DE102015206554A1 - A method of making a metal foam core for a die cast component, metal foam core and die cast component having such a foam metal core made therewith - Google Patents

Abstract

The invention relates to a method for producing a metal foam core (20), which is subsequently used for the production of a partially reinforced metallic die-cast component. According to the invention, reinforcing components (22) in the form of fibers, particles and / or metallic inserts are integrated into the metal foam core (20) during the production of this metal foam core (20). The invention further relates to a correspondingly produced metal foam core (20) and a die-cast component which has at least one such metal foam core (20).

Description

The invention relates to a method for producing a metal foam core, which can be further used for the production of a thus partially reinforced metallic die-cast component.

The invention further relates to a correspondingly produced metal foam core and to a die-cast component which has at least one such metal foam core.

The DE 195 01 508 C1 describes a method for producing a component from die-cast aluminum. The method consists in introducing cores of preformed aluminum foam material into a die casting mold, which remain in the die cast aluminum component after the aluminum has been pressed into the die. By such remaining in the component core made of foamed aluminum z. B. achieved an increase in bending strength.

Complementary will also on the DE 196 50 613 A1 which describes a component with a metal foam core and several methods for producing the component.

Proceeding from this, the invention has the object to show new technical ways and thus to achieve improvements.

This is achieved by an inventive method for producing a metal foam core according to the features mentioned in claim 1. With ancillary claims, the invention also extends to a metal foam core according to the invention and to a metallic die cast component produced therewith. Preferred variants, developments and embodiments are analogous to all subjects of the invention from the dependent claims and also from the following explanations.

The inventive method provides that during the production of the metal foam core reinforcing components in the form of fibers, particles and / or metallic inserts are integrated or incorporated into the metal foam core, which remain in the produced metal foam core.

A correspondingly produced metal foam core according to the invention thus has integrated reinforcing components in the form of fibers, particles and / or at least one metallic insert. The metal foam core preferably has an open-pored foam structure or an open-pore foam structure. It is preferably a light metal foam and in particular an aluminum foam (eg of pure aluminum) or magnesium foam.

The fibers or reinforcing fibers may, for example, be carbon fibers, mineral fibers (for example silicon carbide fibers), glass fibers, metal fibers, metal oxide fibers (for example aluminum oxide fibers) or the like, which may be present both as short fibers and as long fibers. In particular, reinforcing fibers formed as long fibers may be incorporated in a fiber composite structure, for example a fabric structure or the like.

The particles or reinforcing particles, which are understood in particular to be small solid particles, may, for example, be carbon particles, mineral particles, metallic particles, metal oxide particles or the like.

A metal insert is a metallic insert element which can serve to reinforce the metal foam core and / or to reinforce a die-cast component (see below) to be produced in the following. This is, for example, a wire (or also a wire structure), a rod or a piece of sheet metal (for example a sheet-metal strip), which may in particular also be perforated or perforated. Such a metallic insert may also have a shaping brought about by deformation. Metallic inserts may be formed of any metal material. Instead of metallic inserts or in addition thereto, non-metallic inserts, such as ceramic inserts, can be used.

By integrated into the metal foam core reinforcing components or reinforcing components, for example, the mechanical and / or thermal stability is increased. On the one hand, this improves the load capacity of the metal foam core and of the die-cast component produced therewith. On the other hand, lightweight construction potentials arise because, for example, lighter and / or larger metal foam cores can be used.

Another advantageous aspect of the invention is the fact that in particular metallic or optionally non-metallic depositors, which serve the local and in particular load- or functionally correct reinforcement of a die-cast component to be produced in the future, using a metal foam core according to the invention exactly at the appropriate place can be positioned in the cavity of a die-casting tool or die. Thus, for example, reinforcing sheets and the like can be positioned not only on the mold wall, but also, for example, in the middle of the later cast component. The distance of the positioning of the reinforcing element is freely selectable.

A first variant of the method according to the invention provides that the metal foam core is composed of at least two individual layers or layers which are produced (for example by cutting) from a metal foam semifinished product or different metal foam semi-finished products, wherein between the layers (ie between at least two adjacent layers) at least one fiber and / or particle-containing intermediate layer or intermediate layer or at least one metallic insert is arranged. The metal foam semifinished product used preferably has an open-pore foam structure.

The metal foam core produced in this way thus has at least two metal foam layers and at least one reinforcing layer arranged therebetween, which has reinforcing components in the form of fibers and / or particles, or at least one metallic insert arranged therebetween. The fibers and / or particles may be incorporated in a fiber composite structure forming the intermediate layer. The layer composite can be fixed by means of adhesive. The adhesive can be applied over the entire surface or in areas (for example, also linear or punctiform). As an adhesive z. B. a 2-component adhesive based on epoxy resin. The composite can also be fixed by pressing with the aid of a suitable tool. The ply composite may also be fixed by fusing and then fusing the metal foam surfaces or by soldering (i.e., by using a solder material or the like). The cohesive connection brought about can be formed over the entire surface or in regions (for example, also linear or punctiform). The layer composite can also be positively fixed or connected by means of connecting elements. As fasteners, for example, nails, pins, screws, brackets, winding tape or winding wire and the like come into consideration. Preferably, the metal foam semifinished product and the connecting elements are formed from the same metal material or from similar metal materials or alloys. The above-mentioned joining or connection options can also be combined with each other.

A second variant of the method according to the invention provides that the metal foam core is produced by foaming in a core mold (that is to say in a shape corresponding to the core contour) or the like, the reinforcing constituents, i. H. the fibers and / or particles are already admixed with the starting material or are added during foaming. Unlike the method variant explained above, in which the reinforcing components are incorporated only after the metal foam production as reinforcing layer or layers, in this procedure, the integration of the reinforcing components thus already during the metal foam production, wherein the fibers and / or particles are distributed in the foam structure ,

The metal foam core produced in this way can thus have a monolithic foam structure, which is in particular an open-pore foam structure, and fibers and / or particles embedded therein, the fibers and / or particles in particular being distributed evenly or homogeneously in the foam structure are. Foaming in a core form may, for example, be carried out by a powder metallurgy process in which the starting material is a powder mixture containing metal powder and blowing agent (as in US Pat DE 195 01 508 C1 described), wherein the fibers and / or particles of the powder mixture can be mixed before or during foaming. The foaming can also be carried out by a melt metallurgical process, ie by casting a foaming molten metal, wherein the fibers and / or particles of the molten metal before, during or after casting can be mixed. It is particularly preferred in this case for the fibers and / or particles to be admixed with a gas supplied for the purpose of melt foaming (which, for example, flows into the melt bath).

In an analogous manner, metallic inserts can be incorporated into the foam structure by positioning them in the core mold before foaming or potting at the appropriate place.

A metal foam core produced in accordance with the preceding explanations is furthermore used to produce a die-cast component partially reinforced with at least one such metal foam core and / or with at least one metallic insert contained therein. To produce such a die cast component, at least one metal foam core in question is positioned at the intended position in the cavity of a diecasting die or die. Subsequently, the die casting mold is filled with a molten metal, wherein the at least one metal foam core is encapsulated and thereby poured. The molten metal is preferably a light metal melt and, in particular, an aluminum melt (or aluminum alloy melt) or a magnesium melt (or even magnesium alloy melt). By the preferred open-pore Foam structure, the molten metal during casting can penetrate into the foam structure of the metal foam core, which, inter alia, a good fit is achieved. Optionally, the molten metal can pass through an open pore structure through to at least one metal insert contained in the metal foam core, which is poured in this way quasi accurate position. Of course, a metal foam core according to the invention is also suitable for other casting methods, such as, for example, sand, mold, low-pressure or thixotropic injection molding.

A metallic die-cast component produced in this way thus has at least one cast-in metal foam core according to the invention, with which the die-cast component is partially reinforced. Due to the heat of fusion, the metal foam structure, at least partially, can also be melted. This is preferably an engine, chassis or body component, in particular a structural component, for a motor vehicle. Preferably, this die-cast component is formed from an aluminum diecasting alloy and the cast-in metal foam core is formed from a similar aluminum alloy or from pure aluminum. The die cast component can also be formed from another light metal alloy, for example a magnesium alloy, wherein the metal foam core is formed from a similar light metal alloy or a corresponding pure metal, for example pure magnesium.

The invention will now be described by way of example and not by way of limitation with reference to the figures. The features shown in the figures and / or explained below may, even independently of specific combinations of features, be general features of the invention and further develop the invention accordingly.

1 shows in a sectional view of an inventive die-cast component, which is partially reinforced by a metal foam core.

2 shows in a sectional view of a die for producing the die-cast component 1 ,

3 shows a perspective view of a metal foam semi-finished product.

4 to 7 schematically show several possibilities for the production of metal foam cores from the in 3 shown metal foam semi-finished for the in 1 shown die cast component.

8th schematically shows a metal foam core produced in another way.

1 shows a die-cast component 10 , which has a cast-in metal foam core 20 has, with which the die-cast component 10 locally or partially reinforced. The die-cast component 10 is formed, for example, from an aluminum die cast alloy and the metal foam core 20 is formed, for example, from a pure aluminum foam with reinforcing components.

2 shows a diecasting die or a die casting mold 100 for the production of the die-cast component 10 , The die casting mold 100 has a shaping cavity 110 on. For the production of the die-cast component 10 First, the prepared metal foam core 20 at the appropriate place in the cavity 110 positioned. Subsequently, the cavity 110 over the casting chamber 130 using the piston 140 filled with an aluminum alloy melt, wherein the metal foam core 20 poured and poured while permanently.

According to the invention, the metal foam core 20 Reinforcement components in the form of fibers and / or particles, in the metal foam core 20 are integrated. Hereinafter, referring to the 3 to 8th such metal foam cores and processes for their preparation explained, with a fundamental distinction can be made between the integration of reinforcing components after the metal foam production ( 3 to 7 ) and the integration of reinforcing components in metal foam production ( 8th ).

3 shows an aluminum foam semifinished product S with open-pore foam structure (open-pore aluminum foam), which is used as starting material for the production of reinforced metal foam cores 20 is used. For this purpose, several slices are cut from the semifinished product S, from which subsequently the metal foam core 20 is composed, wherein the foam discs individual layers 21 form, between which a reinforcing fibers and / or reinforcing particles containing intermediate layer 22 is arranged. This is in 4 shown, with the liner 22 by way of example, a semi-finished product containing short or long fibers (for example metal, metal oxide, carbon or glass fibers) (this may in particular also be a CFRP or GFRP semi-finished product), woven fabric or the like. The liner 22 but could, for example, by spraying short fibers and / or particles, or z. B. by applying a short fibers and / or particles containing mass, or be formed in any other suitable manner. In the 4 to 7 are for the purpose of a simple illustration and explanation only two equal thickness layers 21 and a liner 22 shown, without the invention being limited thereto. Instead of the intermediate layer 22 can, for example, at least one piece of sheet metal (eg Sheet metal strip), at least one piece of wire (possibly also a rod or a pin), a wire mesh or the like between the foam layers 21 to be ordered.

Another possibility is to introduce in the foam semi-S cutouts, aufzubiegen the foam semi-finished S at these cuts or unfold, bring the reinforcing components and close the unfolded cuts by bending back again.

You foam layers 21 and the liner 22 must be suitably connected or fixed so that the metal foam core formed therefrom 20 has sufficient strength for die casting. This can, for example, by gluing the layers 21 with the liner 22 done as in 5 shown. The adhesive used forms in each case a connecting adhesive layer 23 , Alternatively, the layers can 21 and 22 also be soldered together, so that connecting solder layers 24 result. Furthermore, the layers can 21 and 22 also by melting the metal foam surfaces and then merging with the intermediate layer 22 be connected or fixed so that connecting solidified melt layers 25 result.

6 shows an embodiment in which the layers 21 and 22 using pencils 26 , in particular metal pins, are fixed. The pencils 26 are in particular, as well as the metal foam S, formed of an aluminum material. In the example shown, the pins are 26 further with barbs crashing in the metal foam S 27 educated. The pencils 26 can as additional reinforcing elements or reinforcing components for the metal foam core 20 act. Instead of pins, screws, nails, staples or the like can be used.

7 shows an embodiment in which the layers 21 and 22 by means of a wrap-around winding wire 28 fixed or connected. The winding wire 28 is in particular, as well as the metal foam S, formed of an aluminum material. Instead of a winding wire and a winding tape or the like can be used.

The in connection with the 5 to 7 explained joining or connection options can also be combined with each other. By a specific positioning of the reinforcing fibers and / or reinforcing particles (for example, based on the position, orientation and number), a defined component reinforcement is made possible. Furthermore, the invention makes possible the integral connection of fiber structures (for example CFRP or GFRP) and light metals (for example aluminum or magnesium) in the die-casting process for the production of weight-optimized and light-weight die cast metal components or hybrid lightweight structures.

8th shows a metal foam core 20 formed as a monolithic foam block with an open-pore foam structure, which already in the foam production in a core form fibers 29 (which are exemplified by short fibers), tissue pieces and / or particles have been mixed, which have been distributed substantially homogeneously in the foam structure. Incidentally, such a reinforced foam material can also be used as a starting material for a method in connection with the 3 to 7 explained core production can be used.

LIST OF REFERENCE NUMBERS

10

Die-cast component

20

Metallic foam core

21

Metal foam layer

22

liner

23

adhesive layer

24

solder layer

25

melt layer

26

Pencils)

27

barb

28

winding wire

29

reinforcing fibers

100

Die-casting mold

110

cavity

130

casting chamber

140

piston

S

Metal foam, metal foam semi-finished product

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19501508 C1 [0003, 0017]
• DE 19650613 A1 [0004]

Claims (10)

Method for producing a metal foam core ( 20 ), which in the following for the production of a thus partially reinforced metallic die-cast component ( 10 ), characterized in that reinforcing components in the form of fibers, particles and / or metallic inserts in the metal foam core ( 20 ) to get integrated. Method according to claim 1, characterized in that the metal foam core ( 20 ) from individual layers ( 21 ), which are made of a metal foam semifinished product (S) is composed, wherein between the layers ( 21 ) at least one fiber and / or particle-containing intermediate layer ( 22 ) or at least one metallic inserter is arranged. Method according to claim 2, characterized in that the layers ( 21 . 22 ) by means of adhesive ( 23 ) are fixed. Method according to claim 2, characterized in that the layers ( 21 . 22 ) by melting ( 24 ) of the metal foam surfaces or by soldering ( 25 ) are fixed. Method according to claim 2, characterized in that the layers ( 21 . 22 ) using connectors ( 26 . 28 ) are fixed. Method according to claim 1, characterized in that the metal foam core ( 20 ) is produced by foaming in a core mold, wherein the fibers and / or particles are already admixed with the starting material or are added during foaming and / or wherein the metallic inserts are positioned at the appropriate place in the core mold. Metal foam core ( 20 ) for the production of a partially reinforced die-cast component ( 10 ), this metal foam core ( 20 ) is produced by a method according to one of the preceding claims and has integrated reinforcing components in the form of fibers, particles and / or metallic inserts. Metal foam core ( 20 ) according to claim 7, characterized by an open-pored metal foam structure. Die casting component ( 10 ), in particular engine, chassis or body component, wherein this die-cast component ( 10 ) at least one cast-in metal foam core ( 20 ) according to claim 7 or 8. Die casting component ( 10 ) according to claim 9, characterized in that it is formed from an aluminum die cast alloy and the cast-in metal foam core ( 20 ) is formed of a similar aluminum alloy or of pure aluminum.

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