U.S. patent application number 15/448267 was filed with the patent office on 2017-06-22 for method including fiber reinforced casting article.
The applicant listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to John R. Farris, John Joseph Marcin, Joel H. Wagner.
Application Number | 20170173673 15/448267 |
Document ID | / |
Family ID | 54011496 |
Filed Date | 2017-06-22 |
United States Patent
Application |
20170173673 |
Kind Code |
A1 |
Wagner; Joel H. ; et
al. |
June 22, 2017 |
METHOD INCLUDING FIBER REINFORCED CASTING ARTICLE
Abstract
A method of forming an engine component according to an
exemplary aspect of the present disclosure includes, among other
things, introducing molten metal into a cavity between a shell and
a casting article in the shell. The casting article includes a
ceramic portion and a plurality of fibers. The method further
includes separately removing the ceramic portion and the fibers
from an interior of the component.
Inventors: |
Wagner; Joel H.;
(Wethersfield, CT) ; Farris; John R.; (Bolton,
CT) ; Marcin; John Joseph; (Malborough, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Farmington |
CT |
US |
|
|
Family ID: |
54011496 |
Appl. No.: |
15/448267 |
Filed: |
March 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14744450 |
Jun 19, 2015 |
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15448267 |
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62015003 |
Jun 20, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22D 29/002 20130101;
B22D 29/001 20130101; B22C 9/106 20130101 |
International
Class: |
B22C 9/10 20060101
B22C009/10; B22D 29/00 20060101 B22D029/00 |
Claims
1. A method of forming an engine component, comprising: introducing
molten metal into a cavity between a shell and a casting article in
the shell, the casting article including a ceramic portion and a
plurality of fibers; and separately removing the ceramic portion
and the fibers from an interior of the component.
2. The method as recited in claim 1, further comprising: cooling
the molten metal, wherein the plurality of fibers and the ceramic
portion are removed after the molten metal cools.
3. The method as recited in claim 2, wherein the ceramic portion is
removed from the component using a leaching fluid, and the fibers
are mechanically removed from the component.
4. The method as recited in claim 3, wherein the fibers are blown
out of the component using a pressurized fluid.
5. The method as recited in claim 4, wherein the pressurized fluid
is pressurized air.
6. The method as recited in claim 4, wherein a maximum length of
the fibers is less than a smallest orifice formed in the engine
component.
7. The method as recited in claim 1, wherein the fibers dissolve
during the introducing step.
8. The method as recited in claim 7, wherein the fibers fully
dissolve during the introducing step.
9. The method as recited in claim 7, wherein, after the molten
metal cools, the remainder of the casting article is removed from
the component using a leaching fluid.
10. The method as recited in claim 7, wherein the size and chemical
composition of the fibers is selected such that the fibers will
intentionally dissolve during the introducing step.
11. The method as recited in claim 1, wherein the fibers are
randomly oriented within the ceramic portion.
12. The method as recited in claim 11, wherein the ceramic portion
includes alumina (Al.sub.2O.sub.3).
13. The method as recited in claim 1, wherein the fibers are
provided by one of (1) silicon (Si) fibers, (2) carbon (C) fibers,
and (3) metal fibers.
14. A method of forming an engine component, comprising:
introducing molten metal into a cavity between a shell and a
casting article, the casting article including a ceramic portion
and a plurality of fibers; dissolving the fibers during the
introducing step; and removing the remainder of the casting article
from the interior of the component using a leaching fluid.
15. The method as recited in claim 14, wherein the size and
material of the fibers is selected such that the fibers will
intentionally dissolve during the introducing step.
16. The method as recited in claim 14, wherein the fibers
completely dissolve during the introducing step.
17. The method as recited in claim 14, wherein the ceramic portion
includes alumina (Al.sub.2O.sub.3).
18. The method as recited in claim 14, wherein the fibers are
provided by one of (1) silicon (Si) fibers, (2) carbon (C) fibers,
and (3) metal fibers.
19. A method of forming an engine component, comprising: providing
a ceramic shell and a casting article, the casting article
including a ceramic portion and a plurality of fibers; sintering
the ceramic shell and the casting article, wherein the plurality of
fibers are dissolved by the sintering step; introducing a molten
metal between the shell and the casting article; and removing the
remainder of the casting article from the interior of the
component.
Description
BACKGROUND
[0001] Gas turbine engines include various components, such as
blades, vanes, and blade outer air seals (BOASs), that are exposed
to relatively hot gases during operation of the engine. These
components often include internal passageways for routing a flow of
cooling fluid within the component.
[0002] Components having relatively complex internal passageways
are manufactured using a number of techniques. One example
technique is investment casting. In this technique, casting
articles are used to form internal passageways. In particular,
molten metal is poured around the casting articles, and, after the
metal is allowed to cool, the casting articles are removed from the
interior of the components using a leaching technique, for
example.
SUMMARY
[0003] A method of forming an engine component according to an
exemplary aspect of the present disclosure includes, among other
things, introducing molten metal into a cavity between a shell and
a casting article in the shell. The casting article includes a
ceramic portion and a plurality of fibers. The method further
includes separately removing the ceramic portion and the fibers
from an interior of the component.
[0004] In a further non-limiting embodiment, the foregoing method
includes cooling the molten metal, and the plurality of fibers and
the ceramic portion are removed after the molten metal cools.
[0005] In a further non-limiting embodiment of the foregoing
method, the ceramic portion is removed from the component using a
first leaching fluid, and the fibers are removed from the component
using a second leaching fluid different in chemical composition
than the first leaching fluid.
[0006] In a further non-limiting embodiment of the foregoing
method, the ceramic portion is removed from the component using a
leaching fluid, and the fibers are mechanically removed from the
component.
[0007] In a further non-limiting embodiment of the foregoing
method, the fibers are blown out of the component using a
pressurized fluid.
[0008] In a further non-limiting embodiment of the foregoing
method, the pressurized fluid is pressurized air.
[0009] In a further non-limiting embodiment of the foregoing
method, a maximum length of the fibers is less than a smallest
orifice formed in the engine component.
[0010] In a further non-limiting embodiment of the foregoing
method, the fibers dissolve during the introducing step.
[0011] In a further non-limiting embodiment of the foregoing
method, the fibers fully dissolve during the introducing step.
[0012] In a further non-limiting embodiment of the foregoing
method, after the molten metal cools, the remainder of the casting
article is removed from the component using a leaching fluid.
[0013] In a further non-limiting embodiment of the foregoing
method, the size and chemical composition of the fibers is selected
such that the fibers will intentionally dissolve during the
introducing step.
[0014] In a further non-limiting embodiment of the foregoing
method, the fibers are randomly oriented within the ceramic
portion.
[0015] In a further non-limiting embodiment of the foregoing
method, the ceramic portion includes alumina (Al.sub.2O.sub.3).
[0016] In a further non-limiting embodiment of the foregoing
method, the fibers are provided by one of (1) silicon (Si) fibers,
(2) carbon (C) fibers, and (3) metal fibers.
[0017] A method of forming an engine component according to another
exemplary aspect of this disclosure includes, among other things,
introducing molten metal into a cavity between a shell and a
casting article. The casting article includes a ceramic portion and
a plurality of fibers. The method further includes dissolving the
fibers during the introducing step, and removing the remainder of
the casting article from the interior of the component using a
leaching fluid.
[0018] In a further non-limiting embodiment of the foregoing
method, the size and material of the fibers is selected such that
the fibers will intentionally dissolve during the introducing
step.
[0019] In a further non-limiting embodiment of the foregoing
method, the fibers completely dissolve during the introducing
step.
[0020] In a further non-limiting embodiment of the foregoing
method, the ceramic portion includes alumina (Al.sub.2O.sub.3).
[0021] In a further non-limiting embodiment of the foregoing
method, the fibers are provided by one of (1) silicon (Si) fibers,
(2) carbon (C) fibers, and (3) metal fibers.
[0022] A method of forming an engine component according to yet
another exemplary aspect of this disclosure includes, among other
things, providing a ceramic shell and a casting article. The
casting article includes a ceramic portion and a plurality of
fibers. The method further includes sintering the ceramic shell and
the casting article, wherein the plurality of fibers are dissolved
by the sintering step, introducing a molten metal between the shell
and the casting article, and removing the remainder of the casting
article from the interior of the component.
[0023] The embodiments, examples and alternatives of the preceding
paragraphs, the claims, or the following description and drawings,
including any of their various aspects or respective individual
features, may be taken independently or in any combination.
Features described in connection with one embodiment are applicable
to all embodiments, unless such features are incompatible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The drawings can be briefly described as follows:
[0025] FIG. 1 schematically illustrates an example gas turbine
engine.
[0026] FIG. 2 illustrates an example engine component in phantom,
and further illustrates an example casting article.
[0027] FIG. 3 is a close-up of the encircled area in FIG. 2.
[0028] FIG. 4 is a flow chart representing an example method for
forming a casting article.
[0029] FIG. 5 is a flow chart representing an example method for
forming an engine component.
DETAILED DESCRIPTION
[0030] FIG. 1 schematically illustrates a gas turbine engine 20.
The gas turbine engine 20 is disclosed herein as a two-spool
turbofan that generally incorporates a fan section 22, a compressor
section 24, a combustor section 26 and a turbine section 28.
Alternative engines might include an augmentor section (not shown)
among other systems or features. The fan section 22 drives air
along a bypass flow path B in a bypass duct defined within a
nacelle 15, while the compressor section 24 drives air along a core
airflow path C for compression and communication into the combustor
section 26 then expansion through the turbine section 28. Although
depicted as a two-spool turbofan gas turbine engine in the
disclosed non-limiting embodiment, it should be understood that the
concepts described herein are not limited to use with two-spool
turbofans as the teachings may be applied to other types of turbine
engines including three-spool architectures.
[0031] The exemplary engine 20 generally includes a low speed spool
30 and a high speed spool 32 mounted for rotation about an engine
central longitudinal axis A relative to an engine static structure
36 via several bearing systems 38. It should be understood that
various bearing systems 38 at various locations may alternatively
or additionally be provided, and the location of bearing systems 38
may be varied as appropriate to the application.
[0032] The low speed spool 30 generally includes an inner shaft 40
that interconnects a fan 42, a first (or low) pressure compressor
44 and a first (or low) pressure turbine 46. The inner shaft 40 is
connected to the fan 42 through a speed change mechanism, which in
exemplary gas turbine engine 20 is illustrated as a geared
architecture 48 to drive the fan 42 at a lower speed than the low
speed spool 30. The high speed spool 32 includes an outer shaft 50
that interconnects a second (or high) pressure compressor 52 and a
second (or high) pressure turbine 54. A combustor 56 is arranged in
exemplary gas turbine 20 between the high pressure compressor 52
and the high pressure turbine 54. A mid-turbine frame 57 of the
engine static structure 36 is arranged generally between the high
pressure turbine 54 and the low pressure turbine 46. The
mid-turbine frame 57 further supports bearing systems 38 in the
turbine section 28. The inner shaft 40 and the outer shaft 50 are
concentric and rotate via bearing systems 38 about the engine
central longitudinal axis A which is collinear with their
longitudinal axes.
[0033] The core airflow is compressed by the low pressure
compressor 44 then the high pressure compressor 52, mixed and
burned with fuel in the combustor 56, then expanded over the high
pressure turbine 54 and low pressure turbine 46. The mid-turbine
frame 57 includes airfoils 59 which are in the core airflow path C.
The turbines 46, 54 rotationally drive the respective low speed
spool 30 and high speed spool 32 in response to the expansion. It
will be appreciated that each of the positions of the fan section
22, compressor section 24, combustor section 26, turbine section
28, and fan drive gear system 48 may be varied. For example, gear
system 48 may be located aft of combustor section 26 or even aft of
turbine section 28, and fan section 22 may be positioned forward or
aft of the location of gear system 48.
[0034] FIG. 2 illustrates an example engine component 60 in
phantom. In this example, the engine component 60 is a blade, such
as a blade for use within the turbine section 28 of the engine 20.
It should be understood that this disclosure extends to other
engine components, including vanes and blade outer air seals
(BOASs), as examples. It should be understood that this disclosure
is not limited to components in the turbine section 28, and extends
to other sections of the engine 20.
[0035] The component 60 includes an airfoil section 62, a platform
64, and a root section 66. An example casting article, or core, is
illustrated at 68. The casting article 68 is used during an
investment casting process to form an internal passageway within
the component 60. The shape of the casting article 68 is a negative
of the intended shape of the internal passageway. In this respect,
the casting article 68 may be shaped differently than the specific
casting article 68 illustrated in FIG. 2. Further, while only one
casting article 68 is illustrated, additional casting articles may
be used to provide the component 60 with the intended internal
passageway configuration. In particular, the component 60 may
include internal passageways that direct fluid to an exterior
surface of the component 60 for film cooling.
[0036] FIG. 3 illustrates the detail of the casting article 68. In
this example, the casting article 68 includes a plurality of fibers
70 incorporated into a ceramic material 72. The fibers 70 may be
randomly oriented within the ceramic portion 72 or introduced in an
ordered structure. The fibers 70 increase the strength of the
casting article 68.
[0037] FIG. 4 illustrates an example method 74 of forming the
casting article 68. At 76, a slurry (or mix) of ceramic material is
provided. The slurry may include a carrier fluid or media and
ceramic particles. The carrier fluid can be any known type of
carrier fluid, such as a solvent, water, alcohol, or solid or
semi-solid media such as wax. The ceramic particles may be provided
by any known type of ceramic material, including but not limited to
alumina (Al.sub.2O.sub.3), silica (SiO.sub.2), aluminosilicate
(Al.sub.2SiO.sub.4), and zircon (ZrAl.sub.2O.sub.4). The slurry may
also contain smaller quantities of the elemental oxides for
modification of specific properties. The slurry provided at 76 will
ultimately form the ceramic portion 72 of the casting article 68.
At 78, the fibers 70 are added into the slurry. The fibers may be
silicon (Si) fibers, alumina (Al.sub.2O.sub.3), organic fibers such
as carbon (C) fibers, or metal fibers, to name a few examples. The
volumetric ratio of the fibers to slurry might range from 1% to
50%, depending on casting requirements. In this embodiment, the
fibers may be relatively evenly dispersed, randomly dispersed, or
may be preferentially dispersed within the casting article. Fibers
may take various shapes and sizes from nanoparticle to microfibers
that extend through the components. The fibers may be random or
oriented to maximize physical properties in a desired direction. At
80, the slurry, which now includes the fibers 78, is introduced
into a die, and the casting article 68 is formed.
[0038] FIG. 5 illustrates an example method 82 for forming an
engine component having an internal passageway. The method 82 is an
investment casting technique. At 84, a wax pattern of the engine
component, which includes the casting article 68, is provided. At
86, a ceramic shell is formed around the wax pattern and the
casting article 68. At 88, wax is removed from the ceramic shell
leaving a hollow cavity in the ceramic shell containing the
integral ceramic casting article. At 90, the ceramic shell is
heated to sinter the ceramic. At 92, molten metal is introduced
(e.g., poured) into the ceramic shell, at 88, and replaces the
place of the wax pattern. The molten metal is allowed to cool, and
the casting article 68 is removed at 94.
[0039] Without the fibers 70, the casting article 68 may not
withstand the thermal stresses from the molten metal. The fibers 70
reinforce the casting article 68, and increase the overall
mechanical properties of the casting article 68.
[0040] The size (including the length L and thickness) of the
fibers 68, as well as the chemical composition of the fibers, may
be adjusted such that the fibers either survive the ceramic shell
sintering at step 92 ("option 1" at 96), or are removed (e.g.,
dissolved) by heat ("option 2" at 96). In this example, fibers
comprised of, for example, silicon would likely remain post-pour
and fibers comprised of, for example, carbon would likely be
consumed during the pour and cooling process. In the example where
the fibers 68 do not dissolve during sintering, the fibers 70
survive long enough to keep the casting article 68 intact during
the hot pour of molten metal. Further, by dissolving the fibers,
the ease of removing the casting article at 94 increases.
[0041] At 94, the casting article 68 may be removed chemically or
thermally from out of the component 60. At least the ceramic
portion 72 of the casting article 68 is leachable using a known
leaching fluid (e.g., Sodium Hydroxide). The fibers 70, depending
on their material, may also be leachable. In one example, the
fibers 70 are leached using a different fluid (e.g., a fluid having
a different chemical composition) than the fluid used to leach the
ceramic portion 72 ("option 1" at 98).
[0042] In another example, the ceramic portion 72 is leachable, but
the fibers 70 are not. In that example, the fibers 70 may be
mechanically removed from the component 60. In one example,
mechanical removal includes blowing out (i.e., purging) the fibers
70 using a pressurized fluid that carries the fibers out of the
internal passageway, such as pressurized air ("option 2" at 98). In
this example, it may be important to ensure that the length L of
the fibers 70 is substantially small. In particular, in one
example, the maximum allowable length L of the fibers 70 is less
than the smallest orifice formed in the component 60. Finally, in
the example where the fibers 70 dissolve during step 90, the
ceramic portion 72 can be leached and no further removal of fibers
is required ("option 3" at 98).
[0043] This disclosure provides a casting article having increased
structural integrity, which leads to higher quality components.
Further, the disclosed techniques increase the reliability and
repeatability of the process for removing the casting article 68
from the interior of the component. This reduces cleaning time and
streamlines manufacturing overall.
[0044] It should be understood that terms such as "axial" and
"radial" are used above with reference to the normal operational
attitude of the engine 20. Further, these terms have been used
herein for purposes of explanation, and should not be considered
otherwise limiting. Terms such as "generally," "substantially," and
"about" are not intended to be boundaryless terms, and should be
interpreted consistent with the way one skilled in the art would
interpret the term.
[0045] Although the different examples have the specific components
shown in the illustrations, embodiments of this disclosure are not
limited to those particular combinations. It is possible to use
some of the components or features from one of the examples in
combination with features or components from another one of the
examples.
[0046] One of ordinary skill in this art would understand that the
above-described embodiments are exemplary and non-limiting. That
is, modifications of this disclosure would come within the scope of
the claims. Accordingly, the following claims should be studied to
determine their true scope and content.
* * * * *