be attributed to the hardening of the core layer 2 by the artificial ageing and enables the economical provision of high-strength, soldered components, for example heat exchangers, battery cooling plates or structural components of a motor vehicle. The core layer 2 or the aluminium material 2a can for example have the following composition in wt.-%: [0104] 0.5%≤Si≤0.9%, preferably 0.50%≤Si≤0.65% or 0.60%≤Si≤0.75% or 0.50%≤Si≤0.60%, [0105] Fe≤0.5%, preferably 0.05%≤Fe≤0.5%, particularly preferably 0.05%≤Fe≤0.3%, [0106] Cu≤0.5%, preferably 0.05%≤Cu≤0.3% or 0.1%≤Cu≤0.3%, [0107] Mn≤0.5%, preferably Mn≤0.2%, particularly preferably 0.01%≤Mn≤0.15%, [0108] 0.4%≤Mg≤0.8%, preferably 0.45%≤Mg≤0.8%, particularly preferably 0.45%≤Mg≤0.75%, [0109] Cr≤0.3%, preferably Cr≤0.1%, particularly preferably Cr≤0.05%, [0110] Zn≤0.3%, preferably ≤0.05%, [0111] Ti≤0.3%, [0112] Zr≤0.1%, particularly preferably Zr≤0.05%,
the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%.

[0113] This AlMgSi core alloy or alloy of the aluminium material has a low quenching sensitivity and at the same time has a sufficiently high solidus temperature Tsol such that melting during soldering is avoided. With a low quenching sensitivity, a solution-annealed, quenched T4 structural state is already provided after soldering at cooling rates from 0.5° C./s from 595° C. to 200° C., which causes the significant increase in the yield strength in an artificial ageing.

[0114] In a two-layer variant of the aluminium composite material 1a, it has an outer layer, which is configured as a solder layer 3. Preferably, the aluminium solder alloy of the solder layer has the following composition in wt.-%: [0115] 7.0%≤Si≤13.0%, [0116] Fe≤0.8%, [0117] Cu≤2.5%, [0118] Mn≤0.1%, [0119] Mg≤0.1%, [0120] Cr≤0.1%, [0121] Zn≤2.5%, [0122] Ti≤0.3%, [0123] Zr≤0.1%,
the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%.

[0124] For example, the solder layer consists of an aluminium solder alloy of the type AA4045 or AA4343. The thickness of the solder layer 3 is typically 5% to 15% of the total thickness of the composite material. In principle, the aluminium composite material 1a can also be provided with a solder layer 3 on both sides (not shown here).

[0125] According to a further exemplary embodiment, as FIG. 1b shows, a cladding layer 4, which has an aluminium alloy with an Mg content of <0.1 wt.-%, preferably <0.05 wt.-%, can be applied on the core layer 2 in order to provide improved properties of the aluminium composite material 1 in terms of formability, solderability and corrosion protection. In a particularly preferred embodiment, the cladding layer 3 has an aluminium alloy with the following composition in wt.-%: [0126] Si≤1.0%, [0127] Fe≤2.0%, preferably 0.1%≤Fe≤2.0%, [0128] Cu≤0.3%, [0129] Mn≤0.3%, [0130] Mg≤0.1%, preferably ≤0.05%, [0131] Cr≤0.1%, [0132] Zn≤2.0%, [0133] Ti≤0.3%, [0134] Zr≤0.1%,
the remainder Al and unavoidable impurities individually a maximum of 0.05%, in total a maximum of 0.15%. The cladding layer 3 preferably has 3% to 15% of the thickness of the entire aluminium composite material 1,1′.

[0135] In addition to this embodiment of the aluminium composite material 1, in which three layers are provided, wherein the cladding layer 4 is arranged on one side and the solder layer 3 on the other side of the core layer 2, it is also conceivable, as represented in FIG. 1c and FIG. 1d, that a cladding layer 4 is arranged between the core layer 2 and a solder layer 3. These embodiments are particularly advantageous for corrosion protection. Furthermore, a five-layer variant can be provided, wherein in each case a cladding layer 4 lies on both sides of the core layer 2 and between the core layer 2 and in each case an outer solder layer 3.

[0136] Eight composite materials 1-8 were manufactured with the layer structure mentioned in Table 1. The composite materials 1 and 2 have a cladding layer 4 on both sides of the core layer 2. A solder layer 3 is plated on a cladding layer 4. The composite materials 3 to 6 are two-layered and, in addition to the core layer, only have a one-sided solder layer 3. The composite material 7 is again configured in four layers, but only has on one side of the core layer 2 a cladding layer 4 and a two-sided solder layer 3. Finally, composite material 8 has a core layer 2 with a cladding layer applied thereon.

[0137] The aluminium alloys of the core layer, the cladding layer and the solder layer with the chemical composition indicated in Table 2 were melted and cast as rolling ingots in the so-called direct chill casting process. In a first step, the rolling ingots for the cladding layer and the solder layer were preheated to a rolling temperature in the range of 450° C. to 525° C. and hot-rolled to the required layer thickness. The cast ingots of the core material were subjected to homogenisation annealing at 575° C. with a holding time of 6 h and then joined together with the pre-rolled plates of the cladding layer and of the solder material to form a so-called plating packet. This plating packet was preheated to a rolling temperature in the range of 450° C. to 500° C. and hot-rolled to a thickness of 7 mm. The test materials were then cold-rolled to the end thicknesses indicated in Table 1.

TABLE-US-00001 TABLE 1 Sample Comparison/ Number D Solder alloy Cladding layer no. Invention of layers Core (mm) no./(thickness in %) (thickness in %) 1 Comparison 4 1 2.5 6/(5%) 5/(5%) 2 Invention 4 2 2.5 6/(5%) 5/(5%) 3 Comparison 2 3 1.5 6/(5%) — 4 Invention 2 2 2.5 6/(5%) 5 Comparison 2 3 1.5 6/(5%) 6 Comparison 2 4 0.92 6/(5%) 7 Invention 4 7 2.5 6/(5%) 8 (5%) 8 Invention 3 9 2.0 —  10 (7.5%)

[0138] The solidus temperatures Tsol indicated in Table 2 were calculated using the commercial software FactSage 7.0 and associated thermodynamic databases for aluminium.

TABLE-US-00002 TABLE 2 Chemical composition [wt.-%] of the layers of the composite materials Alloy Function Si Fe Cu Mn Mg Cr Zn Ti Tsol 1 Core 0.44 0.24 0.04 0.05 0.61 0.05 0.00 0.01 618° C. 2 Core 0.74 0.19 0.08 0.09 0.59 0.00 0.00 0.02 600° C. 3 Core 0.60 0.29 0.29 0.34 0.22 0.11 0.08 0.01 619° C. 4 Core 1.0 0.27 0.03 0.11 0.40 0.01 0.04 0.02 593° C. 5 Cladding layer 0.07 0.87 0.00  0.021 0.00 0.00 0.01 0.01 650° C. 6 Solder layer 10.1 0.17 0.00 0.00 0.00 0.00 0.00 0.01 575° C. 7 Core 0.53 0.18 0.14 0.10 0.49  0.001 0.00 0.00 612° C. 8 Cladding layer 0.03 0.24 — — — — — — 9 Core 0.64 0.16 0.10 0.07 0.61 0.01 0.01 0.02 605° C. 10 Cladding layer 0.04 0.24 0.00 0.00 0.00 0.00 0.00 0.01 —

[0139] In order to assess the strength, tensile tests were first carried out on differently composed aluminium composite materials. The results for the yield strength R.sub.p0.2, the tensile strength Rm and for the elongation at break A50 mm after simulated soldering and after artificial ageing can be found in Table 3.

[0140] In simulated soldering, the samples were heated to 595° C. as representative of a typical soldering temperature, held at the soldering temperature for 6 minutes and then cooled to 200° C. at the specified average cooling rate. The average cooling rate is calculated as the temperature difference divided by the time taken to reach 200° C.

[0141] In Table 3, artificial ageing is indicated in the State column, where “45 min @ 205° C.” means artificial ageing for 45 minutes at 205° C. metal temperature. “14 d @ RT” indicates an exposure at room temperature for 14 days.

[0142] While samples 1 to 8 achieved values for the yield strength R.sub.p0.2 between 42 MPa and 62 MPa in the soldered state, it is clear from the results that after an artificial ageing of 205° C. for 45 minutes, an increase of the yield strength R.sub.p0.2 by at least 90 MPa and thus yield strengths R.sub.p0.2 of more than 150 MPa could only be achieved with the samples 2, 4, 7 and 8 according to the invention. Due to the selected composition of the aluminium material of the core layer, the quenching sensitivity is set here such that the soldering process can, for example, act in a typical CAB process with subsequent cooling as a solution annealing with quenching when setting the lower limit for the cooling rate and the material is therefore in the T4 state after soldering. As a result, yield strengths R.sub.p0.2 of more than 150 MPa were achieved with a short artificial ageing of 45 min at 205° C. Although the composite material 6 also shows a corresponding increase in the yield strength R.sub.p0.2, the core layer has an excessively high Si content and thus an excessively low solidus temperature Tsol, such that the composite material 6 tends to melt during soldering. The samples 1, 3 and 5 have compositions of the core material not according to the invention. Samples 3 and 5 have excessive contents of Mn and Cr, such that due to the increased quenching sensitivity, a sufficient increase in strength could not be achieved at the cooling rates adjustable in the soldering process.

TABLE-US-00003 TABLE 3 Tensile test characteristics Sample Average R.sub.p0.2 Rm A50 mm no. C/I cooling rate State [MPa] [MPa] [%] 1 Comparison    1° C./s Soldered 42 137 26 soldered + 45 min @ 205° C. 95 161 19 soldered + 4 h @ 185° C. 151 198 16 soldered + 16 h @ 165° C. 185 227 15 soldered + 14 d @ RT 65 67 28 2 Invention    1° C./s Soldered 59 64 27 soldered + 45 min @ 205° C. 203 255 13 soldered + 4 h @ 185° C. 219 268 11 soldered + 16 h @ 165° C. 232 281 12 soldered + 14 d @ RT 89 200 25 3 Comparison 0.833° C./s Soldered 45 138 22 soldered + 45 min @ 205° C. 47 151 26 soldered + 4 h @ 185° C. 48 151 27 soldered + 16 h @ 165° C. 74 159 19 soldered + 14 d @ RT 52 161 27 4 Invention 0.833° C./s Soldered 60 171 26.5 soldered + 45 min @ 205° C. 207 262 12.6 soldered + 4 h @ 185° C. 236 282 11.5 soldered + 16 h @ 165° C. 237 290 13.4 soldered + 14 d @ RT — — — 5 Comparison 0.833° C./s Soldered 45 149 23.8 soldered + 45 min @ 205° C. 47 151 24.6 soldered + 4 h @ 185° C. 48 151 25.9 soldered + 16 h @ 165° C. 74 159 18.3 soldered + 14 d @ RT 52 161 25.1 6 Comparison    1° C./s Soldered — soldered + 45 min @ 205° C. 168 228 10.1 soldered + 4 h @ 185° C. soldered + 16 h @ 165° C. soldered + 14 d @ RT 85 192 17.2 7 Invention 0.833° C./s soldered 48 148 25.6 soldered + 45 min @ 205° C. 163 213 24.0 soldered + 4 h @ 185° C. 207 247 11.1 soldered + 16 h @ 165° C. 225 268 12.1 soldered + 14 d @ RT 75 183 22.3 8 Invention 0.833° C./s soldered 62 159 25.3 soldered + 45 min @ 205° C. 195 241 24.0 soldered + 4 h @ 185° C. 215 255 11.1 soldered + 16 h @ 165° C. 213 260 12.1 soldered + 14 d @ RT 91 196 22.3

[0143] The quenching sensitivity of the alloy, which is determined by the chemical composition, and the real cooling rate, which is set in the soldering process after the holding time is complete, are important for effective precipitation hardening after the soldering process. Table 4 shows the strengths achievable for different cooling rates using the example of the aluminium composite material No. 2 according to the invention.

TABLE-US-00004 TABLE 4 Tensile test characteristics vs. Cooling rate Soldering Average Cooling temperature rate soldering and holding temperature up Artificial R.sub.p02 R.sub.m A time to 200° C. ageing [MPa] [MPa] [%] 595° C. 0.66° C./s 45 min at 185 243 16.0 6 min 205° C. 595° C.  0.5° C./s 45 min at 165 230 17.0 6 min 205° C. 595° C. 0.33° C./s 45 min at 133 206 18.0 6 min 205° C. 595° C. 0.16° C./s 45 min at 50 149 27.4 6 min 205° C.

[0144] Table 4 shows that a cooling rate of at least 0.5° C./s is required in order to achieve a strength level according to the invention with R.sub.p0.2 greater than 150 MPa in the aluminium composite material No. 2.

[0145] FIG. 2 shows in a perspective view the test arrangement for carrying out the bending tests to determine the maximum bending angle. The tests are based on the specification of the German Association of the Automotive Industry (VDA) 238-100. The test arrangement consists of a bending punch 14, which, in the present case, has a punch radius of 0.4 mm. The sample 15 was previously cut out transversely to the rolling direction with a size of 250 mm×68 mm. Sample 15 was then subjected to two annealings, wherein the first annealing simulates the typical temperature profile of CAB soldering, wherein the soldering temperature at 595° C. with a holding time of 5 minutes and the cooling rate>0.5° C./sec to 200° C. were maintained, and the second annealing corresponds to an artificial ageing for 45 min at 205° C.

[0146] The sample 15 was then cut to a size of 60×60 mm, wherein the edges were milled over and fed to the bending device. When bending the sample through the bending punch, which has a punch radius of 0.4 mm, the force with which the bending punch bends the sample is measured and, after exceeding a maximum and a drop of this maximum of 60 N, the bending process is ended. The opening angle of the curved sample is then measured. The bending behaviour of the sample is generally measured transversely to the rolling direction in order to obtain a reliable statement regarding the bending behaviour during the manufacture of components with high forming requirements. In the present case, the bending behaviour transverse to the rolling direction was tested in the solder-simulated and artificially-aged state, since the bending angle correlates with the ductility in the event of a crash.

[0147] For example, the bending punch 14, which, as represented in FIG. 3, runs parallel to the rolling direction such that the bending line 18 also runs parallel to the rolling direction, presses the sample with a force Fb between two rollers 16, 17 with a roll diameter of 30 mm, which are arranged at a distance of twice the sample thickness+0.5 mm. While the bending punch 14 bends the sample 15, the punch force Fb is measured. If the punch force Fb reaches a maximum and then drops by 60 N, the maximum achievable bending angle is reached. The sample 15 is then removed from the bending device and the bending angle is measured, as represented in FIG. 4. The indicated bending angles were calculated on a reference thickness of 2 mm using the formula:

α.sub.standard=α.sub.measurement×(d.sub.m.sup.1/2/d.sub.standard.sup.1/2)

where α.sub.standard is the standardised bending angle, α.sub.measurement is the measured bending angle, d.sub.standard is the standardised sheet thickness 2 mm and d.sub.m is the measured sheet thickness.

[0148] In the present case, the bending test was carried out on different aluminium composite materials no. 9 and 10. Table 5 shows the different variants that were examined.

TABLE-US-00005 TABLE 5 Solder Cladding layer alloy Core layer no., Sample Comparison/ Number of (thickness layer (thickness no. Invention layers in %) no. in %) 9 Invention 2 6 (5%) 2 — 10 Invention 4 6 (5%) 2 5, both sides, (5% each)

[0149] The results are shown in Tables 6a and 6b. While bending angles of 80°>α.sub.standard>50° were expected, the samples manufactured according to the invention achieved a bending angle α.sub.standard>80°, which is associated with very good crash properties.

[0150] While test sample no. 9 was plated on one side with a solder layer 4 and a layer thickness of 5%, test sample 10 was plated on both sides with a cladding layer 3 consisting of alloy no. 5 of the type AA8079 with a layer thickness of 5% and on one side with an outer solder layer 4 of alloy no. 6 with a layer thickness of 5%. For the test samples 9 and 10 in Table 6a, the solder side was aligned with the rollers 16, 17 in each case. In the test samples 9 and 10 in Table 6b, the solder side of the aluminium composite material was aligned with the punch 14.

[0151] As already stated, it was shown that sample 10 with a cladding layer 3 allowed significantly higher bending angles than sample 9 manufactured from conventional mono-AA6xxx alloys with a solder layer. Cladding layer 3 therefore results in higher ductility in the event of a crash. The combination of a higher-strength core material with ductility-enhancing plating improves performance in the event of a crash, for example of a structural component.

TABLE-US-00006 TABLE 6a Solder side aligned with the rollers Opening angle Bending angle Sample no. β.sub.standard [°] α.sub.standard [°] 9 Invention 123 57 10 Invention 93 87

TABLE-US-00007 TABLE 6b Solder side aligned with the punch Opening angle Bending angle Sample no. β.sub.standard [°] α.sub.standard [°] 9 Invention 103 77 10 Invention 91 89

[0152] FIG. 5 shows in a schematic top view an exemplary embodiment of a heat exchanger 10, a battery cooling plate 19 and a structural part of a motor vehicle 20. The components of the heat exchanger, for example the fins 11 of the heat exchanger 10, consist of an aluminium material 1a, 1b, 1c, 1d, 1e, if described above according to the invention, which is blank or coated on both sides with an aluminium solder. The fins 11 are soldered to tubes 12 in a meander-shaped manner such that a large number of soldered connections are required. Instead of tubes 12, formed plates can also be used which form cavities for guiding media. The tubes 12 can also be manufactured from the aluminium composite material 1 according to the invention. Since they carry the medium and must therefore be protected against corrosion, they can be manufactured with an aluminium composite material according to the invention with a cladding layer 3. A heat exchanger 10 can be exposed, when used for example in a motor vehicle, to corrosive substances, such that the use of the aluminium composite material 1 according to the invention with cladding layer 3 is particularly advantageous.

[0153] The battery cooling plate 19 is shown in a sectional view parallel to the plate plane. A battery cooling plate is usually a large-surface component with meander-shaped cooling channels 19a, which are sealed by a soldered sheet metal as the upper part, not shown here. The parts of the battery cooling plate preferably consist of the described aluminium composite material in order to provide the necessary strength after soldering.

[0154] In a sectional view, a structural component 20 of a motor vehicle is represented as an example in the form of a closed, soldered profile consisting of a U-profile 20a and a striking plate 20b soldered thereto. These typical structural components of a motor vehicle can be provided with the aluminium composite material according to the invention having high strength.

[0155] Alternatively, an aluminium material according to the invention can also be used which, after soldering with a solder layer, is at least in some areas in direct or indirect materially-bonded contact with a solder layer, which is provided, for example, by a soldering foil or a solder component, in order to achieve the advantages according to the invention in relation to the properties of the soldered component from FIG. 5.