Method for producing an aluminum alloy, and component

Abstract

The invention relates to a method for producing an aluminum alloy, in particular for use for a thin-walled body component of a motor vehicle, wherein a starting material (10) which largely contains aluminum is analyzed for the presence of at least one additional metal. At least one additive is added to the starting material (10), and the content of copper in the starting material (10) is determined. Cerium and / or lanthanum is added to the starting material (10) as the at least one additive in such a quantity that a mass ratio of copper to cerium and / or lanthanum of approximately 0.5 to approximately 6 is present in the aluminum alloy obtained after adding the at least one additive. The invention additionally relates to a component produced using such a method.

Description

[0001]AUDI AG P22379 __________________________________________________________ Method for producing an aluminum alloy and component __________________________________________________________ DESCRIPTION: The invention relates to a method for producing an aluminum alloy, in which a starting material containing predominantly aluminum is analyzed for the presence of at least one other metal. At least one additive is added to the starting material. Furthermore, the invention relates to a component produced by such a method. Aluminum alloys are used, for example, in automotive engineering to produce components such as die-cast components, which often have very high demands with regard to mechanical properties and corrosion resistance.In particular, a high proportion of copper, iron, and zinc in the aluminum alloys used in production can cause problems with regard to the aforementioned desirable properties of the component. For example, DE 440763 C describes that iron in aluminum forms a compound with the formula FeAl3, which crystallizes in long needles and makes the alloy brittle. Therefore, DE 440763 C proposes alloying cerium, for example, with iron-containing aluminum in such quantities that the iron present reacts entirely with the cerium to form the compound CeFe. The aim of this is to eliminate the harmful crystal type FeAl3 from the alloy and instead form the compound CeFe in small crystals. AT 412726 B describes that it is advantageous to limit the iron, zinc, and copper content in an aluminum alloy to certain maximum values.However, it cannot always be avoided that an alloy intended for the production of a component that must meet high requirements contains components that have an adverse effect on the component's properties. This is particularly true if aluminum scrap is used as the starting material for producing the aluminum alloy. Aluminum alloys produced from aluminum scrap and thus recycled are also referred to as secondary alloys. In contrast, non-recycled aluminum alloys are also referred to as primary alloys or primary aluminum alloys. The composition of primary alloys can be precisely tailored to meet specific requirements. However, from a sustainability and climate protection perspective, it is advantageous to use aluminum secondary alloys.Compared to primary aluminum alloy, carbon dioxide savings in the range of approximately 5 to 17 tons of CO2 per ton of aluminum alloy can be achieved if a recycled secondary alloy is used to manufacture a component instead of the primary aluminum alloy. The object of the present invention is to provide a method of the type mentioned above, by means of which at least one property of the aluminum alloy to be manufactured can be improved particularly easily, and to provide a component manufactured by such a method. This object is achieved by a method having the features of patent claim 1 and by a component having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the dependent patent claims.In the method according to the invention for producing an aluminum alloy, a starting material containing predominantly or predominantly aluminum is analyzed for the presence of at least one other metal. At least one additive is added to the starting material. In the present case, a copper content in the starting material is determined. Then, cerium (Ce) and / or lanthanum (La) is added to the starting material as the at least one additive in an amount such that the aluminum alloy obtained after adding the at least one additive has a mass ratio of copper to cerium and / or lanthanum of approximately 0.5 to approximately 6. Copper does increase the strength of an aluminum alloy through hardening and the formation of an Al2Cu phase or a Q phase, i.e. a phase containing aluminum, copper, and other elements.However, unlike aluminum, copper has a positive electrochemical potential on the order of approximately +0.52 volts. The formation of the Al2Cu phase, for example, therefore leads to corrosive erosion of the less noble aluminum matrix and, consequently, to corrosion of the component if the latter is formed from a correspondingly copper-containing starting material. Due to their electrochemical potential, copper-containing aluminum phases therefore impair the corrosion resistance of a component manufactured from the starting material. One reason for this is the positive electrochemical potential of copper, whereas aluminum has a negative electrochemical potential of approximately -1.66 volts. The electrochemical potential of a copper-aluminum mixed phase such as Al2Cu is therefore higher than the electrochemical potential of an aluminum matrix in the form of a solid solution, which contains aluminum with trace amounts.If such a material containing a copper-aluminum mixed phase comes into contact with a liquid electrolyte, for example in the form of salt water or the like, the less noble material, i.e. the material with the lower electrochemical potential, is eroded. This results in corrosion of the component. Since the copper-aluminum mixed phase is more noble than the aluminum matrix, contact of salt water, for example, with a component containing the copper-aluminum mixed phase can lead to severe corrosive attack on the aluminum material of the component. This is counteracted here by adding cerium and / or lanthanum as at least one additive to the copper-containing starting material. At approximately -2.5 volts, cerium and lanthanum have an even lower electrochemical potential than aluminum. In other words, cerium and lanthanum are even less noble than aluminum.Furthermore, cerium and lanthanum are capable of forming intermetallic phases with aluminum and copper. Such AlCu(Ce,La) phases, with a suitable mass ratio of copper to cerium and / or lanthanum—that is, with a suitable mass ratio that can be expressed as the quotient Cu / (Ce + La), have an electrochemical potential that is at least very close to the electrochemical potential of aluminum. By adding the additive in the form of cerium and / or lanthanum in such an amount that the mass ratio of copper to cerium and / or lanthanum in the aluminum alloy obtained after the addition of cerium and / or lanthanum is approximately 0.5 to approximately 6—it is possible to achieve an electrochemical potential of the resulting AlCu(Ce,La) phase of approximately -1.66 volts, which is in the range of the electrochemical potential of pure aluminum.If the AlCu(Ce,La) phase is comparatively rich in cerium and / or lanthanum, the Cu / (Ce+La) mass ratio is in the range of up to about 0.5. If, on the other hand, the AlCu(Ce,La) phase is comparatively rich in copper, the Cu / (Ce+La) mass ratio is in the range of up to about 6. When a melt containing aluminum, copper, cerium, and / or lanthanum solidifies, AlCu(Ce,La) phases with different stoichiometric compositions are formed depending on the solidification rate. Consequently, the casting process used with such a melt, as well as the casting parameters present in the respective casting process, influence the composition of the resulting AlCu(Ce,La) phase. For example, the melt cools more quickly in die casting than in permanent mold casting.The stoichiometric composition of the AlCu(Ce,La) phase therefore depends on the solidification rate and, consequently, in particular, on the casting process and the respective casting parameters. It has been found that with all of these AlCu(Ce,La) phases, with mass ratios ranging from approximately 0.5 to approximately 6, a component made from the resulting aluminum alloy is particularly resistant to corrosion. By adding cerium and / or lanthanum in the correct ratio, it is possible to balance the positive electrochemical potential of copper with the comparatively strongly negative electrochemical potential of cerium and / or lanthanum, such that the formed intermetallic phase, which contains aluminum, copper, cerium, and / or lanthanum, essentially has the electrochemical potential of pure aluminum.In this way, it is also possible to advantageously ensure that the amount of copper contained in the starting material is at least almost completely bound in the AlCu(Ce,La) phases. Consequently, the formation of AlCu phases, which would be unfavorable with regard to the susceptibility to corrosion of the component made from the aluminum alloy, can be prevented. In other words, the formation of the corrosion-damaging AlCu phase in the manufactured component can be avoided. By adding the additive in the form of cerium and / or lanthanum in the described amount, it is possible to ensure that the entire resulting aluminum alloy has a largely uniform electrochemical potential and thus the component made from the aluminum alloy has a high corrosion resistance.By adding cerium and / or lanthanum in the amount described above, which takes into account the copper content in the starting material, the corrosion resistance of the component to be produced from the aluminum alloy can be improved in particular. This property of the aluminum alloy to be produced is consequently improved in a simple manner. The binding of copper by incorporation into the phase containing aluminum and copper as well as cerium and / or lanthanum also advantageously ensures that any zinc (Zn) present in the starting material does not lead to an increase in the susceptibility to corrosion of the component to be produced from the resulting aluminum alloy. In principle, it is true that if both zinc and copper are present in the starting material, the formation of an AlCuZn phase in particular can lead to a high susceptibility to corrosion of the component containing the AlCuZn phase.However, the formation of the AlCuZn phase is advantageously prevented if the copper present in the starting material is at least largely, in particular completely, incorporated into the AlCu(Ce,La) phase. As a result, the setting of the copper in the AlCu(Ce,La) phase or the incorporation of the copper into this phase advantageously prevents a high zinc content of the starting material from leading to unfavorable corrosion properties of the component to be manufactured from the aluminum alloy. Preferably, the at least one additive is added to a melt of the starting material. This is based on the knowledge that during cooling of the melt, into which cerium and / or lanthanum has been introduced as the at least one additive, the intermetallic AlCu(Ce,La) phases are formed even at very high temperatures.Consequently, cerium and / or lanthanum are capable of binding copper in this intermetallic phase very early on while the melt is cooling. In this way, it is particularly possible to achieve that the amount of copper present in the starting material is almost completely introduced or incorporated into the phase containing aluminum and copper as well as cerium and / or lanthanum, and thus virtually rendered harmless. In particular, the phase containing Al and Cu as well as cerium and / or lanthanum forms during the cooling of the melt before any Al-Cu phases form, which would reduce the corrosion resistance of the component made from the aluminum alloy. It is therefore advantageous to introduce the at least one additive in the form of cerium and / or lanthanum into the melt of the starting material.Preferably, an iron content is determined in the starting material, wherein manganese (Mn) and / or molybdenum (Mo) and / or chromium (Cr) and / or tungsten (W) and / or vanadium (V) is added to the starting material as the at least one additive in an amount such that the aluminum alloy obtained after adding the at least one additive has a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium of approximately 0.5 to approximately 20. This is based on the finding that iron has virtually no solubility in aluminum alloys and is therefore almost completely precipitated in the form of coarse intermetallic phases. In a silicon-containing aluminum alloy, the β-Al5FeSi phase is particularly unfavorable because it is acicular or needle-shaped. Such acicular iron-containing phases reduce the ductility of the component obtainable from the aluminum alloy.In addition, such iron-containing intermetallic phases are very brittle and tend to accumulate. With a high iron content in the aluminum alloy, these acicular or needle-shaped iron-containing phases can become very large. Such large intermetallic, iron-containing phases, in particular, have a strong crack-initiating effect and thus usually lead to early failure of the component under mechanical stress. This is primarily due to the low ductility of the component material, which arises from the presence of the acicular or needle-shaped iron-containing phases. By incorporating manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium, the formation of the morphologically unfavorable β-Al5FeSi phase is prevented, and an iron-containing α-phase is formed instead.Such α-phases, which contain manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium in addition to iron and aluminum, ensure a more favorable morphology of the phase containing these additives. In particular, the formation of large, needle-shaped or acicular iron-containing phases is prevented. This leads to an improvement in the mechanical properties of the component to be manufactured from the resulting aluminum alloy. In particular, the ductility of the component formed from the resulting aluminum alloy can be significantly improved in this way. Especially if the component to be manufactured from the resulting aluminum alloy is to have high ductility and good corrosion properties or low susceptibility to corrosion, it is advantageous to determine both the copper content in the starting material and the iron content.Then, by adding the respective additives in the amounts specified here to the starting material, it can be ensured that the mass ratios specified here are established in the resulting aluminum alloy. The associated advantages become particularly apparent when a component such as a body component, in particular a thin-walled body component, for a motor vehicle is produced from the resulting aluminum alloy, in particular in a casting process such as a die-casting process. Preferably, by adding the at least one additive, a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium of approximately 1 to approximately 15 is established in the aluminum alloy. Such a mass ratio has proven advantageous with regard to preventing the formation of morphologically unfavorable iron-containing phases in the aluminum alloy.The latter applies particularly when a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium of approximately 2 to approximately 10 is established in the aluminum alloy by adding the at least one additive. In particular, by adding at least one of the aforementioned additives in the form of manganese, molybdenum, chromium, tungsten and vanadium, the unfavorable ductility due to the presence of iron in the starting material can be largely avoided. In contrast, a good or high ductility of the component that can be produced from the resulting aluminum alloy is achieved. Preferably, the at least one additive is added to the starting material by charging the starting material with an alloy, wherein the alloy contains aluminum as the remainder other than the at least one additive.In this way, it is ensured that no further admixtures in the alloy disrupt the composition of the aluminum alloy to be obtained. The at least one additive contained in the alloy can in particular be introduced into the starting material by adding the alloy to the starting material as a melt. Preferably, the at least one additive is added to the starting material by exposing the starting material to the alloy, which contains between approximately 1 percent by weight and approximately 50 percent by weight of cerium and / or lanthanum, wherein the alloy preferably additionally contains between approximately 1 percent by weight and approximately 20 percent by weight of manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium.Accordingly, by treating the starting material with the alloy, both the adverse effects of a higher copper and zinc content in the starting material and the adverse effects of a higher iron content in the starting material can be counteracted. This is particularly advantageous because, by adding the alloy to the starting material, the resulting aluminum alloy can be improved simultaneously with regard to both the mechanical properties and the corrosion properties of the component to be produced. Preferably, a starting alloy containing silicon (Si) is used as the starting material. In particular, aluminum alloys containing silicon are preferably used to produce body components, in particular thin-walled body components, for a motor vehicle, for example in a die-casting process.Accordingly, it is advantageous if the starting material already contains silicon in addition to aluminum. Preferably, a starting alloy is used as the starting material, which is obtained by melting components made from a respective aluminum alloy. Thus, a so-called recycled secondary alloy or recycled aluminum secondary alloy can be used as the starting alloy. This is advantageous because the energy required to produce the resulting aluminum alloy is significantly lower than is the case when using primary aluminum alloys. An aluminum-containing secondary alloy makes it possible to save over 8 kg of CO2 equivalents per kilogram of aluminum alloy, particularly compared to average aluminum primary alloys available in Europe. This corresponds to over 90 percent of the carbon dioxide footprint generated during the production of the aluminum alloy.Accordingly, this makes it possible to significantly reduce the carbon footprint even in areas where component properties are demanding, such as casting, particularly die casting, of preferably thin-walled body components. In particular, the starting alloy can be obtained by melting motor vehicle components made from a particular aluminum alloy. This makes it particularly easy to ensure that motor vehicle components to be manufactured from the resulting aluminum alloy have favorable properties for these motor vehicle components. Advantageously, however, it is not necessary to initially sort the motor vehicle components made from the respective aluminum alloy into very pure types. Rather, different components such as body components and engine blocks or the like can be used to provide the starting alloy.For example, in the manufacture of an engine block for a motor vehicle made from an aluminum alloy, copper is often deliberately added to achieve a high level of strength. However, in the manufacture of a motor vehicle component, where corrosion resistance is of greater importance, such a high copper content is disadvantageous. In this case, however, this is of minor importance. Because cerium and / or lanthanum are added to the starting material or starting alloy as at least one additive in the appropriate amount, the unfavorable properties with regard to corrosion resistance, which are caused by the presence of copper, are eliminated or compensated for. Thus, a particularly broad spectrum of motor vehicle components made from respective aluminum alloys can be used to provide the starting alloy.Preferably, the aluminum alloy obtained after adding the at least one additive is used to produce a body component for a motor vehicle. Particularly for body components exposed to environmental influences such as salts or water containing other ions, it is important to keep the body component's susceptibility to corrosion particularly low. This is achieved here. In particular, the aluminum alloy obtained after adding the at least one additive can be used to produce a thin-walled body component, preferably with a wall thickness of approximately 1 mm to approximately 6 mm, in particular approximately 2 mm to approximately 5 mm.Particularly for such thin-walled body components, the use of an aluminum alloy, preferably containing silicon, is advantageous, as it gives the component good properties in terms of corrosion resistance and preferably also ductility. The component according to the invention for a motor vehicle, which can in particular be a thin-walled body component for the motor vehicle, is produced by a method according to the invention. Accordingly, this component is particularly simple and improved with regard to at least one property. The advantages and preferred embodiments described for the method according to the invention also apply to the component according to the invention and vice versa. The invention therefore also includes developments of the component according to the invention which have features as have already been described in connection with the developments of the method according to the invention.For this reason, the corresponding developments of the component according to the invention are not described again here. The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations which each have a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive. Exemplary embodiments of the invention are described below. In this regard, Fig. 1 shows a highly schematic view of a starting alloy prepared by melting aluminum scrap, which is analyzed for the content of certain ingredients using an analysis device; Fig. 2 shows the addition of an alloy containing additives to the starting alloy or the molten starting material; Fig.3 schematically shows the aluminum alloy obtained by adding the at least one additive to the starting alloy; and Fig. 4 schematically shows a component obtained from the aluminum alloy according to Fig. 3, which is used, for example, as a thin-walled body component in a motor vehicle. The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another and which each also develop the invention independently of one another. Therefore, the disclosure is intended to include combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.In the figures, like reference numerals designate functionally equivalent elements. Fig. 1 shows a highly schematic illustration of how a starting material 10, which is to be used to produce an aluminum alloy 12 (see Fig. 3), is obtained by melting aluminum scrap. Accordingly, the starting material 10 is a so-called secondary alloy. The aluminum secondary alloy is obtainable by recycling components 14 formed from a respective aluminum alloy. The components 14 illustrating the aluminum scrap are shown schematically in Fig. 1. A motor vehicle component formed from an aluminum alloy, such as a thin-walled body component 16 (see Fig. 4), can be used in a motor vehicle 18.If the body component 16 is subject to high demands with regard to ductility and corrosion resistance, a so-called aluminum-containing primary alloy or primary aluminum alloy is usually used to manufacture the body component 16. Such a primary alloy is not made from recycled aluminum material, but from aluminum-containing raw materials with the addition of further alloying elements intended for the respective application. The preferred use of primary alloys applies in particular to body components 16 in the form of die-cast components containing silicon and aluminum, for example in the form of thin-walled body components 16 with wall thicknesses in the range of approximately 1 mm to approximately 6 mm. The reason for this is the frequently increased proportion of copper, iron, and zinc in recycled secondary alloys, as used here, for example, in the form of the starting material 10 (see Fig. 1).In particular, higher copper and iron contents in the starting material 10 can lead to problems. This could be avoided by using very pure sorted aluminum scrap to provide the starting material 10. This is because the composition of the scrap is then also comparatively uniform. However, such pure sorted aluminum scrap entails increased costs compared to regular (i.e., not laboriously sorted) recycled aluminum secondary alloys. In addition, laboriously and pure sorted aluminum scrap is less available than regular aluminum secondary alloys. Therefore, in terms of costs, it is more advantageous if such a secondary alloy obtained by recycling non-purely sorted aluminum scrap is used as the starting material 10, which is shown schematically in Fig. 1. The starting material 10 is shown in Fig.1 as a melt held in a container 20. In the melt or starting alloy, the copper and iron content is determined, preferably in percent by weight. For example, an analysis device 22 shown schematically in Fig. 1 can be used for this purpose, which can be designed as a mass spectrometer or the like. Once the copper and iron content in the starting material 10 is known, an alloy 24, shown schematically in Fig. 2, which contains at least one additive, is added to the starting material 10. The alloy 24 can also be referred to as a repair alloy, since the additives contained in the alloy 24 ensure that properties of the aluminum alloy 12 obtained as a result of the supply or addition of the at least one additive (see Fig. 3) or of the component to be manufactured from the aluminum alloy 12 (see Fig.4). The alloy additive in the form of alloy 24 shown schematically in Fig. 2 can be used similarly to a tablet and added to the melt of the starting material 10, as illustrated in Fig. 2 by an arrow 26. The alloy 24 contains the additives in respective amounts which lead to preferably improving both the mechanical properties and the corrosion properties of the component produced from the resulting aluminum alloy 12 (see Fig. 3), in particular body component 16 (see Fig. 4). The corresponding process sequence can be as follows. The starting alloy or starting material 10 obtained by melting the aluminum scrap or the components 14 is analyzed with regard to its copper and iron content.The alloy 24 or repair alloy is then added to the melt of the starting material 10 in a ratio that takes into account, on the one hand, the copper content in the starting material 10 and, on the other hand, the iron content in the starting material 10. The alloy 24 therefore preferably has a composition that takes into account both the copper and iron content in the starting material 10. If the starting material 10 contains copper, the alloy 24 preferably has a content of between approximately 1 percent by weight and approximately 50 percent by weight of cerium (Ce) and / or lanthanum (La). In this way, it can be ensured that in the resulting aluminum alloy 12 (see Fig. 3), to which cerium and / or lanthanum was added as an additive, a mass ratio of copper to cerium and / or lanthanum in the range of approximately 0.5 to 6 is established.This is based on the knowledge that cerium and lanthanum have an electrochemical potential of approximately -2.5 volts and are thus less noble than aluminum, which has an electrochemical potential of approximately -1.66 volts. In contrast, copper has a positive electrochemical potential. By adding cerium and / or lanthanum to the starting material 10, the formation of an AlCu phase can be prevented, which would lead to a high susceptibility to corrosion of the manufactured component. If cerium and / or lanthanum are present in the melt in the appropriate amount, then AlCu(Ce,La) phases form in the melt instead. These intermetallic phases, which contain copper and aluminum as well as cerium and / or lanthanum, ensure, on the one hand, that all of the copper present in the starting material 10 is bound or bound into these AlCu(Ce,La) phases, thus preventing the formation of corrosion-damaging AlCu phases.Furthermore, by adding cerium and / or lanthanum in the appropriate mass ratio, it can be ensured that the resulting AlCu(Ce,La) phase has an electrochemical potential that is at least very close to the approximately -1.66 volts of aluminum. Since the component formed from the aluminum alloy 12, in particular the body component 16 (see Fig. 4), thus has a uniform electrochemical potential overall, the component, in particular the body component 16, has a very high corrosion resistance. In the present case, according to Fig. 2, the addition of the alloy 24 to the starting material 10 also takes into account the inherently unfavorable effect of an increased iron content in the starting material 10.If the starting material 10 contains iron, manganese (Mn) and / or molybdenum (Mo) and / or chromium (Cr) and / or tungsten (W) and / or vanadium (V) is additionally added to the alloy 24 in an order of magnitude of preferably about 0.5 weight percent to about 20 weight percent. As the remainder other than the at least one additive, the alloy 24 in the present case contains aluminum. The presence of manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium in the alloy 24 ensures that in the aluminum alloy 12 obtained after the addition of at least one of these additives (see Fig. 3), a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium is established which is in the range of 0.5 to 20, in particular in the range of 1 to 15, preferably in the range of 2 to 10.The provision of additives in the form of manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium in the alloy 24 prevents the formation of acicular iron phases in the component formed from the resulting aluminum alloy 12, in particular body component 16. The formation of such acicular or needle-like iron phases would lead to unfavorable mechanical properties of the manufactured component, which are expressed in particular in low ductility of the component. This is prevented here. Consequently, the component produced from the aluminum alloy 12, in particular the body component 16 shown schematically and by way of example in Fig. 4, also has improved properties with regard to high ductility. From the aluminum alloy 12, which is obtainable by adding the alloy 24 to the starting material 10 (cf. Fig.2), components, in particular body components 16, can therefore be produced by casting, in particular by die casting, which are capable of meeting very high requirements for corrosion resistance and ductility. The process described here for producing the aluminum alloy 12 (see Fig. 3) is based on the knowledge that, to date, aluminum-containing secondary alloys have only been used in a very limited range of applications due to their often elevated iron, copper, and zinc content. One reason for this is that elevated copper and zinc contents in the starting material significantly reduce the corrosion resistance of the available components. This is particularly true when compared to the production of components from an aluminum-containing primary alloy.On the other hand, the mechanical properties of components obtained from secondary alloys without the addition of alloy 24 are significantly poorer than would be the case with the use of aluminum primary alloys due to increased iron contents. Therefore, to date, primary alloys have primarily been used to manufacture components that are required to meet high requirements with regard to mechanical properties and corrosion resistance. This applies in particular to body components 16, for example in the form of the thin-walled body component 16 shown here as an example, which is obtainable by casting, in particular by die casting. However, the use of primary alloys entails a significantly higher carbon dioxide footprint than is the case with the use of the starting material 10 described here.As explained above, the use of alloy 24 advantageously and surprisingly makes it possible to use even non-purely sorted, but rather regular, recycled secondary alloys in the form of starting material 10 for manufacturing components such as the thin-walled body component 16 shown here as an example. This is because the properties of starting material 10 can be significantly improved by the addition of alloy 24. This applies both to corrosion resistance and mechanical properties. By using alloy 24 or repair alloy for aluminum-containing secondary alloys, it is therefore possible, with the mixing ratios explained above, to achieve high corrosion resistance and good mechanical properties of the components to be manufactured, in particular body components 16.Accordingly, secondary alloys can be used as the starting material 10 even for components that have to meet high requirements in this regard. This enables the use of secondary alloys in a significantly larger or broader range of applications without any significant additional effort. In particular, the carbon dioxide footprint can be significantly reduced in demanding areas such as structural casting, i.e., the production of structural components such as thin-walled body components 16. For example, a carbon dioxide saving in the range of over 8 kg CO2 equivalents per kilogram of produced aluminum alloy 12 can be achieved. This is very advantageous with regard to reducing the carbon dioxide footprint. Fig. 4 illustrates by way of example that the at least one, preferably thin-walled, body component 16 can be advantageously used in the motor vehicle 18.Overall, the examples demonstrate how a process can be provided to improve the properties of secondary aluminum alloys.

Claims

PATENT CLAIMS:

1. A method for producing an aluminum alloy (12), in particular for use for a thin-walled body component (16) of a motor vehicle (18), in which a predominantly aluminum-containing starting material (10) is analyzed for the presence of at least one other metal, and in which at least one additive is added to the starting material (10), characterized in that a copper content is determined in the starting material (10), wherein cerium and / or lanthanum is added to the starting material (10) as the at least one additive in an amount such that a mass ratio of copper to cerium and / or lanthanum of approximately 0.5 to approximately 6 is present in the aluminum alloy (12) obtained after adding the at least one additive.

2. The method according to claim 1, characterized in that the at least one additive is added to a melt of the starting material (10). 3.Method according to one of the preceding claims, characterized in that an iron content is determined in the starting material (10), wherein the starting material (10) is supplied with at least one additive, manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium, in an amount such that a mass ratio of iron to manganese and / or molybdenum and / or vanadium in the aluminum alloy (12) obtained after the supply of the at least one additive is obtained. Chromium and / or tungsten and / or vanadium of approximately 0.5 to approximately 20 is present.

4. The method according to claim 3, characterized in that in the aluminum alloy (12) a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium of approximately 1 to approximately 15 is set by adding the at least one additive.

5. The method according to claim 4, characterized in that in the aluminum alloy (12) a mass ratio of iron to manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium of approximately 2 to approximately 10 is set by adding the at least one additive.

6. The method according to any one of the preceding claims, characterized in that the at least one additive is added to the starting material (10) by applying an alloy (24) to the starting material (10) which contains aluminum as the remainder other than the at least one additive.Method according to claim 6, characterized in that the at least one additive is added to the starting material (10) by applying to the starting material (10) the alloy (24) which contains between about 1 percent by weight and about 50 percent by weight of cerium and / or lanthanum and between about 1 percent by weight and about 20 percent by weight of manganese and / or molybdenum and / or chromium and / or tungsten and / or vanadium.

8. Method according to one of the preceding claims, characterized in that a starting alloy containing silicon is used as the starting material (10) and / or a starting alloy obtained by melting components (14) formed from a respective aluminum alloy, in particular motor vehicle components formed from a respective aluminum alloy, is used as the starting material (10).

9. Method according to one of the preceding claims, characterized in that the aluminum alloy (12) obtained after adding the at least one additive is used to produce a, in particular thin-walled, body component (16) for a motor vehicle (18).

10. Component, in particular thin-walled body component (16), for a motor vehicle (18), wherein the component is produced by a method according to one of the preceding claims.

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