WO2023099080A1

WO2023099080A1 - Aluminium die casting alloy

Info

Publication number: WO2023099080A1
Application number: PCT/EP2022/079580
Authority: WO
Inventors: Marc Hummel; Steffen Otterbach; Heinz-Werner HÖPPEL; Marius KOHLHEPP
Original assignee: Audi Ag
Priority date: 2021-12-03
Filing date: 2022-10-24
Publication date: 2023-06-08
Also published as: EP4441265A1; DE102021131973A1; CN118339319A

Abstract

The invention relates to an aluminum die casting alloy having the following alloy constituents: 5 to 9.5 wt. %, in particular 6 to 8 wt. %, silicon; 0.0001 to 0.3 wt. %, in particular 0.001 to 0.3 wt. %, in particular 0.05 to 0.25 wt. %, in particular 0.07 to 0.2 wt. %, chromium; 0.0001 to 0.3 wt. %, in particular 0.001 to 0.3 wt. %, in particular 0.05 to 0.25 wt. %, in particular 0.05 to 0.2 wt. %, manganese; 0.0001 to 0.2 wt. %, in particular 0.001 to 0.15 wt. %, in particular 0.01 to 0.15 wt. %, molybdenum and/or tungsten; remainder aluminium and unavoidable impurities.

Description

Die-cast aluminum alloy

DESCRIPTION:

The invention relates to an aluminum die-cast alloy, a method for the heat treatment of a component for a motor vehicle made from such an aluminum die-cast alloy, and a component for a motor vehicle.

EP 1 443 122 B1 discloses an aluminum alloy for die-casting components with high elongation in the cast state. Further compositions for die-cast aluminum alloys are described in EP 1 719 820 A2, DE 10 2006 039 684 B4, DE 10 2010 055 011 A1 or DE 10 2019 205 267 B3.

DE 10 2005 037 738 A1 describes an aluminum cast alloy containing silicon, magnesium, iron, copper, zinc, manganese, titanium, zirconium, nickel and cobalt.

An aluminum-silicon cast alloy is known from EP 1 978 120 A1, which additionally contains, inter alia, magnesium, titanium, zirconium, manganese, iron, copper and nickel.

A hardenable aluminum cast alloy with silicon, magnesium, nickel and cobalt is described in DE 100 62 547 A1.

The alloy compositions known from these documents are used for engine components such as crankcases, cylinder heads and possibly pistons. Usually, die-cast components, which have very high demands on their mechanical properties, are manufactured using an aluminum-silicon alloy and a T6 heat treatment, usually consisting of solution annealing, quenching and aging. Since the ductility of the components decreases with increasing strength due to the brittle silicon eutectic and the Al(Fe,Mn)Si phases in the material, particularly high-strength alloys cannot be used universally for structural cast parts, since they have the minimum level of ductility that is usually found resulting from crash requirements or joining operations can no longer be guaranteed. This leads to limited joinability and problems in component design, especially with regard to crash requirements, which is why these alloys cannot be used universally in vehicles. Since iron and manganese are required for alloy castability and component demoldability, low-strength alloys are often resorted to due to poor ductility in such cases, which often leads to increases in vehicle weight, fuel consumption and fuel consumption due to the increase in component size CCh emissions leads.

Curing via the painting process with a T5 heat treatment also has a high potential for cost savings, since this means that a separate subsequent heat treatment can be completely eliminated. However, since this variant does not allow the silicon to be shaped, the ductility is even lower than that of T6 alloys with the same strength. In such cases, large amounts of copper are often used in addition to magnesium in order to achieve greater strength at the comparatively low temperatures during the painting process. This significantly reduces corrosion resistance and ductility. Due to the fact that no solution annealing is carried out during the T5 heat treatment, the silicon eutectic is cross-linked in contrast to T6 heat-treated alloys, which means that both the ductility and the maximum final strength are even lower for the same material. Therefore, when the highest demands are placed on mechanical properties and corrosion, the only option is usually to use an energy-intensive and costly T6 heat treatment. EP 2 471 966 A1 describes an aluminium-silicon alloy consisting of 6-11.8% silicon, 0.02-0.5% magnesium, 0.005-0.7% manganese, 0.0005-0.6% % copper, 0.001 - 0.06% titanium, 0.03 - 0.3% iron, and max. 0.2% molybdenum and max. 0.2% zirconium and optionally 70 - 400 ppm strontium.

An aluminum alloy for components with increased strength, in particular for structural and chassis parts of a motor vehicle, containing 9 to 11.5% by weight silicon, 0.5 to 0.8% by weight manganese, 0.2 to 1.0% by weight % magnesium, 0.1 to 1.0% by weight copper, 0.2 to 1.5% by weight zinc, 0.05 to 0.4% by weight zirconium, 0.01 to 0.4% by weight .% Cr, max. 0.2 wt.% iron, max. 0.15 wt.% titanium, 0.01 to 0.02 wt.% strontium and the remainder aluminum and manufacturing impurities totaling max. 0.5 Gew is described in EP 2 653 579 B1.

EP 2 735621 B1 relates to a similar aluminum alloy for components with increased strength, in particular for structural and chassis parts of a motor vehicle, containing 9 to 11.5% by weight silicon and 0.45 to 0.8% by weight manganese 0.2 to 1.0% by weight magnesium, 0.1 to 1.0% by weight copper, max. 0.2% by weight zinc, max. 0.4% by weight zirconium, max. 0.4 wt% chromium, 0.3 wt% max molybdenum, 0.2 wt% max iron, 0.15 wt% max titanium, 0.01 to 0.02 wt% % strontium and the remainder aluminum and production-related impurities totaling max. 0.5% by weight.

However, none of the alloys mentioned are able to solve the problem explained above with regard to the conflict of objectives between high ductility and sufficient strength of the components produced from the alloys mentioned.

It is therefore the object of the present invention to create an aluminum die-cast alloy which has both high strength, in particular a high 0.2% proof stress, and high ductility. According to the invention, this object is achieved by the features mentioned in claim 1.

The die-cast aluminum alloy according to the invention, which contains 5 to 9.5% by weight, in particular 6 to 8% by weight, silicon as alloy components;

0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight, in particular 0.05 to 0.25% by weight, in particular 0.07 to 0.2% by weight, chromium ; 0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight, in particular 0.05 to 0.25% by weight, in particular 0.05 to 0.2% by weight, manganese; 0.0001 to 0.2% by weight, in particular 0.001 to 0.15% by weight, in particular 0.01 to 0.15% by weight, molybdenum and/or tungsten; The remainder is aluminum and unavoidable impurities, shows a significant increase in ductility compared to known solutions with the same high strength, so that in the case of a T6 or T7 heat treatment, it can be used universally in a vehicle to achieve maximum savings to achieve weight, direct material costs and CO2. Furthermore, optional T5 hardening via the painting process and the use of the alloy in its naturally hard version are possible. With both types of heat treatment, the composition of the alloy results in less distortion, which means that the costs for straightening processes can be kept low.

Due to the increased ductility, components made from the aluminum die-cast alloy according to the invention, which can be used in all areas of automotive structural castings and in particular in crash-relevant areas, can continue to be joined using standard methods such as semi-tubular punch riveting. It is therefore not necessary to resort to lower-strength alloys and the associated greater component cross-sections or wall thicknesses, which means that vehicle weight, fuel consumption and CO2 emissions can be reduced. In addition to the improved ductility, the alloy according to the invention has increased thermal and electrical conductivity, which is relevant for applications in e-mobility, for example. These advantages result, among other things, from the reduction in the silicon content from the usual 8 to 12% by weight to 5 to 9.5% by weight, in particular to 6 to 8% by weight, since the proportion of brittle phases decreases in this way in the material is reduced and the ductility increases significantly. The lower castability caused by the lower silicon content can be compensated for by adding zinc, strontium, nickel and/or zirconium.

Furthermore, in the aluminum die-cast alloy according to the invention, the manganese content was reduced from 0.5 to 0.8% by weight, which is usual for die-cast alloys, to 0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight. in particular 0.05 to 0.25% by weight, in particular 0.05 to 0.2% by weight. This reduces the proportion of brittle Al(Fe,Mn)Si phases in the material, which in known alloys often cause cracks during deformation and reduce ductility. This allows the ductility to be increased considerably.

In order to continue to prevent mold sticking despite the described reduction in the content of silicon and manganese and to ensure demoldability, the aluminum die-cast alloy according to the invention additionally has 0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight. -%, in particular 0.05 to 0.25% by weight, in particular 0.07 to 0.2% by weight, chromium and 0.0001 to 0.2% by weight, in particular 0.001 to 0.15% by weight .-%, in particular 0.01 to 0.15 wt .-%, molybdenum and / or tungsten. This combination of the elements mentioned is particularly effective in preventing mold sticking, particularly in the stated contents, which is why significantly lower additions of the respective elements are sufficient than when manganese is added alone.

In this case, chromium advantageously reduces the diffusion from the mold steel and thus the erosion of the mold and the development of an unwanted connection between the mold and the component in a particularly effective manner. The inventors have found that below a content of 0.0001% by weight, in particular 0.001% by weight, in particular 0.05% by weight, in particular 0.07% by weight, the described effect is too weak and it continues to become one Mold wear and mold sticking can occur. Above a chromium content of 0.3% by weight, in particular 0.25% by weight, in particular 0.2% by weight, however, the strength can drop sharply, since chromium increases the quench sensitivity of the alloy. In addition, the formation of coarse phases can lead to a reduction in ductility.

A further advantage of the aluminum die-casting alloy according to the invention is that chromium, manganese, molybdenum and tungsten prevent the formation of the needle-shaped β-AlFeSi phase and thus also the connection between the mold and the component. In addition, a reduction in the ductility of the material can be counteracted in this way, since the ß-AlFeSi phase has very negative effects on the ductility. It was found that the above limits for the proportions of the respective elements are particularly effective, since with higher proportions the ductility decreases again due to the formation of large, coarse phases and with lower proportions the effect is too weak, so that the ß-AIFeSi -phase continues to occur and the ductility also decreases. Surprisingly, therefore, the maximum ductility lies in the stated range of the proportions of the individual elements.

The use of molybdenum and/or tungsten also ensures that excess chromium and manganese are set early in a comparatively small, rounded phase. This prevents the primary, coarse formation of iron-rich phases, which contributes to a further increase in ductility. The optimum ductility also lies in this range with regard to the proportions of molybdenum and/or tungsten mentioned. If too little molybdenum and/or tungsten is added, coarse iron-rich phases continue to exist, which reduce ductility.

In a very advantageous development of the invention, it can be provided that the ratio of the sum of the proportions of molybdenum and tungsten to the sum of the proportions of manganese, iron and chromium is 0.1 to 0.5. It was surprisingly found that at the stated Mo+W/Mn+Fe+Cr ratio, suddenly round Al(Mo,W)Si phases without Iron content are formed, which improve the ductility significantly. However, if the sum of the proportions of molybdenum and tungsten is too high, the proportion of these rounded phases in the material becomes too high, so that the ductility drops again. The ratio is dependent on the solidification speed of the alloy and thus on the respective component. This effect is also relevant for the use of recycled secondary alloys to improve sustainability, since the iron content here is higher as impurities. These usually severely limit the ductility of secondary alloys. By choosing a suitable ratio of the sum of the proportions of molybdenum and tungsten to the sum of the proportions of manganese, iron and chromium, the formation of primary AlFeSi phases can be prevented and the ductility can be increased considerably.

In a very advantageous development of the die-cast aluminum alloy, it can contain 0.25 to 0.6% by weight, in particular 0.3 to 0.45% by weight, of magnesium. The addition of this proportion of magnesium leads to the formation of the hardening Mg2Si phase and also ensures strong solid solution hardening. The specified upper limit of 0.6% by weight advantageously prevents embrittlement of the alloy.

In a very advantageous development of the die-cast aluminum alloy, it can have 0.08 to 0.35% by weight of zinc. The proportion of zinc mentioned improves the castability and the surface quality of the alloy and increases its strength by stimulating Mg2Si nucleation. Because the proportion of 0.35% by weight is not exceeded, a reduction in adhesive adhesion and an increase in the tendency to corrode can be counteracted.

Furthermore, the aluminum die-cast alloy can contain 0.05 to 0.3% by weight of zirconium.

In addition, it can be provided that the die-cast aluminum alloy has 0.05 to 0.2% by weight of titanium. Both zirconium and titanium serve to refine the grains and thereby improve the ductility and strength of the alloy. The resulting Ti and Zr phases result in a further increase in strength. The specified range represents the optimum for these purposes.

In a very advantageous development of the invention, it can be provided that the ratio of the proportion of titanium to the proportion of zirconium is 0.8 to 4.0. Surprisingly, it has turned out to be particularly advantageous if the proportion of titanium is greater than the proportion of zirconium.

In a very advantageous development of the die-cast aluminum alloy, it can have 0.006 to 0.025% by weight of strontium. This proportion of strontium ennobles or refines the silicon eutectic and thereby increases both the castability and the ductility of the alloy.

Furthermore, the die-cast aluminum alloy can contain 0.0001 to 0.2% by weight of vanadium.

In addition, it can be provided that the die-cast aluminum alloy has 0.0001 to 0.2% by weight of cobalt.

Both vanadium and cobalt can be used to improve the demoldability of the component made from the alloy after the casting process.

In a very advantageous development of the die-cast aluminum alloy, it can contain 0.05 to 0.5% by weight, in particular 0.05 to 0.3% by weight, of copper. The use of copper can result in the formation of a Q phase (AUMgsSirCua) and, similar to the use of magnesium, the strength can be increased during a subsequent heat treatment, in particular a T6/T7 heat treatment. Furthermore, the copper content mentioned improves the nucleation and the precipitation kinetics of Mg2Si and is therefore particularly useful in combination with magnesium particularly effective. The upper limit of 0.5% by weight, in particular 0.3

% by weight, prevents the negative influence of copper on the corrosion properties of the alloy.

As an alternative to this, the die-cast aluminum alloy can have 0.05 to 0.7% by weight, in particular 0.05 to 0.35% by weight, of copper. The formation of a Q-phase (AUMgsSirC^) can also be achieved through the stated proportion of copper and, similar to the use of magnesium, the strength during a subsequent heat treatment, for example a T5 or a T6/T7 heat treatment, can be increased . Furthermore, this copper content also improves the nucleation and precipitation kinetics of Mg2Si and is therefore particularly effective in combination with magnesium. The upper limit of 0.7% by weight in this case, in particular 0.35% by weight, prevents the negative influence of copper on the corrosion properties of the alloy.

Furthermore, the die-cast aluminum alloy can contain 0.05 to 0.3% by weight, in particular 0.1 to 0.2% by weight, nickel. The use of nickel is particularly advantageous when a component produced from an aluminum die-cast alloy according to the invention is to be subjected to a T5 heat treatment.

In a further advantageous embodiment of the invention, the die-cast aluminum alloy can contain 0.0001 to 0.1% by weight of tin and/or tantalum. These two elements, alone or in combination with one another, are able to bind voids during casting. As a result, they prevent cold aging in the period from casting to curing in a T5 heat treatment, ie a heat treatment in connection with or during vehicle painting, in particular cathode dip painting. This improves the subsequent artificial aging in the painting process, as the strength increases significantly faster than without the addition of tin and/or tantalum. A method of heat treating a component for a motor vehicle made of an aluminum die casting alloy according to any one of claims 1 to 11 is specified in claim 15. The component is subjected to a first annealing for a period of 20 to 75 minutes, in particular 20 to 45 minutes, at a temperature of 320 to 470° C., in particular 380 to 450° C., then for a period of 5 to 35 minutes , in particular 5 to 20 min, at a temperature of 460 to 535 ° C, in particular 490 to 520 ° C, subjected to a second annealing, then at 3 to 200 K / s, in air in particular at 3 to 12 K / s and at water, in particular at 80 to 200 K/s, then subjected to a first exposure for a period of 40 to 150 min, in particular 40 to 90 min, at a temperature of 100 to 180 °C, in particular 120 to 170 °C, and then subjected to a second aging for a period of 30 to 120 minutes, in particular 40 to 80 minutes, at a temperature of 180 to 300° C., in particular 200 to 240° C. In the case of such a heat treatment, the addition of nickel and tin and/or tantalum can be dispensed with. The copper content can also be slightly reduced if copper is added to the alloy.

In an advantageous development of the method, it can be provided that the component is subjected to a third exposure for a period of 5 to 60 minutes, in particular 5 to 30 minutes, at a temperature of 210 to 300° C., in particular 230 to 260° C . This represents another way to improve ductility, as it allows for higher and more uniform deformation in the multiaxial stress state. This type of heat treatment advantageously leads to increased electrical and thermal conductivity. However, this can sometimes also be observed with the other heat treatment methods mentioned herein.

A further method for the heat treatment of a component for a motor vehicle made from an aluminum die-casting alloy according to one of Claims 1 to 14 is specified in Claim 17. The component is heated for a period of 15 to 30 minutes at a temperature of at least 160° C., in particular 160 to 200° C., in particular 160 to 180° C., subjected to a painting process, in particular a cathode dip painting. In this method, the use of the above-mentioned proportions of copper, nickel, tin and/or tantalum in particular can ensure faster and better curing during the painting process, while at the same time having a lesser effect on corrosion. As a result, the aluminum die-cast alloy according to the invention can be used in expanded areas compared to known alloys, in which a T6/T7 heat treatment was previously necessary due to high demands on the mechanical properties of the component. Despite the relatively simple heat treatment, in which the component is "only" subjected to a painting process, in particular a cathode dip painting, it is possible to achieve high strength without reducing the corrosion resistance. As a result, in addition to reducing the vehicle weight due to the elimination of the heat treatment systems that would otherwise be required, high cost savings and a reduction in energy costs and the CCh footprint can be achieved. Nevertheless, the punch riveting capability of the component is also guaranteed with this heat treatment process.

A component for a motor vehicle made from an aluminum die casting alloy according to any one of claims 1 to 14 or made by a method according to any one of claims 15 to 17 is set out in claim 18.

Various alloys are compared below with regard to their strength, ductility, castability and corrosion properties. The results are presented in a table:

Comparison alloys and states used:

Alloy 1 : AISi1O,5MnO,6OMgO,3OSrO,O12TiO,O6 (standard reference alloy) / T6 condition

Alloy 2: AISi9Mn0.60Sr0.012Ti0.06 / F-temper Alloy 3: AISi7.5Mn0.50Mg0.30Sr0.012Ti0.06 / T5 temper

Alloy 4: AISi8.5CuO.8MnO.5FeO.3 / T5 condition

Alloys according to the present invention and states used:

Alloy 5: AISi7ZnO.2CrO.15Mo0.075Mn0.05Ti0, 12Zr0.06Sr0.012W0.01 /

F state

Alloy 6:

AISi7MgO.4ZnO.2CrO, 15Mo0.075Mn0.05Ti0, 12Zr0.06Sr0.012W0.01 / T7 temper

Alloy 7:

AISi7MgO.4CrO, 15CuO, 1Mo0.075Mn0.05Sn0.05Ti0, 12Zr0.06Sr0.012W0.01 /

T5 condition

* Warp assuming T6 heat treatment has been performed

In the table mean:

Rm: tensile strength

Rp0.2: 0.2% proof stress

A5: Elongation at break FDI: strength-ductility index, calculated from the material parameters Rm, Rp0.2 and A5 relevant to the design of vehicle body components; FDI = (Rm+3*Rp0.2)/4*A5/100

For the FDI, the strength values were weighted according to prioritization in body construction (Rm: single; Rp0.2: triple). The mean strength value was multiplied by the elongation at break A5 with the appropriate weighting (Rm: once, Rp0.2: three times) and divided by the divisor 100 for reasons of clarity.

The following conclusions can be drawn from the test results presented in the table:

The alloy 5 corresponding to the present invention has a significantly higher elongation at break with the same 0.2% proof stress in comparison to the naturally hard comparison alloy 2, which can be attributed to the advantageous combination of chromium, molybdenum, manganese and tungsten. In addition, the flowability is increased through the use of zinc.

Alloy 6 according to the present invention has a significantly higher 0.2% yield strength in the T7 temper than comparative Alloy 1 in the T6 temper and yet has a higher elongation at break. As a result, despite its high strength, it can be used universally in the body and can also be joined without any problems. Flowability is also improved due to the use of zinc.

Alloy 7, which corresponds to the present invention, was hardened via the cathode dip painting process and is superior to comparison alloys 3 and 4, which were also hardened in the painting process. The 0.2% yield point and elongation at break are higher than in comparison alloy 3 due to the addition of copper and the combination of chromium, molybdenum, manganese and tungsten. The limited copper content results in high corrosion resistance. Although comparison alloy 4 has a slightly higher 0.2% yield strength, the elongation at break is high Amounts of iron and manganese very low. The corrosion resistance is also poor due to the high copper content.

In addition, Alloys 5, 6 and 7 have higher thermal and electrical conductivity than all four comparison alloys, as well as increased resistance to distortion when subjected to a T6/T7 heat treatment.

The examples show that the alloys according to the present invention are superior to the comparison alloys in all tempers (F, T6 or T7, T5).

Claims

PATENT CLAIMS:

1 . Die-cast aluminum alloy with the following alloy components:

5 to 9.5% by weight, in particular 6 to 8% by weight, silicon,

0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight, in particular 0.05 to 0.25% by weight, in particular 0.07 to 0.2% by weight, chromium , 0.0001 to 0.3% by weight, in particular 0.001 to 0.3% by weight, in particular 0.05 to 0.25% by weight, in particular 0.05 to 0.2% by weight manganese 0.0001 to 0.2% by weight, in particular 0.001 to 0.15% by weight, in particular 0.01 to 0.15% by weight, molybdenum and/or tungsten,

remainder aluminum and unavoidable impurities.

2. Aluminum die-cast alloy according to claim 1, characterized in that the ratio of the sum of the proportions of molybdenum and tungsten to the sum of the proportions of manganese, iron and chromium is 0.1 to 0.5.

3. aluminum die-cast alloy according to claim 1 or 2, characterized by

0.25 to 0.6% by weight, in particular 0.3 to 0.45% by weight, magnesium.

4. aluminum die-cast alloy according to claim 1, 2 or 3, characterized by

0.08 to 0.35% by weight zinc.

5. aluminum die-cast alloy according to any one of claims 1 to 4, characterized by

0.05 to 0.3% by weight zirconium.

6. aluminum die-cast alloy according to any one of claims 1 to 5, characterized by

0.05 to 0.2% by weight titanium.

7. aluminum die-cast alloy according to claims 5 and 6, characterized in that the ratio of the content of titanium to the content of zirconium is 0.8 to 4.0.

8. aluminum die-cast alloy according to any one of claims 1 to 7, characterized by

0.006 to 0.025% by weight strontium.

9. aluminum die-cast alloy according to any one of claims 1 to 8, characterized by

0.0001 to 0.2% by weight vanadium.

10. Die-cast aluminum alloy according to any one of claims 1 to 9, characterized by

0.0001 to 0.2% by weight cobalt.

11 . Die-cast aluminum alloy according to one of claims 1 to 10, characterized by

0.05 to 0.5% by weight, in particular 0.05 to 0.3% by weight, copper.

12. Die-cast aluminum alloy according to any one of claims 1 to 10, characterized by

0.05 to 0.7% by weight, in particular 0.05 to 0.35% by weight copper.

13. aluminum die-cast alloy according to any one of claims 1 to 12, characterized by

0.05 to 0.3% by weight, in particular 0.1 to 0.2% by weight, nickel.

14. aluminum die-cast alloy according to any one of claims 1 to 13, characterized by

0.0001 to 0.1% by weight of tin and/or tantalum.

15. A method for the heat treatment of a component for a motor vehicle made from an aluminum die-cast alloy according to any one of claims 1 to 11, wherein the component for a period of 20 to 75 minutes, in particular 20 to 45 min, at a temperature of 320 to 470 °C, in particular 380 to 450 °C, is subjected to a first annealing, then for a period of 5 to 35 min, in particular 5 to 20 min, at a temperature of 460 to 535° C., in particular 490 to 520° C., is subjected to a second annealing, then quenched at 3 to 200 K/s, in the case of air in particular at 3 to 12 K/s and in the case of water in particular at 80 to 200 K/s is then subjected to a first aging for a period of 40 to 150 minutes, in particular 40 to 90 minutes, at a temperature of 100 to 180° C., in particular 120 to 170° C., and then for a period of 30 to 120 minutes , in particular 40 to 80 min, at a temperature of 180 to 300 ° C, in particular 200 to 240 ° C, is subjected to a second aging.

16. The method according to claim 15, characterized in that the component is subjected to a third aging for a period of 5 to 60 min, in particular 5 to 30 min, at a temperature of 210 to 300 °C, in particular 230 to 260 °C .

17. A method for the heat treatment of a component for a motor vehicle made from an aluminum die-cast alloy according to any one of claims 1 to 14, wherein the component is heated for a period of 15 to 30 minutes at a temperature of at least 160 °C, in particular 160 to 200 °C , In particular 160 to 180 ° C, a painting process, in particular a cathode dip painting is subjected.

18. A component for a motor vehicle, made from an aluminum die-cast alloy according to any one of claims 1 to 14 or made by a method according to any one of claims 15 to 17.