U.S. patent application number 14/348390 was filed with the patent office on 2014-09-25 for injection molding of amorphous alloy using an injection molding system.
The applicant listed for this patent is Michael Blaine Deming, John Kang, Sean Timothy O'Keeffe, Tran Quoc Pham, Theodore Andrew Waniuk. Invention is credited to Michael Blaine Deming, John Kang, Sean Timothy O'Keeffe, Tran Quoc Pham, Theodore Andrew Waniuk.
Application Number | 20140284019 14/348390 |
Document ID | / |
Family ID | 44936520 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140284019 |
Kind Code |
A1 |
Kang; John ; et al. |
September 25, 2014 |
INJECTION MOLDING OF AMORPHOUS ALLOY USING AN INJECTION MOLDING
SYSTEM
Abstract
Disclosed is an injection molding system including a plunger rod
and a melt zone that are provided in-line and on a horizontal axis.
The plunger rod is moved in a horizontal direction through the melt
zone to move molten material into a mold. The melt zone can have a
vessel that is configured to receive the plunger therethrough. A
transfer sleeve provided between the vessel and the mold and/or an
inlet into a mold can also be horizontally in line with the
plunger. The injection molding system can perform the melting and
molding processes under a vacuum.
Inventors: |
Kang; John; (Coto de Caza,
CA) ; O'Keeffe; Sean Timothy; (Tustin, CA) ;
Pham; Tran Quoc; (Anaheim, CA) ; Deming; Michael
Blaine; (Trabuco Canyon, CA) ; Waniuk; Theodore
Andrew; (Lake Forest, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kang; John
O'Keeffe; Sean Timothy
Pham; Tran Quoc
Deming; Michael Blaine
Waniuk; Theodore Andrew |
Coto de Caza
Tustin
Anaheim
Trabuco Canyon
Lake Forest |
CA
CA
CA
CA
CA |
US
US
US
US
US |
|
|
Family ID: |
44936520 |
Appl. No.: |
14/348390 |
Filed: |
September 30, 2011 |
PCT Filed: |
September 30, 2011 |
PCT NO: |
PCT/US11/54153 |
371 Date: |
May 23, 2014 |
Current U.S.
Class: |
164/512 ;
164/254; 164/312 |
Current CPC
Class: |
B22D 17/2038 20130101;
B22D 17/04 20130101; B22D 17/28 20130101; B22D 17/203 20130101;
B22D 17/14 20130101; B22D 17/2023 20130101 |
Class at
Publication: |
164/512 ;
164/312; 164/254 |
International
Class: |
B22D 17/14 20060101
B22D017/14; B22D 17/04 20060101 B22D017/04; B22D 17/28 20060101
B22D017/28 |
Claims
1. An injection molding system comprising: a melt zone configured
to melt meltable material received therein, and a plunger rod
configured to eject molten material from the melt zone and into a
mold, wherein the plunger rod and melt zone are provided in-line
and on a horizontal axis, such that the plunger rod is moved in a
horizontal direction through the melt zone to move the molten
material into the mold.
2. The system according to claim 1, wherein the melt zone comprises
a vessel having a body for receiving the meltable material, the
body configured to receive the plunger rod therethrough in a
horizontal direction to move the molten material.
3. The system according to claim 2, wherein the vessel comprises
one or more temperature regulating lines configured to flow a
liquid therein for regulating a temperature of the vessel.
4. The system according to claim 1, further comprising an induction
source positioned within the melt zone that is configured to melt
the meltable material.
5. The system according to claim 1, further comprising a transfer
sleeve between the melt zone and the mold configured to receive the
molten material therethrough.
6. The system according to claim 1, further comprising at least one
vacuum source that is configured to apply vacuum pressure to at
least the melt zone and mold.
7. The system according to claim 1, wherein the meltable material
is an alloy and wherein the mold is configured to form a molded
bulk amorphous alloy object.
8. An injection molding system comprising: a vessel comprising a
body for receiving meltable material and configured to melt the
material therein, a plunger rod configured to move molten material
from the vessel, through a transfer sleeve, and into a mold,
wherein the plunger rod, vessel, and transfer sleeve are provided
in-line and on a horizontal axis, such that the plunger rod is
moved in a horizontal direction through the vessel to move the
molten material into the transfer sleeve.
9. The system according to claim 8, wherein the vessel comprises
one or more temperature regulating lines configured to flow a
liquid therein for regulating a temperature of the vessel.
10. The system according to claim 8, further comprising an
induction source positioned adjacent the vessel that is configured
to melt the meltable material.
11. The system according to claim 8, further comprising at least
one vacuum source that is configured to apply vacuum pressure to at
least the vessel and the mold.
12. The system according to claim 8, wherein the meltable material
is an alloy and wherein the mold is configured to form a molded
bulk amorphous alloy object.
13. An injection molding system comprising: a temperature regulated
vessel comprising a body for receiving amorphous alloy material and
configured to melt the amorphous alloy material therein, the vessel
comprising one or more temperature regulating lines configured to
flow a liquid therein for regulating a temperature of the vessel;
an induction source positioned adjacent the temperature regulated
vessel that is configured to melt the amorphous alloy material; a
vacuum mold configured to receive molten amorphous alloy through an
inlet and configured to mold the molten amorphous alloy material
and under vacuum, and a plunger rod configured to eject the molten
amorphous alloy material from the body of the temperature regulated
vessel into the vacuum mold, wherein the temperature regulated
vessel, the inlet of the vacuum mold, and the plunger rod are
provided in-line and on a horizontal axis, such that the plunger
rod is moved in a horizontal direction through the body of the
temperature regulated vessel to eject molten material from the
temperature regulated vessel and into the vacuum mold via the
inlet.
14. The system according to claim 13, further comprising a transfer
sleeve between the temperature regulated vessel and the mold
configured to receive the molten material therethrough.
15. The system according to claim 13, further comprising at least
one vacuum source that is configured to apply vacuum pressure to at
least the temperature regulated vessel and mold.
16. The system according to claim 13, wherein the meltable material
is an alloy and wherein the mold is configured to form a molded
bulk amorphous alloy object.
Description
BACKGROUND
[0001] 1. Field
[0002] The present disclosure is generally related to a system and
method for melting and molding meltable materials, including
amorphous alloys.
[0003] 2. Description of Related Art
[0004] Various methods have been used to mold molten metal
materials. For example, die casting generally consists of injecting
molten metal under high pressure into a mold. There are two methods
typically used to inject molten metal into a mold: cold chamber and
hot chamber. In hot chamber methods, low melting point alloys are
used in a gooseneck feeding system, where the injection mechanism
is immersed in the molten metal bath. On the other hand, in cold
chamber methods, higher melting point alloys (e.g., aluminum alloy)
can be used and melted in a crucible before pouring into a cold
chamber. Some variations of a cold chamber include squeeze casting
and semi-solid molding.
[0005] Another method of forming and molding material is called
"Metal Injection Molding" or MIM, where granular particles of
certain metal are mixed with a binder, formed into shape, and then
the binder is stripped and sintered.
SUMMARY
[0006] One aspect of the disclosure provides an injection molding
system having: a melt zone configured to melt meltable material
received therein, and a plunger rod configured to eject molten
material from the melt zone and into a mold, wherein the plunger
rod and melt zone are provided in-line and on a horizontal axis,
such that the plunger rod is moved in a horizontal direction
through the melt zone to move the molten material into the
mold.
[0007] Another aspect of the disclosure provides an injection
molding system having: a vessel that has a body for receiving
meltable material and configured to melt the material therein, a
plunger rod configured to move molten material from the vessel,
through a transfer sleeve, and into a mold, wherein the plunger
rod, vessel, and transfer sleeve are provided in-line and on a
horizontal axis, such that the plunger rod is moved in a horizontal
direction through the vessel to move the molten material into the
transfer sleeve.
[0008] Yet another aspect of the disclosure provides an injection
molding system having: a temperature regulated vessel, an induction
source, a vacuum mold, and a plunger rod. The temperature regulated
vessel has a body for receiving amorphous alloy material and
configured to melt the amorphous alloy material therein, as well as
one or more temperature regulating lines configured to flow a
liquid therein for regulating a temperature of the vessel. The
induction source is positioned adjacent the temperature regulated
vessel and is configured to melt the amorphous alloy material. The
vacuum mold is configured to receive molten amorphous alloy through
an inlet and configured to mold the molten amorphous alloy material
and under vacuum. The plunger rod is configured to eject the molten
amorphous alloy material from the body of the temperature regulated
vessel into the vacuum mold. The temperature regulated vessel, the
inlet of the vacuum mold, and the plunger rod are provided in-line
and on a horizontal axis, such that the plunger rod is moved in a
horizontal direction through the body of the temperature regulated
vessel to eject molten material from the temperature regulated
vessel and into the vacuum mold via the inlet.
[0009] Other features and advantages of the present disclosure will
become apparent from the following detailed description, the
accompanying drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 illustrates a schematic diagram of an exemplary
injection molding system in accordance with an embodiment.
[0011] FIG. 2 illustrates a vessel and an induction source that can
be used in a melt zone of the system of FIG. 1 in accordance with
an embodiment.
[0012] FIGS. 3 and 4 illustrate a plan view and a cross sectional
view (taken along line 4-4 of FIG. 3), respectively, of a vacuum
mold that can be used with the system of FIG. 1 in accordance with
an embodiment.
[0013] FIG. 5 provides a temperature-viscosity diagram of an
exemplary bulk solidifying amorphous alloy.
[0014] FIG. 6 provides a schematic of a
time-temperature-transformation (TTT) diagram for an exemplary bulk
solidifying amorphous alloy.
DETAILED DESCRIPTION
[0015] The methods, techniques, and devices illustrated herein are
not intended to be limited to the illustrated embodiments. All
publications, patents, and patent applications cited in this
Specification are hereby incorporated by reference in their
entirety.
[0016] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e., to at least one) of the grammatical object
of the article. By way of example, "a polymer resin" means one
polymer resin or more than one polymer resin. Any ranges cited
herein are inclusive. The terms "substantially" and "about" used
throughout this Specification are used to describe and account for
small fluctuations. For example, they can refer to less than or
equal to .+-.5%, such as less than or equal to .+-.2%, such as less
than or equal to .+-.1%, such as less than or equal to .+-.0.5%,
such as less than or equal to .+-.0.2%, such as less than or equal
to .+-.0.1%, such as less than or equal to .+-.0.05%.
[0017] As disclosed herein, a system (or a device or a machine) is
configured to perform injection molding of material(s) (such as
amorphous alloys). The system is configured to process such
materials or alloys by melting at higher melting temperatures
before injecting the molten material into a mold for molding. As
further described below, parts of the system are positioned in-line
with each other. In accordance with some embodiments, parts of the
system (or access thereto) are aligned on a horizontal axis.
[0018] FIG. 1 illustrates a schematic diagram of such an exemplary
system. More specifically, FIG. 1 illustrates an injection molding
system 10. In accordance with an embodiment, injection molding
system 10 has a melt zone 12 configured to melt meltable material
received therein, and at least one plunger rod 14 configured to
eject molten material from melt zone 12 and into a mold 16. At
least plunger rod 14 and melt zone 12 are provided in-line and on a
horizontal axis (e.g., X axis), such that plunger rod 14 is moved
in a horizontal direction (e.g., along the X-axis) substantially
through melt zone 12 to move the molten material into mold 16. The
mold can be positioned adjacent to the melt zone.
[0019] The meltable material can be received in the melt zone in
any number of forms. For example, the meltable material may be
provided into melt zone 12 in the form of an ingot (solid state), a
semi-solid state, a slurry that is preheated, powder, pellets, etc.
In some embodiments, a loading port (such as the illustrated
example of an ingot loading port 18) may be provided as part of
injection molding system 10. Loading port 18 can be a separate
opening or area that is provided within the machine at any number
of places. In an embodiment, loading port 18 may be a pathway
through one or more parts of the machine. For example, the material
(e.g., ingot) may be inserted in a horizontal direction into vessel
20 by plunger 14, or may be inserted in a horizontal direction from
the mold side of the injection system 10 (e.g., through mold 16
and/or through a transfer sleeve 30 into vessel 20). In other
embodiments, the meltable material can be provided into melt zone
12 in other manners and/or using other devices (e.g., through an
opposite end of the injection system).
[0020] Melt zone 12 includes a melting mechanism configured to
receive meltable material and to hold the material as it is heated
to a molten state. The melting mechanism may be in the form of a
vessel 20, for example, that has a body 22 for receiving meltable
material and configured to melt the material therein. FIG. 2
illustrates an exemplary schematic view of a vessel 20 comprising a
body 22 (or base) for meltable material to be melted therein. A
vessel as used throughout this disclosure is a container made of a
material employed for heating substances to high temperatures. For
example, in an embodiment, the vessel may be a crucible, such as a
boat style crucible, or a skull crucible. In an embodiment, vessel
20 is a cold hearth melting device that is configured to be
utilized for meltable material(s) while under a vacuum (e.g.,
applied by a vacuum device 38 or pump). In one embodiment,
described further below, the vessel is a temperature regulated
vessel.
[0021] Vessel 20 may also have an inlet for inputting material
(e.g., feedstock) into a receiving or melting portion 24 of its
body. In the embodiment shown in FIG. 2, body 22 of vessel 20
comprises a substantially U-shaped structure. However, this
illustrated shape is not meant to be limiting. Vessel 20 can
comprise any number of shapes or configurations. Body 22 of the
vessel has a length and can extend in a longitudinal and horizontal
direction, such that molten material is removed horizontally
therefrom using plunger 14. For example, the body may comprise a
base with side walls extending vertically therefrom. The material
for heating or melting may be received in a melting portion 24 of
the vessel. Melting portion 24 is configured to receive meltable
material to be melted therein. For example, melting portion 24 has
a surface for receiving material. Vessel 20 may receive material
(e.g., in the form of an ingot) in its melting portion 24 using one
or more devices of an injection system for delivery (e.g., loading
port and plunger).
[0022] In an embodiment, body 22 and/or its melting portion 24 may
comprise substantially rounded and/or smooth surfaces. For example,
a surface of melting portion 24 may be formed in an arc shape.
However, the shape and/or surfaces of body 22 are not meant to be
limiting. Body 22 may be an integral structure, or formed from
separate parts that are joined or machined together. Body 22 may be
formed from any number of materials (e.g., copper, silver), include
one or more coatings, and/or configurations or designs. In an
embodiment, body 22 of vessel 20 is formed from a material that
does not give off or transfer contaminants to the meltable/molten
material. For example, one or more surfaces may have recesses or
grooves therein.
[0023] The body 22 of vessel 20 may be configured to receive the
plunger rod therethrough in a horizontal direction to move the
molten material. That is, in an embodiment, the melting mechanism
is on the same axis as the plunger rod, and the body can be
configured and/or sized to receive at least part of the plunger
rod. Thus, plunger rod 14 can be configured to move molten material
(after heating/melting) from the vessel by moving substantially
through vessel 20, and into mold 16. Referencing the illustrated
embodiment of system 10 in FIG. 1, for example, plunger rod 14
would move in a horizontal direction from the right towards the
left, through body 22 of vessel 20, moving and pushing the molten
material towards mold 16.
[0024] To heat melt zone 12 and melt the meltable material received
in vessel 20, injection system 10 also includes a heat source that
is used to heat and melt the meltable material At least melting
portion 24 of the vessel, if not substantially the entire body 22
itself, is configured to be heated such that the material received
therein is melted. Heating is accomplished using, for example, an
induction source 26 positioned within melt zone 12 that is
configured to melt the meltable material. In an embodiment,
induction source 26 is positioned adjacent body 22 of vessel 20.
For example, as shown in FIG. 2, induction source 26 may be in the
form of a coil positioned in a helical pattern substantially around
a length of body 22. Accordingly, vessel 20 is configured to
inductively melt a meltable material (e.g., an inserted ingot)
within melting portion 24 by supplying power to induction
source/coil 26, using a power supply or source 28. Induction coil
26 is configured to heat up and melt any material that is contained
by vessel 20 without melting and wetting vessel 20. Induction coil
26 emits radiofrequency (RF) waves towards vessel 20. As shown,
body 22 and coil 26 surrounding vessel 20 may be configured to be
positioned in a horizontal direction along a horizontal axis (e.g.,
X axis).
[0025] In one embodiment, the vessel 20 is a temperature regulated
vessel. Such a vessel may include one or more temperature
regulating lines, such as cooling line(s) 25 shown in FIG. 2,
configured to flow a liquid (e.g., water, or other fluid) therein
for regulating a temperature of the vessel (e.g., to force cool the
vessel). Such a forced-cool crucible can also be provided on the
same axis as the plunger rod. The cooling line(s) 25 assist in
preventing excessive heating and melting of the body 12 of the
vessel 20 itself. The cooling line(s) 25 assist in keeping the
vessel at a temperature which resists wetting of the melting/molten
material (e.g., molten amorphous alloy). Cooling line(s) may be
connected to a cooling system configured to induce flow of a liquid
in the vessel. The cooling line(s) 25 may include one or more
inlets and outlets for the liquid or fluid to flow therethrough.
The inlets and outlets of the cooling lines may be configured in
any number of ways and are not meant to be limited. For example,
cooling line(s) 25 may be positioned relative to melting portion 24
such that material thereon is melted and the vessel temperature is
regulated (i.e., heat is absorbed, and the vessel is cooled). For
example, in the illustrative embodiment shown in FIG. 2, for a boat
or crucible type vessel that comprises a length and extends in a
longitudinal direction, its melting portion 24 may also extend in a
longitudinal direction. In accordance with an embodiment, cooling
line(s) 25 may be positioned in a longitudinal direction relative
to melting portion 24. For example, the cooling line(s) 25 may be
positioned in a base of the body 22 (e.g., underneath its material
receiving surface). In another embodiment, the cooling line(s) 25
may be positioned in a horizontal or lateral direction. The number,
positioning and/or direction of the cooling line(s) 25 should not
be limited. The cooling liquid or fluid may be configured to flow
through the cooling line(s) 25 during melting of the meltable
material, when induction source 26 is powered.
[0026] After the material is melted in the vessel 20, plunger 14
may be used to force the molten material from the vessel 20 and
into a mold 16 for molding into an object, a part or a piece. In
instances wherein the meltable material is an alloy, such as an
amorphous alloy, the mold 16 is configured to form a molded bulk
amorphous alloy object, part, or piece. Mold 16 has an inlet for
receiving molten material therethrough. An output of the vessel 20
and an inlet of the mold 16 can be provided in-line and on a
horizontal axis such that plunger rod 14 is moved in a horizontal
direction through body 22 of the vessel to eject molten material
and into the mold 16 via its inlet.
[0027] As previously noted, systems such as injection molding
system 10 that are used to mold materials such as metals or alloys
may implement a vacuum when forcing molten material into a mold or
die cavity. Injection molding system 10 can further includes at
least one vacuum source 38 or pump that is configured to apply
vacuum pressure to at least melt zone 12 and mold 16. The vacuum
pressure may be applied to at least the parts of the injection
molding system 10 used to melt, move or transfer, and mold the
material therein. For example, the vessel 20, transfer sleeve 30,
and plunger rod 14 may all be under vacuum pressure and/or enclosed
in a vacuum chamber.
[0028] In an embodiment, mold 16 is a vacuum mold that is an
enclosed structure configured to regulate vacuum pressure (e.g.,
via a valve 33) therein when molding materials. FIGS. 3 and 4
illustrate one embodiment of a vacuum mold 16 that can be used with
injection molding system 10. For example, in an embodiment, vacuum
mold 16 comprises a first plate 32 (also referred to as an "A" mold
or "A" plate), a second plate 34 (also referred to as a "B" mold or
"B" plate), and a vacuum ejector box 36 positioned adjacently
(respectively) with respect to each other. First plate 32 and
second plate 34 each have a mold cavity 42 and 44, respectively,
associated therewith for molding melted material therebetween. As
shown in the representative cross-sectional view of FIG. 3, the
cavities 42 and 44 are configured to mold molten material received
therebetween via an injection sleeve 30 or transfer sleeve. Mold
cavities 42 and 44 may include a part cavity for forming and
molding a part therein.
[0029] Generally, first plate 32 may be connected to transfer
sleeve 30. In accordance with an embodiment, plunger rod 14 is
configured to move molten material from vessel 20, through a
transfer sleeve 20, and into mold 16. Transfer sleeve 30 (sometimes
referred to as a cold sleeve or injection sleeve in the art) may be
provided between melt zone 12 and mold 16. Transfer sleeve 30 has
an opening that is configured to receive and allow transfer of the
molten material therethrough and into mold 16 (using plunger 14).
Its opening may be provided in a horizontal direction along the
horizontal axis (e.g., X axis). The transfer sleeve need not be a
cold chamber. In an embodiment, at least plunger rod 14, vessel 20
(e.g., its receiving or melting portion), and opening of the
transfer sleeve 30 are provided in-line and on a horizontal axis,
such that plunger rod 14 can be moved in a horizontal direction
through vessel 20 in order to move the molten material into (and
subsequently through) the opening of transfer sleeve 30.
[0030] Referring back to FIGS. 3 and 4, first plate 32 can include
the inlet of the mold 16 such that molten material can be inserted
therein. Molten material is pushed in a horizontal direction
through transfer sleeve 30 and into the mold cavity(ies) via the
inlet between the first and second plates, 32 and 34. During
molding of the material, the at least first and second plates 32
and 34 are configured to substantially eliminate exposure of the
material (e.g., amorphous alloy) therebetween to at least oxygen
and nitrogen. Specifically, a vacuum is applied such that
atmospheric air is substantially eliminated from within the plates
32 and 34 and their cavities 42 and 44. A vacuum pressure is
applied to an inside of vacuum mold 16 using at least one vacuum
source 32 that is connected via vacuum lines. For example, the
vacuum pressure or level on the system can be held between
1.times.10.sup.-1 to 1.times.10.sup.4 Torr during the melting and
subsequent molding cycle. In another embodiment, the vacuum level
is maintained between 1.times.10.sup.-2to about 1.times.10.sup.--4
Torr during the melting and molding process. Of course, other
pressure levels or ranges may be used, such as 1.times.10.sup.-9
Torr to about 1.times.10.sup.-3 Torr, and/or 1.times.10.sup.-3 Torr
to about 0.1 Torr.
[0031] The vacuum ejector box 36 is positioned adjacent at least
first and second plates 32 and 34. In an embodiment, the ejector
box is enclosed and is configured to be vacuum sealed by vacuum
pressure from vacuum source 38 (pump). In an embodiment, included
in the enclosed vacuum ejector box 36 has an ejector mechanism 46
configured to eject molded (amorphous alloy) material from the mold
cavity between the at least first and second plates 32 and 34.
Ejector mechanism 46 can be vacuum sealed within the enclosed
vacuum ejector box 36 and any adjacent plate or interface sealed
with the open face of the box 36. Ejector mechanism 46 may include
an ejector plate 66, in accordance with an embodiment. The ejector
plate is configured to move within the enclosed ejector box to
eject the molded material from the mold 16. More specifically,
ejector plate 66 may have one or more (multiple) ejector pins (not
shown) extending in a linear direction therefrom. Upon movement of
ejector plate 66, the ejector pins are moved relatively to eject
the molded material from the mold cavity of mold 16. The ejection
mechanism is associated with or connected to an actuation mechanism
(not shown) that is configured to be actuated in order to eject the
molded material or part (e.g., after first and second parts 32 and
34 are moved horizontally and relatively away from each other,
after vacuum pressure between the plates 32 and 34 is released).
The ejector pins may be configured to push molded material away
from cavity 44, for example.
[0032] The illustrated mold 16 in FIGS. 3 and 4 is one example of a
mold 16 that can be used with injection molding system 10. It
should be understood that alternate types of molds may also be
employed. For example, any number of additional plates may be
provided between and/or adjacent the first and second plates to
form the mold. Molds known as "A" series, "B" series, and/or "X"
series molds, for example, may be implemented in injection molding
system 10.
[0033] Generally, the injection molding system 10 may be operated
in the following manner: The vacuum is applied to the injection
molding system 10. Meltable material (e.g., amorphous alloy or BMG)
is loaded into a feed mechanism (e.g., loading port 18) while held
under vacuum, and a single ingot (feedstock) is loaded, inserted
and received into the melt zone 12 into the vessel 20 (surrounded
by the induction coil 26). The injection molding machine "nozzle"
stroke or plunger 14 can be used to move the material, as needed,
into the melting portion 24 of the vessel 20. The material is
heated through the induction process. In an embodiment, the
injection molding machine controls the temperature through a closed
loop system, which will stabilize the material at a specific
temperature (e.g., using a temperature sensor and a controller). In
another embodiment, the injection molding machine controls the
temperature through an open loop system. During heating/melting, a
cooling system can be activated to flow a (cooling) liquid in any
cooling line(s) of the vessel 20. Once the temperature is achieved
and maintained to melt the meltable material, the machine will then
begin the injection of the molten material from vessel 20, through
transfer sleeve 20, and into vacuum mold 16 by moving in a
horizontal direction (from right to left) along the horizontal
axis. This may be controlled using plunger 14, which can be
activated using a servo-driven drive or a hydraulic drive. The mold
16 is configured to receive molten material through an inlet and
configured to mold the molten material under vacuum. That is, the
molten material is injected into a cavity between the at least
first and second plates to mold the part in the mold 16. Once the
mold cavity has begun to fill, vacuum pressure (via the vacuum
lines and vacuum source 38) can be held at a given pressure to
"pack" the molten material into the remaining void regions within
the mold cavity and mold the material. After the molding process
(e.g., approximately 10 to 15 seconds), the vacuum pressure applied
to the mold 16 is released. For example, the pressure can be
released using vacuum break valve 33 and/or the vacuum port. Mold
16 is then opened to relieve pressure and to expose the part to the
atmosphere. Ejector mechanism 46 is actuated to eject the
solidified, molded object from between the at least first and
second plates of mold 16 (ejector plate 66 is moved in a horizontal
and linear direction (e.g., towards the right) via an actuation
device and the ejector pins assist in ejecting the part from the
cavity). Thereafter, the process can begin again. Mold 16 can then
be closed by moving at least the at least first and second plates
relative to and towards each other such that the first and second
plates are adjacent each other. The melt zone 12 and mold 16 is
evacuated via the vacuum source once the plunger 14 has moved back
into a load position, in order to insert and melt more material and
mold another part.
[0034] Accordingly, the herein disclosed embodiments illustrate an
exemplary injection system that has its melting system in-line with
at least one plunger rod along a horizontal axis. The system does
not require use of a separate chamber to melt and then pour molten
metal into the plunger cavity/cold sleeve, as in known systems. The
system does not need to include immersion of the plunging system
into a molten metal bath, as well as reduced or no sintering. Also,
it more precisely controls the volume of feed stock/inserted
material and final molded part, and reduces heat loss. System 10
enables molding of material is that is substantially free of
contamination because it is formed from a clean melt with low
oxygen and nitrogen (due to applied vacuum pressure). Additionally,
the material is also substantially free of contamination because,
in accordance with an embodiment, the meltable material is
configured to be melted in a vessel comprising a surface which does
not give off contaminants (such as known graphite crucibles which
can induce carbine particles into the melt). System 10 further
provides a more efficient delivery method to its mold.
[0035] The disclosed system enables injection molding of objects to
be performed at a faster volumetric flow rate than plastic
injection molding techniques (but may be slower than conventional
die cast machines). For example, the flow rate of casting using the
herein described system(s) may be performed at approximately zero
to 1,000 cm.sup.3.
[0036] Although not described in great detail, the disclosed
injection system may include additional parts including, but not
limited to, one or more sensors, flow meters, etc. (e.g., to
monitor temperature, cooling water flow, etc.), and/or one or more
controllers. Also, seals can be provided with or adjacent any of
number of the parts to assist during melting and formation of a
part of the molten material when under vacuum pressure, by
substantially limiting or eliminating substantial exposure or
leakage of air. For example, the seals may be in the form of an
O-ring. A seal is defined as a device that can be made of any
material and that stops movement of material (such as air) between
parts which it seals. The injection system may implement an
automatic or semi-automatic process for inserting meltable material
therein, applying a vacuum, heating, injecting, and molding the
material to form a part.
[0037] The material to be molded (and/or melted) using any of the
embodiments of the injection system as disclosed herein may include
any number of materials and should not be limited. In one
embodiment, the material to be molded using the disclosed injection
molding system 10 is an amorphous alloy, which are metals that may
behave like plastic, or alloys with liquid atomic structures.
[0038] Bulk-solidifying amorphous alloys, or bulk metallic glasses
("BMG"), are a recently developed class of metallic materials.
These alloys may be solidified and cooled at relatively slow rates,
and they retain the amorphous, non-crystalline (i.e., glassy) state
at room temperature. Amorphous alloys have many superior properties
than their crystalline counterparts. However, if the cooling rate
is not sufficiently high, crystals may form inside the alloy during
cooling, so that the benefits of the amorphous state can be lost.
For example, one challenge with the fabrication of bulk amorphous
alloy parts is partial crystallization of the parts due to either
slow cooling or impurities in the raw alloy material. As a high
degree of amorphicity (and, conversely, a low degree of
crystallinity) is desirable in BMG parts, there is a need to
develop methods for casting BMG parts having controlled amount of
amorphicity.
[0039] FIG. 5 (obtained from U.S. Pat. No. 7,575,040) shows a
viscosity-temperature graph of an exemplary bulk solidifying
amorphous alloy, from the VIT-001 series of Zr--Ti--Ni--Cu--Be
family manufactured by Liquidmetal Technology. It should be noted
that there is no clear liquid/solid transformation for a bulk
solidifying amorphous metal during the formation of an amorphous
solid. The molten alloy becomes more and more viscous with
increasing undercooling until it approaches solid form around the
glass transition temperature. Accordingly, the temperature of
solidification front for bulk solidifying amorphous alloys can be
around glass transition temperature, where the alloy will
practically act as a solid for the purposes of pulling out the
quenched amorphous sheet product.
[0040] FIG. 6 (obtained from U.S. Pat. No. 7,575,040) shows the
time-temperature-transformation (TTT) cooling curve of an exemplary
bulk solidifying amorphous alloy, or TTT diagram. Bulk-solidifying
amorphous metals do not experience a liquid/solid crystallization
transformation upon cooling, as with conventional metals. Instead,
the highly fluid, non crystalline form of the metal found at high
temperatures (near a "melting temperature" Tm) becomes more viscous
as the temperature is reduced (near to the glass transition
temperature Tg), eventually taking on the outward physical
properties of a conventional solid.
[0041] Even though there is no liquid/crystallization
transformation for a bulk solidifying amorphous metal, a "melting
temperature" Tm may be defined as the thermodynamic liquidus
temperature of the corresponding crystalline phase. Under this
regime, the viscosity of bulk-solidifying amorphous alloys at the
melting temperature could lie in the range of about 0.1 poise to
about 10,000 poise, and even sometimes under 0.01 poise. A lower
viscosity at the "melting temperature" would provide faster and
complete filling of intricate portions of the shell/mold with a
bulk solidifying amorphous metal for forming the BMG parts.
Furthermore, the cooling rate of the molten metal to form a BMG
part has to such that the time-temperature profile during cooling
does not traverse through the nose-shaped region bounding the
crystallized region in the TTT diagram of FIG. 6. In FIG. 6, Tnose
is the critical crystallization temperature Tx where
crystallization is most rapid and occurs in the shortest time
scale.
[0042] The supercooled liquid region, the temperature region
between Tg and Tx is a manifestation of the extraordinary stability
against crystallization of bulk solidification alloys. In this
temperature region the bulk solidifying alloy can exist as a high
viscous liquid. The viscosity of the bulk solidifying alloy in the
supercooled liquid region can vary between 10.sup.12 Pa s at the
glass transition temperature down to 10.sup.5 Pa s at the
crystallization temperature, the high temperature limit of the
supercooled liquid region. Liquids with such viscosities can
undergo substantial plastic strain under an applied pressure. The
embodiments herein make use of the large plastic formability in the
supercooled liquid region as a forming and separating method.
[0043] One needs to clarify something about Tx. Technically, the
nose-shaped curve shown in the TTT diagram describes Tx as a
function of temperature and time. Thus, regardless of the
trajectory that one takes while heating or cooling a metal alloy,
when one hits the TTT curve, one has reached Tx. In FIG. 5 (b), Tx
is shown as a dashed line as Tx can vary from close to Tm to close
to Tg.
[0044] The schematic TTT diagram of FIG. 6 shows processing methods
of die casting from at or above Tm to below Tg without the
time-temperature trajectory (shown as (1) as an example trajectory)
hitting the TTT curve. During die casting, the forming takes place
substantially simultaneously with fast cooling to avoid the
trajectory hitting the TTT curve. The processing methods for
superplastic forming (SPF) from at or below Tg to below Tm without
the time-temperature trajectory (shown as (2), (3) and (4) as
example trajectories) hitting the TTT curve. In SPF, the amorphous
BMG is reheated into the supercooled liquid region where the
available processing window could be much larger than die casting,
resulting in better controllability of the process. The SPF process
does not require fast cooling to avoid crystallization during
cooling. Also, as shown by example trajectories (2), (3) and (4),
the SPF can be carried out with the highest temperature during SPF
being above Tnose or below Tnose, up to about Tm. If one heats up a
piece of amorphous alloy but manages to avoid hitting the TTT
curve, you have heated "between Tg and Tm", but one would have not
reached Tx.
[0045] Typical differential scanning calorimeter (DSC) heating
curves of bulk-solidifying amorphous alloys taken at a heating rate
of 20 C/min describe, for the most part, a particular trajectory
across the TTT data where one would likely see a Tg at a certain
temperature, a Tx when the DSC heating ramp crosses the TTT
crystallization onset, and eventually melting peaks when the same
trajectory crosses the temperature range for melting. If one heats
a bulk-solidifying amorphous alloy at a rapid heating rate as shown
by the ramp up portion of trajectories (2), (3) and (4) in FIG. 6,
then one could avoid the TTT curve entirely, and the DSC data would
show a glass transition but no Tx upon heating. Another way to
think about it is trajectories (2), (3) and (4) can fall anywhere
in temperature between the nose of the TTT curve (and even above
it) and the Tg line, as long as it does not hit the crystallization
curve. That just means that the horizontal plateau in trajectories
might get much shorter as one increases the processing
temperature.
Phase
[0046] The term "phase" herein can refer to one that can be found
in a thermodynamic phase diagram. A phase is a region of space
(e.g., a thermodynamic system) throughout which all physical
properties of a material are essentially uniform. Examples of
physical properties include density, index of refraction, chemical
composition and lattice periodicity. A simple description of a
phase is a region of material that is chemically uniform,
physically distinct, and/or mechanically separable. For example, in
a system consisting of ice and water in a glass jar, the ice cubes
are one phase, the water is a second phase, and the humid air over
the water is a third phase. The glass of the jar is another
separate phase. A phase can refer to a solid solution, which can be
a binary, tertiary, quaternary, or more, solution, or a compound,
such as an intermetallic compound. As another example, an amorphous
phase is distinct from a crystalline phase.
Metal, Transition Metal, and Non-metal
[0047] The term "metal" refers to an electropositive chemical
element. The term "element" in this Specification refers generally
to an element that can be found in a Periodic Table. Physically, a
metal atom in the ground state contains a partially filled band
with an empty state close to an occupied state. The term
"transition metal" is any of the metallic elements within Groups 3
to 12 in the Periodic Table that have an incomplete inner electron
shell and that serve as transitional links between the most and the
least electropositive in a series of elements. Transition metals
are characterized by multiple valences, colored compounds, and the
ability to form stable complex ions. The term "nonmetal" refers to
a chemical element that does not have the capacity to lose
electrons and form a positive ion.
[0048] Depending on the application, any suitable nonmetal
elements, or their combinations, can be used. The alloy (or "alloy
composition") can comprise multiple nonmetal elements, such as at
least two, at least three, at least four, or more, nonmetal
elements. A nonmetal element can be any element that is found in
Groups 13-17 in the Periodic Table. For example, a nonmetal element
can be any one of F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb,
Bi, C, Si, Ge, Sn, Pb, and B. Occasionally, a nonmetal element can
also refer to certain metalloids (e.g., B, Si, Ge, As, Sb, Te, and
Po) in Groups 13-17. In one embodiment, the nonmetal elements can
include B, Si, C, P, or combinations thereof. Accordingly, for
example, the alloy can comprise a boride, a carbide, or both.
[0049] A transition metal element can be any of scandium, titanium,
vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,
yttrium, zirconium, niobium, molybdenum, technetium, ruthenium,
rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten,
rhenium, osmium, iridium, platinum, gold, mercury, rutherfordium,
dubnium, seaborgium, bohrium, hassium, meitnerium, ununnilium,
unununium, and ununbium. In one embodiment, a BMG containing a
transition metal element can have at least one of Sc, Y, La, Ac,
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. Depending on the
application, any suitable transitional metal elements, or their
combinations, can be used. The alloy composition can comprise
multiple transitional metal elements, such as at least two, at
least three, at least four, or more, transitional metal
elements.
[0050] The presently described alloy or alloy "sample" or
"specimen" alloy can have any shape or size. For example, the alloy
can have a shape of a particulate, which can have a shape such as
spherical, ellipsoid, wire-like, rod-like, sheet-like, flake-like,
or an irregular shape. The particulate can have any size. For
example, it can have an average diameter of between about 1 micron
and about 100 microns, such as between about 5 microns and about 80
microns, such as between about 10 microns and about 60 microns,
such as between about 15 microns and about 50 microns, such as
between about 15 microns and about 45 microns, such as between
about 20 microns and about 40 microns, such as between about 25
microns and about 35 microns. For example, in one embodiment, the
average diameter of the particulate is between about 25 microns and
about 44 microns. In some embodiments, smaller particulates, such
as those in the nanometer range, or larger particulates, such as
those bigger than 100 microns, can be used.
[0051] The alloy sample or specimen can also be of a much larger
dimension. For example, it can be a bulk structural component, such
as an ingot, housing/casing of an electronic device or even a
portion of a structural component that has dimensions in the
millimeter, centimeter, or meter range.
Solid Solution
[0052] The term "solid solution" refers to a solid form of a
solution. The term "solution" refers to a mixture of two or more
substances, which may be solids, liquids, gases, or a combination
of these. The mixture can be homogeneous or heterogeneous. The term
"mixture" is a composition of two or more substances that are
combined with each other and are generally capable of being
separated. Generally, the two or more substances are not chemically
combined with each other.
Alloy
[0053] In some embodiments, the alloy composition described herein
can be fully alloyed. In one embodiment, an "alloy" refers to a
homogeneous mixture or solid solution of two or more metals, the
atoms of one replacing or occupying interstitial positions between
the atoms of the other; for example, brass is an alloy of zinc and
copper. An alloy, in contrast to a composite, can refer to a
partial or complete solid solution of one or more elements in a
metal matrix, such as one or more compounds in a metallic matrix.
The term alloy herein can refer to both a complete solid solution
alloy that can give single solid phase microstructure and a partial
solution that can give two or more phases. An alloy composition
described herein can refer to one comprising an alloy or one
comprising an alloy-containing composite.
[0054] Thus, a fully alloyed alloy can have a homogenous
distribution of the constituents, be it a solid solution phase, a
compound phase, or both. The term "fully alloyed" used herein can
account for minor variations within the error tolerance. For
example, it can refer to at least 90% alloyed, such as at least 95%
alloyed, such as at least 99% alloyed, such as at least 99.5%
alloyed, such as at least 99.9% alloyed. The percentage herein can
refer to either volume percent or weight percentage, depending on
the context. These percentages can be balanced by impurities, which
can be in terms of composition or phases that are not a part of the
alloy.
Amorphous or Non-Crystalline Solid
[0055] An "amorphous" or "non-crystalline solid" is a solid that
lacks lattice periodicity, which is characteristic of a crystal. As
used herein, an "amorphous solid" includes "glass" which is an
amorphous solid that softens and transforms into a liquid-like
state upon heating through the glass transition. Generally,
amorphous materials lack the long-range order characteristic of a
crystal, though they can possess some short-range order at the
atomic length scale due to the nature of chemical bonding. The
distinction between amorphous solids and crystalline solids can be
made based on lattice periodicity as determined by structural
characterization techniques such as x-ray diffraction and
transmission electron microscopy.
[0056] The terms "order" and "disorder" designate the presence or
absence of some symmetry or correlation in a many-particle system.
The terms "long-range order" and "short-range order" distinguish
order in materials based on length scales.
[0057] The strictest form of order in a solid is lattice
periodicity: a certain pattern (the arrangement of atoms in a unit
cell) is repeated again and again to form a translationally
invariant tiling of space. This is the defining property of a
crystal. Possible symmetries have been classified in 14 Bravais
lattices and 230 space groups.
[0058] Lattice periodicity implies long-range order. If only one
unit cell is known, then by virtue of the translational symmetry it
is possible to accurately predict all atomic positions at arbitrary
distances. The converse is generally true, except, for example, in
quasi-crystals that have perfectly deterministic tilings but do not
possess lattice periodicity.
[0059] Long-range order characterizes physical systems in which
remote portions of the same sample exhibit correlated behavior.
This can be expressed as a correlation function, namely the
spin-spin correlation function: G(x, x')=s(x), s(x').
[0060] In the above function, s is the spin quantum number and x is
the distance function within the particular system. This function
is equal to unity when x=x' and decreases as the distance |x-x'|
increases. Typically, it decays exponentially to zero at large
distances, and the system is considered to be disordered. If,
however, the correlation function decays to a constant value at
large |x-x'|, then the system can be said to possess long-range
order. If it decays to zero as a power of the distance, then it can
be called quasi-long-range order. Note that what constitutes a
large value of |x-x'| is relative.
[0061] A system can be said to present quenched disorder when some
parameters defining its behavior are random variables that do not
evolve with time (i.e., they are quenched or frozen)--e.g., spin
glasses. It is opposite to annealed disorder, where the random
variables are allowed to evolve themselves. Embodiments herein
include systems comprising quenched disorder.
[0062] The alloy described herein can be crystalline, partially
crystalline, amorphous, or substantially amorphous. For example,
the alloy sample/specimen can include at least some crystallinity,
with grains/crystals having sizes in the nanometer and/or
micrometer ranges. Alternatively, the alloy can be substantially
amorphous, such as fully amorphous. In one embodiment, the alloy
composition is at least substantially not amorphous, such as being
substantially crystalline, such as being entirely crystalline.
[0063] In one embodiment, the presence of a crystal or a plurality
of crystals in an otherwise amorphous alloy can be construed as a
"crystalline phase" therein. The degree of crystallinity (or
"crystallinity" for short in some embodiments) of an alloy can
refer to the amount of the crystalline phase present in the alloy.
The degree can refer to, for example, a fraction of crystals
present in the alloy. The fraction can refer to volume fraction or
weight fraction, depending on the context. A measure of how
"amorphous" an amorphous alloy is can be amorphicity. Amorphicity
can be measured in terms of a degree of crystallinity. For example,
in one embodiment, an alloy having a low degree of crystallinity
can be said to have a high degree of amorphicity. In one
embodiment, for example, an alloy having 60 vol % crystalline phase
can have a 40 vol % amorphous phase.
Amorphous Alloy or Amorphous Metal
[0064] An "amorphous alloy" is an alloy having an amorphous content
of more than 50% by volume, preferably more than 90% by volume of
amorphous content, more preferably more than 95% by volume of
amorphous content, and most preferably more than 99% to almost 100%
by volume of amorphous content. Note that, as described above, an
alloy high in amorphicity is equivalently low in degree of
crystallinity. An "amorphous metal" is an amorphous metal material
with a disordered atomic-scale structure. In contrast to most
metals, which are crystalline and therefore have a highly ordered
arrangement of atoms, amorphous alloys are non-crystalline.
Materials in which such a disordered structure is produced directly
from the liquid state during cooling are sometimes referred to as
"glasses." Accordingly, amorphous metals are commonly referred to
as "metallic glasses" or "glassy metals." In one embodiment, a bulk
metallic glass ("BMG") can refer to an alloy, of which the
microstructure is at least partially amorphous. However, there are
several ways besides extremely rapid cooling to produce amorphous
metals, including physical vapor deposition, solid-state reaction,
ion irradiation, melt spinning, and mechanical alloying. Amorphous
alloys can be a single class of materials, regardless of how they
are prepared.
[0065] Amorphous metals can be produced through a variety of
quick-cooling methods. For instance, amorphous metals can be
produced by sputtering molten metal onto a spinning metal disk. The
rapid cooling, on the order of millions of degrees a second, can be
too fast for crystals to form, and the material is thus "locked in"
a glassy state. Also, amorphous metals/alloys can be produced with
critical cooling rates low enough to allow formation of amorphous
structures in thick layers--e.g., bulk metallic glasses.
[0066] The terms "bulk metallic glass" ("BMG"), bulk amorphous
alloy ("BAA"), and bulk solidifying amorphous alloy are used
interchangeably herein. They refer to amorphous alloys having the
smallest dimension at least in the millimeter range. For example,
the dimension can be at least about 0.5 mm, such as at least about
1 mm, such as at least about 2 mm, such as at least about 4 mm,
such as at least about 5 mm, such as at least about 6 mm, such as
at least about 8 mm, such as at least about 10 mm, such as at least
about 12 mm. Depending on the geometry, the dimension can refer to
the diameter, radius, thickness, width, length, etc. A BMG can also
be a metallic glass having at least one dimension in the centimeter
range, such as at least about 1.0 cm, such as at least about 2.0
cm, such as at least about 5.0 cm, such as at least about 10.0 cm.
In some embodiments, a BMG can have at least one dimension at least
in the meter range. A BMG can take any of the shapes or forms
described above, as related to a metallic glass. Accordingly, a BMG
described herein in some embodiments can be different from a thin
film made by a conventional deposition technique in one important
aspect--the former can be of a much larger dimension than the
latter.
[0067] Amorphous metals can be an alloy rather than a pure metal.
The alloys may contain atoms of significantly different sizes,
leading to low free volume (and therefore having viscosity up to
orders of magnitude higher than other metals and alloys) in a
molten state. The viscosity prevents the atoms from moving enough
to form an ordered lattice. The material structure may result in
low shrinkage during cooling and resistance to plastic deformation.
The absence of grain boundaries, the weak spots of crystalline
materials in some cases, may, for example, lead to better
resistance to wear and corrosion. In one embodiment, amorphous
metals, while technically glasses, may also be much tougher and
less brittle than oxide glasses and ceramics.
[0068] Thermal conductivity of amorphous materials may be lower
than that of their crystalline counterparts. To achieve formation
of an amorphous structure even during slower cooling, the alloy may
be made of three or more components, leading to complex crystal
units with higher potential energy and lower probability of
formation. The formation of amorphous alloy can depend on several
factors: the composition of the components of the alloy; the atomic
radius of the components (preferably with a significant difference
of over 12% to achieve high packing density and low free volume);
and the negative heat of mixing the combination of components,
inhibiting crystal nucleation and prolonging the time the molten
metal stays in a supercooled state. However, as the formation of an
amorphous alloy is based on many different variables, it can be
difficult to make a prior determination of whether an alloy
composition would form an amorphous alloy.
[0069] Amorphous alloys, for example, of boron, silicon,
phosphorus, and other glass formers with magnetic metals (iron,
cobalt, nickel) may be magnetic, with low coercivity and high
electrical resistance. The high resistance leads to low losses by
eddy currents when subjected to alternating magnetic fields, a
property useful, for example, as transformer magnetic cores.
[0070] Amorphous alloys may have a variety of potentially useful
properties. In particular, they tend to be stronger than
crystalline alloys of similar chemical composition, and they can
sustain larger reversible ("elastic") deformations than crystalline
alloys. Amorphous metals derive their strength directly from their
non-crystalline structure, which can have none of the defects (such
as dislocations) that limit the strength of crystalline alloys. For
example, one modern amorphous metal, known as VitreloyTM, has a
tensile strength that is almost twice that of high-grade titanium.
In some embodiments, metallic glasses at room temperature are not
ductile and tend to fail suddenly when loaded in tension, which
limits the material applicability in reliability-critical
applications, as the impending failure is not evident. Therefore,
to overcome this challenge, metal matrix composite materials having
a metallic glass matrix containing dendritic particles or fibers of
a ductile crystalline metal can be used. Alternatively, a BMG low
in element(s) that tend to cause embitterment (e.g., Ni) can be
used. For example, a Ni-free BMG can be used to improve the
ductility of the BMG.
[0071] Another useful property of bulk amorphous alloys is that
they can be true glasses; in other words, they can soften and flow
upon heating. This can allow for easy processing, such as by
injection molding, in much the same way as polymers. As a result,
amorphous alloys can be used for making sports equipment, medical
devices, electronic components and equipment, and thin films. Thin
films of amorphous metals can be deposited as protective coatings
via a high velocity oxygen fuel technique.
[0072] A material can have an amorphous phase, a crystalline phase,
or both. The amorphous and crystalline phases can have the same
chemical composition and differ only in the microstructure--i.e.,
one amorphous and the other crystalline. Microstructure in one
embodiment refers to the structure of a material as revealed by a
microscope at 25X magnification or higher. Alternatively, the two
phases can have different chemical compositions and
microstructures. For example, a composition can be partially
amorphous, substantially amorphous, or completely amorphous.
[0073] As described above, the degree of amorphicity (and
conversely the degree of crystallinity) can be measured by fraction
of crystals present in the alloy. The degree can refer to volume
fraction of weight fraction of the crystalline phase present in the
alloy. A partially amorphous composition can refer to a composition
of at least about 5 vol % of which is of an amorphous phase, such
as at least about 10 vol %, such as at least about 20 vol %, such
as at least about 40 vol %, such as at least about 60 vol %, such
as at least about 80 vol %, such as at least about 90 vol %. The
terms "substantially" and "about" have been defined elsewhere in
this application. Accordingly, a composition that is at least
substantially amorphous can refer to one of which at least about 90
vol % is amorphous, such as at least about 95 vol %, such as at
least about 98 vol %, such as at least about 99 vol %, such as at
least about 99.5 vol %, such as at least about 99.8 vol %, such as
at least about 99.9 vol %. In one embodiment, a substantially
amorphous composition can have some incidental, insignificant
amount of crystalline phase present therein.
[0074] In one embodiment, an amorphous alloy composition can be
homogeneous with respect to the amorphous phase. A substance that
is uniform in composition is homogeneous. This is in contrast to a
substance that is heterogeneous. The term "composition" refers to
the chemical composition and/or microstructure in the substance. A
substance is homogeneous when a volume of the substance is divided
in half and both halves have substantially the same composition.
For example, a particulate suspension is homogeneous when a volume
of the particulate suspension is divided in half and both halves
have substantially the same volume of particles. However, it might
be possible to see the individual particles under a microscope.
Another example of a homogeneous substance is air where different
ingredients therein are equally suspended, though the particles,
gases and liquids in air can be analyzed separately or separated
from air.
[0075] A composition that is homogeneous with respect to an
amorphous alloy can refer to one having an amorphous phase
substantially uniformly distributed throughout its microstructure.
In other words, the composition macroscopically comprises a
substantially uniformly distributed amorphous alloy throughout the
composition. In an alternative embodiment, the composition can be
of a composite, having an amorphous phase having therein a
non-amorphous phase. The non-amorphous phase can be a crystal or a
plurality of crystals. The crystals can be in the form of
particulates of any shape, such as spherical, ellipsoid, wire-like,
rod-like, sheet-like, flake-like, or an irregular shape. In one
embodiment, it can have a dendritic form. For example, an at least
partially amorphous composite composition can have a crystalline
phase in the shape of dendrites dispersed in an amorphous phase
matrix; the dispersion can be uniform or non-uniform, and the
amorphous phase and the crystalline phase can have the same or a
different chemical composition. In one embodiment, they have
substantially the same chemical composition. In another embodiment,
the crystalline phase can be more ductile than the BMG phase.
[0076] The methods described herein can be applicable to any type
of amorphous alloy. Similarly, the amorphous alloy described herein
as a constituent of a composition or article can be of any type.
The amorphous alloy can comprise the element Zr, Hf, Ti, Cu, Ni,
Pt, Pd, Fe, Mg, Au, La, Ag, Al, Mo, Nb, Be, or combinations
thereof. Namely, the alloy can include any combination of these
elements in its chemical formula or chemical composition. The
elements can be present at different weight or volume percentages.
For example, an iron "based" alloy can refer to an alloy having a
non-insignificant weight percentage of iron present therein, the
weight percent can be, for example, at least about 20 wt %, such as
at least about 40 wt %, such as at least about 50 wt %, such as at
least about 60 wt %, such as at least about 80 wt %. Alternatively,
in one embodiment, the above-described percentages can be volume
percentages, instead of weight percentages. Accordingly, an
amorphous alloy can be zirconium-based, titanium-based,
platinum-based, palladium-based, gold-based, silver-based,
copper-based, iron-based, nickel-based, aluminum-based,
molybdenum-based, and the like. The alloy can also be free of any
of the aforementioned elements to suit a particular purpose. For
example, in some embodiments, the alloy, or the composition
including the alloy, can be substantially free of nickel, aluminum,
titanium, beryllium, or combinations thereof. In one embodiment,
the alloy or the composite is completely free of nickel, aluminum,
titanium, beryllium, or combinations thereof.
[0077] For example, the amorphous alloy can have the formula (Zr,
Ti).sub.a(Ni, Cu, Fe).sub.b(Be, Al, Si, B).sub.c, wherein a, b, and
c each represents a weight or atomic percentage. In one embodiment,
a is in the range of from 30 to 75, b is in the range of from 5 to
60, and c is in the range of from 0 to 50 in atomic percentages.
Alternatively, the amorphous alloy can have the formula (Zr,
Ti).sub.b(Ni, Cu).sub.b(Be).sub.c, wherein a, b, and c each
represents a weight or atomic percentage. In one embodiment, a is
in the range of from 40 to 75, b is in the range of from 5 to 50,
and c is in the range of from 5 to 50 in atomic percentages. The
alloy can also have the formula (Zr, Ti).sub.b(Ni,
Cu).sub.b(Be).sub.c, wherein a, b, and c each represents a weight
or atomic percentage. In one embodiment, a is in the range of from
45 to 65, b is in the range of from 7.5 to 35, and c is in the
range of from 10 to 37.5 in atomic percentages. Alternatively, the
alloy can have the formula (Zr).sub.a(Nb, Ti).sub.b(Ni,
Cu).sub.c(Al).sub.d, wherein a, b, c, and d each represents a
weight or atomic percentage. In one embodiment, a is in the range
of from 45 to 65, b is in the range of from 0 to 10, c is in the
range of from 20 to 40 and d is in the range of from 7.5 to 15 in
atomic percentages. One exemplary embodiment of the aforedescribed
alloy system is a Zr--Ti--Ni--Cu--Be based amorphous alloy under
the trade name Vitreloy.TM., such as Vitreloy-1 and Vitreloy-101,
as fabricated by Liquidmetal Technologies, CA, USA. Some examples
of amorphous alloys of the different systems are provided in Table
1.
[0078] The amorphous alloys can also be ferrous alloys, such as
(Fe, Ni, Co) based alloys. Examples of such compositions are
disclosed in U.S. Pat. Nos. 6,325,868; 5,288,344; 5,368,659;
5,618,359; and 5,735,975, Inoue et al., Appl. Phys. Lett., Volume
71, p 464 (1997), Shen et al., Mater. Trans., JIM, Volume 42, p
2136 (2001), and Japanese Patent Application No. 200126277 (Pub.
No. 2001303218 A). One exemplary composition is
Fe.sub.72Al.sub.5Da.sub.2P.sub.11C.sub.6B.sub.4. Another example is
Fe.sub.72Al.sub.7Zr.sub.10Mo.sub.5W.sub.2B.sub.15. Another
iron-based alloy system that can be used in the coating herein is
disclosed in U.S. Patent Application Publication No. 2010/0084052,
wherein the amorphous metal contains, for example, manganese (1 to
3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1
atomic %) in the range of composition given in parentheses; and
that contains the following elements in the specified range of
composition given in parentheses: chromium (15 to 20 atomic %),
molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5
to 16 atomic %), carbon (3 to 16 atomic %), and the balance
iron.
[0079] The aforedescribed amorphous alloy systems can further
include additional elements, such as additional transition metal
elements, including Nb, Cr, V, and Co. The additional elements can
be present at less than or equal to about 30 wt %, such as less
than or equal to about 20 wt %, such as less than or equal to about
10 wt %, such as less than or equal to about 5 wt %. In one
embodiment, the additional, optional element is at least one of
cobalt, manganese, zirconium, tantalum, niobium, tungsten, yttrium,
titanium, vanadium and hafnium to form carbides and further improve
wear and corrosion resistance. Further optional elements may
include phosphorous, germanium and arsenic, totaling up to about
2%, and preferably less than 1%, to reduce melting point. Otherwise
incidental impurities should be less than about 2% and preferably
0.5%.
TABLE-US-00001 TABLE 1 Exemplary amorphous alloy compositions Alloy
Atm % Atm % Atm % Atm % Atm % Atm % 1 Zr Ti Cu Ni Be 41.20% 13.80%
12.50% 10.00% 22.50% 2 Zr Ti Cu Ni Be 44.00% 11.00% 10.00% 10.00%
25.00% 3 Zr Ti Cu Ni Nb Be 56.25% 11.25% 6.88% 5.63% 7.50% 12.50% 4
Zr Ti Cu Ni Al Be 64.75% 5.60% 14.90% 11.15% 2.60% 1.00% 5 Zr Ti Cu
Ni Al 52.50% 5.00% 17.90% 14.60% 10.00% 6 Zr Nb Cu Ni Al 57.00%
5.00% 15.40% 12.60% 10.00% 7 Zr Cu Ni Al Sn 50.75% 36.23% 4.03%
9.00% 0.50% 8 Zr Ti Cu Ni Be 46.75% 8.25% 7.50% 10.00% 27.50% 9 Zr
Ti Ni Be 21.67% 43.33% 7.50% 27.50% 10 Zr Ti Cu Be 35.00% 30.00%
7.50% 27.50% 11 Zr Ti Co Be 35.00% 30.00% 6.00% 29.00% 12 Au Ag Pd
Cu Si 49.00% 5.50% 2.30% 26.90% 16.30% 13 Au Ag Pd Cu Si 50.90%
3.00% 2.30% 27.80% 16.00% 14 Pt Cu Ni P 57.50% 14.70% 5.30% 22.50%
15 Zr Ti Nb Cu Be 36.60% 31.40% 7.00% 5.90% 19.10% 16 Zr Ti Nb Cu
Be 38.30% 32.90% 7.30% 6.20% 15.30% 17 Zr Ti Nb Cu Be 39.60% 33.90%
7.60% 6.40% 12.50% 18 Cu Ti Zr Ni 47.00% 34.00% 11.00% 8.00% 19 Zr
Co Al 55.00% 25.00% 20.00%
[0080] In some embodiments, a composition having an amorphous alloy
can include a small amount of impurities. The impurity elements can
be intentionally added to modify the properties of the composition,
such as improving the mechanical properties (e.g., hardness,
strength, fracture mechanism, etc.) and/or improving the corrosion
resistance. Alternatively, the impurities can be present as
inevitable, incidental impurities, such as those obtained as a
byproduct of processing and manufacturing. The impurities can be
less than or equal to about 10 wt %, such as about 5 wt %, such as
about 2 wt %, such as about 1 wt %, such as about 0.5 wt %, such as
about 0.1 wt %. In some embodiments, these percentages can be
volume percentages instead of weight percentages. In one
embodiment, the alloy sample/composition consists essentially of
the amorphous alloy (with only a small incidental amount of
impurities). In another embodiment, the composition includes the
amorphous alloy (with no observable trace of impurities).
[0081] In one embodiment, the final parts exceeded the critical
casting thickness of the bulk solidifying amorphous alloys.
[0082] In embodiments herein, the existence of a supercooled liquid
region in which the bulk-solidifying amorphous alloy can exist as a
high viscous liquid allows for superplastic forming. Large plastic
deformations can be obtained. The ability to undergo large plastic
deformation in the supercooled liquid region could be used for the
forming and/or cutting process. As oppose to solids, the liquid
bulk solidifying alloy deforms locally which drastically lowers the
required energy for cutting and forming. The ease of cutting and
forming depends on the temperature of the alloy, the mold, and the
cutting tool. As higher is the temperature, the lower is the
viscosity, and consequently easier is the cutting and forming.
[0083] Embodiments herein can utilize a thermoplastic-forming
process with amorphous alloys carried out between Tg and Tx, for
example. Herein, Tx and Tg are determined from standard DSC
measurements at typical heating rates (e.g. 20.degree. C/min) as
the onset of crystallization temperature and the onset of glass
transition temperature.
[0084] The amorphous alloy components can have the critical casting
thickness and the final part can have thickness that is thicker
than the critical casting thickness. Moreover, the time and
temperature of the heating and shaping operation is selected such
that the elastic strain limit of the amorphous alloy could be
substantially preserved to be not less than 1.0%, and preferably
not being less than 1.5%. In the context of the embodiments herein,
temperatures around glass transition means the forming temperatures
can be below glass transition, at or around glass transition, and
above glass transition temperature, but preferably at temperatures
below the crystallization temperature T.sub.x. The cooling step is
carried out at rates similar to the heating rates at the heating
step, and preferably at rates greater than the heating rates at the
heating step. The cooling step is also achieved preferably while
the forming and shaping loads are still maintained.
[0085] The aforedescribed embodiments of the injection molding
system 10 can be used in a fabrication device and/or process
including using BMG (or amorphous alloys). Because of the superior
properties of BMG, BMG can be made into structural components of
bulk amorphous alloy in a variety of objects, devices and parts.
One such type of device is an electronic device.
[0086] Electronic Devices
[0087] The embodiments herein can be valuable in the fabrication of
electronic devices using a BMG. An electronic device herein can
refer to any electronic device known in the art. For example, it
can be a telephone, such as a cell phone, and a land-line phone, or
any communication device, such as a smart phone, including, for
example an iPhoneTM, and an electronic email sending/receiving
device. It can be a part of a display, such as a digital display, a
TV monitor, an electronic-book reader, a portable web-browser
(e.g., iPadTM), and a computer monitor. It can also be an
entertainment device, including a portable DVD player, conventional
DVD player, Blu-Ray disk player, video game console, music player,
such as a portable music player (e.g., iPodTM), etc. It can also be
a part of a device that provides control, such as controlling the
streaming of images, videos, sounds (e.g., Apple TVTM), or it can
be a remote control for an electronic device. It can be a part of a
computer or its accessories, such as the hard drive tower housing
or casing, laptop housing, laptop keyboard, laptop track pad,
desktop keyboard, mouse, and speaker. The article can also be
applied to a device such as a watch or a clock.
[0088] While the principles of the disclosure have been made clear
in the illustrative embodiments set forth above, it will be
apparent to those skilled in the art that various modifications may
be made to the structure, arrangement, proportion, elements,
materials, and components used in the practice of the
disclosure.
[0089] It will be appreciated that various of the above-disclosed
and other features and functions, or alternatives thereof, may be
desirably combined into many other different systems/devices or
applications. Various presently unforeseen or unanticipated
alternatives, modifications, variations, or improvements therein
may be subsequently made by those skilled in the art which are also
intended to be encompassed by the following claims.
* * * * *