U.S. patent application number 15/781670 was filed with the patent office on 2018-09-27 for methods of making metal matrix composites including inorganic particles and discontinuous fibers.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Jason D. Anderson, Jordan A. Campbell, Douglas P. Goetz, Gareth A. Hughes, Douglas E. Johnson, Colin McCullough, Elizaveta Y. Plotnikov, Gang Qi, Anatoly Z. Rosenflanz, Sandeep K. Singh, Fabian Stolzenburg, Jean A. Tangeman, David M. Wilson, Yong K. Wu.
Application Number | 20180272428 15/781670 |
Document ID | / |
Family ID | 58995208 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180272428 |
Kind Code |
A1 |
Plotnikov; Elizaveta Y. ; et
al. |
September 27, 2018 |
Methods of Making Metal Matrix Composites Including Inorganic
Particles and Discontinuous Fibers
Abstract
A method of making a porous metal matrix composite is provided.
The method includes mixing a metal powder, a plurality of inorganic
particles, and a plurality of discontinuous fibers to form a
mixture, wherein the metal powder comprises aluminum, magnesium, an
aluminum alloy, or a magnesium alloy. The method further includes
sintering the mixture to form the porous metal matrix composite.
Typically, the inorganic particles comprise porous particles or
ceramic bubbles or glass bubbles, and the inorganic particles and
the discontinuous fibers are dispersed in the metal. The metal
matrix composite has a lower density than the metal and an
acceptable yield strength.
Inventors: |
Plotnikov; Elizaveta Y.;
(St. Paul, MN) ; Johnson; Douglas E.;
(Minneapolis, MN) ; McCullough; Colin;
(Chanhassen, MN) ; Anderson; Jason D.; (Richfield,
MN) ; Qi; Gang; (Stillwater, MN) ; Wu; Yong
K.; (Woodbury, MN) ; Singh; Sandeep K.;
(Rosemount, MN) ; Hughes; Gareth A.; (St. Paul,
MN) ; Wilson; David M.; (Bloomington, MN) ;
Rosenflanz; Anatoly Z.; (Maplewood, MN) ; Goetz;
Douglas P.; (St. Paul, MN) ; Campbell; Jordan A.;
(La Jolla, CA) ; Stolzenburg; Fabian; (Woodbury,
MN) ; Tangeman; Jean A.; (Minneapolis, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
58995208 |
Appl. No.: |
15/781670 |
Filed: |
December 6, 2016 |
PCT Filed: |
December 6, 2016 |
PCT NO: |
PCT/US2016/065101 |
371 Date: |
June 5, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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62264571 |
Dec 8, 2015 |
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62264564 |
Dec 8, 2015 |
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62356610 |
Jun 30, 2016 |
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62372088 |
Aug 8, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2003/1106 20130101;
C22C 32/00 20130101; C22C 32/0089 20130101; B22F 2301/058 20130101;
C22C 49/14 20130101; C22C 47/14 20130101; B22F 2301/052 20130101;
C22C 49/06 20130101; B22F 3/1118 20130101; C22C 49/04 20130101;
B22F 3/1112 20130101; B22F 3/11 20130101 |
International
Class: |
B22F 3/11 20060101
B22F003/11 |
Claims
1. A method of making a porous metal matrix composite comprising:
a. mixing a metal powder, a plurality of inorganic particles, and a
plurality of discontinuous fibers, thereby forming a mixture; and
b. sintering the mixture, thereby forming the porous metal matrix
composite.
2. The method of claim 1, wherein the mixture is sintered in a
die.
3. The method of claim 1, wherein the sintering is performed at a
temperature of between 250 degrees Celsius and 1,000 degrees
Celsius, inclusive.
4. The method of claim 1, wherein the sintering comprises applied
pressure.
5. The method of claim 4, wherein the sintering is performed at a
pressure of between 4 megapascals and 200 megapascals,
inclusive.
6. The method of claim 1, wherein the mixing is performed using an
acoustic mixer, a mechanical mixer, or a tumbler.
7. The method of claim 1, wherein the mixture comprises the
inorganic particles and the discontinuous fibers dispersed in the
metal powder.
8. The method of claim 1, wherein the plurality of inorganic
particles comprises porous particles comprising porous metal oxide
particles, porous metal hydroxide particles, porous metal
carbonates, porous carbon particles, porous silica particles,
porous dehydrated aluminosilicate particles, porous dehydrated
metal hydrate particles, zeolite particles, porous glass particles,
expanded perlite particles, expanded vermiculite particles, porous
sodium silicate particles, engineered porous ceramic particles,
agglomerates of nonporous primary particles, or combinations
thereof.
9. The method of claim 1, wherein the plurality of inorganic
particles comprises ceramic bubbles or glass bubbles.
10. The method of claim 1, wherein the plurality of discontinuous
fibers comprises glass, alumina, aluminosilicate, carbon, basalt,
or a combination thereof.
11. The method of claim 1, wherein the metal comprises aluminum,
magnesium, an aluminum alloy, or a magnesium alloy.
12. The method of claim 1, wherein the metal matrix composite has
an envelope density that is at least 8% less than the density of
the metal and can withstand a strain of 1% prior to fracture.
13. The method of claim 12, wherein the metal matrix composite can
withstand a strain of 2% prior to fracture.
14. The method of claim 1, wherein the metal matrix composite has a
yield strength of 50 megapascals or greater.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to methods of making metal
matrix composites, which include a mixture of a metal base with
other materials, such as filler materials.
BACKGROUND
[0002] Metal matrix composites have long been recognized as
promising materials due to their combination of high strength and
stiffness combined with low weight. Metal matrix composites
typically include a metal matrix reinforced with fibers or other
filler materials.
SUMMARY
[0003] The present disclosure provides methods for making a
lightweighted metal matrix composite. There remains a need for
methods of forming metal matrix composites that have a lower
envelope density than the metal while maintaining certain levels of
physical properties.
[0004] In an aspect, the present disclosure provides a method of
making a porous metal matrix composite. The method includes mixing
a metal powder, a plurality of inorganic particles, and a plurality
of discontinuous fibers, thereby forming a mixture. The method
further includes sintering the mixture, thereby forming the porous
metal matrix composite. Typically, the inorganic particles and the
discontinuous fibers are dispersed in the metal.
[0005] Various unexpected results and advantages are obtained in
exemplary embodiments of the present disclosure. An advantage of at
least one exemplary embodiment of the present disclosure is that a
porous metal matrix composite is manufactured, the metal matrix
composite containing inorganic particles and discontinuous fibers
dispersed in metal exhibiting both a lower envelope density than
the metal and an acceptable yield strength (e.g., plastic yielding
in a tensile stress-strain curve). Moreover, it is not necessary to
use any coating on the inorganic particles to provide metal matrix
composites having inorganic particles effectively dispersed in the
metal, according to at least some exemplary embodiments of the
present disclosure. The inorganic particles are typically intact
within the metal matrix composite, with minimal broken particles in
at least some exemplary embodiments of the present disclosure.
[0006] The above summary of the present disclosure is not intended
to describe each disclosed embodiment or every implementation of
the present disclosure. The description that follows more
particularly exemplifies illustrative embodiments. In several
places throughout the application, guidance is provided through
lists of examples, which examples can be used in various
combinations. In each instance, the recited list serves only as a
representative group and should not be interpreted as an exclusive
list.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The disclosure may be more completely understood in
consideration of the following detailed description of various
embodiments of the disclosure in connection with the accompanying
figure, in which:
[0008] FIG. 1 is a schematic cross-section view of a metal matrix
composite manufactured according to an exemplary embodiment of the
present disclosure.
[0009] FIG. 2 is a graph of stress-strain curves for exemplary and
comparative matrices prepared according to the present
disclosure.
[0010] FIG. 3 is a graph of stress-strain curves for additional
exemplary matrices and comparative matrices.
[0011] FIG. 4 is a graph of stress-strain curves for further
exemplary matrices and comparative matrices.
[0012] FIG. 5 is a graph of stress-strain curves for another
exemplary matrix.
[0013] FIG. 6 is a graph of stress-strain curves for still further
exemplary matrices.
[0014] FIG. 7 is a graph of stress-strain curves for yet another
exemplary matrix.
[0015] While the above-identified drawings, which may not be drawn
to scale, set forth embodiments of the present disclosure, other
embodiments are also contemplated, as noted in the Detailed
Description.
DETAILED DESCRIPTION
[0016] For the following Glossary of defined terms, these
definitions shall be applied for the entire application, unless a
different definition is provided in the claims or elsewhere in the
specification.
Glossary
[0017] Certain terms are used throughout the description and the
claims that, while for the most part are well known, may require
some explanation. It should be understood that, as used herein:
[0018] As used in this specification and the appended embodiments,
the singular forms "a", "an", and "the" include plural referents
unless the content clearly dictates otherwise. As used in this
specification and the appended embodiments, the term "or" is
generally employed in its sense including "and/or" unless the
content clearly dictates otherwise.
[0019] As used in this specification, the recitation of numerical
ranges by endpoints includes all numbers subsumed within that range
(e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).
[0020] Unless otherwise indicated, all numbers expressing
quantities or ingredients, measurement of properties and so forth
used in the specification and embodiments are to be understood as
being modified in all instances by the term "about." Accordingly,
unless indicated to the contrary, the numerical parameters set
forth in the foregoing specification and attached listing of
embodiments can vary depending upon the desired properties sought
to be obtained by those skilled in the art utilizing the teachings
of the present disclosure. At the very least, and not as an attempt
to limit the application of the doctrine of equivalents to the
scope of the claimed embodiments, each numerical parameter should
at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
[0021] The terms "comprises" and variations thereof do not have a
limiting meaning where these terms appear in the description and
claims.
[0022] The words "preferred" and "preferably" refer to embodiments
of the disclosure that may afford certain benefits, under certain
circumstances. However, other embodiments may also be preferred,
under the same or other circumstances. Furthermore, the recitation
of one or more preferred embodiments does not imply that other
embodiments are not useful, and is not intended to exclude other
embodiments from the scope of the disclosure.
[0023] Reference throughout this specification to "one embodiment,"
"certain embodiments," "one or more embodiments" or "an
embodiment," whether or not including the term "exemplary"
preceding the term "embodiment," means that a particular feature,
structure, material, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
certain exemplary embodiments of the present disclosure. Thus, the
appearances of the phrases such as "in one or more embodiments,"
"in certain embodiments," "in one embodiment," "in many
embodiments" or "in an embodiment" in various places throughout
this specification are not necessarily referring to the same
embodiment of the certain exemplary embodiments of the present
disclosure. Furthermore, the particular features, structures,
materials, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0024] The term "dispersed" with respect to one or more fillers in
a metal matrix refers to the one or more fillers distributed
throughout the metal matrix, for instance providing a substantially
homogeneous metal matrix composite including the metal and the
filler(s). This is in contrast to areas of a metal matrix composite
having a concentration of one or more fillers that is at least
twice as high as an area in a different location of the metal
matrix composite (e.g., layers or clusters of a filler within the
metal matrix composite). Although it may be possible to observe a
sufficiently small volume of a metal matrix composite in which the
one or more fillers is not exactly homogenously distributed in the
metal matrix, the filler(s) is still dispersed in the metal.
[0025] The term "sinter" refers to making a powdered material
coalesce into a solid or porous mass by heating it without complete
liquefaction. Optionally, the powdered material is also compressed
during sintering.
[0026] The term "envelope density" with respect to particles refers
to the mass divided by the envelope volume. The "envelope volume"
refers to the sum of the volumes of the solid in each particle and
any voids in the particle. Similarly, the term "envelope density"
with respect to a metal matrix composite refers to the mass divided
by the envelope volume, where the "envelope volume" refers to the
sum of the volumes of the solid in the metal matrix composite and
any voids in the metal matrix composite.
[0027] The term "skeleton density" with respect to porous particles
refers to the mass divided by the skeleton volume. The "skeleton
volume" refers to the sum of the volumes of the solid material and
any closed pores within the particle.
[0028] The term "average true density" with respect to glass
bubbles refers to the mean of the density of the glass bubbles
rather than the density of a volume of glass bubbles (which is
dependent on compaction of the glass bubbles in that volume).
[0029] The term "plastic yield" refers to the stress at which a
predetermined amount of permanent deformation of a material
occurs.
[0030] The term "tensile plastic yield" refers to the stress at
which a predetermined amount of permanent deformation of a material
occurs while the material is being subjected to a tensile
force.
[0031] The term "softening point" refers to the temperature, or
range of temperatures, at which a material (e.g., in a solid phase)
begins to slump under its own weight. For materials that have a
definite melting point (e.g., metals), the softening point is
generally regarded as being the melting point of the metal or metal
alloy. However, for materials that do not have a definite melting
point, the softening point may be the temperature at which elastic
behavior of the material changes to plastic flow. For example, the
softening point of a glass, a glass-ceramic, or a porcelain may
occur at a glass-transition temperature of the material, and may be
defined by a viscosity of 10.sup.7.65 poise. The softening point of
glass is typically determined, for example, by the Vicat method
(e.g., ASTM-D1525 or ISO 306) or by the Heat Deflection Test (e.g.,
ASTM-D648).
[0032] The term "uncoated" with respect to glass bubbles refers to
the absence of any additional material (i.e., having a composition
different from the glass) applied to an exterior surface of the
glass bubbles.
[0033] The term "yield strength" refers to the stress at which it
is considered that plastic elongation of a material has commenced.
As used herein, the yield strength is determined at an offset of
0.2%. ASTM B557M-15 discloses "7.6 Yield Strength--Determine yield
strength by the offset method at an offset of 0.2%. Acceptance or
rejection of material may be decided on the basis of
Extension-Under-Load Method. For referee testing, the offset method
shall be used. 7.6.1 Offset Method--To determine the yield strength
by the "offset method," it is necessary to secure data (autographic
or numerical) from which a stress-strain diagram may be drawn. Then
on the stress-strain diagram (FIG. 16) lay off Om equal to the
specified value of the offset, draw mn parallel to OA, and thus
locate r, the intersection of mn with the stress-strain diagram
(Note 12). In reporting values of yield strength obtained by this
method, the specified value of "offset" used should be stated in
parentheses after the term yield strength. Thus: Yield strength
(offset=0.2%)=360 MPa".
[0034] The term "transitional-alumina" refers to any alumina from
aluminum hydroxide to alpha-alumina. Specific transitional-alumina
particles include delta-alumina, eta-alumina, theta-alumina,
chi-alumina, kappa-alumina, rho-alumina, and gamma-alumina. The
transitional-alumina particles are generated during the heat
treatment of aluminum hydroxide or aluminum oxy hydroxide. The most
thermodynamically stable form is generally alpha-alumina.
[0035] Various exemplary embodiments of the disclosure will now be
described. Exemplary embodiments of the present disclosure may take
on various modifications and alterations without departing from the
spirit and scope of the disclosure. Accordingly, it is to be
understood that the embodiments of the present disclosure are not
to be limited to the following described exemplary embodiments, but
are to be controlled by the limitations set forth in the claims and
any equivalents thereof.
[0036] In an aspect, the present disclosure provides a method of
making a porous metal matrix composite. The method includes mixing
a metal powder, a plurality of inorganic particles, and a plurality
of discontinuous fibers to form a mixture. The method further
includes sintering the mixture to form the porous metal matrix
composite.
[0037] In some embodiments, mixing of the metal powder, inorganic
particles, and discontinuous fibers is performed manually, such as
by shaking by hand a container holding the materials. Often,
shaking is performed for at least 15 seconds, at least 20 seconds,
at least 30 seconds, at least 45 seconds, or at least 60 seconds,
and up to 2 minutes, up to 100 seconds, up to 90 seconds, or up to
70 seconds. When manually mixing the components for a metal matrix
composite, optionally a container holding the materials is inverted
at least once. In certain embodiments, mixing of the metal powder,
inorganic particles, and discontinuous fibers is performed using an
acoustic mixer, a mechanical mixer, a shaker table, or a tumbler.
Mixing using an apparatus may similarly be performed for at least
15 seconds, at least 20 seconds, at least 30 seconds, at least 45
seconds, or at least 60 seconds, and up to 2 minutes, up to 100
seconds, up to 90 seconds, or up to 70 seconds. The mixture created
by mixing the components comprises the inorganic particles and the
discontinuous fibers dispersed in the metal powder. As discussed
above, having the inorganic particles and discontinuous fibers
dispersed in the metal powder provides a substantially homogeneous
mixture.
[0038] Following mixing, the mixture is sintered. In most
embodiments, the sintering is performed for a time of at least 30
minutes, at least 60 minutes, at least 90 minutes, or at least 2
hours, and up to 3 hours or up to 24 hours; such as between 30
minutes and 3 hours, inclusive. Typically, the mixture is sintered
in a die (e.g., a mold). The sintering is usually performed in a
hot press or a furnace at a temperature of at least 250 degrees
Celsius (.degree. C.), at least 300.degree. C., at least
400.degree. C., at least 500.degree. C., or at least 600.degree.
C., and up to 1,000.degree. C., up to 900.degree. C., up to
800.degree. C., or up to 700.degree. C.; such as between
250.degree. C. and 1,000.degree. C., inclusive, or between
400.degree. C. and 900.degree. C., or between 600.degree. C. and
800.degree. C. In many embodiments, the temperature is increased at
a steady rate until a desired maximum temperature is reached.
[0039] In certain embodiments, the sintering further comprises
applying pressure to the mixture in the die. For instance,
sintering is optionally performed at a pressure of at least 4
megapascals (MPa), at least 5 MPa, at least 7 MPa, at least 10 MPa,
at least 12 MPa, at least 15 MPa, or at least 20 MPa; and up to 200
MPa, up to 150 MPa, up to 100 MPa, up to 75 MPa, up to 50 MPa, or
up to 25 MPa; such as between 4 MPa and 200 MPa, inclusive, between
4 MPa and 50 MPa, inclusive, or between 15 MPa and 200 MPa,
inclusive. In certain embodiments, the die is flushed with an inert
gas (e.g., nitrogen or argon) following the release of applied
pressure.
[0040] Following the sintering process, the metal matrix composite
can be allowed to cool (e.g., within or outside the hot press or
furnace). In some embodiments, the metal matrix composite is
allowed to furnace cool (i.e., by turning off the furnace and
waiting for the metal matrix composite to cool down on its own). In
other embodiments, a coolant, for instance and without limitation,
an inert gas (e.g., nitrogen, argon, etc.), is passed through the
hot press or furnace to help the metal matrix composite to cool
down faster.
[0041] Referring to FIG. 1, a schematic cross-section view of a
porous metal matrix composite 100 is provided, prepared according
to exemplary embodiments of the present disclosure. The porous
metal matrix composite 100 includes a metal 10, a plurality of
inorganic particles 12, and a plurality of discontinuous fibers 14.
The inorganic particles 12 and the discontinuous fibers 14 are
dispersed in the metal 10. For simplicity, the metal matrix
composite is illustrated as having a monolithic shape; however, the
metal matrix composite may be formed in a number of various shapes
depending on the intended application. Metal matrix composites are
applicable to industries such as construction, automotive, and
electronics, in which a particular metal component may be replaced
with a metal matrix composite component.
[0042] In many embodiments, the metal comprises a porous matrix
structure. A porous matrix structure is usually obtained from
powdered metal, wherein the powder contains a metal structure in
which a gas (e.g., air) is incorporated into the solid metal
structure. Typically, the metal is present in an amount of 50
weight percent or more of the metal matrix composite, 55 weight
percent or more, 60 weight percent or more, 65 weight percent or
more, 70 weight percent or more, or 75 weight percent or more; and
in an amount of 95 weight percent or less, 90 weight percent or
less, 85 weight percent or less, or 80 weight percent or less.
Stated another way, the metal may be present in an amount of
between 50 weight percent and 95 weight percent, inclusive, of the
metal matrix composite, or between 70 weight percent and 95 weight
percent, inclusive, of the metal matrix composite. The metal
comprises aluminum, magnesium, or alloys thereof (i.e., an aluminum
alloy or a magnesium alloy). Suitable metals include for instance
and without limitation, pure aluminum (aluminum powder with purity
of at least 99.0%, e.g., AA1100, AA1050, AA1070 etc., such as pure
aluminum powder commercially available from Eckart (Louisville,
Ky.)); or an aluminum alloy containing aluminum and 0.2 to 2% by
mass of another metal. Such alloys include: Al--Cu alloys (AA2017
etc.), Al--Mg alloys (AA5052 etc.), Al--Mg--Si alloys (AA6061
etc.), Al--Zn--Mg alloys (AA7075 etc.) and Al--Mn alloys, either
alone or as a mixture of two or more. Various suitable metal
powders are commercially available from Atlantic Equipment
Engineers (Upper Saddle River, N.J.).
[0043] Typically, when the metal is used in the form of a powder,
the metal powder comprises an average particle size of 300
nanometers (nm) or more, 400 nm or more, 500 nm or more, 750 nm or
more, 1 micrometer (.mu.m) or more, 2 .mu.m or more, 5 .mu.m or
more, 7 .mu.m or more, 10 .mu.m or more, 20 .mu.m or more, 35 .mu.m
or more, 50 .mu.m or more, or 75 .mu.m or more; and 100 .mu.m or
less, 75 .mu.m or less, 50 .mu.m or less, 35 .mu.m or less, or 25
.mu.m or less. Stated another way, the metal powder comprises an
average particle size ranging between 300 nm and 100 .mu.m,
inclusive; ranging between 1 .mu.m and 100 .mu.m, inclusive; or
ranging between 1 .mu.m and 50 .mu.m, inclusive. The particle size
can be analyzed, for instance, using light microscopy and laser
diffraction.
[0044] Suitable inorganic particles include particles having a
maximum envelope density of 2.00 grams per cubic centimeter or
less, 1.75 grams per cubic centimeter or less, 1.50 grams per cubic
centimeter or less, 1.25 grams per cubic centimeter or less, or
1.00 grams per cubic centimeter or less. Typically, the plurality
of inorganic particles comprises a substantially spherical shape or
an acicular shape, while in some embodiments the inorganic
particles comprise multicelled bubbles. The particles generally
have an aspect ratio of longest axis to shortest axis of 2:1 or
less.
[0045] Typically, the plurality of inorganic particles comprises an
average particle size of 50 nanometers (nm) or more, 250 nm or
more, 500 nm or more, 750 nm or more, 1 micrometer (.mu.m) or more,
2 .mu.m or more, 5 .mu.m or more, 7 .mu.m or more, 10 .mu.m or
more, 20 .mu.m or more, 35 .mu.m or more, 50 .mu.m or more, 75
.mu.m or more, or 100 .mu.m or more; and 5 millimeters (mm) or
less, 3 mm or less, 2 mm or less, 1 mm or less, 750 .mu.m or less,
500 .mu.m or less, or 250 .mu.m or less. Stated another way, the
plurality of inorganic particles comprises an average particle size
ranging between 50 nm and 5 mm, inclusive; ranging between 1 .mu.m
and 1 mm, inclusive; or ranging between 10 .mu.m and 500 .mu.m,
inclusive.
[0046] The amount of inorganic particles dispersed in the metal is
not particularly limited. The plurality of inorganic particles is
often present in an amount of at least 1 weight percent of the
metal matrix composite, at least 2 weight percent, at least 5
weight percent, at least 8 weight percent, at least 10 weight
percent, at least 15 weight percent, or at least 20 weight percent
of the metal matrix composite; and up to 50 weight percent, up to
28 weight percent, up to 26 weight percent, up to 24 weight
percent, or up to 22 weight percent of the metal matrix composite.
In certain embodiments, the inorganic particles are present in the
metal matrix composite in an amount of between 1 weight percent and
30 weight percent, or between 2 weight percent and 25 weight
percent, or between 2 weight percent and 15 weight percent,
inclusive, of the metal matrix composite. Including less than 1
weight percent of the inorganic particles results in a minimal
decrease in envelope density of the metal matrix composite, while
including more than 30 weight percent of the inorganic particles
negatively impacts the mechanical properties of the metal matrix
composite due to the metal matrix composite containing an
insufficient amount of metal and fibers.
[0047] In certain embodiments the plurality of inorganic particles
comprise porous particles. As used herein, "porous particles"
refers to both particles that have pores themselves, and
agglomerates of nonporous primary particles including pores between
at least some of the nonporous primary particles. Examples of
useful porous particles include for instance and without
limitation, porous metal oxide particles, porous metal hydroxide
particles, porous metal carbonates, porous carbon particles, porous
silica particles, porous dehydrated aluminosilicate particles,
porous dehydrated metal hydrate particles, zeolite particles,
porous glass particles, expanded perlite particles, expanded
vermiculite particles, porous sodium silicate particles, engineered
porous ceramic particles, agglomerates of nonporous primary
particles, or combinations thereof. In certain embodiments, the
metal of the metal oxide, metal hydroxide, or metal carbonate is
selected from aluminum, magnesium, zirconium, calcium, or
combinations thereof. In select embodiments, the porous particles
comprise porous alumina particles, porous carbon particles, porous
silica particles, porous aluminum hydroxide particles, or
combinations thereof. The porous particles typically have had
associated water removed from them, usually by heating the porous
particles. Optionally, the porous particles comprise
transitional-alumina particles. Suitable porous particles include
for instance and without limitation, Versal 250 boehmite powder
commercially available from UOP LLC (Des Plaines, Ill.), YH-D 16
boehmite powder, Zibo Yinghe Chemical Company, Ltd. (Shandong,
China), and Alumax PB300 boehmite, PIDC International (Ann Arbor,
Mich.).
[0048] In certain embodiments, the plurality of inorganic particles
comprises ceramic bubbles or glass bubbles. Suitable materials for
ceramic bubbles and glass bubbles includes, for instance and
without limitation, alumina, aluminosilicate, silica, or
combinations thereof. Commercially available glass bubbles include,
for example, the LightStar, EconoStar, and High Alumina censopheres
available from Cenostar Corporation (Amesbury, Mass.). Preferably,
the ceramic bubbles and glass bubbles are uncoated (e.g., with a
metal material, which has been used to aid in wetting of the
bubbles by the metal matrix).
[0049] In embodiments in which the metal has a high melting point
(e.g., aluminum) and the inorganic particles are glass bubbles, the
plurality of (e.g., uncoated) glass bubbles advantageously
comprises glass that withstands heating to a temperature of 700
degrees Celsius for at least two hours without softening. The use
of high temperature resistant glass bubbles allows their
incorporation in metal matrix composites that otherwise would be
prepared at a temperature elevated enough to damage the glass
bubbles, such as by softening at least some of the glass bubbles to
the point that they deform and/or break.
[0050] One suitable type of glass bubbles includes bubbles that
leach less than 100 micrograms of sodium ion per gram of glass
bubbles in deionized water when stirred with the deionized water
for 2 hours. An advantage of glass bubbles with such a low sodium
leaching rate is that they are useful in electronics applications
where the leaching of sodium ions is often unacceptable. In an
embodiment, suitable compounds used for the preparation of such low
sodium glass bubbles include silica, lime, boric acid, calcium
phosphate, calcined alumina silicate, and magnesium silicate. In
certain embodiments, such low sodium glass bubbles exhibit a
softening temperature between 717.degree. C. and 735.degree. C.,
inclusive, as measured by thermal dilatometry.
[0051] Preferably, the inorganic particles comprise uncoated
inorganic particles. Advantageously, employing uncoated inorganic
particles provides a savings in material costs and coating time.
Methods according to at least certain embodiments of the present
disclosure prepare porous metal matrix composites in which the
inorganic particles are dispersed in the metal without requiring
any further material to improve contact between the inorganic
particles and the metal.
[0052] The plurality of discontinuous fibers dispersed in the metal
matrix composite is not particularly limited, and for example
includes inorganic fibers, such as glass, alumina, aluminosilicate,
carbon, basalt, or a combination thereof. More particularly, in
certain embodiments the fibers comprise at least one metal oxide,
alumina, alumina-silica, or a combination thereof. The
discontinuous fibers have an average length of less than 5
centimeters, which tend to be more conducive to dispersion in a
metal matrix than longer fibers. In many embodiments, the fibers
have an average length that is shorter than the smallest dimension
of the mold or die used to form a metal matrix composite, so that
the orientation of the fibers is not restricted by the mold or die.
Often, a ratio of the fiber length to the smallest dimension of the
mold or die is <1:1. In certain embodiments, the discontinuous
fibers have an average length of less than 4 centimeters, less than
3 centimeters, or less than 2 centimeters. Discontinuous fibers may
be formed from continuous fibers, for example, by methods known in
the art such as chopping and milling. Typically, the plurality of
discontinuous fibers comprises an aspect ratio of 10:1 or
greater.
[0053] Suitable discontinuous fibers can have a variety of
compositions, such as ceramic fibers. The ceramic fibers can be
produced in continuous lengths, which are chopped or sheared, as
discussed herein, to provide the ceramic fibers of the present
disclosure. The ceramic fibers can be produced from a variety of
commercially available ceramic filaments. Examples of filaments
useful in forming the ceramic fibers include the ceramic oxide
fibers sold under the trademark NEXTEL (3M Company, St. Paul,
Minn.). NEXTEL is a continuous filament ceramic oxide fiber having
low elongation and shrinkage at operating temperatures, and offers
good chemical resistance, low thermal conductivity, thermal shock
resistance, and low porosity. Specific examples of NEXTEL fibers
include NEXTEL 312, NEXTEL 440, NEXTEL 550, NEXTEL 610 and NEXTEL
720. NEXTEL 312 and NEXTEL 440 are refractory aluminoborosilicate
that includes Al.sub.2O.sub.3, SiO.sub.2 and B.sub.2O.sub.3. NEXTEL
550 and NEXTEL 720 are aluminosilica and NEXTEL 610 is alumina.
During manufacture, the NEXTEL filaments are coated with organic
sizings or finishes which serves as aids in textile processing.
Sizing can include the use of starch, oil, wax or other organic
ingredients applied to the filament strand to protect and aid
handling. The sizing can be removed from the ceramic filaments by
heat cleaning the filaments or ceramic fibers as a temperature of
700.degree. C. for one to four hours.
[0054] The ceramic fibers can be cut or chopped so as to provide
relatively uniform lengths, which can be accomplished by cutting
continuous filaments of the ceramic material in a mechanical
shearing operation or laser cutting operation, among other cutting
operations. Given the highly controlled nature of such cutting
operations, the size distribution of the ceramic fibers is very
narrow and allow to control the composite property.
[0055] The length of the ceramic fiber can be determined, for
instance, using an optical microscope (Olympus MX61, Tokyo, Japan)
fit with a CCD Camera (Olympus DP72, Tokyo, Japan) and analytic
software (Olympus Stream Essentials, Tokyo, Japan). Samples may be
prepared by spreading representative samplings of the ceramic fiber
on a glass slide and measuring the lengths of at least 200 ceramic
fibers at 10.times. magnification.
[0056] Suitable fibers include for instance ceramic fibers
available under the trade name NEXTEL (available from 3M Company,
St. Paul, Minn.), such as NEXTEL 312, 440, 610 and 720. One
presently preferred ceramic fiber comprises polycrystalline
.alpha.-Al.sub.2O.sub.3. Suitable alumina fibers are described, for
example, in U.S. Pat. No. 4,954,462 (Wood et al.) and U.S. Pat. No.
5,185,299 (Wood et al.). Exemplary alpha alumina fibers are
marketed under the trade designation NEXTEL 610 (3M Company, St.
Paul, Minn.). In some embodiments, the alumina fibers are
polycrystalline alpha alumina fibers and comprise, on a theoretical
oxide basis, greater than 99 percent by weight Al.sub.2O.sub.3 and
0.2-0.5 percent by weight SiO.sub.2, based on the total weight of
the alumina fibers. In other embodiments, some desirable
polycrystalline, alpha alumina fibers comprise alpha alumina having
an average grain size of less than one micrometer (or even, in some
embodiments, less than 0.5 micrometer). In some embodiments,
polycrystalline, alpha alumina fibers have an average tensile
strength of at least 1.6 GPa (in some embodiments, at least 2.1
GPa, or even, at least 2.8 GPa). Suitable aluminosilicate fibers
are described, for example, in U.S. Pat. No. 4,047,965 (Karst et
al). Exemplary aluminosilicate fibers are marketed under the trade
designations NEXTEL 440, and NEXTEL 720, by 3M Company (St. Paul,
Minn.). Aluminoborosilicate fibers are described, for example, in
U.S. Pat. No. 3,795,524 (Sowman). Exemplary aluminoborosilicate
fibers are marketed under the trade designation NEXTEL 312 by 3M
Company. Boron nitride fibers can be made, for example, as
described in U.S. Pat. No. 3,429,722 (Economy) and U.S. Pat. No.
5,780,154 (Okano et al.).
[0057] Ceramic fibers can also be formed from other suitable
ceramic oxide filaments. Examples of such ceramic oxide filaments
include those available from Central Glass Fiber Co., Ltd. (e.g.,
EFH75-01, EFH150-31). Also preferred are aluminoborosilicate glass
fibers which are which contain less than about 2% alkali or are
substantially free of alkali (i.e., "E-glass" fibers). E-glass
fibers are available from numerous commercial suppliers.
[0058] The amount of discontinuous fibers dispersed in the metal
matrix composite is not particularly limited. The plurality of
fibers is often present in an amount of at least 1 weight percent
of the metal matrix composite, at least 2 weight percent, at least
3 weight percent, at least 5 weight percent, at least 10 weight
percent, at least 15 weight percent, at least 20 weight percent, or
at least 25 weight percent of the metal matrix composite; and up to
50 weight percent, up to 45 weight percent, up to 40 weight
percent, or up to 35 weight percent of the metal matrix composite.
In certain embodiments, the fibers are present in the metal matrix
composite in an amount of between 1 weight percent and 50 weight
percent, or between 2 weight percent and 25 weight percent, or
between 5 weight percent and 15 weight percent, inclusive, of the
metal matrix composite. Including less than 1 weight percent of the
fibers results in a minimal increase in strength of the metal
matrix composite, while including more than 50 weight percent of
the fibers negatively impacts the envelope density of the metal
matrix composite due to the metal matrix composite containing an
insufficient amount of metal and inorganic particles. In certain
embodiments, the plurality of inorganic particles and the plurality
of discontinuous fibers are present in combination in an amount of
between 5 weight percent and 50 weight percent, inclusive, of the
metal matrix composite.
[0059] Advantageously, the metal matrix composite exhibits both a
decreased envelope density (as compared to the pure metal) and
acceptable mechanical properties. For instance, the metal matrix
composite typically has an envelope density between 1.35 and 2.70
grams per cubic centimeter, inclusive or between 1.80 and 2.50
grams per cubic centimeter, inclusive. For example, the metal
matrix composite may have an envelope density of at least 1.60
grams per cubic centimeter, at least 1.75, at least 1.90, at least
2.00, at least 2.10, or at least 2.25 grams per cubic centimeter;
and an envelope density of up to 2.70, up to 2.60, up to 2.50, up
to 2.40, or up to 2.30 grams per cubic centimeter.
[0060] In certain embodiments, the metal comprises aluminum or
alloys thereof and the metal matrix composite has an envelope
density between 1.80 and 2.50 grams per cubic centimeter,
inclusive; between 2.00 and 2.30 grams per cubic centimeter,
inclusive; or between 1.80 and 2.20 grams per cubic centimeter,
inclusive.
[0061] In certain embodiments, the metal comprises magnesium or
alloys thereof and the metal matrix composite has an envelope
density between 1.35 and 1.60 grams per cubic centimeter,
inclusive; between 1.55 and 1.60 grams per cubic centimeter,
inclusive; or between 1.35 and 1.50 grams per cubic centimeter,
inclusive.
[0062] Advantageously, in many embodiments the metal matrix
composite has an envelope density that is at least 8% less than the
density of the metal (or at least 10% less, at least 12% less, at
least 15% less, or at least 17% less) and can withstand a strain of
1% prior to fracture. This combination of properties provides both
lightweighting of the metal and maintains some of the metal
characteristics in the metal matrix composite. In particular, the
metal matrix composite preferably exhibits a yield strength before
failure in a tensile test. In certain embodiments the metal matrix
composite has a yield strength of 50 megapascals or greater, 75
megapascals or greater, 100 megapascals or greater, 150 megapascals
or greater, or 200 megapascals or greater.
[0063] It was found that the metal matrix composite of at least
certain exemplary embodiments of the present disclosure exhibits a
stress-strain curve that shows a plastic yielding behavior, and the
metal matrix composite of at least certain exemplary embodiments of
the present disclosure exhibits a stress-strain curve that shows a
tensile plastic yield behavior. That is to say, that the
stress-strain curve exhibits a region of plastic flow. The plastic
yield curve and tensile plastic yield curve are in contrast to a
purely brittle failure mechanism. That is to say, the purely
brittle behavior exhibits only an elastic region within the
stress-strain curve, and no (or very little) region of plastic
flow. Surprisingly, the combination of both inorganic particles and
discontinuous fibers as fillers in metal matrix composites
according to at least some embodiments of the disclosure provided a
plastic yield curve and/or a tensile plastic yield behavior upon
testing. For instance, referring to FIG. 3, the stress-strain curve
for Example 13, containing both fibers and porous inorganic
particles (described in detail below), shows a yield before a
brittle failure mechanism. In certain embodiments, the metal matrix
composite can withstand a strain of 1%, 1.5%, or 2% prior to
fracture. Moreover, it was unexpected that the metal powder
remained separate from the porous inorganic particles, as opposed
to being pushed into some of the pores of the porous inorganic
particles during sintering (particularly sintering under applied
pressure). The porous inorganic particles further, interestingly,
did not tend to become damaged (e.g., crumble or crush) during
sintering, but rather maintained their porous skeletal
structures.
[0064] In many embodiments, the metal matrix composite exhibits an
ultimate tensile strength of 25 megapascals (MPa) or greater, such
as 40 MPa or greater, 50 MPa or greater, 75 MPa or greater, 100 MPa
or greater, 150 MPa or greater, 200 MPa or greater, 250 MPa or
greater, or 300 MPa or greater. It can further be useful to
consider the tensile strength of a metal matrix composite as it
relates to the envelope density of the metal matrix composite as
typically tensile strength is sacrificed during lightweighting of a
composite. In some embodiments, the metal matrix composite has an
envelope density between 1.80 and 2.50 grams per cubic centimeter,
inclusive, and an ultimate tensile strength of 50 MPa or greater,
100 MPa or greater, 150 MPa or greater, 200 MPa or greater, 250 MPa
or greater, or 300 MPa or greater.
[0065] Advantageously, in certain embodiments desirable mechanical
properties are obtained without requiring fillers beyond the
inorganic particles and the discontinuous fibers. In such
embodiments, the metal matrix composite consists essentially of a
metal, a plurality of inorganic particles, and a plurality of
discontinuous fibers. The metal matrix composite thus may further
contain additives that do not substantially impact the mechanical
properties of the metal matrix composite. In contrast, a metal
matrix composite consisting essentially of a metal, a plurality of
inorganic particles, and a plurality of discontinuous fibers could
not further include additives such as materials used to aid
dispersion of the fillers.
[0066] Metal matrix composites according to aspects of the present
disclosure can be prepared according to various suitable methods
known to the skilled practitioner, including powder metallurgy
processes such as hot pressing, powder extrusion, hot rolling,
heating followed by warm rolling, cold compaction and sintering,
and hot isostatic pressing. In an embodiment, the metal matrix
composites may be prepared by mixing a metal powder, the plurality
of inorganic particles, and the plurality of discontinuous fibers
to disperse the inorganic particles and discontinuous fibers in the
metal powder, followed by sintering of the mixture to form a metal
matrix composite. For instance, such a powder metallurgy method is
described in detail below in Example 1.
Exemplary Embodiments
[0067] Embodiment 1 is a method of making a porous metal matrix
composite. The method includes mixing a metal powder, a plurality
of inorganic particles, and a plurality of discontinuous fibers,
thereby forming a mixture. The method further includes sintering
the mixture, thereby forming the porous metal matrix composite.
[0068] Embodiment 2 is the method of embodiment 1, wherein the
mixture is sintered in a die.
[0069] Embodiment 3 is the method of embodiment 1 or embodiment 2,
wherein the sintering is performed at a temperature of between 250
degrees Celsius and 1,000 degrees Celsius, inclusive.
[0070] Embodiment 4 is the method of any of embodiments 1 to 3,
wherein the sintering comprises applied pressure.
[0071] Embodiment 5 is the method of embodiment 4, wherein the
sintering is performed at a pressure of between 4 megapascals and
200 megapascals, inclusive.
[0072] Embodiment 6 is the method of any of embodiments 1 to 5,
wherein the sintering is performed for a time of between 30 minutes
and 3 hours, inclusive.
[0073] Embodiment 7 is the method of any of embodiments 1 to 6,
wherein the mixing is performed using an acoustic mixer, a
mechanical mixer, or a tumbler.
[0074] Embodiment 8 is the method of any of embodiments 1 to 7,
wherein the mixture comprises the inorganic particles and the
discontinuous fibers dispersed in the metal powder.
[0075] Embodiment 9 is the method of any of embodiments 1 to 8,
wherein the metal matrix composite has an envelope density that is
at least 8% less than the density of the metal and can withstand a
strain of 1% prior to fracture.
[0076] Embodiment 10 is the method of embodiment 9, wherein the
metal matrix composite can withstand a strain of 2% prior to
fracture.
[0077] Embodiment 11 is the method of any of embodiments 1 to 10,
wherein the metal matrix composite has a yield strength of 50
megapascals or greater.
[0078] Embodiment 12 is the method of any of embodiments 1 to 11,
wherein the metal matrix composite has a yield strength of 100
megapascals or greater.
[0079] Embodiment 13 is the method of any of embodiments 1 to 12,
wherein the metal matrix composite has an ultimate tensile strength
of 100 megapascals or greater.
[0080] Embodiment 14 is the method of any of embodiments 1 to 13,
wherein the metal matrix composite has an ultimate tensile strength
of 200 megapascals or greater.
[0081] Embodiment 15 is the method of any of embodiments 1 to 14,
wherein the metal matrix composite has an ultimate tensile strength
of 300 megapascals or greater.
[0082] Embodiment 16 is the method of any of embodiments 1 to 15,
wherein the plurality of inorganic particles comprises porous
particles.
[0083] Embodiment 17 is the method of embodiment 16, wherein the
porous particles have a maximum envelope density of 2 grams per
cubic centimeter or less.
[0084] Embodiment 18 is the method of embodiment 15 or embodiment
16, wherein the porous particles comprise porous metal oxide
particles, porous metal hydroxide particles, porous metal
carbonates, porous carbon particles, porous silica particles,
porous dehydrated aluminosilicate particles, porous dehydrated
metal hydrate particles, zeolite particles, porous glass particles,
expanded perlite particles, expanded vermiculite particles, porous
sodium silicate particles, engineered porous ceramic particles,
agglomerates of nonporous primary particles, or combinations
thereof.
[0085] Embodiment 19 is the method of any of embodiments 16 to 18,
wherein the porous particles comprise porous alumina particles,
porous carbon particles, porous silica particles, porous aluminum
hydroxide particles, or combinations thereof.
[0086] Embodiment 20 is the metal matrix composite of embodiment
19, wherein the porous particles comprise transitional-alumina
particles.
[0087] Embodiment 21 is the method of any of embodiments 1 to 15,
wherein the plurality of the inorganic particles comprise ceramic
bubbles or glass bubbles.
[0088] Embodiment 22 is the method of embodiment 21, wherein the
glass bubbles comprise glass that withstands heating to a
temperature of 700 degrees Celsius for at least two hours without
softening.
[0089] Embodiment 23 is the method of embodiment 21 or embodiment
22, wherein the glass bubbles leach less than 100 micrograms of
sodium ion per gram of glass bubbles in deionized water when
stirred with the deionized water for 2 hours.
[0090] Embodiment 24 is the method of any of embodiments 1 to 23,
wherein the plurality of inorganic particles comprise a maximum
envelope density of 2 grams per cubic centimeter or less.
[0091] Embodiment 25 is the method of any of embodiments 21 to 23,
wherein the plurality of inorganic particles comprises alumina,
aluminosilicate, silica, or combinations thereof.
[0092] Embodiment 26 is the method of any of embodiments 18 to 21,
24, or 25, wherein the inorganic particles comprise multicelled
bubbles.
[0093] Embodiment 27 is the method of any of embodiments 1 to 26,
wherein the plurality of inorganic particles has a substantially
spherical shape or an acicular shape.
[0094] Embodiment 28 is the method of any of embodiments 1 to 27,
wherein the plurality of inorganic particles has an average
particle size ranging between 50 nanometers (nm) and 5 millimeters
(mm), inclusive.
[0095] Embodiment 29 is the method of any of embodiments 1 to 28,
wherein the plurality of inorganic particles has an average
particle size ranging between 1 micrometer (.mu.m) and 1 mm,
inclusive.
[0096] Embodiment 30 is the method of any of embodiments 1 to 29,
wherein the plurality of inorganic particles has an average
particle size ranging between 10 .mu.m and 500 .mu.m,
inclusive.
[0097] Embodiment 31 is the method of any of embodiments 1 to 30,
wherein the plurality of discontinuous fibers comprises glass,
alumina, aluminosilicate, carbon, basalt, or a combination
thereof.
[0098] Embodiment 32 is the method of any of embodiments 1 to 31,
wherein the plurality of discontinuous fibers has an aspect ratio
of 10:1 or greater.
[0099] Embodiment 33 is the method of any of embodiments 1 to 32,
wherein the metal comprises a porous matrix structure.
[0100] Embodiment 34 is method of any of embodiments 1 to 33,
wherein the metal comprises aluminum or alloys thereof.
[0101] Embodiment 35 is the method of any of embodiments 1 to 34,
wherein the metal matrix composite has an envelope density between
1.80 and 2.50 grams per cubic centimeter, inclusive.
[0102] Embodiment 36 is the method of any of embodiments 1 to 34,
wherein the metal matrix composite has an envelope density between
2.00 and 2.30 grams per cubic centimeter, inclusive.
[0103] Embodiment 37 is the method of any of embodiments 1 to 34,
wherein the metal matrix composite has an envelope density between
1.80 and 2.20 grams per cubic centimeter, inclusive.
[0104] Embodiment 38 is the method of any of embodiments 1 to 33,
wherein the metal comprises magnesium or alloys thereof.
[0105] Embodiment 39 is the method of embodiment 38, wherein the
metal matrix composite has an envelope density between 1.35 and
1.60 grams per cubic centimeter, inclusive.
[0106] Embodiment 40 is the method of embodiment 38 or embodiment
39, wherein the metal matrix composite has an envelope density
between 1.55 and 1.60 grams per cubic centimeter, inclusive.
[0107] Embodiment 41 is the method of embodiment 38 or embodiment
39, wherein the metal matrix composite has an envelope density
between 1.35 and 1.50 grams per cubic centimeter, inclusive.
[0108] Embodiment 42 is the method of any of embodiments 1 to 41,
wherein the metal matrix composite exhibits a yield strength before
failure in a tensile test.
[0109] Embodiment 43 is the method of any of embodiments 1 to 42,
wherein the metal is present in an amount of between 50 weight
percent and 95 weight percent, inclusive, of the metal matrix
composite.
[0110] Embodiment 44 is the method of any of embodiments 1 to 43,
wherein the plurality of inorganic particles is present in an
amount of between 2 weight percent and 50 weight percent,
inclusive, of the metal matrix composite.
[0111] Embodiment 45 is the method of any of embodiments 1 to 44,
wherein the plurality of discontinuous fibers is present in an
amount of between 2 weight percent and 25 weight percent,
inclusive, of the metal matrix composite.
[0112] Embodiment 46 is the method of any of embodiments 1 to 45,
wherein the plurality of inorganic particles and the plurality of
discontinuous fibers are present in combination in an amount of
between 5 weight percent and 50 weight percent, inclusive, of the
metal matrix composite.
[0113] Embodiment 47 is the method of any of embodiments 1 to 46,
wherein the envelope density of the inorganic particles is at least
40% less than the density of the metal.
[0114] Embodiment 48 is the metal matrix composite of any of
embodiments 1 to 47, wherein the envelope density of the inorganic
particles is at least 50% less than the density of the metal.
[0115] Embodiment 49 is the metal matrix composite of any of
embodiments 1 to 48, wherein the metal matrix composite consists
essentially of the metal; the plurality of inorganic particles; and
the plurality of discontinuous fibers.
EXAMPLES
[0116] These Examples are merely for illustrative purposes and are
not meant to be overly limiting on the scope of the appended
claims. Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the present disclosure are
approximations, the numerical values set forth in the specific
examples are reported as precisely as possible. Any numerical
value, however, inherently contains certain errors necessarily
resulting from the standard deviation found in their respective
testing measurements. At the very least, and not as an attempt to
limit the application of the doctrine of equivalents to the scope
of the claims, each numerical parameter should at least be
construed in light of the number of reported significant digits and
by applying ordinary rounding techniques.
Summary of Materials
[0117] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by weight.
Table 1 provides a description and a source for materials used in
the Examples below:
TABLE-US-00001 TABLE 1 Summary of Materials Name Description Source
Al 6063 powder Gas atomized aluminum 6063 The Aluminium Powder
powder Company, Sutton Coldfield, UK Al 1-511 powder Eckart 1-511
gas atomized Eckart America Corp, 99.5% aluminum powder Louisville,
KY Al 1-131 powder Eckart 1-131 gas atomized Eckart America Corp,
99.5% aluminum powder Louisville, KY Ceramic Fibers Chopped alumina
NEXTEL 3M Company, St. Paul, MN 610 fibers, 180 micrometers long
Glass Fibers 1/32'' milled glass fibers Fibre Glast Developments
Corp, Brookville, OH Cenospheres Cenostar cenospheres Cenostar
Corp, Amesbury, Econostar, Lightstar, and MA High Alumina, grade
106 Glass bubbles High temperature glass Preparatory Example 1
bubbles Alumina particles Versal 250 boehmite powder, UOP LLC, Des
Plaines, IL heat treated to 600.degree. C. Silicon carbide Silicon
carbide, partially 3M Company, St. Paul, MN sintered agglomerate
Silica SiO.sub.2 US Silica, Frederick, MD Lime CaCO.sub.3 Imerys,
Roswell, GA Boric Acid B(OH).sub.3 US Borax, Boron, CA Calcium
phosphate Ca(H.sub.2PO.sub.4).sub.2.cndot.H.sub.2O Spectrum, New
Brunswick, NJ Alumina silicate Calcined Al.sub.2Si.sub.2O.sub.7
Gelest, Morrisville, PA Magnesium silicate
3MgO.sub.4SiO.sub.2.cndot.2H.sub.2O Alfa Aesar, Ward Hill, MA Zinc
sulfate ZnSO.sub.4.cndot.7H.sub.2O Spectrum, New Brunswick, NJ CMC
Carboxymethyl cellulose Ashland Inc., Covington, KY
Test Method 1. Three-Point Bend Test
[0118] The stress and strain of metal matrix composites was
determined using a three-point bend test. In the three-point bend
test, a sample was placed lengthwise between two cylindrical
supports spaced apart by 32 millimeters (mm). A third loading
cylinder suspended from the load cell of the testing apparatus was
lowered so as to touch the sample at its midpoint. A
software-controlled load frame provided by MTS Systems Corporation
(Eden Prairie, Minn.) fitted with a 100 kilonewton (KN) load cell
was used to apply a load to the center of the sample via the middle
loading cylinder. The system measured the force being applied to
the sample and the displacement of the middle loading cylinder from
its starting position for each timepoint. These values were
converted to stress and strain, respectively, using standard force
equations.
Test Method 2. Acoustic Dispersion Method
[0119] To homogeneously disperse one or more filler materials in a
metal, all materials were poured into a 50 milliliter (mL) glass
vial, which was then capped securely. Next, the vial was loaded in
a Resodyn LabRAM acoustic mixer (Resodyn Corporation, Butte,
Mont.), and shaken at 70% intensity using automatic frequency
adjustment for 3 minutes, after which point it was tapped against a
hard surface 3-5 times to allow all materials to settle at the
bottom on the vial.
Test Method 3. Ion Leaching Test
[0120] A sample of 100 g glass bubbles were stirred with 1000 g
deionized (DI) water in a sonicator for approximately 2 hours. Then
the glass bubbles were separated from the DI water by centrifuging
at 10,000 rotations per minute (rpm) for 10 minutes. The ion
concentrations in the resulting leachate solutions were measured by
ion chromatography. Individual calibration curves for each ion were
prepared by plotting the area of each ion in the standards versus
the concentration of that ion in the standard. The concentration of
each ion that leached from the samples was determined using the
measured area of each ion. The identity of each ion was achieved
through retention matching only.
Test Method 4. Manual Dispersion Method
[0121] To manually disperse one or more filler materials in a
metal, all materials were poured into a 50 milliliter (mL) glass
vial, which was then capped securely. Next, the vial was manually
shaken for 30 seconds, after which point it was tapped against a
hard surface 3-5 times to allow all materials to settle at the
bottom on the vial.
Preparatory Example 1
[0122] The amount of each material listed in Table 2 below was
mixed and placed into a fused silica crucible. Then the mixture was
heated in a furnace at 2320 degrees Fahrenheit (1271 degrees
Celsius) for 4 hours. Next, the material was cooled to room
temperature (e.g., about 23 degrees Celsius). The material was
chiseled out from the crucible and crushed to frit particles by a
disk mill (BICO Inc., Burbank, Calif.). The maximum size of the
frit was less than 5 millimeters (mm). The frit particles were then
jet-milled to powder with a particle size mass-median-diameter
(D50) of 20 micrometers (.mu.m) using a jet mill (Hosokawa Alpine,
Augsburg, Germany). 1000 g of the powder was then mixed with 1100 g
of water, 2 weight percent additional boric acid, and 0.3 weight
percent of sulfur from Zinc sulfate, as well as 1 weight percent
CMC, each based on the total weight of the glass powders. The total
solid of the slurry was made to 48 weight percent. The water/frit
powder slurry was milled down to D50 of 1.4 .mu.m primary particle
size by a LabStar mill (NETZSCH Premier Technologies, LLC, Exton,
Pa.). The slurry from the milling was spray dried to form
agglomerated feed particles. The glass bubbles were produced
through a natural gas flame from the spray dried feed. The total
glass bubble density and flame conditions were as listed in Table 3
below. The resulting bubbles had a D5 of 7 micrometers, a D50 of 35
micrometers, and a D90 of 60 micrometers.
TABLE-US-00002 TABLE 2 Materials and amounts, in grams, for mixing
and melting. Alumina Boric calcium silicate, Magnesium Sample
Silica Lime Acid phosphate calcined silicate B-1 301.3 185.9 89.4
49.5 94.8 87.5 B-2 292.4 190.7 81.0 37.4 136.3 66.1
TABLE-US-00003 TABLE 3 Flame forming conditions and glass bubble
density. Flame Flows (SLPM) Density Sample Air Natural Gas oxygen
(g/cm.sup.3) B-1A 265 30 -- 0.8249 B-1B 285 30 -- 0.8878 B-1C 241
30 5 0.8180 B-2A 265 30 -- 0.7650 B-2B 285 30 -- 0.7960 B-2C 241 30
5 0.8553
TABLE-US-00004 TABLE 4 Ion chromatography results. Concentration
ion in B-1 Glass Ion Bubbles (.mu.g ion/g bubble) Cations Sodium 53
.+-. 7 Potassium 23 .+-. 13 Calcium 190 .+-. 36 Anions Fluoride
Below LOD, .ltoreq.4 Chloride Below LOD, .ltoreq.9 Nitrite 13 .+-.
2 Bromide 24 .+-. 4 Sulfate 240 .+-. 12 Nitrate 22 .+-. 3 Phosphate
260 .+-. 4
Comparative Example 1
[0123] 10 grams (g) of Al 1-511 powder was poured into a circular
graphite die with 1.5 inch (3.81 centimeter) inner diameter. The Al
1-511 powder was sintered as follows: The die was loaded into an
HP50-7010 hot press (Thermal Technology LLC, Santa Rosa, Calif.),
and the setup was pumped down to vacuum. The die was heated from
room temperature at 25 degrees Celsius per minute (deg C./min) to
600 degrees Celsius, where it was held for 15 minutes (min). After
the 15 min hold at temperature, 640 kilograms (kg) of force (800
pounds per square inch of pressure for this sized die) was applied
at 600 degrees Celsius for 1 hour (hr). The pressure was then
released, the chamber was flooded with nitrogen, and the die was
allowed to furnace cool back down to room temperature. The
dimensions of the resulting sintered disk, as well as its mass,
were measured to calculate a bulk density of 1.91 grams per cubic
centimeter (g/cc), which is 29% lower than that of fully dense pure
aluminum. A strip was cut out of the middle of the disk having a
width of approximately 0.5 inches (1.27 centimeters) and a length
of 1.5 inches (3.81 centimeters), and this strip was subjected to
the Three-Point Bend Test described above. The sample had a maximum
tensile strength of 31 megapascals (MPa), giving it a strength to
density ratio of 16. The results are shown in Table 5 below.
Comparative Example 2
[0124] 10 g of Al 1-511 powder and 1 g of glass bubbles were mixed
via the Manual Dispersion Method described above, and the mixture
was poured into the same graphite die as in Comparative Example 1.
The setup then underwent the same sintering procedure described in
Comparative Example 1 above. The resulting sintered disk had a
density of 1.58 g/cc. The results of the Three-Point Bend Test are
shown in Table 5 below and in FIG. 2.
Comparative Example 3
[0125] 10 g of Al 1-511 powder and 1 g of ceramic fibers were mixed
via the Manual Dispersion Method described above, and the mixture
was poured into the same graphite die as in Comparative Examples 1
and 2. The setup then underwent the same sintering procedure
described in Comparative Example 1 above. The resulting disk had a
density of 2.11 g/cc. The results of the Three-Point Bend Test are
shown in Table 5 below and in FIG. 2.
Comparative Example 4
[0126] 9 g of Al 1-511 powder, 0.3 g of glass bubbles, and 1.7 g of
ceramic fibers were loosely stirred, and the mixture was poured
into the same graphite die as in Comparative Examples 1-3. The
setup then underwent the same sintering procedure described in
Comparative Example 1 above. The resulting disk had a density of
1.72 g/cc. The results of the Three-Point Bend Test are shown in
Table 5 below and in FIG. 2.
Example 5
[0127] 9 g of Al 1-511 powder, 0.3 g of glass bubbles, and 1.7 g of
ceramic fibers were mixed via the Manual Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 1-4. The setup then underwent the
same sintering procedure described in Comparative Example 1 above.
The resulting disk had a density of 1.83 g/cc. The results of the
Three-Point Bend Test are shown in Table 5 below.
Example 6
[0128] 10 g of Al powder, 0.5 g of glass bubbles, and 0.5 g of
fibers were mixed via the Manual Dispersion Method described above,
and the mixture was poured into the same graphite die as in
Comparative Examples 1-4 and Example 5. The setup then underwent
the same sintering procedure described in Comparative Example 1
above. The resulting disk had a density of 1.71 g/cc. The results
of the Three-Point Bend Test are shown in Table 5 below.
Example 7
[0129] 8 g of Al 1-511 powder, 0.45 g of glass bubbles, and 2.55 g
of ceramic fibers were mixed via the Manual Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 1-4 and Examples 5-6. The setup then
underwent the same sintering procedure described in Comparative
Example 1 above. The resulting disk had a density of 1.78 g/cc. The
results of the Three-Point Bend Test are shown in Table 5
below.
Example 8
[0130] 7 g of Al 1-511 powder, 0.6 g of glass bubbles, and 3.4 g of
ceramic fibers were mixed via the Manual Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 1-4 and Examples 5-7. The setup then
underwent the same sintering procedure described in Comparative
Example 1 above. The resulting disk had a density of 1.63 g/cc. The
results of the Three-Point Bend Test are shown in Table 5
below.
TABLE-US-00005 TABLE 5 Ceramic Ultimate Envelope Com- Al Bubble
Fiber strength density posite (weight %) (weight %) (weight %)
(MPa) (g/cc) CE-1 100 0 0 31 1.91 CE-2 91 9 0 18 1.58 CE-3 91 0 9
57 2.11 CE-4 82 3 15 18 1.72 EX-5 82 3 15 54 1.83 EX-6 91 4.5 4.5
28 1.71 EX-7 73 4 23 43 1.78 EX-8 64 5 31 32 1.63
Comparative Example 9
[0131] 10.8 grams (g) of Al 6063 powder was poured into a circular
graphite die with a 1.575 inch (4.00 centimeter) inner diameter.
The Al 6063 powder was sintered as follows: The die was loaded into
a Toshiba Machine GMP-411VA glass mold press machine (Toshiba
Machine Co., Numazu-shi, Japan), and the setup was flooded with
nitrogen for 60 seconds, then pumped down to vacuum. The die was
heated from 40 degrees Celsius at 28 degrees Celsius per minute
(deg C./min) to 600 degrees Celsius. Once the die reached 600
degrees C., it was held at that temperature while the force on the
die was gradually increased from zero applied force to 21,000
Newtons (2400 psi (or 16.55 MPa) of pressure for this sized die).
The gradual increase in force occurred approximately linearly over
the course of 20 minutes. Once the full force of 21,000 N was
reached, the die was held in this state at 600 degrees C. for 1
hour. The pressure was then released, and the die was allowed to
furnace cool down to room temperature. The dimensions of the
resulting sintered disk, as well as its mass, were measured to
calculate an envelope density of 2.51 grams per cubic centimeter
(g/cc), which is 7% lower than that of fully dense aluminum 6063. A
strip was cut out of the middle of the disk having a width of
approximately 0.5 inches (1.27 centimeters) and a length of 1.5
inches (3.81 centimeters), and this strip was subjected to the
Three-Point Bend Test described above. The sample had an ultimate
tensile strength of 203 megapascals (MPa). The results are shown in
Table 6 below and in FIG. 3.
Comparative Example 10
[0132] 8.64 g of Al 6063 powder and 0.48 g of alumina powder were
mixed via the Acoustic Dispersion Method described above, and the
mixture was poured into the same graphite die as in Comparative
Example 9. The setup then underwent the same sintering procedure
described in Comparative Example 9 above. The resulting sintered
disk had an envelope density of 2.34 g/cc. The results of the
Three-Point Bend Test are shown in Table 6 below and in FIG. 3.
Comparative Example 11
[0133] 9.72 g of Al 6063 powder and 1.56 g of ceramic fibers were
mixed via the Acoustic Dispersion Method described above, and the
mixture was poured into the same graphite die as in Comparative
Examples 9-10. The setup then underwent the same sintering
procedure described in Comparative Example 9 above. The resulting
disk had an envelope density of 2.65 g/cc. The results of the
Three-Point Bend Test are shown in Table 6 below and in FIG. 3.
Example 12
[0134] 7.56 g of Al 6063 powder, 0.48 g of alumina powder, and 1.56
g of ceramic fibers were mixed via the Acoustic Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 9-11. The setup then underwent the
same sintering procedure described in Comparative Example 9 above.
The resulting disk had an envelope density of 2.45 g/cc. The
results of the Three-Point Bend Test are shown in Table 6 below and
in FIG. 3.
Example 13
[0135] 5.4 g of Al 6063 powder, 0.96 g of alumina powder, and 1.56
g of ceramic fibers were mixed via the Acoustic Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 9-11 and Example 12. The setup then
underwent the same sintering procedure described in Comparative
Example 9 above. The resulting disk had an envelope density of 2.11
g/cc. The results of the Three-Point Bend Test are shown in Table 6
below and in FIG. 3.
Example 14
[0136] 5.4 g of Al 6063 powder, 0.96 g of alumina powder, and 1.56
g of ceramic fibers were mixed via the Acoustic Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Examples 9-11 and Examples 12-13. The die was
loaded into a Toshiba Machine GMP-411VA glass mold press machine
(Toshiba Machine Co., Numazu-shi, Japan), and the setup was flooded
with nitrogen for 60 seconds, then pumped down to vacuum. The die
was heated from 40 degrees Celsius at 30 deg C./min to 630 degrees
Celsius. Once the die reached 630 degrees Celsius, it was held at
that temperature while the force on the die was gradually increased
from zero applied force to 34,664 Newtons (4000 psi (or 27.58 MPa)
of pressure for this sized die). The gradual increase in force
occurred approximately linearly over the course of 20 minutes. Once
the full force of 34,664 N was reached, the die was held in this
state at 630 degrees C. for 1 hour. The pressure was then released,
and the die was allowed to furnace cool down to room temperature.
The resulting disk had an envelope density of 2.19 g/cc. The
results of the Three-Point Bend Test are shown in Table 6 below and
in FIG. 3.
TABLE-US-00006 TABLE 6 Compositions and mechanical properties of
examples. Ultimate Envelope Al Alumina Ceramic Fiber strength
density Strain-to- Composite (weight %) (weight %) (weight %) (MPa)
(g/cc) Failure (%) CE-9 100 0 0 203 2.51 >4% (max measurable)
CE-10 95 5 0 132 2.34 1.3 CE-11 86 0 14 279 2.65 >4% (max
measurable) EX-12 79 5 16 182 2.45 1.2 EX-13 68 12 20 106 2.11 0.8
EX-14 68 12 20 186 2.19 0.9
Comparative Example 15
[0137] 10.8 grams (g) of Al 6063 powder was poured into a circular
graphite die with 1.575 inch (4.00 centimeter) inner diameter. The
Al 6063 powder was sintered as follows: The die was loaded into a
Toshiba Machine GMP-411VA glass mold press machine (Toshiba Machine
Co., Numazu-shi, Japan), and the setup was flooded with nitrogen
for 60 seconds, then pumped down to vacuum. The die was heated from
40 degrees Celsius at 28 degrees Celsius per minute (deg C./min) to
615 degrees Celsius. Once the die reached 615 deg C., it was held
at that temperature while the force on the die was gradually
increased from zero force to 21,000 Newtons (1600 psi of pressure
for this sized die). The gradual increase in force occurred
approximately linearly over the course of 20 minutes. Once the full
force of 21,000 N was reached, the die was held in this state at
600 deg C. for 1 hour. The pressure was then released, and the die
was allowed to furnace cool down to room temperature. The
dimensions of the resulting sintered disk, as well as its mass,
were measured to calculate an envelope density of 2.51 grams per
cubic centimeter (g/cc), which is 7% lower than that of fully dense
aluminum 6063. A strip was cut out of the middle of the disk having
a width of approximately 0.5 inches (1.27 centimeters) and a length
of 1.575 inches (4.00 centimeters), and this strip was subjected to
the Three-Point Bend Test described above. The sample had an
ultimate tensile strength of 203 megapascals (MPa). The results are
shown in Table 7 below and FIG. 4.
Example 16
[0138] 5.4 g of Al 1-511 powder, 0.96 g of glass bubbles, and 0.78
g of ceramic fibers were mixed via the Acoustic Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Comparative Example 15. The die was loaded into a Toshiba
Machine GMP-411VA glass mold press machine (Toshiba Machine Co.,
Numazu-shi, Japan), and the setup was flooded with nitrogen for 60
seconds, then pumped down to vacuum. The die was heated from 40
degrees Celsius at 30 degrees Celsius per minute (deg C./min) to
615 degrees Celsius. Once the die reached 615 deg C., it was held
at that temperature while the force on the die was gradually
increased from zero force to 13,954 Newtons (1600 psi of pressure
for this sized die). The gradual increase in force occurred
approximately linearly over the course of 20 minutes. Once the full
force of 13,954 N was reached, the die was held in this state at
615 deg C. for 1 hour. The pressure was then released, and the die
was allowed to furnace cool down to room temperature. The resulting
disk had an envelope density of 1.93 g/cc. The results of the
Three-Point Bend Test are shown in Table 7 below and FIG. 4.
Example 17
[0139] 5.4 g of Al 1-511 powder, 0.96 g of glass bubbles, and 0.78
g of ceramic fibers were mixed via the Acoustic Dispersion Method
described above, and the mixture was poured into the same graphite
die as in Example 16. The setup then underwent the same sintering
procedure described in Example 16 above. The resulting disk had an
envelope density of 1.91 g/cc. The results of the Three-Point Bend
Test are shown in Table 7 below and FIG. 4.
Example 18
[0140] 5.4 g of Al 1-511 powder, 0.96 g of Lightstar 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 1.93 g/cc. The
results of the Three-Point Bend Test are shown in Table 7 below and
FIG. 4.
Example 19
[0141] 5.4 g of Al 1-511 powder, 0.96 g of High Alumina 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 1.95 g/cc. The
results of the Three-Point Bend Test are shown in Table 7 below and
FIG. 4.
Example 20
[0142] 5.4 g of Al 1100 powder, 0.96 g of Econostar 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 1.93 g/cc. The
results of the Three-Point Bend Test are shown in Table 7 below and
FIG. 4.
TABLE-US-00007 TABLE 7 Compositions and mechanical properties of
examples. Ultimate Envelope Al Bubble Ceramic Fiber strength
density Strain-to- Composite (weight %) (weight %) (weight %) (MPa)
(g/cc) Failure (%) CE-15 100 0 0 203 2.51 >4% (max measurable)
EX-16 76 13 11 153 1.93 1.1% EX-17 76 13 11 150 1.91 1.3% EX-18 76
13 11 149 1.93 1.6% EX-19 76 13 11 157 1.95 1.8% EX-20 76 13 11 149
1.93 1.6%
Example 21
[0143] 5.4 g of Al 1-511 powder, 0.96 g of partially sintered
silicon carbide agglomerate particles, and 0.78 g of ceramic fibers
were mixed via the Acoustic Dispersion Method described above, and
the mixture was poured into the same graphite die as in Example 16.
The setup then underwent the same sintering procedure described in
Example 16 above. The resulting disk had an envelope density of
2.28 g/cc, an ultimate tensile strength of 190 MPa, and a
strain-to-failure of 3.4%. The results of the Three-Point Bend Test
are shown in FIG. 5.
Example 22
[0144] 5.94 g of A11-131 powder, 0.96 g of Lightstar 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 1.98 g/cc. The
results of the Three-Point Bend Test are shown in Table 8 below and
in FIG. 6.
Example 23
[0145] 7.56 g of Al 1-131 powder, 0.6 g of Lightstar 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 2.21 g/cc.
[0146] The results of the Three-Point Bend Test are shown in Table
8 and in FIG. 6.
Example 24
[0147] 7.02 g of Al 1-131 powder, 0.72 g of Lightstar 106
cenospheres, and 0.78 g of ceramic fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 2.12 g/cc. The
results of the Three-Point Bend Test are shown in Table 8 and in
FIG. 6.
Example 25
[0148] 7.02 g of Al powder, 0.72 g of Lightstar 106 cenospheres,
and 0.78 g of ceramic fibers were mixed via the Acoustic Dispersion
Method described above, and the mixture was poured into the same
graphite die as in Example 16. The setup then underwent the same
sintering procedure described in Example 16 above. The resulting
disk had an envelope density of 2.00 g/cc. The results of the
Three-Point Bend Test are shown in Table 8 and in FIG. 6.
TABLE-US-00008 TABLE 8 Compositions and mechanical properties of
examples. Al Bubble Ceramic Ultimate Envelope Strain-to- (weight
(weight Fiber strength density Failure Composite %) %) (weight %)
(MPa) (g/cc) (%) EX-22 77 13 10 189 1.98 1.7% EX-23 84 7 9 185 2.21
2.8% EX-24 82.5 8.5 9 179 2.12 2.3% EX-25 82.5 8.5 9 160 2.00
2.4%
Example 26
[0149] 5.94 g of Al 1-131 powder, 0.84 g of Lightstar 106
cenospheres, and 1.016 g of glass fibers were mixed via the
Acoustic Dispersion Method described above, and the mixture was
poured into the same graphite die as in Example 16. The setup then
underwent the same sintering procedure described in Example 16
above. The resulting disk had an envelope density of 2.00 g/cc, an
ultimate tensile strength of 159 MPa, and a strain-to-failure of
1.8%. The results of the Three-Point Bend Test are shown in FIG.
7.
[0150] While the specification has described in detail certain
exemplary embodiments, it will be appreciated that those skilled in
the art, upon attaining an understanding of the foregoing, may
readily conceive of alterations to, variations of, and equivalents
to these embodiments. Furthermore, all publications and patents
referenced herein are incorporated by reference in their entirety
to the same extent as if each individual publication or patent was
specifically and individually indicated to be incorporated by
reference. Various exemplary embodiments have been described. These
and other embodiments are within the scope of the following
claims.
* * * * *