U.S. patent application number 15/695310 was filed with the patent office on 2019-03-07 for compositionally-graded metal-ceramic structure and method for manufacturing the same.
This patent application is currently assigned to The Boeing Company. The applicant listed for this patent is The Boeing Company. Invention is credited to Dennis Lynn Coad, James R. Dobbs, Ali Yousefiani, Bruno Zamorano Senderos.
Application Number | 20190072365 15/695310 |
Document ID | / |
Family ID | 63168343 |
Filed Date | 2019-03-07 |
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United States Patent
Application |
20190072365 |
Kind Code |
A1 |
Zamorano Senderos; Bruno ;
et al. |
March 7, 2019 |
COMPOSITIONALLY-GRADED METAL-CERAMIC STRUCTURE AND METHOD FOR
MANUFACTURING THE SAME
Abstract
A compositionally-graded structure including a body having a
first major surface and a second major surface opposed from the
first major surface along a thickness axis, the body including a
metallic component and a ceramic component, wherein a concentration
of the ceramic component in the body is a function of location
within the body along the thickness axis, wherein transitions of
the concentration of the ceramic component in the body are
continuous such that distinct interfaces are not macroscopically
established within the body, and wherein the concentration of the
ceramic component is at least 95 percent by volume at at least one
location within the body along the thickness axis.
Inventors: |
Zamorano Senderos; Bruno;
(Huntsville, AL) ; Coad; Dennis Lynn; (Madison,
AL) ; Dobbs; James R.; (Huntsville, AL) ;
Yousefiani; Ali; (Tustin, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Assignee: |
The Boeing Company
Chicago
IL
|
Family ID: |
63168343 |
Appl. No.: |
15/695310 |
Filed: |
September 5, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2998/10 20130101;
C22C 32/0052 20130101; B22F 2302/05 20130101; B22F 3/15 20130101;
F41H 5/0421 20130101; B22F 2998/10 20130101; B22F 3/15 20130101;
C22C 1/05 20130101; B22F 3/15 20130101; B22F 3/14 20130101; B22F
3/02 20130101; C22C 1/05 20130101; B22F 3/10 20130101; B22F 2207/01
20130101; C22C 29/10 20130101; C22C 32/0073 20130101; B22F 2301/205
20130101; B22F 2998/10 20130101; C22C 29/14 20130101; F41H 5/0428
20130101; B22F 3/10 20130101; B22F 3/14 20130101; B22F 3/02
20130101 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
1. A compositionally-graded structure comprising: a body having a
first major surface and a second major surface opposed from said
first major surface along a thickness axis, said body comprising a
metallic component and a ceramic component, wherein a concentration
of said ceramic component in said body is a function of location
within said body along said thickness axis, wherein transitions of
said concentration of said ceramic component in said body are
continuous such that distinct interfaces are not macroscopically
established within said body, and wherein said concentration of
said ceramic component is at least 95 percent by volume at at least
one location within said body along said thickness axis.
2. The compositionally-graded structure of claim 1 wherein said
metallic component comprises a titanium alloy.
3. The compositionally-graded structure of claim 2 wherein said
ceramic component comprises titanium diboride.
4. The compositionally-graded structure of claim 3 wherein said
body further comprises titanium boride.
5. The compositionally-graded structure of claim 2 wherein said
ceramic component comprises titanium carbide.
6. The compositionally-graded structure of claim 1 wherein said
metallic component comprises a metal element, and wherein said
ceramic component also comprises said metal element.
7. The compositionally-graded structure of claim 1 wherein said
function is substantially linear.
8. The compositionally-graded structure of claim 1 wherein said
function is non-linear.
9. The compositionally-graded structure of claim 1 wherein said
concentration of said ceramic component is about 100 percent by
volume at at least one location within said body along said
thickness axis.
10. The compositionally-graded structure of claim 1 wherein said
concentration of said ceramic component is at least 95 percent by
volume proximate said first major surface.
11. The compositionally-graded structure of claim 10 wherein said
concentration of said ceramic component is at most 20 percent by
volume proximate said second major surface.
12. The compositionally-graded structure of claim 10 wherein said
concentration of said ceramic component is at most 10 percent by
volume proximate said second major surface.
13. The compositionally-graded structure of claim 10 wherein said
concentration of said ceramic component is about 0 percent by
volume proximate said second major surface.
14. The compositionally-graded structure of claim 1 wherein: said
concentration of said ceramic component is at least 95 percent by
volume proximate said first major surface; and a concentration of
said metallic component is at least 80 percent by volume proximate
said second major surface.
15. An armor panel comprising: a compositionally-graded structure
comprising: a body having a first major surface and a second major
surface opposed from said first major surface along a thickness
axis, said body comprising a metallic component and a ceramic
component, wherein a concentration of said ceramic component in
said body is a function of location within said body along said
thickness axis, wherein transitions of said concentration of said
ceramic component in said body are continuous such that distinct
interfaces are not macroscopically established within said body,
and wherein said concentration of said ceramic component is at
least 95 percent by volume at at least one location within said
body along said thickness axis; and an anti-spalling layer adjacent
to said second major surface of said body.
16. The armor panel of claim 15 wherein said anti-spalling layer
comprises high-density polyethylene.
17. A method for manufacturing a compositionally-graded structure
comprising: assembling a powder layup comprising at least a first
powdered material and a second powdered material, said first
powdered material comprising a ceramic component and said second
powdered material comprising a metallic component, said powder
layup comprising: a first layer comprising a first concentration of
said ceramic component; a second layer comprising a second
concentration of said ceramic component and a first concentration
of said metallic component; and a third layer comprising a third
concentration of said ceramic component and a second concentration
of said metallic component; pressing said powder layup to yield a
compact; and heat treating said compact.
18. The method of claim 17 wherein said ceramic component comprises
titanium diboride and said metallic component comprises a titanium
alloy.
19. The method of claim 17 wherein said heat treating comprises hot
isostatic pressing.
20. The method of claim 17 wherein said heat treating comprises hot
pressing.
Description
FIELD
[0001] This application relates to compositionally-graded
metal-ceramic structures and, more particularly, to high-energy
impact protection by way of compositionally-graded metal-ceramic
structures.
BACKGROUND
[0002] High-energy impact protection is often desired for a variety
of applications. As one example, space vehicles encounter various
space debris, such as micrometeoroids and man-made orbital debris.
Therefore, space vehicles typically include a high-energy impact
protection layer to mitigate the risks associated with collisions
with space debris. As another example, certain types of terrestrial
vehicles, such as aircraft (e.g., helicopters) and ground vehicles
(e.g., military and law enforcement vehicles), are armored to
protect against ballistic threats.
[0003] In the case of ballistic threats, current state-of-the-art
armor is typically constructed from ceramic materials, such as
alumina, silicon carbide and boron carbide, which tend to blunt,
erode, decelerate and deflect projectiles. Alumina is relatively
low-cost, but requires a higher area density to achieve effective
protection, thereby limiting the use of alumina-based armor to
terrestrial vehicles. When weight is an important consideration,
such as for aircraft, more expensive boron carbide-based armor is
commonly used.
[0004] Unfortunately, the ceramic materials used to manufacture
current state-of-the-art armor are relatively heavy, thereby
increasing vehicle fuel consumption and limiting useful
applications. Such ceramic materials also present manufacturability
issues that increase overall cost and limit fabrication options.
Furthermore, the ceramic materials of current state-of-the-art
armor tend to shatter upon impact, leaving little or no material to
impede subsequent impacts. As such, current state-of-the-art armor
is relatively dense/heavy, yet offers only limited multi-hit
protection.
[0005] Accordingly, those skilled in the art continue with research
and development efforts in the field of high-energy impact
protection.
SUMMARY
[0006] In one example, the disclosed compositionally-graded
structure includes a body having a first major surface and a second
major surface opposed from the first major surface along a
thickness axis, the body including a metallic component and a
ceramic component, wherein a concentration of the ceramic component
in the body is a function of location within the body along the
thickness axis, wherein transitions of the concentration of the
ceramic component in the body are continuous such that distinct
interfaces are not macroscopically established within the body, and
wherein the concentration of the ceramic component is at least 95
percent by volume at at least one location within the body along
the thickness axis.
[0007] In one example, the disclosed armor panel includes a
compositionally-graded structure and an anti-spalling layer. The
compositionally-graded structure includes a body having a first
major surface and a second major surface opposed from the first
major surface along a thickness axis, the body including a metallic
component and a ceramic component, wherein a concentration of the
ceramic component in the body is a function of location within the
body along the thickness axis, wherein transitions of the
concentration of the ceramic component in the body are continuous
such that distinct interfaces are not macroscopically established
within the body, and wherein the concentration of the ceramic
component is at least 95 percent by volume at at least one location
within the body along the thickness axis. The anti-spalling layer
is adjacent to the second major surface of the body.
[0008] In one example, the disclosed method for manufacturing a
compositionally-graded structure includes steps of: (1) assembling
a powder layup that includes at least a first powdered material and
a second powdered material, the first powdered material including a
ceramic component and the second powdered material including a
metallic component, the powder layup including: (a) a first layer
having a first concentration of the ceramic component; (b) a second
layer having a second concentration of the ceramic component and a
first concentration of the metallic component; and (c) a third
layer having a third concentration of the ceramic component and a
second concentration of the metallic component; (2) pressing the
powder layup to yield a compact; and (3) heat treating the
compact.
[0009] Other examples of the disclosed compositionally-graded
metal-ceramic structures, armor panels, and methods will become
apparent from the following detailed description, the accompanying
drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic cross-sectional view of one example of
the disclosed compositionally-graded structure;
[0011] FIG. 2 is a graphical depiction of the compositional
distribution (percent by volume versus position) of the
compositionally-graded structure of FIG. 1;
[0012] FIG. 3 is a graphical depiction of one alternative, though
non-limiting, example of a compositional distribution of the
disclosed compositionally-graded structure;
[0013] FIG. 4 is a graphical depiction of another alternative,
though non-limiting, example of a compositional distribution of the
disclosed compositionally-graded structure;
[0014] FIG. 5 is a schematic cross-sectional view of an article (an
armor panel) incorporating the disclosed compositionally-graded
structure;
[0015] FIG. 6 is a flow diagram depicting one example of the
disclosed method for manufacturing a compositionally-graded
structure;
[0016] FIG. 7 is a schematic representation of an example powder
layup formed pursuant to the method of FIG. 6;
[0017] FIG. 8 is a scanning electron microscope backscattered
electron micrograph of a sample compositionally-graded structure
formed pursuant to the method of FIG. 6;
[0018] FIG. 9 is a flow diagram of an aircraft manufacturing and
service methodology; and
[0019] FIG. 10 is a block diagram of an aircraft.
DETAILED DESCRIPTION
[0020] Referring to FIG. 1, one example of the disclosed
compositionally-graded structure, generally designated 10, may
include a body 12 having a first major surface 14 (e.g., a striking
surface) and a second major surface 16 (e.g., a backside surface).
The second major surface 16 may be opposed from the first major
surface 14 along a thickness axis T. The thickness axis T may be
generally perpendicular to the first major surface 14, generally
perpendicular to the second major surface 16 or generally
perpendicular to both the first major surface 14 and the second
major surface 16.
[0021] The body 12 of the compositionally-graded structure 10 may
be a consolidated mass, and may include a metallic component 18 and
a ceramic component 20. Plural metallic components 18 and/or plural
ceramic components 20 may be used without departing from the scope
of the present disclosure. Furthermore, other components (other
than the metallic component 18 and the ceramic component 20) may be
included in the body 12, whether by addition or in situ formation,
without departing from the scope of the present disclosure.
[0022] The metallic component 18 of the body 12 of the
compositionally-graded structure 10 may be a metal or metal alloy.
As one specific, non-limiting example, the metallic component 18 of
the body 12 may be a titanium alloy, such as Ti-6Al-4V. As another
specific, non-limiting example, the metallic component 18 of the
body 12 may be an aluminum alloy, such as a 7000-series aluminum
alloy (e.g., aluminum 7075). As yet another specific, non-limiting
example, the metallic component 18 of the body 12 may be a nickel
alloy, such as a nickel-based superalloy (e.g., Inconel 625).
[0023] The ceramic component 20 of the body 12 of the
compositionally-graded structure 10 may be a ceramic material.
Various ceramic materials may be used as the ceramic component 20
of the body 12. Examples of ceramic materials suitable for use as
the ceramic component 20 of the body 12 include, without
limitation, titanium diboride (TiB.sub.2), titanium boride (TiB),
titanium carbide (TiC), chromium carbide (e.g., Cr.sub.23C.sub.6),
silicon carbide (SiC), tungsten carbide (WC), and the like.
[0024] The composition of the ceramic component 20 may be selected
based on the composition of the metallic component 18, and vise
versa. In a particular implementation, a metal element may be
common to both the metallic component 18 and the ceramic component
20. In one expression, titanium may be common to both the metallic
component 18 and the ceramic component 20. In another expression,
aluminum may be common to both the metallic component 18 and the
ceramic component 20. In yet another expression, chromium may be
common to both the metallic component 18 and the ceramic component
20.
[0025] Thus, the body 12 of the compositionally-graded structure 10
may be formed from a material system that includes both a metallic
component 18 and a ceramic component 20. While the compositions of
the metallic component 18 and the ceramic component 20 are design
choices that may widely vary without departing from the scope of
the present disclosure, it is believed that certain advantages may
be gained by selecting a material system in which there is a metal
element common to both the metallic component 18 and the ceramic
component 20. Specific, non-limiting examples of such material
systems include titanium alloy/titanium diboride; titanium
alloy/titanium boride/titanium diboride; titanium alloy/titanium
boride; titanium alloy/titanium carbide; aluminum alloy/aluminum
oxide; nickel-chromium alloy/chromium carbide.
[0026] As shown in FIG. 1, the composition of the body 12 of the
compositionally-graded structure 10 may be graded along the
thickness axis T of the body 12. Therefore, the concentrations of
the metallic component 18 and the ceramic component 20 within the
body 12 are functions of location within the body 12 along the
thickness axis T. Significantly, transitions of the concentrations
of the metallic component 18 and the ceramic component 20 within
the body 12 are continuous, which is to say that distinct
interfaces (e.g., layers) are not macroscopically established
within the body 12.
[0027] Referring to FIG. 2, the concentrations of the metallic
component 18 and/or the ceramic component 20 versus location within
the body 12 along the thickness axis T may be substantially linear
functions. The concentration of the metallic component 18 may
linearly transition from a relatively low concentration proximate
(at or near) the first major surface 14 to a relatively high
concentration proximate the second major surface 16, while the
concentration of the ceramic component 20 may linearly transition
from a relatively high concentration proximate the first major
surface 14 to a relatively low concentration proximate the second
major surface 16. Therefore, depending upon location within the
body 12 along the thickness axis T, compositionally the body 12 may
be substantially ceramic, substantially metallic or some
combination of ceramic and metallic.
[0028] As one specific, non-limiting example, the concentration of
the metallic component 18 may linearly transition from zero (or
about zero) proximate the first major surface 14 to about 100
percent by volume proximate the second major surface 16, while the
concentration of the ceramic component 20 may linearly transition
from about 100 percent by volume proximate the first major surface
14 to zero (or about zero) proximate the second major surface
16.
[0029] As another specific, non-limiting example, the concentration
of the metallic component 18 may linearly transition from at most
about 5 percent by volume proximate the first major surface 14 to
at least about 90 percent by volume proximate the second major
surface 16, while the concentration of the ceramic component 20 may
linearly transition from at least about 95 percent by volume
proximate the first major surface 14 to at most about 10 percent by
volume proximate the second major surface 16.
[0030] As yet another specific, non-limiting example, the
concentration of the metallic component 18 may linearly transition
from at most about 5 percent by volume proximate the first major
surface 14 to at least about 80 percent by volume proximate the
second major surface 16, while the concentration of the ceramic
component 20 may linearly transition from at least about 95 percent
by volume proximate the first major surface 14 to at most about 20
percent by volume proximate the second major surface 16.
[0031] Alternatively, the concentrations of the metallic component
18 and/or the ceramic component 20 versus location within the body
12 along the thickness axis T may be non-linear functions. In one
variation, the concentration of the metallic component 18 may
transition from a relatively low concentration proximate the first
major surface 14 to a relatively high concentration proximate the
second major surface 16, while the concentration of the ceramic
component 20 may transition from a relatively high concentration
proximate the first major surface 14 to a relatively low
concentration proximate the second major surface 16. In another
variation, the concentration of the metallic component 18 may
transition from a relatively low concentration proximate the first
major surface 14 to a relatively high concentration between the
first and second major surfaces 14, 16, and then back to a
relatively low concentration proximate the second major surface 16.
In yet another variation, the concentration of the ceramic
component 20 may transition from a relatively low concentration
proximate the first major surface 14 to a relatively high
concentration between the first and second major surfaces 14, 16,
and then back to a relatively low concentration proximate the
second major surface 16. Therefore, the composition of the body 12
may be continuously transitioned in numerous ways along the
thickness axis T.
[0032] Referring to FIG. 3, as one specific, non-limiting example,
the body 12 of the compositionally-graded structure 10 may include
a titanium alloy (e.g., Ti-6Al-4V) as the metallic component 18 and
both titanium diboride and titanium boride as the ceramic component
20. The concentrations of titanium diboride and titanium boride
(ceramic component 20) within the body 12 along the thickness axis
T are non-linear functions of location, while the concentration of
the titanium alloy (metallic component 18) within the body 12 along
the thickness axis T is a linear function of location.
[0033] Referring to FIG. 4, as another specific, non-limiting
example, the body 12 of the compositionally-graded structure 10 may
include a titanium alloy (e.g., Ti-6Al-4V) as the metallic
component 18 and both titanium diboride and titanium boride as the
ceramic component 20. The concentrations of titanium diboride and
titanium boride (ceramic component 20) within the body 12 along the
thickness axis T are non-linear functions of location, and the
concentration of the titanium alloy (metallic component 18) within
the body 12 along the thickness axis T is also a non-linear
function of location.
[0034] The disclosed compositionally-graded structure 10 may have a
relatively high concentration of the ceramic component 20 at at
least one location within the body 12 along the thickness axis T.
The location having a relatively high concentration of the ceramic
component 20 may be proximate the first major surface 14 of the
body 12, though various other configurations are also contemplated
and will not result in a departure from the scope of the present
disclosure. As one example, the concentration of the ceramic
component 20 may be at least about 95 percent by volume at at least
one location within the body 12 along the thickness axis T. As
another example, the concentration of the ceramic component 20 may
be at least about 96 percent by volume at at least one location
within the body 12 along the thickness axis T. As another example,
the concentration of the ceramic component 20 may be at least about
97 percent by volume at at least one location within the body 12
along the thickness axis T. As another example, the concentration
of the ceramic component 20 may be at least about 98 percent by
volume at at least one location within the body 12 along the
thickness axis T. As another example, the concentration of the
ceramic component 20 may be at least about 99 percent by volume at
at least one location within the body 12 along the thickness axis
T. As yet another example, the concentration of the ceramic
component 20 may be about 100 percent by volume at at least one
location within the body 12 along the thickness axis T.
[0035] Referring to FIG. 5, one example of the disclosed armor
panel, generally designated 30, may include the disclosed
compositionally-graded structure 10' and an anti-spalling layer 32
adjacent to the compositionally-graded structure 10'. Additional
layers may be included in the disclosed armor panel 30 without
departing from the scope of the present disclosure.
[0036] In one particular construction, the concentration of the
metallic component 18 (FIG. 1) of the body 12' of the
compositionally-graded structure 10' may be relatively low
proximate the first major surface 14' and relatively high proximate
the second major surface 16', while the concentration of the
ceramic component 20 (FIG. 1) may be relatively high proximate the
first major surface 14' to a relatively low proximate the second
major surface 16'. Therefore, the anti-spalling layer 32 may be
positioned adjacent to the second major surface 16' of the body 12'
of the compositionally-graded structure 10'.
[0037] Various materials may be used to form the anti-spalling
layer 32 of the disclosed armor panel 30. As one specific,
non-limiting example, the anti-spalling layer 32 may be formed from
(or may include) high-density polyethylene. As another specific,
non-limiting example, the anti-spalling layer 32 may be formed from
(or may include) aramid fibers. The cross-sectional thickness of
the anti-spalling layer 32 (relative to the thickness axis T' of
the compositionally-graded structure 10') may be a design
consideration, and may vary depending on, for example, the
cross-sectional thickness of the compositionally-graded structure
10'.
[0038] Referring to FIG. 6, disclosed is a method, generally
designated 60, for manufacturing the disclosed
compositionally-graded structure. The disclosed method 60 employs
powder processing techniques to yield a compositionally-graded
structure having a body that includes a metallic component and a
ceramic component, wherein concentrations of the metallic component
and the ceramic component in the body are functions of location
within the body along the thickness axis of the body, and wherein
transitions of the concentrations of the metallic component and the
ceramic component in the body are continuous such that distinct
interfaces are not macroscopically established within the body.
[0039] The method 60 may begin at Block 62 with step of materials
selection. The materials selection step may include selecting at
least one metallic component (in powdered form) and at least one
ceramic component (in powdered form) for use in subsequent steps of
the method 60. Non-limiting examples of suitable metallic
components and suitable ceramic components are disclosed herein.
Optionally, the metallic component and the ceramic component may be
selected such that a metal element is common to both the metallic
component and the ceramic component. For example, the metallic
component may be a powdered titanium alloy (e.g., Ti-6Al-4V) and
the ceramic component may be a powdered titanium-containing ceramic
material, such as titanium diboride, titanium boride and/or
titanium carbide.
[0040] At Block 64, the metallic component and the ceramic
component selected at Block 62 may be used to assemble a powder
layup having a plurality of layers of powdered material. In one
expression, assembling a powder layup includes laying up at least
three layers of powdered material. In another expression,
assembling a powder layup includes laying up at least five layers
of powdered material. In yet another expression, assembling a
powder layup includes laying up at least ten layers of powdered
material. Without being limited to any particular theory, it is
believed that using a powder layup having a greater number of
layers of powdered material may result in a compositionally-graded
structure having a smoother transition in composition across the
thickness axis.
[0041] Adjacent layers (if not all layers) of powdered material of
the powder layup may have different compositions, with each layer
being formed from the metallic component (unmixed), the ceramic
component (unmixed) or by thoroughly mixing (e.g., by shaking,
using a rotary ball mixer, or any other mixing procedure) the
metallic component and the ceramic component in different ratios.
Each layer of the powder layup may include at least one of the
metallic component and the ceramic component, wherein the
concentration of the metallic component ranges from 0 to 100
percent by volume and the concentration of the ceramic component
ranges from 0 to 100 percent by volume.
[0042] A non-limiting example powder layup 80 (contained in a die
82) is shown in FIG. 7. The example powder layup 80 includes six
layers 84, 86, 88, 90, 92, 94. The first layer 84 of the powder
layup 80 includes about 100 percent by weight of the metallic
component. The second layer 86 of the powder layup 80 includes a
mixture containing about 80 percent by weight of the metallic
component and about 20 percent by weight of the ceramic component.
The third layer 88 of the powder layup 80 includes a mixture
containing about 60 percent by weight of the metallic component and
about 40 percent by weight of the ceramic component. The fourth
layer 90 of the powder layup 80 includes a mixture containing about
40 percent by weight of the metallic component and about 60 percent
by weight of the ceramic component. The fifth layer 92 of the
powder layup 80 includes a mixture containing about 20 percent by
weight of the metallic component and about 80 percent by weight of
the ceramic component. The sixth layer 94 of the powder layup 80
includes about 100 percent by weight of the ceramic component.
[0043] At Block 66, the powder layup assembled at Block 64 may be
pressed to form a compact that is not yet synthesized. As shown in
FIG. 7, the powder layup 80 may be assembled in a die 82 and the
die 82 may be pressed (e.g., by a plug that is sized and shaped to
engage the die 82), such as in a hydraulic press (not shown), under
ambient conditions to yield a compact. Pressing (Block 66) may be
performed at pressures ranging, for example, from about 10 kpsi to
about 16 kpsi.
[0044] Rather than pressing (Block 66) the fully assembled powder
layup, one alternative approach to pressing (Block 66) includes
pressing each layer of powdered material as it is added to the
powder layup. For example, referring to FIG. 7, a first layer 84 of
powdered material may be laid down (Block 64) and then pressed
(Block 66). Then a second layer 86 of powdered material may be
layered over the pressed first layer 84, and the combination of the
pressed first layer 84 and the unpressed second layer 86 may be
pressed, and so on. Another alternative approach to pressing (Block
66) includes pressing two or more adjacent layers of powdered
material prior to adding additional layers of powdered
material.
[0045] At this point, those skilled in the art will appreciate
that, while assembling the powder layup (Block 64) and pressing
(Block 66) are shown in FIG. 6 as two separate steps, the steps of
assembling the powder layup (Block 64) and pressing (Block 66) may
be performed simultaneously without departing from the scope of the
present disclosure.
[0046] At Block 68, the compact formed at Block 66 may be heat
treated to form a consolidated mass (the compositionally-graded
structure). Various heat treatments may be used at Block 68 without
departing from the scope of the present disclosure.
[0047] In one implementation, the heat treatment step (Block 68)
includes hot pressing. The hot pressing process may include one or
more consolidating process parameters, such as a consolidating
pressure, a consolidating temperature and a consolidating time. The
hot pressing process may be performed by any suitable hot pressing
apparatus, such as a graphite press, operating under the
consolidating process parameters. For example, the compact may be
consolidated at the consolidating temperature and under the
consolidating pressure for a period of time (e.g., the
consolidating time). The hot pressing process may be performed
under inert conditions (e.g., argon gas).
[0048] Those skilled in the art will appreciate that the hot
pressing process consolidating process parameters will depend on
the composition of the metallic component and the ceramic component
used to form the compact. For example, when a titanium
alloy/titanium diboride material system is used, hot pressing
(Block 68) may be performed at a temperature ranging from about
800.degree. C. to about 1,400.degree. C. and a pressure ranging
from about 40 MPa to about 50 MPa for at least about 30 minutes
(e.g., one hour).
[0049] In another implementation, the heat treatment step (Block
68) includes hot isostatic pressing (HlPing or HIP consolidating).
The hot isostatic pressing process may include one or more
consolidating process parameters, such as a consolidating pressure,
a consolidating temperature and a consolidating time. The hot
isostatic pressing process may be performed by any suitable hot
isostatic pressing apparatus operating under the consolidating
process parameters. For example, the compact may be consolidated at
the consolidating temperature and under the consolidating pressure
for a period of time (e.g., the consolidating time). The hot
isostatic pressing process may be performed using a commercially
available hot isostatic pressing machine.
[0050] Those skilled in the art will appreciate that the hot
isostatic pressing process consolidating process parameters will
depend on the composition of the metallic component and the ceramic
component used to form the compact. For example, when a titanium
alloy/titanium diboride material system is used, hot isostatic
pressing (Block 68) may be performed at a temperature ranging from
about 1400.degree. C. to about 1,800.degree. C. and a pressure
ranging from about 150 MPa to about 250 MPa for at least about 30
minutes (e.g., one to two hours).
[0051] At Block 70, the consolidated mass formed at Block 68 may
optionally be subjected to one or more post-processing operations.
Examples of post-processing operations include, without limitation,
trimming, machining and the like.
[0052] Referring to FIG. 8, there is shown a scanning electron
microscope backscattered electron micrograph of a sample
compositionally-graded structure formed pursuant to the method 60
of FIG. 6. The sample was prepared by hot isostatic pressing a
compact at 1700.degree. C. and 200 MPa for 2 hours. The compact was
formed from a powder layup having six layers of powdered material
(100 percent by weight metallic component; 80/20; 60/40; 40/60;
20/80; 0 percent by weight metallic component) using powdered
Ti-6A1-4V as the metallic component and powdered titanium diboride
as the ceramic component. As shown in FIG. 8, the sample exhibited
a primarily ceramic composition proximate the first major surface
(top of the image) and a primarily metallic composition proximate
the second major surface (bottom of the image), with a continuous
transition in concentration (no distinct interfaces).
[0053] Accordingly, the disclosed compositionally-graded structure
may be suitable for use as (or in) high-energy impact protection
apparatus (e.g., armor panels). The continuous transition from
primarily ceramic material to primarily metallic material has the
potential to slow impact wave propagation, which may provide
greater impact energy absorption, thereby reducing the amount (and
weight) of material required for high-energy impact protection.
Furthermore, the continuous transition from primarily ceramic
material to primarily metallic material may offer greater multi-hit
performance.
[0054] Examples of the disclosure may be described in the context
of an aircraft manufacturing and service method 100, as shown in
FIG. 9, and an aircraft 102, as shown in FIG. 10. During
pre-production, the aircraft manufacturing and service method 100
may include specification and design 104 of the aircraft 102 and
material procurement 106. During production, component/subassembly
manufacturing 108 and system integration 110 of the aircraft 102
takes place. Thereafter, the aircraft 102 may go through
certification and delivery 112 in order to be placed in service
114. While in service by a customer, the aircraft 102 is scheduled
for routine maintenance and service 116, which may also include
modification, reconfiguration, refurbishment and the like.
[0055] Each of the processes of method 100 may be performed or
carried out by a system integrator, a third party, and/or an
operator (e.g., a customer). For the purposes of this description,
a system integrator may include without limitation any number of
aircraft manufacturers and major-system subcontractors; a third
party may include without limitation any number of venders,
subcontractors, and suppliers; and an operator may be an airline,
leasing company, military entity, service organization, and so
on.
[0056] As shown in FIG. 10, the aircraft 102 produced by example
method 100 may include an airframe 118 with a plurality of systems
120 and an interior 122. Examples of the plurality of systems 120
may include one or more of a propulsion system 124, an electrical
system 126, a hydraulic system 128, and an environmental system
130. Any number of other systems may be included.
[0057] The disclosed compositionally-graded metal-ceramic
structures and methods may be employed during any one or more of
the stages of the aircraft manufacturing and service method 100. As
one example, components or subassemblies corresponding to
component/subassembly manufacturing 108, system integration 110,
and or maintenance and service 116 may be fabricated or
manufactured using the disclosed compositionally-graded
metal-ceramic structures and methods. As another example, the
airframe 118 may be constructed using the disclosed
compositionally-graded metal-ceramic structures and methods. Also,
one or more apparatus examples, method examples, or a combination
thereof may be utilized during component/subassembly manufacturing
108 and/or system integration 110, for example, by substantially
expediting assembly of or reducing the cost of an aircraft 102,
such as the airframe 118 and/or the interior 122. Similarly, one or
more of system examples, method examples, or a combination thereof
may be utilized while the aircraft 102 is in service, for example
and without limitation, to maintenance and service 116.
[0058] The disclosed compositionally-graded metal-ceramic
structures and methods are described in the context of an aircraft
(e.g., helicopters). However, one of ordinary skill in the art will
readily recognize that the disclosed compositionally-graded
metal-ceramic structures and methods may be utilized for a variety
of applications. For example, the disclosed compositionally-graded
metal-ceramic structures and methods may be implemented in various
types of vehicles including, for example, passenger ships,
automobiles, marine products (boats, motors, etc.) and the like.
Various non-vehicle applications, such as body armor, are also
contemplated.
[0059] Although various examples of the disclosed
compositionally-graded metal-ceramic structures, armor panels, and
methods have been shown and described, modifications may occur to
those skilled in the art upon reading the specification. The
present application includes such modifications and is limited only
by the scope of the claims.
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