U.S. patent application number 12/083519 was filed with the patent office on 2008-10-30 for method for the production of a composite material or a precursor product for the production of a composite material.
This patent application is currently assigned to Neue Materialien Fuerth GmbH. Invention is credited to Mark Hartmann, Andreas Lohmueller, Robert F. Singer.
Application Number | 20080264594 12/083519 |
Document ID | / |
Family ID | 37758826 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080264594 |
Kind Code |
A1 |
Lohmueller; Andreas ; et
al. |
October 30, 2008 |
Method for the Production of a Composite Material or a Precursor
Product for the Production of a Composite Material
Abstract
The invention relates to a method for the production of a
starting product for the production of a composite material having
a metallic matrix phase and a reinforcement phase, with the
following steps: Providing an extruder device having a die (4),
Feeding the metallic matrix phase in a first portion of the
extruder device, Transport of the metallic matrix phase in the
direction of the die (4), Feeding reinforcement particles forming
the reinforcement phase in the region of a second portion of the
extruder device, Producing a mixture formed from the reinforcement
particles and the at least partially melted on metallic matrix
phase and further transport of the mixture through the die (4).
Inventors: |
Lohmueller; Andreas;
(Fuerth, DE) ; Hartmann; Mark; (Kempten, DE)
; Singer; Robert F.; (Erlangen, DE) |
Correspondence
Address: |
KANESAKA BERNER AND PARTNERS LLP
1700 DIAGONAL RD, SUITE 310
ALEXANDRIA
VA
22314-2848
US
|
Assignee: |
Neue Materialien Fuerth
GmbH
Fuerth
DE
|
Family ID: |
37758826 |
Appl. No.: |
12/083519 |
Filed: |
October 26, 2006 |
PCT Filed: |
October 26, 2006 |
PCT NO: |
PCT/EP2006/010306 |
371 Date: |
June 6, 2008 |
Current U.S.
Class: |
164/97 |
Current CPC
Class: |
B22D 19/14 20130101;
B21C 23/01 20130101; B22D 19/02 20130101; B22D 17/007 20130101;
B21C 23/005 20130101; B22D 17/2061 20130101 |
Class at
Publication: |
164/97 |
International
Class: |
B22D 19/14 20060101
B22D019/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 3, 2005 |
DE |
10 2005 052 470.2 |
Claims
1. Method for the production of a composite material having a
metallic matrix phase and a reinforcement phase or a precursor
product for the production of a composite material with the
following steps: Providing an extruder device with a die (4),
Feeding the metallic matrix phase in a first portion of the
extruder device, Transport of the metallic matrix phase in the
direction of the die (4), Feeding reinforcement particles forming
the reinforcement phase in the region of a second portion of the
extruder device, Producing a mixture created from the reinforcement
particles and the at least partially melted on metallic matrix
phase and further transport of the mixture through the die (4),
wherein the mixture is cooled to a temperature below the solidus
temperature of the metallic matrix phase before or during passing
through the die.
2. Method according to claim 1, wherein the metallic matrix phase
and/or the reinforcement particles are fed to the extruder device
under an atmosphere of inert gas.
3. Method according to claim 1, wherein the metallic matrix phase
is fed in the form of solid metal particles.
4. Method according to claim 1, wherein the metal particles are
formed from magnesium, zinc or aluminum or an alloy predominantly
contained in one of the preceding metals.
5. Method according to claim 1, wherein the metal particles form a
granulate with an average diameter in the range of 1 .mu.m to 10
mm.
6. Method according to claim 1, wherein the reinforcement particles
are produced from a metallic and/or non-metallic, inorganic
material.
7. Method according to claim 1, wherein the reinforcement particles
are present in the form of fibers and/or particles.
8. Method according to claim 1, wherein the fibers have a thickness
in the range of 3 to 20 .mu.m.
9. Method according to claim 1, wherein the fibers have a length in
the range of 5 .mu.m to 10 mm.
10. Method according to claim 1, wherein the particles have an
average diameter in the range of 10 nm to 100 .mu.m.
11. Method according to claim 1, wherein the metal particles are at
least partially melted on in the second portion of the extruder
device during the transport in the direction of the die (4).
12. (canceled)
13. Method according to claim 1, wherein the solidified mixture is
broken up into a granulate.
14. Method according to claim 1, wherein a contact time between the
at least partially melted on metallic matrix phase and the
reinforcement phase is less than 20 minutes, preferably less than
15 minutes.
15. Method according to claim 1, wherein the extruder device has at
least one, preferably two, worm shaft(s) for the transport.
16. Method according to claim 1, wherein the extruder device has at
least one mixing equipment.
17. Use of a precursor product produced according to claim 1 for
the production of a molded part produced by a casting method.
Description
[0001] Method for the production of a composite material or a
precursor product for the production of a composite material.
[0002] The invention relates to a method for the production of a
composite material or a precursor product for the production of a
precursor product for the production of a composite material.
[0003] Metallic composite materials are generally known according
to the prior art. In this connection these are particularly
composite materials for which a reinforcement phase is included in
a metallic matrix phase. Depending on the demands on the composite
material the reinforcement phase can be made of particles, in
particular non-metallic particles, or of fibers. According to the
prior art it is furthermore known how to produce molded parts made
of composite materials by means of a casting method. For this the
melted metal is mixed in a container with the reinforcement phase
by means of a stirrer and then transferred to a casting device.
According to the prior art the problem occurs that the
reinforcement phase is not distributed homogeneously in the
metallic matrix phase. This can be caused by the formation of
agglomerates of the particles forming the reinforcement phase.
Regardless of this the reinforcement phase can sink or swim in the
molten mass due to differences in density. The thus caused
inhomogeneities lead to poor mechanical properties for the product
produced from the molten mass.
[0004] EP 0 409 966 A1 discloses a method for the production of a
composite material for which metallic material is fed to an
extruder device. The metallic material can be an alloy with a
discontinuous phase.
[0005] WO 00/49192 describes a method for the production of a
metal-matrix composite material. In this connection the
matrix-metal is plasticized in a processing unit comprising an
extruder, and a reinforcement component is fed to the extruder by
means of a side-feeder device. The mixture of plasticized
matrix-metal and reinforcement component is homogenized in the
extruder.
[0006] The object of the invention is to eliminate the
disadvantages according to the prior art. In particular a method is
to be specified for the production of a starting product which
makes possible the production of a composite material with improved
homogeneity.
[0007] This object is solved with the features of claim 1.
Advantageous embodiments of the invention result from the features
of claims 2 to 17.
[0008] According to the invention a method is provided to produce a
composite material having a metallic matrix phase and a
reinforcement phase or a precursor product for the production of a
composite material with the following steps:
Providing an extruder device having a die, Feeding the metallic
matrix phase in a first portion of the extruder device, Transport
of the metallic matrix phase in the direction of the die, Feeding
reinforcement particles forming the reinforcement phase in the
region of a second portion of the extruder device, and Producing a
mixture created from the reinforcement particles and the at least
partially melted on metallic matrix phase and further transport of
the mixture through the die, wherein the mixture is advantageously
cooled to a temperature below the solidus temperature of the
metallic matrix phase before, during or after passing through the
die.
[0009] The suggested method provides a relatively simple and
inexpensive way to produce a composite material or a precursor
product for the production of a composite material in which the
reinforcement phase is homogeneously distributed. Segregation
processes are avoided by using an extruder device as suggested by
the invention. In accordance with the purpose of the present
invention the term "extruder device" is understood to be a device
with which the metallic matrix phase and the reinforcement
particles are mixed intensively, in particular using the effects of
shearing force, and in this connection the mixture which is forming
is transported in the direction of an outlet opening or a die.
[0010] Such extruder devices are also called "compounders." Use of
such an extruder device surprisingly enables the production of a
homogeneous mixture from a granulate with an average grain size in
the range of 1 to 10 mm which forms the metallic matrix phase and a
reinforcement phase which is, for example, formed from particles
with an average grain diameter of less than 100 .mu.m or short
fibers with a thickness of 5 to 10 .mu.m. The production of a
homogenous mixture starting with materials with such different
average grain diameters has not been possible up to now according
to the prior art.
[0011] The composite material which can be produced with the method
is present in solid form. In this connection these can particularly
be conventional profiles which can be produced by means of
extrusion. The profiles can be rods, hollow profiles and similar
for example. Furthermore the method according to the invention can
also be used to produce precursor products for the production of a
composite material. Such precursor products can be either solid or
fluid. A solid precursor product can be a granulate in particular
which can be produced by breaking up previously produced rods.
While still in fluid form the precursor product can however also be
fed after passing through the outlet opening of the extruder device
directly to a further device for the production of molded
parts.
[0012] According to the method of the invention it is provided that
the reinforcement particles and the at least partially melted on
metallic matrix phase are mixed. In this connection it can happen
that the reinforcement particles are brought into contact with the
metallic matrix phase before, during or after the partial melting
on of same. It is advantageous, however, when the metallic matrix
phase is at least partially melted on before being brought into
contact with the reinforcement phase. A "partial melting on" of the
metallic matrix phase is done by heating same to a temperature
above the solidus temperature and below the liquidus temperature.
In this connection the metallic matrix phase can first be heated to
a temperature above the liquidus temperature and then cooled to the
range between liquidus and solidus temperature. However, it is also
possible to only heat the metallic matrix phase to a temperature
above the solidus temperature and below the liquidus temperature.
By cooling the mixture to a temperature below the solidus
temperature of the metallic matrix phase before, during or after
passing through the die, it is advantageously possible to break up
the solidified mixture into a granulate. However, it is also
possible to cut the solidified mixture into rod-shaped
semi-finished products, wires, bars or rods with a predetermined
length.
[0013] According to an advantageous embodiment it is provided that
the metallic matrix phase and/or the reinforcement particles are
fed to the extruder device in an atmosphere of inert gas. This
makes it relatively easy to avoid an undesired reaction with oxygen
and/or nitrogen.
[0014] According to a further embodiment it is provided that the
metallic matrix phase is fed in the form of solid metal particles.
The metal particles are advantageously made of magnesium, zinc or
aluminum or an alloy predominantly contained in one of the
preceding metals.
[0015] Although the feeding of the metallic matrix phase in the
form of solid metal particles is preferred, it is also possible to
feed the metallic matrix phase to the extruder device in a melted
or partially melted state.
[0016] The reinforcement particles can be produced from a metallic
and/or a non-metallic, inorganic material. In case metallic
materials are used, materials which have a low solubility during
the metallic matrix phase are selected. Such non-metallic materials
include in particular ceramic materials, for example aluminum oxide
or SiC, or other suitable reinforcement phases.
[0017] The reinforcement particles can be in the form of fibers
and/or particles. In this connection the fibers advantageously have
a thickness in the range of 3 to 20 .mu.m. Furthermore they can
have a length in the range of 5 .mu.m to 10 mm.
[0018] The particles advantageously have an average diameter of 10
nm to 100 .mu.m. The method according to the invention enables the
production of a homogeneous starting product even when the average
diameter of the metal particles and the reinforcement particles
significantly differ from one another.
[0019] According to a further advantageous embodiment it is
provided that the metal particles are only partially melted on
while being transported in the direction of the die in the second
portion of the extruder device. The partially melting on of the
metal particles is done by setting a temperature which is in the
2-phase area between the solidus and the liquidus temperature. In
this range the matrix phase is only partially fluid, i.e. it
consists of a mixture of solid phase and molten mass. Reinforcement
particles introduced therein are distributed particularly
homogeneously. In particular the crystals already located in the
molten mass prevent segregation by gravitational sinking and/or the
creation of agglomerates. This enables a particularly homogeneous
mixture with the reinforcement particles.
[0020] According to a further embodiment the mixture which is
leaving the die in a fluid state is fed to a casting device. The
casting device can be a device for performing a gravitational
casting method, a pressure casting method, an injection casting
method or a thixomolding method. Energy can be saved with the
suggested method. Regardless of this, this can be used to
accelerate a method for the production of a molded part.
[0021] According to a further advantageous embodiment a contact
time between the at least partially melted on metallic matrix phase
and the reinforcement phase is less than 20 minutes, preferably
less than 15 minutes. Due to this extremely short contact time
undesired reactions between the metallic molten mass and the
reinforcement phase and/or the formation of undesired metastable
phases can be avoided. A composite material produced from the
starting product according to the invention exhibits improved
properties.
[0022] The extruder device can have at least one, preferably two,
worm shafts for the transport. In particular, a double worm shaft
extruder device which has two parallel arranged, advantageously
partially intermeshing worm shafts has been shown to be
particularly suitable for performing the method according to the
invention. An outstanding homogeneity of the produced mixture can
be achieved therewith.
[0023] The homogeneity can still be increased even more according
to a further embodiment by means of equipping the extruder device
with at least one mixing device. These can be intermeshing, gear
wheel-like devices on the worm shafts of the double worm shaft
extruder device.
[0024] According to a further provision the use of the precursor
product according to the invention is provided for the production
of a molded part produced by a casting method. The casting method
can be a gravitational casting method, a pressure casting method,
an injection casting method and similar. It has been shown to be
particularly advantageous to use the starting product for the
so-called "thixomolding method". Thixomolding methods are known for
example from EP 0 409 966 B1.
[0025] Hereinafter, an example of an embodiment of the invention
will be explained in more detail with reference to the drawings.
The figures are listed below:
[0026] FIG. 1 a picture of the texture of a first composite
material,
[0027] FIG. 2 a picture of the texture of a second composite
material and
[0028] FIG. 3 a schematic sectional view of an extruder device.
[0029] FIG. 1 shows a reflected light microscopic view of a
composite material produced by means of the method according to the
invention. A magnesium alloy has been used as the starting material
for the metallic phase, which contains 9% in weight aluminum and 1%
in weight zinc (AZ91). Particles produced from SiC with an average
grain size of 5 to 15 .mu.m, preferably approximately 10 .mu.m,
have been used for the reinforcement phase. The portion of the
reinforcement phase has been 10% by volume.
[0030] The metallic matrix phase has been heated to a temperature
in the range between the solidus and the liquidus temperature to
produce the composite material. The partially fluid molten mass has
been added to the reinforcement phase. Due to the crystals,
magnesium mixed crystals in this case, contained in the partially
fluid molten mass, segregation or formation of agglomerates does
not occur between the reinforcement phase. The particles of the
reinforcement phase are kept uniformly distributed in the volume,
wherein segregations are prevented by the primary crystals located
between the reinforcement phase.
[0031] FIG. 2 shows the same alloy, wherein the metallic matrix
phase has been heated here however to a temperature above the
liquidus temperature and then the reinforcement phase has been
added. It can be observed here that the reinforcement phase is not
as uniformly distributed as with the method using a partially fluid
metal molten mass. This is attributed to the circumstance that, due
to the lack of the magnesium primary phase, the reinforcement phase
has more freedom of movement in the molten mass and therefore there
a formation of segregations and/or agglomerates has a higher
probability.
[0032] For the extruder device shown in FIG. 3 a worm shaft which
can be driven with a drive 3 is housed in a cylinder 1. According
to an advantageous embodiment two worm shafts 2 can also be
provided in the cylinder 1. A die which is advantageously provided
with a cooler is designated with the reference numeral 4. A first
feeder device 5 is provided for feeding metal granulate in a first
portion of the cylinder 1 located in the vicinity of the drive 3.
The first feeder device comprises a suction conveyor 6, a first
feeding hopper 7 set downstream, a first dosing worm shaft 8 and a
first feeding shaft 9 which is provided with a first connection 10
for feeding inert gas. The inert gas can be argon for example.
[0033] A second feeder device 11 for feeding reinforcement phase is
provided in a second portion of the cylinder 1 which is located in
the vicinity of the die 4, downstream to the first portion. The
second feeder device 11 comprises a second feeding hopper 12, a
second dosing worm shaft 13 set downstream, a second feeding shaft
14 with a second connection 15 for feeding inert gas. Reference
numeral 16 designates a fixed strand leaving the die 4 and
reference numeral 17 designates strip heaters which surround the
cylinder 1.
[0034] The device is operated as follows to perform the method
according to the invention:
[0035] For example magnesium granulate with an average diameter of
4 mm is drawn in by the suction conveyor 6 and is fed to the
cylinder 1 in the first portion via the first feeding hopper 7 as
well as the first dosing worm shaft 8 via the feeding shaft 9 under
an atmosphere of inert gas. The magnesium granulate is transported
with the worm shaft 2 in the direction of the die 4. In this
connection it is heated to a temperature above the solidus
temperature with the strip heaters 17. The magnesium granulate is
at least partially melted on in the region of the second portion.
In the second portion reinforcement particles are added in turn
under an atmosphere of inert gas via the second feeding hopper 12,
the second dosing worm shaft 13 and the second feeding shaft 14. In
this connection this can be short fibers with a thickness of 5 to
10 .mu.m which are several centimeters in length. In the second
portion the reinforcement phase is mixed intensively with the
partially melted on magnesium by means of the rotation of the worm
shaft 2 and then enters the die 4. There the mixture is cooled and
leaves the die in the form of the strand 16. The strand 16 can then
be broken up into a granulate. The produced granulate is used as
the starting product for the production of composite materials. In
particular it can be processed further with the thixomolding
method.
[0036] According to a variant of the suggested method, it is also
possible to feed the mixture while still in its fluid state when it
leaves the die 4, for example, directly to a casting device set
downstream, in particular a thixomolding device or a pressure
casting device.
LIST OF REFERENCE NUMERALS
[0037] 1 Cylinder [0038] 2 Worm shaft [0039] 3 Drive [0040] 4 Die
[0041] 5 First feeder device [0042] 6 Suction conveyor [0043] 7
First feeding hopper [0044] 8 First dosing worm shaft [0045] 9
First feeding shaft [0046] 10 First connection [0047] 11 Second
feeder device [0048] 12 Second feeding hopper [0049] 13 Second
dosing worm shaft [0050] 14 Second feeding shaft [0051] 15 Second
connection [0052] 16 Strand [0053] 17 Strip heaters
* * * * *