EP1171642A2

EP1171642A2 - Highly ductile magnesium alloys, method of preparing same and their use

Info

Publication number: EP1171642A2
Application number: EP00922597A
Authority: EP
Inventors: Wolfgang Sebastian; Heinz Haferkamp; Peter Juchmann
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 1999-04-03
Filing date: 2000-04-03
Publication date: 2002-01-16
Also published as: WO2000060131A8; WO2000060131A3; DE19915238A1; WO2000060131A2

Abstract

The invention relates to a magnesium alloy which contains less than 1.8 % by weight additions or traces of Cd, traces of up to 0.1 % by weight Cu, up to 0.05 % by weight Fe and up to 0.005 % by weight Ni, and between 0.5 and 20 % by weight Li. Said magnesium alloy is characterized by a tensile strength of at least 227 MPa, an impact strength, measured in unnotched samples, of at least 72 J, and a breaking elongation, measured in tensile-test specimens, of at least 26 %; or a tensile strength of at least 250 MPa, an impact strength, measured in unnotched samples, of at least 72 J and a breaking elongation, measured in tensile-test specimens, of at least 21 %; or an impact strength, measured in unnotched samples, of at least 72 J and a breaking elongation, measured in tensile-test specimens, of at least 18 %. The invention also relates to a magnesium alloy which is selected from the group of alloys on an AM, AZ or ZE basis and can in addition contain lithium, manganese, aluminium, calcium, strontium, zinc, zirconium or at least one rare-earth element, including yttrium. The invention also relates to a method for producing a semi-finished product from a magnesium alloy or a component prepared with or from same and/or a composite element comprising at least such a semi-finished product or component. The method is characterized in that the alloy is melted at temperatures of between 550 and 900 °C and one or more moulded parts are produced by casting with or without additional pressure and then possibly subjected to heat treatment.

Description

Magnesium alloys of high ductility, process for their production and their use

The invention relates to magnesium alloys of high ductility, processes for their production and their use, in particular lithium-containing magnesium alloys.

Because of their very low density, magnesium alloys are approximately in the range from 1.2 to 1.9 g / cm ³ , occasionally, especially in the case of particularly lithium-rich magnesium alloys, down to about 0.9 g / cm ³ as metallic construction materials of particular interest for vehicle and aircraft construction. In the future, they will be used more and more for the lightweight construction of motor vehicles and airplanes in order to be able to compensate for the weight of additional elements due to increasing comfort and safety standards, particularly in new low-emission automobiles. They are also of interest for transportable devices or systems that are particularly light-weight for other reasons. The lightweight construction enables the construction of energy-saving vehicles and planes, such as the 3-liter motor vehicle, to a particular extent. Among the manufacturing processes, die-casting and reshaping, forging, rolling and possibly subsequent reshaping, such as stretching or deep-drawing, will become increasingly important in the future, since these processes can be used to manufacture lightweight components such as seats and windows - and door frames, elements of vehicle cells and vehicle outer skins, housings, floor elements, covers, tank elements, tank flaps, brackets, supports, brackets, angles, crash elements, impact absorbers, impact shields and impact carriers, small parts or corresponding components for aircraft, for which there is an increasing demand .

The cold formability of the commercially available magnesium alloys is limited due to the hexagonal crystal structure and the associated low ductility. Polycrystalline magnesium and most magnesium alloys behave brittle at room temperature. In addition to good mechanical properties such as high tensile strength, ductile behavior is necessary for numerous applications or for certain manufacturing processes for semi-finished products made of magnesium alloys. An improved forming, energy absorption and deformation behavior requires a higher ductility and possibly also a higher strength and toughness. For this are To develop magnesium alloys with these properties or to further develop their manufacturing processes, because many material variants have material properties that vary widely with the manufacturing state.

Ductility is the ability of a material to undergo a permanent change in shape, which in the uniaxial state is ideally without any elastic component according to the stress-strain diagram. This property is limited by the occurrence of the break. In general, the permanent elongation achieved in the tensile test up to fracture is considered ductility. As a measure of the ductility, the constriction of the fracture, impact work and notch impact work can also be viewed, each with a slightly different statement. These properties can be determined in accordance with EN 10 002, Part 1, or in accordance with DIN 50115 and 50116. The elongation at break A = A _p ι _ast characterizes the change in shape with its plastic component under a largely uniaxial load. In addition, according to the stress-strain diagram, the elastic component of the expansion A _e ι _ast and the sum of the elastic and plastic component D = ΣA = A _e i _ast + A _p ι _ast can be determined. A highly plastic material is called ductile.

When specifying the elongation at break and the tensile strength for various magnesium alloys, it becomes clear that the elongation at break can often have higher values if only medium-high values of the tensile strength are achieved and that conversely only medium-high values of the elongation at break are achieved with high values of the tensile strength. Very high tensile strength values can only be achieved with comparatively low elongation at break values.

The elasticity denotes the elastic part of the stress-strain diagram according to Hook's law, where under ideal linear-elastic conditions there is no permanent change in shape.

Furthermore, the yield point ratio V can be specified as the ratio of the yield stress F = R _P02 to the tensile stress Z = R _m . This results in two values for the largely uniaxial load that characterize the elasticity, two the plasticity and two their relationship to one another. The ratio of the elastic to the plastic part of the stretch gives the best approximation to reality. The impact work is above all a measure of the energy consumption of a semi-finished product and of plastic behavior, i.e. of the deformability and rate of deformation. A high impact work is therefore essential for the use of deformation elements such as crash elements, impact dampers, impact shields and impact carriers. The impact work - measured on notched specimens - is more meaningful than the notched impact work due to higher absolute values for magnesium alloys and affects a largely uniaxial load. The impact energy, which is always determined on notched specimens, also characterizes the susceptibility of a material to failure under three-axis loading. Their significance is particularly low if the execution of the notch significantly influences the values of the impact energy. The impact work and the notch impact work are measured under dynamic load and can give an indication of the energy absorption and deformability. In comparison, tensile and compression tests are carried out under quasi-static loads. A conclusion from uniaxial to multiaxial properties or relationships is only partially possible.

The values listed below measured on samples in a certain manufacturing condition therefore reflect the current material properties. They provide an indication of the forming behavior that previously occurred during the forming process. In this state, it is possible to draw a conclusion about the properties and behavior of a semi-finished product or even a component with this semi-finished product, which may be further refined, in later use. Furthermore, a conclusion can be drawn about the material properties of formed alloys, e.g. by bending, pressing, pressure rolling, stretch drawing, deep drawing, hydroforming or rolling professionals to be shaped into further processed semi-finished products. Since the change in the material properties from the cast to the extruded state is similar to the change in the material properties from the cast to the forged, rolled or a similar formed state, it is therefore also possible to draw a conclusion about another formed state.

For the use of lightweight components, the elastic properties (rigidity) are usually emphasized, as long as the deformation properties and thus the energy absorption of the element and the plastic behavior are not important, as in an accident. For this reason, the plastic and, in particular, the plastic and / or elastic properties play a role with regard to the multiple reshaping. These properties are typically for use on the the respective ambient temperature, in extreme cases in the range from -40 ° C to +90 ° C, but at individual points in the vehicle or plane to the locally lower or higher temperatures. However, the load state is usually multi-axis. The conclusion from uniaxial to multiaxial load states is all the more possible the more isotropic the structure.

For the production of such automotive elements, the production by die casting or extrusion, forging and / or rolling is particularly suitable. Prerequisite for the use of semi-finished products made of magnesium alloys or of components or parts made from them in automobiles may be the fulfillment of certain property profiles depending on the application, e.g. in the case of deformation elements, seat and door frames, a tensile strength of the light material of at least 100 MPa, preferably of at least 130 MPa, together with an elongation at break measured at room temperature of at least 10%, preferably of at least 15%. The higher the tensile strength, elongation at break and other properties that indicate high ductility and energy consumption, the more suitable these semi-finished products or components are generally for use. Furthermore, higher strength values and a higher ductility are also a relief and in some cases also a prerequisite for the shaping of cast blanks or for the further shaping of already shaped blanks or semi-finished products. The higher these properties are in the cast state, the higher these are usually also in the formed state. A higher ductility can facilitate the forming or the re-forming, in particular the extrusion. Therefore, an elongation at break of at least 10% is also helpful for the subsequent manufacturing steps for elements made of magnesium alloys. A tensile strength of at least 150 MPa measured at room temperature, preferably of at least 180 MPa, or an elongation at break of at least 18%, preferably of at least 20%, particularly preferably of at least 25%, is therefore recommended for several reasons. The elongation at break in commercially available magnesium alloys, measured at room temperature, is usually less than 12%.

In the case of stronger substitution of other alloys by magnesium alloys, in order to save fuel by saving weight or to enable the installation of additional elements without weight gain, the further development of the technology of the known magnesium alloys and the research of further magnesium alloys is necessary, particularly with regard to the combination of properties ductility - strength. Basically, there are various options for increasing the ductility and thus the elongation at break in magnesium alloys and related lightweight materials:

1. A very limited possibility of this increase results from optimization of the manufacturing process in connection with heat treatment processes and / or via optimized manufacturing parameters e.g. during extrusion. However, it is important when forming e.g. by extrusion that the dynamic recrystallization occurring does not lead to coarse grain formation. Because the energy absorption and the mechanical properties of an alloy should generally be greater, the smaller the average grain size. The goal of alloy development can be a modification of the microstructure by forming temperature-stable precipitates or / and a stabilization of the microstructure by influencing the grain growth in order to produce the finest possible grain and the lowest possible porosity.

2. When the crystal structure of the Mg main phase changes from the hexagonally closest spherical packing to the body-centered cubic crystal structure e.g. due to a higher addition of a doping element such as e.g. at least 10.8% by weight of Li, in order to produce a homogeneous β-lithium-magnesium mixed crystal without further doping elements, there is an improved elongation at break and better formability at room temperature due to an increased number of sliding systems. However, strength and corrosion resistance can deteriorate.

3. Because grain boundaries and other structural inhomogeneities or structural defects such as Inclusions, pores, coarse precipitates, oxide streaks and segregations when moving dislocations act as barriers, a refinement of the structure, a reduction in structural inhomogeneity errors or the avoidance of certain structural inhomogeneity errors can lead to an increase in strength, elongation at break and energy absorption. However, the relationships are very complex in individual cases. The refinement is an important tool to activate further deformation systems that allow grain boundary gliding and new flow processes at room temperature and thus improve ductility. This can be done by adding grain-refining additives or / and by heterogeneous nucleation when solidifying cast materials made of alloys with certain additives.

Even the commercially available magnesium casting alloys or magnesium wrought alloys are in the cast and, if appropriate, subsequently formed, in particular extruded, pressed, rolled or / and forged, and if appropriate subsequently heat-treated, state Usually previously of relatively low ductility and low energy absorption. For the inexpensive manufacture of semi-finished products, in particular for vehicles and airplanes, there is a need for suitable alloys and simple processes for the production of magnesium alloys with somewhat increased strength and greatly increased ductility.

Since the interest in wrought magnesium alloys has only increased somewhat in recent years, so far only a limited number of alloys are available for large-scale use. These are alloys based on Mg-Al-Zn such as AZ31, AZ61 and AZ80, based on Mg-Zn-Zr such as ZK40 and ZK60 or based on Mg-Mn such as M1.

Haferkamp, Bach, Bohling & Juchmann (Proc. 3 ^rd Int. Magnesium Conf. Manchester April 10-12, 1996, The Institute of Materials, London 1997, ed .: GW Lorimer) or Haferkamp, Bach & Juchmann ("Stand und Development trends of density-reduced magnesium materials ", lecture at the advanced training event" Magnesium - Properties, Applications, Potentials "of the German Society for Materials Science Clausthal-Zellerfeld 1997) describe lithium-containing magnesium alloys based on MgLi without and with AI, AlZn, Ca, Si, SiCa , AICa, CaAlZn or SiAIZn. For the elongation at break or tensile strength, values for MgLi40at% Al6at%, for example of 19% or about 260 MPa, for MgLi40at% Si3at% 29% or about 152 MPa and for MgLi40at% 42% or about 134 MPa are given. Due to the small laboratory extrusion press used for those experiments, however, the forming speed and the degree of forming were low.

Furthermore, Haferkamp, Bach, Bohling & Juchmann presented values of elongation at break and tensile strength at the magnesium conference in Garmisch-Partenkirchen 1992 (Magnesium Alloys and Their Applications, Eds .: BL Mordike & F. Hehmann, Oberursel 1992, 243-250) which led to values of up to 25% and 239 MPa for MgLiAl, possibly with Zn.

The NASA report N67-22072, SP-5068, Properties and current applications of magnesium-lithium alloys, 1967, indicates possibilities for increasing the strength of lithium-containing magnesium alloys and reports singular values of high elongation at break or high tensile strength, but it is assume that with the then usual manufacturing processes and available raw materials high Contamination occurred which greatly influenced the result in this regard and significantly impaired the corrosion resistance compared to the high-purity alloys that can be produced today.

It was therefore the task of proposing magnesium alloys of increased ductility and, if possible, also increased energy absorption, strength and toughness, by selecting the parameters which are most likely to act for these purposes, which have the lowest possible density and, moreover, can also be produced as simply and inexpensively as possible.

The object is achieved with a magnesium alloy, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and bis can contain to 0.005% by weight Ni, the content of Li 0.5 to 20% by weight, the tensile strength at least 227 MPa, the impact energy measured at least 72 J and the elongation at break measured at tensile specimens at least 26%.

The remaining contents of the chemical composition mentioned consist predominantly or essentially of magnesium. Contents of cadmium interfere with processing only because of their toxicity, but are otherwise of particular advantage in terms of formability. Trace levels of copper, iron and nickel should be as low as possible, since they have a negative effect on processing and / or material properties.

The composition of the magnesium alloys varied only slightly or almost not at all from the composition of the melt to the composition before or after the extrusion to the composition of the semi-finished product made therefrom.

The problem is solved with the same chemical compositions with a magnesium alloy, whose Li content is 0.5 to 20% by weight, whose tensile strength is at least 250 MPa, whose impact energy measured on non-notched samples is at least 72 J and their elongation at break measured on tensile samples at least 21 %, preferably at least 30% or whose Li content is 0.5 to 20% by weight, whose tensile strength is at least 276 MPa, the impact energy measured on non-notched samples is at least 70 J and the elongation at break measured on tensile samples is at least 18%, preferably at least 25%.

The object is also achieved with a magnesium alloy, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and can contain up to 0.005% by weight of Ni, which, in addition to Mg, contains 0.5 to 10% by weight of Al and 0.1 to 3% by weight of Mn, the tensile strength of which is at least 200 MPa, the elongation at break measured on tensile samples at least 12%, the compressive strength of which is at least 240 MPa and the impact energy measured on unslotted samples is at least 25 J.

The object is also achieved with a magnesium alloy, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and can contain up to 0.005% by weight of Ni, which contains 0.5 to 10% by weight of Al, 0.1 to 3% by weight of Mn and 0.5 to 20% by weight of Li in addition to Mg, and the elongation at break measured on Tensile tests is at least 12%.

The object is also achieved with a magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and may contain up to 0.005% by weight of Ni, which contains 0.5 to 10% by weight of Al, 0.1 to 3% by weight of Zn and 0.5 to 20% by weight of Li, the tensile strength of which is at least 210 MPa, the elongation at break of which, measured on tensile specimens, is at least 20% and the impact energy, measured on unskilled specimens, of at least 90 J. Their compressive strength can be at least 350 MPa, preferably at least 365 MPa, particularly preferably at least 380 MPa. The magnesium alloy preferably has a content of at least one rare earth element SE including Y of at least 0.1% by weight of SE in each case, particularly preferably of at least 0.5% by weight, very particularly preferably of at least 0.6% by weight. , or / and a content of at least one element from the group of cerium, praseodymium, neodymium, samarium, gadolinium, ytterbium, lanthanum and yttrium. In any case, the total content of all rare earth elements is up to 1% by weight.

The object is also achieved with a magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and can contain up to 0.005% by weight of Ni, which in addition to Mg contains 0.1 to 3% by weight of Zn and in each case 0.1 to 1% by weight of at least one rare earth element and / or Y, their Tensile strength at least 230 MPa, the impact energy of which is at least 50 J measured on unskilled specimens and whose elongation at break measured on tensile specimens is at least 20%. It preferably has a yield strength, measured on tensile samples, of at least 170 MPa.

The object is also achieved with a magnesium alloy, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and can contain up to 0.005% by weight of Ni, which in addition to Mg contains 0.1 to 3% by weight of Zn each contains 0.1 to 1% by weight of at least one rare earth element including Y and 0.5 to 20% by weight of Li and their elongation at break measured at least 20% on tensile samples.

The object is also achieved with a magnesium alloy which essentially consists of an alloy which is selected from the group of alloys based on AM, AZ or ZE and which contains an addition of lithium, manganese, aluminum, calcium, strontium, zinc, zirconium or may contain at least one rare earth element including yttrium. Here, the term “essentially” means that contents of further elements not specifically mentioned can occur up to 8% by weight, preferably up to 4% by weight.

The object is also achieved with a magnesium alloy modified by at least one addition from the group of lithium, calcium, strontium, zirconium and at least one rare earth element SE including yttrium, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight of Ni, the compressive strength of which is at least 260 MPa, preferably at least 300 MPa, particularly preferably at least 340 MPa, very particularly preferably at least 380 MPa, the impact energy measured on non-notched samples of at least 72 J, preferably at least 90 J, and whose elongation at break measured on tensile samples is at least 18%, preferably at least 20%, particularly preferably at least 22%, very particularly preferably at least 24%. Their tensile strength can be at least 260 MPa, preferably at least 290 MPa, particularly preferably at least 320 MPa. These magnesium alloys preferably have a base of AM, AZ or ZE. The semifinished product or component according to the invention preferably consists essentially of a magnesium alloy which is selected from the group of alloys based on AM, AS, AZ, EZ, MA, SA, ZA or ZE with added lithium. The total content of rare earth elements is in any case only up to 1% by weight.

The magnesium alloy can have a plastic portion of the stress determined in tensile tests according to the stress-strain diagram from the difference between tensile stress and yield stress of at least 50 MPa. The above material properties according to the invention apply in particular to formed magnesium alloys. It can have a structure with an average grain size of at most 50 μm, preferably of at most 25 μm, particularly preferably of at most 15 μm, very particularly preferably of at most 8 μm. The structure can be determined on the bevels using the usual stereometric methods. It can be extruded, rolled or / and forged and have a dynamically recrystallized, fine-grained structure, in particular with an average grain size of not more than 20 μm, and a precipitation phase content of not more than 5% by volume, preferably not more than 3.5 or even no more than 2% by volume.

The object is also achieved with a method for producing a semifinished product from a magnesium alloy according to the invention or a component or / and composite produced therefrom or / and composite with at least one such semifinished product or component, which is characterized in that the alloy at temperatures in the range from 550 to 900 ° C melted and one or more moldings are produced by casting without or with additional pressure and, if necessary, also heat-treated afterwards. Sand casting, gravity die casting, continuous casting, squeeze casting or die casting are preferred.

Usually, there are higher material properties if the cast molding is processed, if necessary thereafter heat-treated, then formed, in particular by extrusion, forging or / and rolling, and then heat-treated if necessary. The molded body to be formed - in particular a block, a bolt or a slab - is preferably homogenized at temperatures in the range from 300 to 420 ° C. for 0.5 to 48 hours, particularly preferably in the range from 330 to 380 ° C. over 2 to 24 hours . In particular, the molded body to be shaped can be extruded at extrusion temperatures in the range from 100 to 450 ° C., preferably in the range from 180 to 320 ° C. become. In this case, extrusion can be carried out at a pressing speed in the range from 0.5 to 20 m / min, preferably at 1 to 18 m / min, particularly preferably at 5 to 16 m / min, very particularly preferably at 10 to 15 m / min. In addition, the shaped body, the semifinished product or the component can be stored after forming at temperatures in the range from 50 to 200 ° C., preferably in the range from 80 to 150 ° C. The shaped body or the shaped semi-finished product can be deformed further, for example by stretch drawing, deep drawing, bending, pressing, pressure rolling, hydroforming, roll profiling, and / or straightening. The molded body, the semifinished product or component can be processed after the original shaping, shaping or after further shaping, for example by turning, milling, drilling, separating, tumbling, punching, deburring, shaping, grinding, lapping and / or polishing, for example by degreasing or de-oiling and / or surface treatment, for example by pickling and / or coating, in particular also by painting. Furthermore, the molded body, the semifinished product and / or component can be made by at least one low-heat joining process such as gluing, riveting, inserting, pressing, pressing, clinching, folding, shrinking or screwing and / or at least one heat-introducing joining process such as composite casting, composite forging, composite extrusion, Composite rolling, soldering or welding, in particular beam welding or fusion welding, are connected to at least one similar or different type of shaped body, semi-finished product or component. The different types of elements can consist, for example, of a low or no magnesium alloy, for example of an aluminum alloy or a steel.

The object is further achieved with a semifinished product made of a magnesium alloy according to the invention or with a component or composite produced therewith or from it with at least one such semifinished product or component or can be produced by the method according to the invention.

It has been shown that the modification of grain sizes and phase distributions by adding alloying elements such as lithium or rare earth elements SE including yttrium and lanthanum and their mixtures is helpful to produce significantly stronger and / or more ductile magnesium alloys. In particular, the addition of lithium or at least one rare earth element such as cerium, praseodymium, neodymium, samarium, gadolinium, ytterbium, lanthanum and yttrium has proven to be favorable for the further development of magnesium alloys. For the purposes of this application, semi-finished products are to be understood as shaped bodies which have not yet been completed and are ready for use in their respective application. On the other hand, components are the shaped articles suitable for the intended purpose. However, both terms flow smoothly into one another, since the same molded body can be a semifinished product for one purpose, but can already be a component for the other. Furthermore, for reasons of linguistic simplification, the text does not make a strict distinction between semifinished product and component, or both are mentioned at the same time or only spoken of magnesium alloy, although both may be meant.

The semi-finished products made of magnesium alloys according to the invention or the components made therefrom or components made therefrom can be used as gear housings, steering wheel skeletons, wishbones, frame elements, elements of vehicle cells or vehicle outer skins, cockpit supports, housings, floor elements, covers, tank elements, tank flaps, holders, supports, brackets, angles , Hollow profiles, pipes, deformation elements, crash elements, crash absorbers, impact absorbers, impact shields, impact carriers, small parts such as gears, as wheels and other types of wheels, as welded profile constructions, for the vehicle body, for seat, window or / and door frames, as semi-finished products or Component in the automobile or airplane.

Process for the production of extruded profiles:

The processes for producing extruded profiles from the alloys according to the invention are described in detail in a patent application filed on the same day by the same applicant; that application is considered to be fully included in this application by name.

It is preferable to start from high-purity, commercially available alloys. Possibly. these alloys are alloyed with additives. The high-purity alloys can absorb small amounts of contaminants from the crucible during the melting process. The alloys can be melted, for example, in a nickel and chromium-free steel crucible under a protective gas atmosphere, for example Ar or / and SF ₆ . The process steps are known in principle, but require a different modification or optimization depending on the alloy. The prerequisite for the further processing of magnesium alloys by extrusion, rolling and / or forging is the production of suitable materials, for example in the form of blocks, bolts or slabs. There are two main options for the production of bolts for extrusion:

In the first method, a bolt with a very large diameter can be cast, which can then be pressed with a high-performance extrusion press into round bolts with a diameter that corresponds to the recipient diameter. The segregation is reduced by the thermomechanical treatment.

A less complex process than this double extrusion is the production of the bolts by sand, mold or continuous casting with a sufficiently large machining allowance. However, care must be taken to ensure that there are no major segregations that are not or only insufficiently compensated for by long homogenization times. Otherwise, the consequences could be poor compressibility and a greater spread of the mechanical properties, in particular the ductility.

The cast bolts can first be subjected to heat treatment depending on the alloy composition in e.g. 350 ° C are homogenized in the range from 6 h to 12 h in order to eliminate segregations in the structure, which in some cases to improve heterogeneous structure and to increase the pressability. Then the homogenized bolts can be machined to the required dimensions.

Segregations can lead to uneven deformation and, in the case of critical extrusion conditions, to cracks or local melting, which can result in poor surface quality. If the bolts are not homogenized well, an unnecessarily high compression pressure is required during extrusion. The homogenized bolts are then prepared for extrusion.

The extrusion of the magnesium alloys can be carried out in the same extrusion plants that are used for the extrusion of aluminum alloys, both via direct and indirect extrusion. The deformation behavior must only be specifically taken into account when designing the tool (die). Sharp-edged inlets, such as those used with aluminum alloys, should be avoided with magnesium alloys, otherwise there is a risk of surface cracks. In In many cases, an entry angle of approx. 50 ° is used for magnesium alloys, for example, for the matrices of round profiles.

The most important parameter besides the extrusion temperature is the extrusion speed, because it significantly influences the properties and the surface quality of the extrusion profiles. A high pressure also requires a high extrusion speed, which is sought for economic reasons. A high extrusion speed is usually associated with an even better surface quality. The pressability of the magnesium alloys is comparable to that of hard-pressed aluminum alloys. A high extrusion speed is desirable from an economic point of view, but is not always feasible with magnesium alloys. Despite certain knowledge of the extrusion of magnesium alloys, the parameters for the extrusion usually have to be worked out in detail, since there is a great potential for optimization.

The extrusion is advantageously followed by a heat treatment. This heat treatment is of particular interest for the lithium-containing alloys, while the other extruded modified alloys according to the invention are not greatly improved by this heat treatment. The semi-finished products can be straightened if necessary, zJ3. further deformed by bending, pressing, pressure rolling, stretch drawing, deep drawing, hydroforming or roll profiling, e.g. processed, joined and / or e.g. by cutting, drilling, milling, grinding, lapping, polishing can be surface-treated by etching, painting or other coating. With the alloys according to the invention, solid and extruded profiles in simple or complicated cross sections can be extruded without problems. In this case, semi-finished products can be improved or components can be produced from them or, if necessary, from them.

When joining, the semi-finished product or the component made therefrom or with it can be produced using at least one low-heat joining process such as gluing, riveting, plugging, pressing, pressing, clinching, folding, shrinking or screwing and / or at least one heat-generating joining process such as composite casting, composite forging, composite extrusion , Composite rolling, soldering or welding, in particular beam welding or fusion welding, are connected to a similar or different type of semi-finished product or component. The different type of semifinished product or component can also essentially consist of a magnesium alloy or of another alloy or also consist of a non-metallic material. It can have the same or a different geometry as the semi-finished product or component according to the invention. The joining process can be used in particular to produce a housing, an apparatus, a system, a profile construction and / or a cladding from several elements.

Examples:

The following examples according to the invention represent selected embodiments without restricting the invention.

In the alloy designations used, A AI, E denotes at least one rare earth element SE, with Y also being counted among the rare earth elements, M or MN Mn, S Si and Z Zn - usually with content in% by weight, unless stated otherwise. With commonly used alloy information such as AZ31 are indicated by the numbers, as usual for the respective alloy, only in the order of magnitude, which can vary to a relatively wide extent, as is customary in the industry. In addition, a low manganese content may be present in the starting alloy used in the examples and the modified AZ-based alloys produced therewith. All examples showed traces of less than 0.1 wt% Cd, less than 0.05 wt% Cu, less than 0.04 wt% Fe and less than 0.003 wt% Ni .

The alloys were made as high-purity, commercially available alloys or usually from high-purity starting alloys such as, for example, AM, AZ or ZE alloys or by adding high-purity magnesium HP-Mg, a rare earth element-containing master alloy with a ratio of Nd to other rare earths including yttrium of 0.92, a zirconium-containing master alloy and / or of lithium. The standard alloys contained an Mn content of up to about 0.2% by weight. The alloys were melted in a steel crucible under the protective gas atmosphere of an Ar-SF ₆ mixture. The blanks required for the subsequent extrusion were poured into a cylindrical steel mold with machining allowance. The element contents obtained were checked spectroscopically. With all alloys, care was taken to ensure that the structure of the cast body is as homogeneous as possible and free of impurities, since this can have a sensitive effect on ductility. All alloys could be melted, poured off and processed into bolts without any problems. The bolts were then turned to a diameter of 70 mm and brought to a length of 120 mm. The bolts were then subjected to a homogenization treatment at, for example, 350 ° C. for 4 hours or 12 hours in order to eliminate segregations in the structure and to increase the pressability. Segregations can lead to uneven deformation and, under critical extrusion conditions, to cracks or local melting, which can lead to poor surface qualities. If the bolts are not homogenized well, an unnecessarily high compression pressure is required during extrusion. The homogenized bolts were then well prepared for extrusion.

The homogenized bolts were then heated to the respective extrusion temperature, warmed through and extruded in a 400 t horizontal press. The temperature of the pin is therefore the temperature that the pin has when it enters the extrusion press.

The appropriate extrusion parameters were selected in systematic preliminary tests on the AZ31 reference alloy; The mechanical properties and the average grain sizes were determined on the extruded samples (Tables 1 and 2). The results of the preliminary tests essentially determined the test parameters of the subsequent tests.

During the actual tests, several of the manufacturing parameters were systematically varied (Tables 3d / e). On the one hand the die diameter was varied and the die speed and extrusion temperature were kept constant, on the other hand the die geometry was kept constant and the die speed was varied and finally the extrusion temperature was varied depending on the alloy. The ram speed and the extrusion ratio gave the extrusion speed. With the help of such a parameter matrix, an assessment of the influence of different forming conditions was possible.

It has been shown that high extrusion speeds can usually be achieved with the ductile magnesium alloys. No efforts have yet been made in the tests to achieve the highest extrusion speeds, but rather there is clear potential to be able to achieve significantly higher speeds. The degree of deformation characterizes the degree of cross-sectional reduction during forming and is the natural logarithm of the Ratio of initial cross-section to cross-section specified after forming. It is therefore often correlated with the degree of dynamic recrystallization, whereby if possible no stronger growth of individual grains should occur, but rather a structure which is as fine-grained as possible and which requires high ductility in some magnesium alloys. The more stable the structure of a magnesium alloy, the more fine-grained the structure will remain during forming. It has been found that the degree of deformation is advantageously at least 1.5, preferably at least 2, particularly preferably at least 2.5. If the degree of forming is less than 1.5, the dynamic recrystallization during forming is quite low. A degree of deformation of 3.5 or more could also have been selected in the tests.

All alloys, both the starting alloys and the alloys modified by additives, could easily be formed in a wide range of temperatures, extrusion speeds and extrusion ratios. The bolts showed good compressibility with a large scope in terms of pressing force and pressing speed. The lower extrusion temperature is due to the insufficient plastic deformability below a temperature in the range of about 200 to 220 ° C, the upper extrusion temperature is limited by the proximity to the eutectic temperature and possibly by the first formation of parts of a molten phase.

Depending on the extrusion conditions, there were differences in the structure of the samples despite the same alloy composition. The extrusion pressures that occurred varied depending on the alloy used and the extrusion parameters set. In general, dynamic recrystallization and a reduction in the average grain size occurred during extrusion, which led to different average grain sizes depending on the extrusion parameters and the alloy composition.

The strength values determined on the cast and extruded samples were far higher than expected. Surprisingly, the deformability of these alloys was also very high. It was also surprising that the material properties of the modified alloys varied surprisingly little depending on the extrusion conditions, which is advantageous for production. It was also surprising that the impact energy of the ZE10 alloy was so high. Finally, the extrusion process, which characterizes the extrusion process in the force-displacement diagram, varied with the alloys AZ, AZU3.6 and AZU6.8 differently than expected with increasing lithium content: worse behavior was shown with a small addition of lithium than without or with a higher lithium content. Some of the lithium-containing alloys showed an unexpectedly strong dependence of the material properties on the type of heat treatment when the lithium content was high.

The extruded profiles were processed by milling and turning into round specimens (d ₀ = 5 mm, l ₀ = 5 • d ₀ , small proportionality bar, according to DIN 50 125), pressure tests (d ₀ = 10 mm, l ₀ = 2 • d ₀ , according to DIN 50 106), impact bending tests (10 x 10 x 55 mm, according to DIN 50 116) and notched impact bending tests (according to DIN 50 115). 5 of these samples were produced and tested per alloy and test. For all samples, the longitudinal direction was chosen so that it coincided with the direction of extrusion.

In the tensile test, tensile strength R _m , yield strength = yield strength R _P0 , ₂ and elongation at break A or, in some cases, the fracture constriction in the tensile test at a tensile speed of 0.5 mm / min were determined. Values of the compressive strength R _Dm , compression limit R _D o, ₂ and compression A _D at a printing speed of 0.5 mm / min were obtained in the compression test. The beginning of the plastic deformation (expansion or compression limit) was determined graphically. Brinell hardness measurements were also carried out in accordance with DIN 50351. All measurements took place at room temperature. The results of the mechanical determinations are summarized in Tables 3a-c and those of the structural investigations in Table 3d.

Grindings were produced on selected samples, which were assessed with regard to average grain size, structural inhomogeneities and the type and distribution of the phases separated out. This evaluation was used to further optimize the manufacturing and processing parameters.

The variation of the extrusion parameters had a different influence on the property profile of the extruded magnesium materials. Trends in the material properties of the different alloys depending on the manufacturing parameters can be seen in Tables 3e and 3f. The measurement results of the Brineli hardness determinations made no special statements possible. The Brinell hardness of the extruded samples was found to be 7 to 22% greater than that of the cast samples. The hardness increased with the aluminum content.

The following manufacturing parameters were selected for the Li-haltions Maonesium alloys:

Production of the bolts: casting in tubular molds at a casting temperature of 680 to 720 ° C to larger diameters and turning to usually 70 mm in diameter. The turned bolts were heat treated at 350 ° C for 4 h (= homogenized).

Extrusion: Depending on the sample, an extrusion temperature in the range of 150 to 300 ° C and a time in the range of 50 to 110 min was set for heating and heating the bolt. Preliminary tests were carried out with the reference alloy AZ31 (Tables 1 and 2). The preliminary tests allowed the preselection of the test parameters.

The specific extrusion tests were carried out in a 400 t extrusion press with direct extrusion. Depending on the sample, with a recipient diameter of 74 mm, a recipient temperature in the range from 180 to 259 ° C., a die diameter in the range from 15 to 18 mm, a compression ratio A / A ₀ in the range from 16.9 to 24.3, a degree of deformation φ = ln (A _o / A) in the range from 2.8 to 3.2, a die speed in the range from 191 to 419 mm / min, an extrusion speed in the range from 3.2 to 9.0 m / min, a pressing pressure at the start of the extrusion in the range from 15.2 to 24.3 MPa and a pressure at the end of the extrusion in the range from 10.0 to 14.8 MPa. Only a small part of the experiments are shown in Table 3e.

The influence of the extrusion parameters on the material properties of the lithium-containing alloys and their undoped base alloys was limited. It was particularly low in tensile strength and increased somewhat over the elongation at break and compressive strength up to the impact work.

The extruded AM20U3.6 alloy sometimes had higher mechanical properties than the extruded AM20 alloy (Tables 3a / c). As with the other extruded alloys, the addition of lithium led to a very strong increase in impact work. The extruded AM20 alloy had a very high elastic and a comparatively very low plastic part of the tension in the extruded state (Table 3b). The corresponding plastic portion doubled due to the addition of lithium.

The alloy AZ31U3.6 was not characterized in the cast state in the tensile test, since the porosity of the samples was still somewhat too high to allow characteristic statements. In the extruded state, this alloy had the highest compressive strength values. In the case of AZ31 alloyed with lithium, significantly higher toughness values were determined on notched impact specimens and significantly higher elongations at break than on the associated samples not alloyed with lithium, the highest values occurring with the essentially two-phase AZ31U12.3 alloy. In contrast, the tensile strength decreased with the lithium content. The compressive strength was in the cast state proportional to the lithium content, but the highest in extruded samples at medium lithium contents. Among the alloys in the as-cast state, the AZ31U6.8 alloy had an astonishingly high mean yield strength of 122 MPa. The deformability of the base grid of the AZ31 was increased by the addition of lithium and the possibly modified excretion phase. The AZ31U6.8 alloy showed a lower tensile and compressive strength than the AZ31U3.6 alloy, but a high compression limit and high elongation at break. The addition of lithium improved the formability.

In the case of lithium-containing alloys and their starting alloys, the stress under pressure had a different effect than that under tension: unlike tensile strength, the compressive strength and, in some cases, the compression limit increased from AZ31 with the lithium content to AZ31U3.6. Due to its high lithium content, the AZ31U6.8 alloy had the highest compression limit and fracture compression and a very high compressive strength based on average values (Table 3a) among all samples in this series. In this series, the fracture compression of the samples in the cast state was higher than that of the extruded samples.

The cast ZE10 alloy had a very low elastic component, but an almost average high plastic component of the stress. The elastic content could be increased significantly by adding lithium. On the other hand, the ZE10 alloy gained an extraordinarily high elastic part of the tension during extrusion, while the plastic part remained approximately constant. With the ZE10 and ZE10U3.7 alloys, all mechanical properties of cast samples increased with the lithium Content drastically. In the corresponding extruded samples, the mechanical properties, with the exception of tensile strength and yield strength, increased significantly with the lithium content. The alloy ZE10U3.7 showed the highest values of the impact work among the examined lithium-containing magnesium alloys, whereby due to crash tests on deformation elements from the invention

Magnesium alloys are assumed that the alloy MgU15.5AI2.5Zn0.8 should have even higher values of impact energy and notched impact energy than the alloy ZE10U3.7. Up to 140 J were measured on individual samples of the ZE10U3.7 alloy; other samples were taken through the abutment of the testing machine without breaking completely, so that no measured value of the impact work could then be determined. The maximum applicable impact energy was 150 J.

The degree of deformation had a considerable influence on the impact work of the lithium-containing samples. The impact energy for the lithium-containing magnesium alloys with a degree of deformation φ of 2.83 was often about 30 to 65% higher than for φ = 3.06 (Table 3f). With lower degrees of deformation and thus with smaller compression ratios, the impact energy was much higher. This tendency did not or only weakly occurred in the samples from unmodified starting alloys and in the samples alloyed with Ca or Zr. With the lithium-containing samples, the best impact work was achieved at forming temperatures of 200 to 250 ° C. The forming speed (= extrusion speed) had little effect on tensile strength and elongation at break.

The pressure-pressure curves during extrusion of the lithium-containing alloys at 200 ° C showed that with the alloy AZ31 + 12at% Li as well as AZ31, the material of the bolt did not flow until a higher pressure, for example at 16 MPa Comparison to the alloys AM20 + 12at% ü, AZ31 + 21at% Li and ZE10 + 12at% Li, where the flow started at about 12.5 MPa, but also a more favorable, lower pressure was determined after a longer path.

The examples have shown that the magnesium alloys according to the invention are suitable for extrusion, but also in principle, in addition or as an alternative to extrusion, they are also suitable for other types of shaping and further shaping on account of their material properties. Table 1: Results of the preliminary tests to determine the extrusion parameters with the AZ31 alloy at an extrusion temperature of 400 ° C, a die diameter of 16 mm, recipient diameter of 74 mm and compression ratio of 1:21:

Table 2: Influence of the compression ratio on the average grain sizes and the mechanical properties from the tensile test at an extrusion temperature of 400 ° C. in the preliminary tests to determine the extrusion parameters

Tables 3 and 4 mean "casting" = material in the as-cast state and "extr." = Casting material which was subsequently formed by homogenization and extrusion (extrusion), "B" = example according to the invention and "VB" = comparative example according to the prior art.

Table 3a: Average values of the measurement results of the mechanical tests averaged over the various samples of the lithium-containing magnesium alloys and their starting alloys

Table 3b: Average values of the values that can be determined from the stress-strain diagram of the tensile tests for lithium-containing magnesium alloys and their initial alloys. F = R _P02 = yield stress = elastic part of the stress. V = yield strength ratio = F: Z. R _m = tensile stress. Z = elastic + plastic part of the tension:

Table 3c: Highest mean values of the measurement results of the mechanical properties selected from various individual samples of the lithium-containing magnesium alloys

Table 3d: Structural components in the as-cast state after homogenization at 350 ° C for 4 h or after extrusion as well as predominantly occurring grain sizes ( ^* = before hot aging):

Table 3e: Process parameters and average grain size for the lithium-containing magnesium alloys and their starting alloys

Table 3f: Manufacturing parameters and material properties of individually selected extruded samples of the lithium-containing alloys and their starting alloys: bolts - length 120 mm, diameter 70 mm; Mold diameter usually 90 mm

Claims

PATENT CLAIMS

1. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. % Can contain Ni, characterized in that their Li content 0.5 to 20% by weight, their tensile strength at least 227 MPa, their impact energy measured on non-notched samples at least 72 J and their elongation at break measured on tensile samples at least 26 % is.

2. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. % Can contain Ni, characterized in that their Li content 0.5 to 20% by weight, their tensile strength at least 250 MPa, their impact energy measured on non-notched samples at least 72 J and their elongation at break measured on tensile samples at least 21 % is.

3. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. % Can contain Ni, characterized in that their Li content 0.5 to 20% by weight, their tensile strength at least 276 MPa, their impact energy measured on non-notched samples at least 70 J and their elongation at break measured on tensile samples at least 18 % is.

4. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. % Ni, characterized in that it contains 0.5 to 10% by weight of Al and 0.1 to 3% by weight of Mn in addition to Mg, that its tensile strength is at least 200 MPa and that its elongation at break measured on tensile samples is at least 12% that their compressive strength is at least 240 MPa and that their impact energy is at least 25 J when measured on notched specimens.

5. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. - May contain Ni, characterized in that it contains 0.5 to 10 wt .-% Al, Mg, 0.1 to 3 wt .-% Mn and 0.5 to 20 wt .-% Li and that its elongation at break is measured in addition to Mg Tensile tests is at least 12%.

6. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. -% Ni, characterized in that it contains 0.5 to 10 wt .-% Al, 0.1 to 3 wt .-% Zn and 0.5 to 20 wt .-% Li, that their tensile strength is at least 210 MPa, that their elongation at break measured at least 20% on tensile samples and that their impact energy measured at least 90 J on non-notched samples.

7. Magnesium alloy according to at least one of claims 1 to 6, characterized in that it has a content of at least one rare earth element SE including Y of at least 0.1 wt.% SE in each case, the total content of all rare earth elements up to 1 wt. % is.

8. Magnesium alloy according to at least one of claims 1 to 7, characterized in that it contains at least one element from the group of cerium, praseodymium, neodymium, samarium, gadolinium, ytterbium, lanthanum and yttrium.

9. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. -% Ni, characterized in that, in addition to Mg, it contains 0.1 to 3% by weight of Zn and 0.1 to 1% by weight of at least one rare earth element and / or Y, that its tensile strength is at least 230 MPa and that its impact energy is measured on notched specimens at least 50 J and that their elongation at break measured on tensile specimens is at least 20%.

10. Magnesium alloy, the additives or traces of Cd less than 1.8% by weight and the traces of up to 0.1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight. % Ni can contain, characterized in that in addition to Mg 0.1 to 3% by weight Zn each 0.1 to 1% by weight of at least one rare earth element including Y and 0.5 to 20 wt .-% Li and that their elongation at break measured on tensile specimens is at least 20%.

11. Magnesium alloy according to at least one of the preceding claims, characterized in that it consists essentially of an alloy which is selected from the group of alloys based on AM, AZ, EZ, MA, ZA or ZE and which contains an addition of lithium, Manganese, aluminum, calcium, strontium, zinc, zirconium or at least one rare earth element including yttrium.

12. Magnesium alloy modified by at least one addition from the group consisting of lithium, calcium, strontium, zirconium and at least one rare earth element SE including yttrium, the additions or traces of Cd less than 1.8% by weight and the traces of up to 0, Can contain 1% by weight of Cu, up to 0.05% by weight of Fe and up to 0.005% by weight of Ni, characterized in that their compressive strength is at least 260 MPa, that their impact energy, measured on unslotted samples, is at least 72 J and that their elongation at break, measured on tensile specimens, is at least 18%.

13. Magnesium alloy according to at least one of the preceding claims, characterized in that it has a plastic portion of the stress determined in the tensile test according to the stress-strain diagram from the difference between tensile stress and yield stress of at least 50 MPa.

14. Magnesium alloy according to at least one of the preceding claims, characterized in that it has a structure with an average grain size of at most 50 microns.

15. Magnesium alloy according to at least one of the preceding claims, characterized in that it is extruded, rolled or / and forged and has a dynamically recrystallized fine-grained structure and a content of precipitation phases of not more than 5% by volume.

16. A method for producing a semifinished product from a magnesium alloy according to at least one of the preceding claims or one therewith or therefrom Component or / and composite produced with at least one such semi-finished product or component, characterized in that the alloy is melted at temperatures in the range from 550 to 900 ° C and that one or more moldings are produced by casting without or with additional pressure and, if appropriate, also then be heat treated.

17. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / and composite according to claim 16, characterized in that the molded body is optionally processed, then optionally heat-treated, then formed, in particular by extrusion, forging or / and rolling, and then optionally heat treated.

18. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / and composite according to claim 16 or 17, characterized in that the molded body to be formed at temperatures in the range from 300 to 420 ° C over 0.5 to 48 h is homogenized, preferably in the range from 330 to 380 ° C. over 2 to 24 h.

19. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / and composite according to at least one of claims 16 to 18, characterized in that the molded body to be formed is extruded at extrusion temperatures in the range from 100 to 450 ° C.

20. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or according to at least one of claims 16 to 19, characterized in that extrusion is carried out at a pressing speed in the range from 0.5 to 20 m / min .

21. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / and composite according to at least one of claims 16 to 20, characterized in that the shaped body, the semifinished product or component after forming at temperatures in the range of 50 up to 200 ° C.

22. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / or composite according to at least one of claims 16 to 21, characterized in that the deformed shaped body or the deformed semifinished product is further deformed, e.g. by stretch drawing, deep drawing, bending, pressing, pressure rolling, roll forming and / or straightening.

23. A method for producing a semi-finished product from a magnesium alloy or a component or / and composite produced therefrom or / and composite according to at least one of claims 16 to 22, characterized in that the shaped body, the semi-finished product or component is processed, e.g. by turning, milling, drilling, cutting, tumbling, punching, deburring, shaping, grinding, lapping or / and polishing, e.g. by degreasing or de-oiling and / or surface treatment e.g. by pickling and / or coating.

24. A method for producing a semifinished product from a magnesium alloy or a component or / and composite produced therefrom or / or composite according to at least one of claims 16 to 23, characterized in that at least one molded body, semifinished product and / or component by at least one low-heat joining process such as Gluing, riveting, inserting, pressing on, pressing in, clinching, folding, shrinking or screwing and / or at least one heat-generating joining process such as e.g. Composite casting, composite forging, composite extrusion, composite rolling, soldering or welding, in particular beam welding or fusion welding, is connected to at least one similar or different type of shaped body, semi-finished product or component.

25. Semi-finished product made of a magnesium alloy or a component or composite produced therefrom or composite with at least one such semi-finished product or component, characterized in that it is a magnesium alloy according to at least one of claims 1 to 15.

26. semi-finished product made of a magnesium alloy or a component or composite produced therefrom or composite with at least one such semi-finished product or component, characterized in that it is manufactured according to at least one of claims 16 to 24.

27. Use of a semifinished product made of a magnesium alloy according to at least one of claims 1 to 15 or a component made therefrom or / and a composite with at least one such semifinished product and / or component as a gear housing, steering wheel skeleton, wishbone arm, frame element, element of vehicle cell or Vehicle outer skin, cockpit bracket, housing, floor element, cover, tank element, fuel filler flap, bracket, support, bracket, bracket, hollow profile, tube, deformation element, crash element, crash absorber, impact absorber, impact shield, impact carrier, small parts such as a gear, an impeller and other types of wheels , as welded profile constructions, for the vehicle body, for seat, window and / or door frames, as semi-finished products, components or assemblies on or in the automobile or aircraft.

28. Use of a semifinished product made of a magnesium alloy, a component made therefrom or / and a composite with at least one such semifinished product and / or component - produced according to at least one of claims 16 to 24 - as a gear housing, steering wheel skeleton, wishbone arm, frame element, element of vehicle cell or vehicle outer skin, cockpit support, housing, floor element, cover, tank element, fuel filler flap, bracket, support, support, angle, hollow profile, tube, deformation element, crash element, crash absorber, impact damper, impact shield, impact support, small parts such as a gear, an impeller and others Types of wheels, as welded profile constructions, for the vehicle body, for seat, window or / and door frames, as semi-finished products, components or composites on or in the automobile or aircraft.