U.S. patent application number 14/443964 was filed with the patent office on 2015-10-01 for additives for improving the castability of aluminum-boron carbide composite material.
The applicant listed for this patent is ALCAN INTERNATIONAL LIMITED. Invention is credited to Neivi Andrade, Joseph Langlais, Jean-Alain Laurin.
Application Number | 20150275338 14/443964 |
Document ID | / |
Family ID | 50730443 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150275338 |
Kind Code |
A1 |
Langlais; Joseph ; et
al. |
October 1, 2015 |
ADDITIVES FOR IMPROVING THE CASTABILITY OF ALUMINUM-BORON CARBIDE
COMPOSITE MATERIAL
Abstract
The present disclosure provides additives capable of undergoing
a peritectic reaction with boron in aluminum-boron carbide
composite materials. The additive may be selected from the group
consisting of vanadium, zirconium, niobium, strontium, chromium,
molybdenum, hafnium, scandium, tantalum, tungsten and combination
thereof, is used to maintain the fluidity of the molten composite
material, prior to casting, to facilitate castability.
Inventors: |
Langlais; Joseph;
(Jonquiere, CA) ; Andrade; Neivi; (Contrecoeur,
CA) ; Laurin; Jean-Alain; (Chicoutimi, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALCAN INTERNATIONAL LIMITED |
Montreal |
|
CA |
|
|
Family ID: |
50730443 |
Appl. No.: |
14/443964 |
Filed: |
November 19, 2013 |
PCT Filed: |
November 19, 2013 |
PCT NO: |
PCT/CA2013/050881 |
371 Date: |
May 19, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61727949 |
Nov 19, 2012 |
|
|
|
Current U.S.
Class: |
420/531 ;
164/57.1 |
Current CPC
Class: |
B22D 19/14 20130101;
C22C 49/14 20130101; B22D 2/008 20130101; B22D 21/007 20130101;
C22C 21/00 20130101; B22C 9/22 20130101; C22C 49/06 20130101; C22C
32/0057 20130101; C22C 1/026 20130101; C22C 32/0047 20130101; B22D
25/06 20130101; C22C 1/1068 20130101 |
International
Class: |
C22C 32/00 20060101
C22C032/00; C22C 49/14 20060101 C22C049/14; B22D 21/00 20060101
B22D021/00; C22C 49/06 20060101 C22C049/06; C22C 21/00 20060101
C22C021/00; C22C 1/02 20060101 C22C001/02 |
Claims
1. A cast composite material comprising (i) aluminum, (ii) products
of a peritectic reaction between an additive and boron, (iii)
dispersed boron carbide particles and (iv) optionally titanium,
wherein: the additive is selected from the group consisting of
chromium, molybdenum, vanadium, niobium, zirconium, strontium,
scandium and any combination thereof; and a sample of the composite
material has a fluidity, after having been heated, prior to
casting, to a temperature of about 700.degree. C. for about 120
minutes, corresponding to a cast length of at least 100 mm when
measured using a mold having a groove for containing the sample,
the groove having a width of about 33 mm, a height of between about
6.5 mm and about 4.0 mm and being downwardly inclined, from an
horizontal axis, of about 10.degree..
2. The cast composite material of claim 1, wherein the cast length
is at least 190 mm.
3. The cast composite material of claim 1, wherein the cast
composite material is submitted to holding during a holding time
and to casting during a casting time and wherein the combination of
the holding time and the casting time is at least 120 minutes.
4. (canceled)
5. The cast composite material of claim 1, wherein the additive is
scandium.
6. The cast composite material of claim 1, wherein the additive is
strontium.
7. The cast composite material of claim 1, wherein the additive is
zirconium.
8. The cast composite material of claim 1, wherein the
concentration (v/v) of the dispersed boron carbide particles is
between 4% and 40% with respect to the total volume of the cast
composite material.
9. The cast composite material of claim 8, wherein the
concentration (w/w) of the additive is between 0.47% and 8.00% with
respect to the total weight of the cast composite material.
10. The cast composite material of claim 9, further comprising
titanium at a concentration (w/w) between 0.50% and 4.00% with
respect to the total weight of the cast composite material.
11-20. (canceled)
21. A method of preparing a cast composite material, said method
comprising: (a) combining (i) a molten aluminum alloy comprising an
additive capable of undergoing a peritectic reaction with boron and
optionally titanium with (ii) a source of boron carbide particles
so as to provide a molten composite material comprising products of
the peritectic reaction between the additive and boron and
dispersed boron carbide particles, wherein: the additive is
selected from the group consisting of chromium, molybdenum,
vanadium, niobium, zirconium, strontium, scandium, and any
combination thereof; and a sample of the composite material has a
fluidity, after having been heated, prior to casting, to a
temperature of about 700.degree. C. for about 120 minutes,
corresponding to a cast length of at least 100 mm when measured
using a mold having a groove for containing the sample, the groove
having a width of about 33 mm, a height of between about 6.5 mm and
about 4.0 mm and being downwardly inclined, from an horizontal
axis, of about 10.degree.; and (b) casting the molten composite so
as to form the cast composite material.
22. The method of claim 21, wherein the cast length is at least 190
mm.
23. The method of claim 21, further comprising, prior to step (b),
holding the molten composite material during a holding time and
casting the molten composite during a casting time, wherein the
combination of the holding time and the casting time is at least
120 minutes.
24-41. (canceled)
42. A cast composite material obtained by the method of claim
21.
43-46. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional
patent application 61/727,949 filed on Nov. 19, 2012 and herewith
incorporated in its entirety.
TECHNOLOGICAL FIELD
[0002] The present invention relates to cast aluminum/boron carbide
composite metal matrix material having products obtained from a
peritectic reaction to increase their fluidity prior to casting.
The reaction products are obtained by using additives capable of
undergoing a perictectic reaction with the boron of the boron
carbide.
BACKGROUND
[0003] To increase the fluidity of the molten Al--B.sub.4C mixture,
and as described in U.S. Pat. No. 7,562,962, titanium can be added.
When titanium is added to the mixture of molten aluminum metal and
B.sub.4C powder, reaction products are formed near the interface of
the B.sub.4C particles and the aluminum matrix which "poison" the
B.sub.4C particles. The reaction products are taught to shield the
B.sub.4C particles from the aluminum.
[0004] It would be highly desirable to be provided with means and
methods of maintaining a proper fluidity of a molten Al--B.sub.4C
mixture prior to casting and shaping. The means and methods would
preferably provide/maintain a fluidity amenable to shaping and/or
casting in industrial settings.
BRIEF SUMMARY
[0005] The present disclosure provides a cast composite material
comprising aluminum, products of a peritectic reaction between an
additive and boron as well as dispersed boron carbide particles.
The presence of the products of the peritectic reaction maintains
the fluidity of the molten composite material, prior to casting,
and facilitate castability and shaping of the composite
material.
[0006] In a first aspect, the present disclosure provides a cast
composite material comprising (i) aluminum, (ii) products of a
peritectic reaction between an additive and boron, (iii) dispersed
boron carbide particles and (iv) optionally titanium. The additive
is selected from the group consisting of chromium, molybdenum,
vanadium, niobium, zirconium, strontium, scandium, and any
combination thereof. A sample of the composite material has a
fluidity, after having been heated, prior to casting, to a
temperature of about 700.degree. C. for about 120 minutes,
corresponding to a cast length of at least 100 mm when measured
using a mold having a groove for containing the sample, the groove
having a width of about 33 mm, a height of between about 6.5 mm and
about 4.0 mm and being downwardly inclined, from an horizontal
axis, of about 10.degree.. In an embodiment, the cast length of the
sample is at least 190 mm. In another embodiment, the cast
composite material is submitted to holding during a holding time
and to casting during a casting time and wherein the holding time
and the casting time amounts to 120 minutes. In another embodiment,
the products of the peritectic reaction are provided by combining a
molten aluminum or a molten aluminum alloy with the additive
capable of undergoing the peritectic reaction (prior to the
incorporation of boron carbide particles). In yet a further
embodiment, the additive is selected from the group consisting of
zirconium, strontium, scandium and any combination thereof. In
another embodiment, the additive is scandium. In a further
embodiment, the additive is strontium. In yet a further embodiment,
the additive is zirconium. In an embodiment, the concentration
(v/v) of the dispersed boron carbide particles is between 4% and
40% with respect to the total volume of the cast composite
material. In such embodiment, the concentration (w/w) of the
additive can be between 0.47% and 8.00% with respect to the total
weight of the cast composite material and optionally, the composite
material can further comprise titanium at a concentration (w/w)
between 0.50% and 4.00% with respect to the total weight of the
cast composite material. In another embodiment, the concentration
(v/v) of the dispersed boron carbide particles is between 4.5% and
18.9% with respect to the total volume of the cast composite
material. In such embodiment, the concentration (w/w) of the
additive can be between 0.38% and 4.00% with respect to the total
weight of the cast composite material and, optionally, the cast
composite material further comprises titanium at a concentration
(w/w) between 0.40% and 2.00% with respect to the total weight of
the cast composite material. In another embodiment, the
concentration (v/v) of the dispersed boron carbide particles is
between 19.0% and 28.0% with respect to the total volume of the
cast composite material. In such embodiment, the concentration
(w/w) of the additive can be between 1.68% and 6.00% with respect
to the total weight of the cast composite material and, optionally,
the cast composite material can further comprise titanium at a
concentration (w/w) between 1.80% and 3.00% with respect to the
total weight of the cast composite material. In still another
embodiment, the concentration (v/v) of the dispersed boron carbide
particles is between 25.0% and 28.0% or between 28.0% and 33.0%
with respect to the total volume of the cast composite material. In
such embodiment, the concentration (w/w) of the additive can be
between 0.94% and 4.00% with respect to the total weight of the
cast composite material and, optionally, the cast composite
material can further comprise titanium at a concentration (w/w)
between 1.00% and 2.00% with respect to the total weight of the
cast composite material.
[0007] According to a second aspect, the present disclosure
provides a method of preparing a cast composite material. Broadly
the method comprises (a) combining (i) a molten aluminum alloy
comprising an additive capable of undergoing a peritectic reaction
with boron with (ii) a source of boron carbide particles so as to
provide a molten composite material comprising products of the
peritectic reaction between the additive and boron and dispersed
boron carbide particles and (b) casting the molten composite so as
to form the cast composite material. The additive is selected from
the group consisting of chromium, molybdenum, vanadium, niobium,
zirconium, strontium, scandium, and any combination thereof. A
sample of the composite material has a fluidity, after having been
heated, prior to casting, to a temperature of about 700.degree. C.
for about 120 minutes, corresponding to a cast length of at least
100 mm when measured using a mold having a groove for containing
the sample, the groove having a width of about 33 mm, a height of
between about 6.5 mm and about 4.0 mm and being downwardly
inclined, from an horizontal axis, of about 10.degree.. In an
embodiment, the cast length is at least 190 mm. In still another
embodiment, the method further comprises, prior to step (b),
holding the molten composite material during a holding time and
casting the molten composite during a casting time, wherein the
holding time and the casting time amounts to 120 minutes. In still
another embodiment, the method further comprises, prior to step
(a), providing the molten aluminum alloy by combining a molten
aluminum or a molten aluminum alloy with the additive capable of
undergoing the peritectic reaction. Embodiments with respect to the
type of additives that can be used, the concentration of the
additives, the concentration of the boron carbide particles, the
optional presence of titanium in the composite material have been
described above and do apply herein.
[0008] According to a third aspect, the present disclosure provides
a method of improving the casting and/or shaping properties of a
molten composite material comprising aluminum, products of a
peritectic reaction between an additive and boron, and dispersed
boron carbide particles. Broadly, the method comprises combining
(i) a molten aluminum alloy comprising the additive capable of
undergoing a peritectic reaction with boron with (ii) a source of
boron carbide particles so as to provide a molten composite
material. The additive is selected from the group consisting of
chromium, molybdenum, vanadium, niobium, zirconium, strontium,
scandium, and any combination thereof. A sample of the composite
material has a fluidity, after having been heated, prior to
casting, to a temperature of about 700.degree. C. for about 120
minutes, corresponding to a cast length of at least 100 mm when
measured using a mold having a groove for containing the sample,
the groove having a width of about 33 mm, a height of between about
6.5 mm and about 4.0 mm and being downwardly inclined, from an
horizontal axis, of about 10.degree.. Embodiments with respect to
the cast length, the type of additives that can be used, the
concentration of the additives, the concentration of the boron
carbide particles, the optional presence of titanium in the
composite material have been described above and do apply
herein.
[0009] According to a fourth aspect, the present disclosure
provides a method of facilitating shaping of a molten composite
material of a molten composite material comprising aluminum,
products of a peritectic reaction between an additive and boron,
and dispersed boron carbide particles. Broadly, the method
comprises combining (i) a molten aluminum alloy comprising the
additive capable of undergoing a peritectic reaction with boron
with (ii) a source of boron carbide particles so as to provide a
molten composite material. The additive is selected from the group
consisting of chromium, molybdenum, vanadium, niobium, zirconium,
strontium, scandium, and any combination thereof. A sample of the
composite material having a fluidity, after having been heated,
prior to casting, to a temperature of about 700.degree. C. for
about 120 minutes, corresponding to a cast length of at least 100
mm when measured using a mold having a groove for containing the
sample, the groove having a width of about 33 mm, a height of
between about 6.5 mm and about 4.0 mm and being downwardly
inclined, from an horizontal axis, of about 10.degree.. Embodiments
with respect to the cast length, the type of additives that can be
used, the concentration of the additives, the concentration of the
boron carbide particles, the optional presence of titanium in the
composite material have been described above and do apply
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Having thus generally described the nature of the invention,
reference will now be made to the accompanying drawing in
which:
[0011] FIG. 1 shows the loss of fluidity of molten aluminum mixture
containing different lots of B.sub.4C powder. Results are shown as
fluidity (as measured as a cast length (in mm) of sample measured
using a K-mold) in function of holding time in the furnace (in min)
for various lots (A to E) of B.sub.4C powders (30% v/v) added to
molten aluminum at an initial temperature of 735.degree. C. Results
are shown for lot A containing 3.5% w/w Ti (.diamond-solid.), lot B
containing 3.5% w/w Ti (.box-solid.), lot C containing 3.5% w/w Ti
(.tangle-solidup.), lot D containing 3.0% w/w Ti ( ) and lot E
containing 2.0% Ti w/w (.largecircle.).
[0012] FIG. 2 illustrates an embodiment of a K-mold that can be
used for determining the cast length of the composite material. (A)
Schematic side elevation view of the lower inclined portion 10 of
the K-mold. (B) Schematic top elevation view of the
groove-containing portion 40 of the K-mold. (C) Schematic
cross-sectional view of the groove-containing portion 50 of the
K-mold.
DETAILED DESCRIPTION
[0013] The fabrication of boron metal matrix composites (MMC) with
high B.sub.4C content (e.g., for example at least 30% v/v) usually
requires B.sub.4C powder of exceptional quality. High quality
B.sub.4C powders have a good granulometric distribution and have a
minimum of fine powder-like particles. Generally, only such
B.sub.4C powder may be incorporated in high amounts into the metal
matrix. When the B.sub.4C powder is not of such good quality,
significant losses of fluidity during the holding time of the
molten metal, i.e. prior to casting, can be observed. In addition,
increasing the holding temperature of the molten metal does not
compensate for this loss of fluidity because this can favor the
reaction between the aluminum and the B.sub.4C powder thereby
further increasing the viscosity (loss of fluidity). In such
circumstances, the molten metal behaves as a thixotropic
material.
[0014] FIG. 1 shows the loss of fluidity during the holding time of
a molten composite, prior to casting. In industrial settings, a
certain fluidity is required for a certain amount of time for
allowing the shaping/casting of the Al--B.sub.4C mixture. The
curves shown in FIG. 1 show that the B.sub.4C powder used in the
preparation of the composite material increased the viscosity of
the material and failed to meet the fluidity required in industrial
settings for subsequent steps (shaping for example), even in the
presence of titanium.
[0015] In accordance with the present disclosure, there is provided
a cast Al--B.sub.4C composite material comprising aluminum,
products of a peritectic reaction and dispersed boron carbide
particles. The composite material is obtained by first combining
aluminum (or an aluminum alloy) with an additive (or a combination
of additives) capable of undergoing a peritectic reaction with the
boron of the boron carbide particles and ultimately provide
products of such peritectic reaction in the aluminum or the
aluminum alloy. Once the additive has been included in the aluminum
(or in the aluminum alloy), boron carbide particles are combined
with the aluminum (or the aluminum alloy), thereby causing the
peritectic reaction between the additive and the boron. As shown
herein, the use of the additive in the aluminum/aluminum alloy
(and, ultimately the presence of peritectic reaction products in
the composite material) has been shown useful for maintaining the
fluidity of the molten composite and as such imparts good
castability to a molten composite material. In some embodiments, it
is believed that the use of the additive inhibits or slows down the
formation of reaction products occurring during holding of the
molten composite (such as, for example, the reaction products
occurring between Al and B.sub.4C or between Al and B.sub.4C). In
other embodiments, it has been shown that the additives can be used
to limit the use of titanium in such composite materials without
altering substantially their fluidity. This maintenance in fluidity
of the molten composite material can allow for the lengthening of
the holding time of the molten mixture in the furnace, for using a
lower grade of B.sub.4C source as well as for facilitating shaping
and/or casting of the resulting metal matrix composite(s).
[0016] Prior to being casted, the composite material is in a molten
state and has a fluidity. In the disclosure described herein, the
molten composite material has, prior to casting, a fluidity which
permits casting in an industrial setting. In other to determine the
fluidity of a molten composite material, it is possible to use a
K-mold. Such mold, currently used and known in the art, measures
the length of a sample of the composite material before it
solidifies. The length measured with a K-mold is referred to as a
cast length.
[0017] An embodiment of a K-mold that can be used to determine the
fluidity of a sample of a molten composite material is shown in
FIG. 2. A K-mold is usually composed of two engageable portions, a
lower inclined portion 010 (as shown in FIG. 2A) and a
groove-containing portion 040 (as shown in FIGS. 2B and 2C). When
the sample is inserted in the mold, the inclined portion 010 is
engaged with the groove-containing portion 040. The sample is
allowed to cast along the inclined portion 010 and within the
groove 040 until it sets. The length covered by the sample, usually
measured in millimeters, is a measure of fluidity and refers to a
cast length.
[0018] As shown on FIG. 2A, the lower inclined portion is usually
monolithic and comprises a plane 015 having a smooth surface and
being downwardly inclined from an horizontal axis 020 by an angle
030 of about 10.degree.. The plane 015 is for contacting directly
the external sides 055 of the groove-containing portion 040 (shown
on FIGS. 2B and 2C) and for providing an angle to the groove of
about 10.degree..
[0019] The groove-containing portion 040 is a partially hollowed
structure defining an enclosable groove 050 for containing the
sample of the molten composite (FIG. 2B). As shown on FIG. 2B, the
groove-containing portion has external sides 055 for contacting
directly the plane 015 of the inclined portion 010. In the
embodiment shown in FIG. 2B, the groove 050 contains two different
sections: sections 060 and sections 070 (defining a protuberance).
In some embodiments, the K-mold comprises at least four sections
070 (e.g., four protuberances) located at a distance of 93 mm, 130
mm, 168 mm and 205 mm from the start of the mold (e.g., the
position at which the sample starts contacting the inclined plane
015).
[0020] FIG. 2C shows an enlarged of the enclosable groove 050. The
sections 060 have a similar height 061 of about 6.5 mm. The height
061 is constant between the length defined by the external walls
055. The height 061 is measured with respect to the axis 080
defined by the inclined plane 015 (when the groove-containing
portion 040 is engaged with the inclined portion 010). The sections
070 also have a similar height 071 of about 4 mm. The height 071 is
constant between the length defined by the external walls 055. The
height is measured with respect to the axis 080 defined by the
inclined plane 015 (when the groove-containing portion 040 is
engaged on the inclined portion 010).
[0021] In the context of the present disclosure, the cast composite
material has a fluidity, preferably prior to casting, corresponding
to a cast sample length of at least 100 mm, at least 120 mm, at
least 140 mm, at least 160 mm, at least 180 mm, at least 190 mm or
at least 200 mm. The sample used for determining the fluidity of
the composite material can be heated at a temperature of about
700.degree. C. and for about 120 min to reproduce the industrial
casting settings.
[0022] Thus, the present disclosure also provides a method of
manufacturing a cast composite material. In order to do so, a
molten aluminum alloy (also referred to as an aluminum-base matrix
alloy) comprising the additive (or a combination of additives)
capable of undergoing the peritectic reaction is combined with a
source of boron carbide to provide a molten composite. As shown in
the present disclosure, the fluidity of the molten composite can be
maintained at acceptable industrial levels for a longer period of
time when compared to a similar molten composite which lacks the
additive.
[0023] In the methods described herein, the aluminum or the
aluminum alloy used is provided in a molten form. As such, the
aluminum or the aluminum alloy is preferably heated to its melting
temperature prior to its combination with the B.sub.4C particles.
In an embodiment, the aluminum alloy comprises (in embodiments
consists essentially of and, in further embodiments, consists of)
an additive capable of undergoing the peritectic reaction, the
remainder being essentially aluminum or an aluminum alloy.
Unavoidable or inevitable impurities (at the most 0.05% w/w for
each impurity) can also be present in the alloy (for a total of
impurities of at most 0.15% w/w). Exemplary aluminum alloys
include, but are not limited to, alloys from the 11xx series and
from the 6xxx series. In some embodiments, Ti can be included in
the aluminum or the aluminum alloy. In an alternative embodiment,
if Ti is present in the aluminum or the molten aluminum alloy, it
is considered to be a trace element (e.g. its concentration does
not exceed the concentration of inevitable impurities).
[0024] In an embodiment, the composite material comprises between
4% and 40% (v/v) of B.sub.4C particles and the molarity of the
additive (or the combination of additives) in the composite
material is between 0.01044 and 0.08351. In some embodiments, when
Ti is present in the composite material, the combined molarity of
the additive (or the combination of additives) and Ti is between
0.01044 and 0.08351. In some embodiments, the concentration of the
additive in the composite material can be between 0.47% to 15.32%,
0.47% to 8.00%, 0.90% to 8.00%, 0.95% to 8.00%, 1.00% to 8.00% or
1.10% to 8.00% with respect to the total weight of the composite
material (comprising the B.sub.4C particles). In some embodiments,
the combined concentration of the additive and Ti in the composite
can be between 0.47% to 15.32%, 0.47% to 8.00%, 0.90% to 8.00%,
0.95% to 8.00%, 1.00% to 8.00% or 1.10% to 8.00% with respect to
the total weight of the composite material (comprising the B.sub.4C
particles).
[0025] In another embodiment, the composite material comprises
between 4.5% and 18.9% (v/v) of B.sub.4C particles and the molarity
of the additive (or the combination of additives) in the composite
material is between 0.00835 and 0.04175. In some embodiments, when
Ti is present in the composite material, the combined molarity of
the additive (or the combination of additives) and Ti is between
0.00835 and 0.04175. In some embodiments, the concentration of the
additive in the composite material can be between 0.38% to 7.68%,
0.38% to 4.00%, 0.90% to 4.00%, 0.95% to 4.00%, 1.00% to 4.00% or
1.10% to 4.00% with respect to the total weight of the composite
material (comprising the B.sub.4C particles). In some embodiments,
the combined concentration of the additive and Ti in the composite
can be between 0.38% to 7.68%, 0.38% to 4.00%, 0.90% to 4.00%,
0.90% to 4.00%, 1.00% to 4.00% or 1.10% to 4.00% with respect to
the total weight of the composite material (comprising the B.sub.4C
particles).
[0026] In a further embodiment, the composite material comprises
between 19% and 28% (v/v) of B.sub.4C particles and the molarity of
the additive (or the combination of additives) in the composite
material is between 0.03758 and 0.06263. In some embodiments, when
Ti is present in the composite material, the combined molarity of
the additive (or the combination of additives) and Ti is between
0.03758 and 0.06263. In some embodiments, the concentration of the
additive in the composite material can be between 1.69% to 11.51%
or 1.69% to 6.00% with respect to the total weight of the composite
material (comprising the B.sub.4C particles). In some embodiments,
the combined concentration of the additive and Ti in the composite
can be between 1.69% to 11.51% or 1.69% to 6.00% with respect to
the total weight of the composite material (comprising the B.sub.4C
particles).
[0027] In a further embodiment, the composite material comprises
between 25% and 28% (v/v) or between 28% and 33% (v/v) of B.sub.4C
particles and the molarity of the additive (or the combination of
additives) in the composite material is between 0.02088 and
0.04175. In some embodiments, when Ti is present in the composite
material, the combined molarity of the additive (or the combination
of additives) and Ti is between 0.02088 and 0.04175. In some
embodiments, the concentration of the additive in the composite
material can be between 0.94% to 7.68%, 0.94% to 4.00%, 0.95% to
4.00%, 1.00% to 4.00% or 1.10% to 4.00% with respect to the total
weight of the composite material (comprising the B.sub.4C
particles). In some embodiments, the combined concentration of the
additive and Ti in the composite can be between 0.94% to 7.68%,
0.94% to 4.00%, 0.95% to 4.00%, 1.00% to 4.00% or 1.10% to 4.00%
with respect to the total weight of the composite material
(comprising the B.sub.4C particles).
[0028] The concentration of the additive, provided at a weight
percent concentration or at a certain molarity, whether with
reference to the aluminum alloy or the total composite material, is
to be understood to include all forms of the additives (including
soluble additive, excess additive that comes out of solution as
intermetallics or refractory compounds, as well additive included
in a B-containing peritectic reaction product). The additive
capable of causing the formation of a peritectic reaction's product
can be added in any convenient form, including master alloy (for
example an Al-10% additive master alloy) or as additive-containing
granules or powders. In some embodiments, it can be contemplated to
add the additive as a form of a powder to wrought alloys (including
AA1xxx, AA2xxx, AA3xxx, AA4xxx or AA6xxx) or casting alloys
(including AA2xx or AA3xx).
[0029] Similarly, the titanium concentration or molarity given in
the foregoing description, whether with reference to the aluminum
alloy or the total composite material, represent titanium in all
forms (including soluble Ti, excess Ti coming out of solution as
intermetallics or refractory compounds, as well Ti--B compounds).
The titanium can be added in any convenient form, including master
alloy (for example an Al-10% Ti master alloy) or as titanium
containing granules or powders. In some embodiments, it may be
advisable to use an AA1xxx alloy containing titanium in the
aluminum alloy. In alternative or complementary embodiments, it can
be contemplated to add a titanium as an aluminum alloy such as, for
example, wrought alloys (including AA2xxx, AA3xxx, AA4xxx or
AA6xxx), or casting alloys (including AA2xx or AA3xx).
[0030] In some embodiments, the additive capable of causing the
formation of a peritectic reaction's product can be zirconium and
the aluminum alloy can comprises or contains zirconium. In some
embodiments, when Zr is used as an additive, the composite material
does not comprise Ti (if present, Ti is considered to be a trace
element). In other embodiments, when Zr is used as an additive, Ti
can be present in the composite material. In a composite material
comprising between 4% and 40% (v/v) of B.sub.4C particles,
zirconium can be provided at a concentration of between about 0.95
to about 7.61, between about 1.00 to about 7.61 or between about
1.10 to about 7.61 weight percentage with respect to the composite
material's (comprising the B.sub.4C particles) total weight. In
such embodiment, when Ti is present, it can be provided at a
concentration of between about 0.50 to about 4.00, between about
0.90 to about 4.00, between about 0.95 to about 4.00, between about
1.00 to about 4.00 or between about 1.10 to about 4.00 weight
percentage with respect to the composite material's (comprising the
B.sub.4C particles) total weight. In a composite material
comprising between 4.5% and 18.9% (v/v) of B.sub.4C particles,
zirconium can be provided at a concentration of between about 0.76
to about 3.81, between about 0.90 to about 3.81, between about 0.95
to about 3.81, between about 1.00 to about 3.81 or between about
1.10 to about 3.81 weight percentage with respect to the composite
material's (comprising the B.sub.4C particles) total weight. In
such embodiment, when Ti is present, it can be provided at a
concentration of between about 0.40 to about 2.00, between about
0.90 to about 2.00, between about 0.95 to about 2.00, between about
1.00 to about 2.00 or between about 1.10 to about 2.00 weight
percentage with respect to the composite material's (comprising the
B.sub.4C particles) total weigh. In a composite material comprising
between 19% and 28% (v/v) of B.sub.4C particles, zirconium can be
provided at a concentration of between about 3.43 to about 5.71
weight percentage with respect to the composite material's
(comprising the B.sub.4C particles) total weight. In such
embodiment, when Ti is present, it can be provided at a
concentration of between about 1.80 to about 3.00 weight percentage
with respect of the composite material's (comprising the B.sub.4C
particles) total weight. In a composite material comprising between
25% and 28% (v/v) or 28% and 33% of B.sub.4C particles, zirconium
can be provided at a concentration of between about 1.90 to about
3.81 weight percentage with respect to the composite material's
(comprising the B.sub.4C particles) total weight. In such
embodiment, when Ti is present, it can be provided at whereas
titanium can be provided at a concentration between about 1.00 to
about 2.00 or between about 1.10 to about 2.00 weight percentage
with respect of the composite material's (comprising the B.sub.4C
particles) total weight. It will be understood that the zirconium
concentrations given in the foregoing description, whether with
reference to the aluminum alloy or the total composite material,
represent zirconium in all forms (including soluble Zr, excess Zr
coming out of solution as intermetallics or refractory compounds,
as well Zr--B compounds). The zirconium can be added in any
convenient form, including master alloy (for example an Al-10% Zr
master alloy) or as zirconium containing granules or powders. In
some embodiments, it may be advisable to use an AA1xxx alloy
containing zirconium in the aluminum alloy. In alternative or
complementary embodiments, it can be contemplated to add a
zirconium as an aluminum alloy such as, for example, wrought alloys
(including AA2xxx, AA3xxx, AA4xxx or AA6xxx), or casting alloys
(including AA2xx or AA3xx).
[0031] In some embodiments, the additive capable of causing the
formation of a peritectic reaction's product can be strontium and
the aluminum alloy can comprises or contains strontium in
combination with titanium. In a composite material comprising
between 4% and 40% (v/v) of B.sub.4C particles, strontium can be
provided at a concentration of between about 0.91 to about 7.32,
between about 0.95 to about 7.32, between about 1.00 to about 7.32
or between about 1.10 to about 7.32 weight percentage with respect
to the composite material's (comprising the B.sub.4C particles)
total weight, whereas titanium can be provided at a concentration
of between about 0.50 to about 4.00, between about 0.90 to about
4.00, between about 0.95 to about 4.00, between about 1.00 to about
4.00 or between about 1.10 to about 4.00 weight percentage with
respect to the composite material's (comprising the B.sub.4C
particles) total weight. In a composite material comprising between
4.5% and 18.9% (v/v) of B.sub.4C particles, strontium can be
provided at a concentration of between about 0.73 to about 3.66,
between about 0.90 to about 3.66, between about 0.95 to about 3.66,
between about 1.00 to about 3.66 or between about 1.10 to about
3.66 weight percentage with respect to the composite material's
(comprising the B.sub.4C particles) total weight, whereas titanium
can be provided at a concentration of between about 0.40 to about
2.00, between about 0.90 to about 2.00, between about 0.95 to about
2.00, between about 1.00 to about 2.00 or between about 1.10 to
about 2.00 weight percentage with respect to the composite
material's (comprising the B.sub.4C particles) total weight. In a
composite material comprising between 19% and 28% (v/v) of B.sub.4C
particles, strontium can be provided at a concentration of between
about 3.29 to about 5.49 weight percentage with respect to the
composite material (comprising the B.sub.4C particles) total
weight, whereas titanium can be provided at a concentration between
about 1.80 to about 3.00 weight percentage with respect of the
composite material's (comprising the B.sub.4C particles) total
weight. In a composite material comprising between 25% and 28%
(v/v) or between 28% and 33% of B.sub.4C particles, strontium can
be provided at a concentration of between about 1.83 to about 3.66
weight percentage with respect to the composite material
(comprising the B.sub.4C particles) total weight, whereas titanium
can be provided at a concentration between about 1.00 to about 2.00
or between about 1.10 to about 2.00 weight percentage with respect
of the composite material's (comprising the B.sub.4C particles)
total weight. It will be understood that the strontium
concentrations given in the foregoing description, whether with
reference to the aluminum alloy or the total composite material,
represent strontium in all forms (including soluble Sr, excess Sr
coming out of solution as intermetallics or refractory compounds,
as well Sr--B compounds). The strontium can be added in any
convenient form, including master alloy (for example an Al-10% Sr
master alloy) or as strontium containing granules or powders. In
some embodiments, it may be advisable to use an AA1xxx alloy
containing strontium in the aluminum alloy. In alternative or
complementary embodiments, it can be contemplated to add a
strontium as an aluminum alloy such as, for example, wrought alloys
(including AA2xxx, AA3xxx, AA4xxx or AA6xxx), or casting alloys
(including AA2xx or AA3xx).
[0032] In some embodiments, the additive capable of causing the
formation of a peritectic reaction's product can be scandium and
the aluminum alloy can comprises or contains scandium in
combination with titanium. In a composite material comprising
between 4% and 40% (v/v) of B.sub.4C particles, scandium can be
provided at a concentration of between about 0.47 to about 3.75,
between about 0.90 to about 3.75, between about 1.00 to about 3.75
or between about 1.10 to about 3.75 weight percentage with respect
to the composite material's (comprising the B.sub.4C particles)
total weight, whereas titanium can be provided at a concentration
between about 0.50 to about 4.00, between about 0.90 to about 4.00,
between about 0.95 to about 4.00, between about 1.00 to about 4.00
or between about 1.10 to about 4.00 with respect to the composite
material's (comprising the B.sub.4C particles) total weight. In a
composite material comprising between 4.5% and 18.9% (v/v) of
B.sub.4C particles, scandium can be provided at a concentration of
between about 0.38 to about 1.88, between about 0.90 to about 1.88,
between about 1.00 to about 1.88 or between about 1.10 to about
1.88 weight percentage with respect to the composite material's
(comprising the B.sub.4C particles) total weight, whereas titanium
can be provided at a concentration of between about 0.40 to about
2.00, between about 0.90 to about 2.00, between about 0.95 to about
2.00, between about 1.00 to about 2.00 or between about 1.10 to
about 2.00 weight percentage with respect to the composite
material's (comprising the B.sub.4C particles) total weight. In a
composite material comprising between 19% and 28% (v/v) of B.sub.4C
particles, scandium can be provided at a concentration of between
about 1.69 to about 2.82 weight percentage with respect to the
composite material (comprising the B.sub.4C particles) total
weight, whereas titanium can be provided at a concentration between
about 1.80 to about 3.00 weight percentage with respect of the
composite material's (comprising the B.sub.4C particles) total
weight. In a composite material comprising between 25% and 28%
(v/v) or 28% and 33% of B.sub.4C particles, scandium can be
provided at a concentration of between about 0.94 to about 1.88,
between about 1.00 to about 1.88 or between about 1.10 to about
3.88 weight percentage with respect to the composite material
(comprising the B.sub.4C particles) total weight, whereas titanium
can be provided at a concentration between about 1.00 to about 2.00
or between about 1.10 to about 2.00 weight percentage with respect
of the composite material's (comprising the B.sub.4C particles)
total weight. It will be understood that the scandium
concentrations given in the foregoing description, whether with
reference to the aluminum alloy or the total composite material,
represent scandium in all forms (including soluble Sc, excess Sc
coming out of solution as intermetallics or refractory compounds,
as well Sc--B compounds). The scandium can be added in any
convenient form, including master alloy (for example an Al-10% Sc
master alloy) or as scandium containing granules or powders. In
some embodiments, it may be advisable to use an AA1xxx alloy
containing scandium in the aluminum alloy. In alternative or
complementary embodiments, it can be contemplated to add a scandium
as an aluminum alloy such as, for example, wrought alloys
(including AA2xxx, AA3xxx, AA4xxx or AA6xxx), or casting alloys
(including AA2xx or AA3xx).
[0033] Without wishing to be bound to thery, the additive can be
used in the methods described herein to form reaction products with
B having an enthalpy of formation which is more negative than the
one associated to AlB.sub.2. For example, when vanadium is used in
an aluminum alloy comprising titanium, it is believed, without
being bound by theory, that this addition would force another
reaction with titanium. The reaction product could be a compound
such as (Ti,V)B.sub.2. The formation of such reaction products
would stop or reduce the reaction between the aluminum melt
containing titanium and the B.sub.4C particles. The present
disclosure thus provides for the addition of additive capable of
causing the formation of a peritectic reaction's products as
inhibitors of the reaction between the aluminum melt and the
B.sub.4C particles to maintain the fluidity of the composite until
the composite is shaped, preferably cast.
[0034] Theoretical calculations of the enthalpy of formation of
reaction products expected to form after the addition of various
elements were carried out using the software FactStage.TM. and are
shown in Table 1.
TABLE-US-00001 TABLE 1 Theoretical values of enthalpy of formation
of various reaction products. Peritectic Enthalpy of Element
reaction product formation added with B.sub.4C (kJ/mol) AlB.sub.2
-67 Cr CrB.sub.2 -94 Mo MoB.sub.2 -150 V VB.sub.2 -202 Ta TaB.sub.2
-222 Nb NbB.sub.2 -251 Ti TiB.sub.2 -280 Hf HfB.sub.2 -320 Zr
ZrB.sub.2 -326 W W.sub.2B.sub.9 -375
[0035] In an embodiment, the additive includes, but is not limited
to chromium (Cr), molybdenum (Mo), vanadium (V), niobium (Nb),
hafnium (Hf), zirconium (Zr), strontium (Sr), scandium (Sc),
tantalum (Ta), tungsten (W) as well as any combination thereof. In
another embodiment, the additive includes, but is not limited to
(Mo), vanadium (V), niobium (Nb), hafnium (Hf), zirconium (Zr),
strontium (Sr), scandium (Sc) as well as any combination thereof.
In still another embodiment, the additive includes, but is not
limited to zirconium (Zr), strontium (Sr), scandium (Sc) as well as
any combination thereof. In yet a further embodiment, the additive
comprises or consists of Cr. In yet another embodiment, the
additive comprises or consists of Mo. In still a further
embodiment, the additive comprises or consists of V. In yet another
embodiment, the additive comprises or consists of Nb. In another
embodiment, the additive comprises or consists of Ta. In yet
another embodiment, the additive comprises or consists of W. In
still a further embodiment, the additive comprises or consists of
Hf. In another embodiment, the additive comprises or consists of
Zr. In yet a further embodiment, the additive comprises or consists
of Sr. In still a further embodiment, the additive comprises or
consists of Sc. In one embodiment, the additive comprises or
consists of a combination of Zr and Sc. In another embodiment, the
additive comprises or consists of a combination of Zr and Sr. In
yet another embodiment, the additive comprises or consists of a
combination of Sr and Sc. In yet another embodiment, the additive
comprises or consists of a combination of Zr, Sr and Sc.
[0036] To provide the molten aluminum alloy, the additive(s), an
optionally titanium, is (are) added to molten aluminum or to a
molten aluminum or a molten aluminum alloy. In some embodiments, it
is contemplated to mix/stir the elements of the molten aluminum
alloy to obtain a substantially homogenous molten aluminum alloy.
In alternative or complementary embodiments, it is contemplated to
apply heat to the molten aluminum alloy to obtain a substantially
homogenous molten aluminum alloy.
[0037] In some embodiments and as indicated above, an aluminum
alloy containing titanium can used. In such embodiment, it is not
necessary to add the titanium and the additive (or a combination of
additives) in a specific order to the aluminum or aluminum alloy.
In an embodiment, the titanium is first added to the molten
aluminum/alloy and then the additive(s) is (are) added. In an
alternative embodiment, the additive(s) is (are) first added to the
molten aluminum/alloy and then the titanium is added. In still
another embodiment, the titanium and the additive(s) are added
simultaneously to the molten aluminum/alloy.
[0038] Once the molten aluminum alloy is provided, it is combined
with a source of boron carbide (a boron carbide powder (such as a
free-flowing powder) for example) to provide a molten composite
material comprising dispersed boron carbide particles. In the
molten composite material, it is understood that the aluminum alloy
(supplemented with the additive and optionally titanium) is in a
molten form and that the boron carbide particles are in a solid
form and are at least partially in association with the products of
the peritectic reaction. In some embodiments, it may be advisable
to add the source of boron carbide (e.g., the boron carbide powder)
to the molten aluminum alloy described herein. In some embodiments,
it is contemplated to mix/stir the elements of the molten composite
material to obtain a substantially homogenous molten composite
material having dispersed B.sub.4C-containing particles. The term
"dispersed" means that the B.sub.4C-containing particles are
distributed substantially uniformly throughout the material's
matrix. In some embodiments, it is contemplated that the
mixing/stirring be carried out in a manner that allows the
appropriate wetting of the B.sub.4C particles in the composite
material.
[0039] The molten composite material, due to the presence of the
products of the peritectic reaction products, has a fluidity
amenable for casting in an industrial setting. Fluidity can be
determined by various ways as known by those skilled in the art. In
one example, fluidity is measured with a viscometer. In another
example, fluidity is assessed by measuring the length of a cast
sample in a mold. In order to do so, it is possible to add a
quantity of B.sub.4C powder inside a reactor (capacity of about 35
kg for example) that contains liquid aluminum-based mixture at a
specific temperature (about 700.degree. C. for example) to which a
vacuum is applied. Samples of the mixture of molten metal and
B.sub.4C powder can be obtained at a fixed interval (for example,
every 20 minutes) using a step-mold and having a predetermined
length. In some embodiments, a K-mold step-mold can be used.
Fluidity is quantified as the distance achieved/covered by the
resulting mixture before its solidification. In some embodiments,
the K-mold can be a graphite-coated stainless steel step-mould
having a sample-receiving chamber or groove having a width of 33 mm
(and, in some embodiments, a maximal length of 315 mm) and being
inclined at an angle of about 10.degree.. For example, a molten
composite material achieving a distance of 100 mm after 120 minutes
of holding time in the K-mold described above is considered as
having a fair fluidity for direct chilled casting. In another
example, a molten composite material achieving a distance of 190 mm
after 120 minutes of holding time in the K-mold described above is
considered as having an excellent fluidity for direct chilled
casting. In an embodiment, the fluidity of the composite material
is 190 mm or more after 120 min. In yet further embodiments, the
fluidity of the composite material is of 200 mm or more after 120
minutes. In an embodiment, the fluidity of the molten composite is
at least 100 mm when measured at a temperature of about 700.degree.
C. after a holding time of 120 min. In embodiment, the fluidity of
the composite material is at least 105 mm, 110 mm, 115 mm, 120 mm,
125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm, 155 mm, 160 mm, 165
mm, 170 mm, 175 mm, 180 mm, 181 mm, 182 mm, 183 mm, 184 mm, 185 mm,
186 mm, 187 mm, 188 mm, 189 mm, 190 mm, 191 mm, 192 mm, 193 mm, 194
mm, 195 mm, 196 mm, 197 mm, 198 mm, 199 mm or 200 mm when measured
at a temperature of about 700.degree. C. after a holding time of
120 min. In some embodiments, it is expected that the fluidity of
the molten composite can vary upon holding time and holding
temperature. In other embodiments, the fluidity of the composite
material is not measured upon the mixture of the aluminum alloy and
the boron carbide particles, but after the peritectic reaction
products have been formed or even molten composite material is held
at a specific temperature (e.g., holding temperature) and for a
specific amount of time (e.g., holding time).
[0040] In embodiments, it is contemplated to hold a sample of the
composite material at a specific temperature for allowing the
material to remain in a molten state. In specific embodiments, the
composite material is held at a minimal holding temperature of
equal to or higher than about 660.degree. C., 670.degree. C.,
680.degree. C., 690.degree. C., 700.degree. C., 710.degree. C.,
720.degree. C., 730.degree. C., 740.degree. C., 750.degree. C.,
760.degree. C., 770.degree. C., 780.degree. C., 790.degree. C. or
800.degree. C. In specific embodiments, the composite material is
held at a maximal holding temperature equal to or lower than about
800.degree. C., 790.degree. C., 780.degree. C., 770.degree. C.,
760.degree. C., 750.degree. C., 740.degree. C., 730.degree. C.,
720.degree. C., 710.degree. C., 700.degree. C., 690.degree. C.,
680.degree. C., 670.degree. C. or 660.degree. C. In alternative
embodiments, the composite material is held at a temperature
ranging between the minimal holding temperature as defined above
and the maximal holding temperature as defined above.
[0041] In some embodiments, it is contemplated to hold a sample of
the composite material in a molten state for a specific holding
time. In specific embodiments, the composite material is held for a
minimal holding time of equal to or higher than about 20 min, 30
min, 40, min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110
min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, 180 min,
190 min or 200 min. In specific embodiments, the composite material
is held for a maximal holding time equal to or lower than about 200
min, 190 min, 180 min, 170 min, 160 min, 150 min, 140 min, 130 min,
120 min, 110 min, 100 min, 90 min, 80 min, 70 min, 60 min, 50 min,
40 min 30 min or 20 min. In alternative embodiments, the specific
holding time ranges between the minimal holding time as defined
above and the maximal holding time as defined above.
[0042] In some embodiments, it is contemplated to cast the
composite material during a specific casting time. In specific
embodiments, the composite material is casted for a minimal casting
time of equal to or higher than about 20 min, 30 min, 40, min, 50
min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130
min, 140 min, 150 min, 160 min, 170 min, 180 min, 190 min or 200
min. In specific embodiments, the composite material is casted for
a maximal casting time equal to or lower than about 200 min, 190
min, 180 min, 170 min, 160 min, 150 min, 140 min, 130 min, 120 min,
110 min, 100 min, 90 min, 80 min, 70 min, 60 min, 50 min, 40 min 30
min or 20 min. In alternative embodiments, the specific castung
time ranges between the minimal casting time as defined above and
the maximal casting time as defined above.
[0043] The molten composite is amenable any form of casting
(including DC casting of billets or slabs), casting of ingots for
future remelting and casting as well as casting into shapes using
any convenient form of shape casting. The cast composite can be
further processed and is well adapted for further operations such
as (a) remelting and casting a shape, (b) extrusion and (c) rolling
or (d) forging.
[0044] The method described herein may be used for the preparation
of any shaped aluminum boron carbide composite material,
particularly those containing high levels of B.sub.4C.
Advantageously, in some embodiments, in the presence of additive, a
lower-grade B.sub.4C powder can be used without altering
significantly the fluidity of the molten Al--Ti--B.sub.4C
composite.
[0045] The present invention will be more readily understood by
referring to the following examples which are given to illustrate
the invention rather than to limit its scope.
Example I
[0046] A primary aluminum metal alloy (AA1100) was melted in a
reactor at a temperature of 765.degree. C. Ti was added and then Sr
was added. Thereafter, B.sub.4C particles were injected into the
melt. The final concentrations of Ti and Sr were both 1.65 wt %.
The final concentration of the B.sub.4C particles was 28 vol %.
[0047] The final mixture was held at a temperature of about
700.degree. C. and two fluidity samples were obtained every 20
minutes. The fluidity measurements are shown in Table 2.
TABLE-US-00002 TABLE 2 Fluidity measurements resulting from Example
I. Time Fluidity measurement Fluidity measurement (min) #1 (mm) #2
(mm) 5 161 170 20 179 172 47 185 194 65 199 193 80 186 180 100 180
186 120 205 191
[0048] The results shown in Table 2 indicate that after a holding
time of 120 minutes, the fluidity is higher than 190 mm, thereby
allowing industrial casting of the composite material.
Example II
[0049] A primary aluminum metal alloy (AA1100) was melted in a
reactor at a temperature of 765.degree. C. Zr was added.
Thereafter, B.sub.4C particles were injected into the melt. The
final concentration of Zr was 3.8 wt %. The final concentration of
the B.sub.4C particles was 19 vol %.
[0050] The final mixture was held at a temperature of about
700.degree. C. and two fluidity samples were obtained at various
intervals. Resulting fluidity measurements are shown in Table
3.
TABLE-US-00003 TABLE 3 Fluidity measurements resulting from Example
II. Time Fluidity measurement (min) (mm) 10 260 20 280 40 295 60
306 80 291 100 200 120 210
[0051] The results shown in Table 3 indicate that after a holding
time of 120 minutes, the fluidity is higher 190 mm, thereby
allowing industrial casting of the composite material.
[0052] While the invention has been described in connection with
specific embodiments thereof, it will be understood that the scope
of the claims should not be limited by the preferred embodiments
set forth in the examples, but should be given the broadest
interpretation consistent with the description as a whole.
* * * * *