U.S. patent application number 16/657854 was filed with the patent office on 2021-04-22 for multi-component deposits.
The applicant listed for this patent is Rolls-Royce Corporation, Rolls-Royce North American Technologies, Inc.. Invention is credited to Matthew R. Gold, Peter Joseph Loftus.
Application Number | 20210115566 16/657854 |
Document ID | / |
Family ID | 1000004452370 |
Filed Date | 2021-04-22 |
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United States Patent
Application |
20210115566 |
Kind Code |
A1 |
Gold; Matthew R. ; et
al. |
April 22, 2021 |
MULTI-COMPONENT DEPOSITS
Abstract
The disclosure describes an example technique that includes cold
spraying first particles and second particles of a metal alloy on
at least a portion of a surface of a substrate to form a deposit on
the surface of the substrate. The first and second particles have
been subjected to different heat treatments prior to cold spraying.
Cold spraying involves accelerating the first particles and the
second particles toward the surface of the substrate without
melting or creating other thermally induced changes to a
microstructure of the first and second particles. As a result, the
first particles form a first, heat-treated component and the second
particles form a second non-heat-treated or
differently-heat-treated component, and the particles and substrate
are not subject to a heat treatment during the cold spray process
that may further modify their thermomechanical properties.
Inventors: |
Gold; Matthew R.; (Carmel,
IN) ; Loftus; Peter Joseph; (Greenwood, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Corporation
Rolls-Royce North American Technologies, Inc. |
Indianapolis
Indianapolis |
IN
IN |
US
US |
|
|
Family ID: |
1000004452370 |
Appl. No.: |
16/657854 |
Filed: |
October 18, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2303/30 20130101;
B22F 7/04 20130101; B22F 2301/052 20130101; C23C 30/005 20130101;
B22F 2007/042 20130101; B22F 2301/15 20130101; B22F 2301/10
20130101; B22F 2304/10 20130101; B22F 2303/20 20130101; B22F 1/0085
20130101; C23C 24/04 20130101; B22F 2301/205 20130101; B22F 2301/35
20130101; B22F 2999/00 20130101 |
International
Class: |
C23C 24/04 20060101
C23C024/04; C23C 30/00 20060101 C23C030/00; B22F 1/00 20060101
B22F001/00; B22F 7/04 20060101 B22F007/04 |
Claims
1. A method comprising: cold spraying first particles and second
particles of a metal alloy on at least a portion of a surface of a
substrate to form a deposit on the surface of the substrate,
wherein the first particles form a first component of the deposit
and the second particles form a second component of the deposit,
wherein cold spraying comprises accelerating the first particles
and the second particles toward the surface of the substrate
without creating thermally induced changes to a microstructure of
the respective first and second particles, and wherein the first
and second particles have been subjected to different heat
treatments prior to cold spraying.
2. The method of claim 1, wherein the first particles comprise at
least one of precipitation hardened particles, quenched hardened
particles, or tempered particles.
3. The method of claim 1, wherein a volume percentage of the first
component in the deposit is between about 1% and about 99%.
4. The method of claim 1, wherein the metal alloy comprises at
least one of a Mg-based alloy, a Ni-based alloy, a Ti-based alloy,
a Fe-based alloy, an Al-based alloy, a Co-based alloy, a Ta-based
alloy, a Nb-based alloy, a Zn-based alloy, a Cr-based alloy, or a
Cu-based alloy.
5. The method of claim 1, wherein the surface comprises a cracked
surface, and wherein forming the deposit further comprises filling
the cracked surface with the deposit.
6. The method of claim 1, wherein a tensile strength of the first
particles is at least about twice as high as a tensile strength of
the second particles.
7. The method of claim 1, wherein an elongation of the first
particles is at least about 50% greater than an elongation of the
second particles.
8. The method of claim 1, wherein the metal alloy comprises a first
composition, and wherein the method further comprises forming the
substrate from a second composition, different from the first
composition.
9. The method of claim 1, wherein the first and second particles
and the substrate are not subject to a heat treatment during the
cold spraying that would further modify thermomechanical properties
of the first and second particles and the substrate.
10. The method of claim 1, wherein the second composition comprises
the metal alloy that has not been subjected to a heat treatment
prior to cold spraying.
11. An article comprising: a substrate defining a surface; and a
deposit on the surface of the substrate, wherein the deposit was
formed using cold spraying, wherein the deposit comprises a first
component and a second component, wherein cold spraying comprises
accelerating first particles and second particles of a metal alloy
toward the surface of the substrate without creating thermally
induced changes to a microstructure of the respective first and
second particles, and wherein the first and second particles have
been subjected to different heat treatments prior to cold
spraying.
12. The article of claim 11, wherein the first particles comprise
at least one of precipitation hardened particles, quenched hardened
particles, or tempered particles.
13. The article of claim 11, wherein a volume percentage of the
first component in the deposit is between about 1% and about
99%.
14. The article of claim 11, wherein the metal alloy comprises at
least one of Mg-based alloys, Ni-based alloys, Ti-based alloys,
Fe-based alloys, Al-based alloys, Co-based alloys, Ta-based alloys,
Nb-based alloys, Zn-based alloys, Cr-based alloys, and Cu-based
alloys.
15. The article of claim 11, wherein the surface comprises a
cracked surface, and wherein the deposit fills at least a portion
of the cracked surface.
16. The article of claim 11, wherein a tensile strength of the
first particles is at least about twice as high as a tensile
strength of the second particles.
17. The article of claim 11, wherein an elongation of the first
particles is at least about 50% greater than an elongation of the
second particles.
18. The article of claim 11, wherein the metal alloy comprises a
first composition, and wherein the substrate comprises a second
composition, different from the first composition.
19. The article of claim 11, wherein the first and second particles
and the substrate are not subject to a heat treatment during the
cold spraying that would further modify thermomechanical properties
of the first and second particles and the substrate.
20. The article of claim 11, wherein the second particles comprise
the metal alloy that has not been subjected to a heat treatment
prior to cold spraying.
Description
TECHNICAL FIELD
[0001] The disclosure relates to multi-component deposits and
techniques for forming multi-component deposits.
BACKGROUND
[0002] Heat treatment processes may be used to alter the physical
properties of a component, such as a mechanical part, after the
component has been formed. In a typical heat treatment process, a
fabricated component may be heated to a predefined bulk
temperature, such as a transformation temperature of the
constituent material of the component, held at the temperature for
a period of time to achieve a relatively uniform temperature
throughout the component, and cooled at a predefined cooling rate
to achieve a particular transformation of the constituent material
of the component. As a result, the component may include a
relatively uniform set of physical properties different from the
initial set of physical properties of the component prior to heat
treatment.
SUMMARY
[0003] The disclosure describes example articles, and techniques
and systems for forming the example articles, that include a
deposit having a heat-treated component and either a
non-heat-treated or a differently-heat-treated component.
[0004] In some examples, the disclosure describes an example
technique that includes cold spraying first particles and second
particles of a metal alloy on at least a portion of a surface of a
substrate to form a deposit on the surface of the substrate. The
first and second particles have been subjected to different heat
treatments prior to cold spraying. For example, the first particles
may include particles that have undergone a heat treatment, while
the second particles may include particles that have either
undergone no heat treatment or undergone a different heat treatment
than the first particles. Cold spraying involves accelerating the
first particles and the second particles toward the surface of the
substrate without melting or creating other thermally induced
changes to a microstructure of the first and second particles. As a
result, the first particles form a first, heat-treated component
and the second particles form a second non-heat-treated or
differently-heat-treated component, and the particles and substrate
are not subject to a heat treatment during the cold spray process
that may further modify their thermomechanical properties.
[0005] In some examples, the disclosure describes an example
article that includes a substrate defining a surface and a deposit
on the surface of the substrate in which the deposit was formed
using cold spraying. The deposit includes a first component and a
second component. Cold spraying involves accelerating first
particles and second particles of a metal alloy toward the surface
of the substrate without creating thermally induced changes to a
microstructure of the respective first and second particles. The
first and second particles have been subjected to different heat
treatments prior to cold spraying.
[0006] The details of one or more examples are set forth in the
accompanying drawings and the description below. Other features,
objects, and advantages will be apparent from the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1A is a conceptual cross-sectional view of an example
article including a deposit that includes a first component and a
second component.
[0008] FIG. 1B is a conceptual cross-sectional view of an example
article including a deposit that includes a first component and a
second component.
[0009] FIG. 2 is a conceptual and schematic block diagram of an
example system for forming a deposit on a surface of a substrate by
cold spraying first particles and second particles of a metal alloy
on the surface of the substrate.
[0010] FIG. 3 is a flow diagram illustrating an example technique
for forming a deposit on a surface of a substrate by cold spraying
first particles and second particles of a metal alloy on the
surface of the substrate.
DETAILED DESCRIPTION
[0011] The disclosure generally describes example systems and
techniques for depositing heat treated metal alloys and,
optionally, non-heat-treated metal alloys onto a substrate without
exposing the substrate to high temperatures. The example techniques
involve cold spraying metal alloy particles onto a substrate to
form a deposit. These cold sprayed metal alloy particles include a
mix of particles having a metal alloy that has been heat treated
("heat-treated particles") and particles having the same metal
alloy that either has not been heat treated ("non-heat-treated
particles") or has been heat treated with a different
heat-treatment ("differently-heat-treated particles"). Heat-treated
particles may have properties, such as tensile strength and
elongation, that are improved compared to non-heat-treated
particles of the same composition. In cold spraying, the
heat-treated particles, non-heat-treated particles, and/or
differently-heat-treated particles are directed toward and impact
the substrate while having temperatures that remain below a
temperature at which the particles experience thermally induced
property changes. The cold sprayed particles bond with previously
deposited particles to form a two-component deposit that includes a
heat-treated component and either a non-heat-treated component or a
differently-heat-treated component.
[0012] In some examples, the techniques discussed herein
incorporate heat-treated materials into an article without exposing
an underlying substrate of the article or materials in the deposit
to temperature conditions experienced during heat treatment
processes. For example, deposition of a heat-treated metal alloy
layer may involve first depositing the metal alloy layer and
subsequently exposing both the metal alloy layer and the substrate
to heat treatment conditions, including high temperature conditions
for extended periods of time and/or fast cooling conditions. These
high temperature and/or fast cooling conditions may damage the
substrate and/or produce undesired changes in properties of the
substrate. Cold spray deposition of heat-treated particles may
occur below the melting point or other transition temperature of
the metal alloy and without bulk heating of the underlying
substrate or deposited material, such that the underlying substrate
or deposited material is exposed to lower temperatures than
techniques that incorporate heat-treated materials onto a substrate
without cold spraying. As such, properties of the heat-treated
particles, non-heat-treated particles, and/or
differently-heat-treated particles may be substantially unchanged
after cold spraying.
[0013] In some examples, the techniques discussed herein
incorporate a blend of various heat-treated materials and
non-heat-treated materials into an article. For example, heat
treatment of a metal alloy layer may involve bulk heating the metal
alloy layer to a substantially uniform temperature to produce a
metal alloy layer with substantially homogeneous properties. Cold
spray deposition of the heat-treated particles and
differently-heat-treated or non-heat-treated particles may produce
a deposit that includes properties, such as tensile strength and
elongation, derived from the heat-treated material, and either and
the non-heat-treated material or the differently-heat-treated
material, such that deposits formed from a mix of heat-treated
particles and differently-heat-treated or non-heat-treated
particles may include a greater variety of properties than deposits
formed from heat-treated or non-heat-treated materials alone.
[0014] FIG. 1A is a conceptual cross-sectional view of an example
article 10A that includes a substrate 12 and a deposit 14. In some
examples, article 10A may be a component of a gas turbine engine.
For example, article 10A may be a component with a barrier coating,
a repaired component, a multi-layer component, or the like. Due to
high temperatures experienced in gas turbine engine, components of
gas turbine engines may incorporate heat treated materials to
relieve residual stresses and increase desired properties. In some
examples, substrate 12 includes a bulk material, such as a forged
metal, a cast metal, or a sheet metal, that may be substantially
homogeneous (e.g., homogeneous or nearly homogeneous to the extent
possible by common metallurgy techniques). Bulk materials that may
be used for substrate 12 include, but are not limited to, Ni-based
alloys, Co-based alloys, Ti-based alloys, or Fe-based alloys.
Substrate 12 defines a surface 16. Surface 16 may have a variety of
surface conditions including, but not limited to, an
as-manufactured surface, a2. damaged surface, or the like.
[0015] Deposit 14 is on at least a portion of surface 16 of
substrate 12. While shown in FIG. 1A as covering an entirety of
surface 16, in some instances, deposit 14 may only cover a
particular area, such as a portion of article 10A that may
experience abrasion, high temperatures, or other external phenomena
that induce stresses and/or fractures. Deposit 14 may represent a
one or more of a variety of functional deposits of the metal alloy
on substrate 12 including, but not limited to: a structure
functionally differentiated from substrate 12, such as a flange or
other structure extending from and/or complementary to substrate
12; a repair joint of substrate 12, such as a filler; a coating on
substrate 12, such as a barrier coating; a layer on substrate 12,
such as a layer in a multi-layer part; or the like.
[0016] In some examples, deposit 14 may be configured to improve
properties of substrate 12. For example, substrate 12 may be a
damaged component having cracked surface 16 that includes one or
more cracks that extend into substrate 12. Rather than replace
substrate 12 with a new part or repair substrate 12 using high
temperature techniques, such as welding or post-deposition heat
treatment, deposit 14 may be formed within the one or more cracks
to fill the cracks. As a result, substrate 12 may have improved
properties, such as strength aerodynamic shape, or the like,
compared to substrate 12 prior to receiving deposit 14. In some
examples, deposit 14 and substrate 12 include the same composition,
such that article 10A may have a substantially homogeneous
composition after repair of substrate 12. In some examples, deposit
14 and substrate 12 may include different compositions. For
example, a particular composition of deposit 14 may be better
suited (e.g., more easily bond with substrate 12 using cold
spraying, etc.) as a filler for cracks than a composition of
substrate 12.
[0017] In some examples, deposit 14 may be configured to protect
substrate 12 from physical impact or chemical reactants. For
example, substrate 12 may be a high temperature component, such
that portions of substrate 12 near surface 16 may face a high
temperature environment with reducing agents, such as
calcia-magnesia-alumina-sulfur (CMAS), that may damage substrate
12. To protect substrate 12 from these agents, deposit 14 may
extend continuously across surface 16 to provide a dense, high
strength barrier for substrate 12.
[0018] In some examples, deposit 14 may be configured to complement
substrate 12 as a separate structure that provides additional
functionality to substrate 12. For example, deposit 14 may include
a mechanical component, such as a flange, that is mechanically
coupled to substrate 12 and configured to perform a different
function than substrate 12.
[0019] Deposit 14 includes a metal alloy. Metal alloys may have
constituent elements that, when subjected to various heat
treatments, undergo phase transformations or migrate from solution
to change a microstructure of deposit 14. The metal alloy of
deposit 14 may include any metal alloy whose properties may change,
such as through changes in microstructure or homogeneity of the
metal alloy, in response to heat treatment processes. Metal alloys
that may be used include, but are not limited to, Mg-based alloys,
Ni-based alloys, Ti-based alloys, Fe-based alloys, Al-based alloys,
Co-based alloys, Ta-based alloys, Nb-based alloys, Zn-based alloys,
Cr-based alloys, and Cu-based alloys.
[0020] Deposit 14 is deposited on surface 16 using cold spraying
techniques. As will be explained further in FIG. 2 below, cold
spraying involves accelerating first particles (e.g., heat-treated
particles) and second particles (e.g., differently-heat-treated or
non-heat-treated particles) of the metal alloy constituting at
least a portion of deposit 14 toward surface 16 of substrate 12.
Upon impacting surface 16 or a working surface of deposit 14, the
first and second particles undergo deformation and bond to
substrate 12 and/or previously deposited particles without melting.
As a result of cold spray deposition of the first and second
particles, deposit 14 may have a very dense microstructure and an
interface with substrate 12 that is substantially free of voids,
and may be characterized by grain boundaries and dislocation
networks formed at interfaces of localized deposits corresponding
to deposited first and second particles. Deposit 14 formed from the
first and second particles may have the same or nearly the same
microstructure as the first and second particles before spraying,
i.e., there is no thermally induced microstructure change to the
particles themselves. This may allow better control of the
properties of the particles/domains/regions in the deposit compared
to cases where melting occurs during spraying.
[0021] Deposit 14 includes a first component 18 (e.g., a
heat-treated component) and a second component 20 (e.g., a
differently-heat-treated or non-heat-treated component). While
shown as visually differentiated elements (e.g., interfaces between
deposits) in FIG. 1A to emphasize a relationship of first component
18 and second component 20 to first particles and second particles,
respectively, it will be understood that deposits of heat-treated
metal alloys corresponding to first component 18 and
non-heat-treated or differently-heat-treated metal alloys
corresponding to second component 20 may not be differentiated by
clear physical boundaries due to bonding of the metal alloy
deposits from the particles, and that portions of deposit 14
corresponding to first component 18 and second component 20 may be
differentiated by any differences in properties derived from heat
treatment processes of the metal alloy, as will be described
further below.
[0022] First component 18 may include any portion of deposit 14
that includes a metal alloy that has undergone heat treatment prior
to deposition on surface 16. Heat treatment may include any process
that involves application of heat or cold to a bulk material to
change properties of the bulk material. First component 18 may
include a heat-treated metal alloy formed from a variety of heat
treatments including, but not limited to, annealing, hardening
(e.g., aging), surface hardening, and the like. Mechanical
properties of first component 18 may depend on a composition of
first component 18, a type of heat treatment previously applied to
first component 18, and/or various parameters used to cold spray
heat-treated particles of the metal alloy on surface 16.
[0023] Second component 20 may include any portion of deposit 14
that includes a metal alloy that has been subjected to a different
heat treatment than first component 18, such as no heat treatment
or another heat treatment. While second component 20 may have a
same composition (i.e., same chemistry) as first component 18,
second component 20 may have properties that are different from,
and may be complementary to, first component 18. In some examples,
second component 20 includes a metal alloy that has not undergone
or been subjected to heat treatment. For example, second component
20 may include a metal alloy that has not undergone an amount
(e.g., high enough temperature, long enough period of time) of bulk
heating or cooling sufficient to cause a change in microstructure
or homogeneity of the metal alloy. In some examples, second
component 20 includes a metal alloy that has undergone or been
subjected to a different heat treatment than first component 18. In
some examples, the second component may include a heat-treated
composition having a same chemistry and different heat treatment as
first component 18. For example, second component 20 may include a
metal alloy that has undergone a heat treatment that has caused
different changes in microstructure or homogeneity of the metal
alloy than the heat treatment of first component 18. Certain heat
treatments directed toward creating more homogeneous
microstructures, such as annealing, may complement heat-treatments
directed toward precipitating constituents, such as hardening, such
that deposit 14 may have a blend of properties that result from
more than one heat-treatment. First component 18 may include a
heat-treated metal alloy formed from a variety of heat treatments
including, but not limited to, annealing, hardening (e.g., aging),
surface hardening, and the like.
[0024] First component 18 and/or second component 20 may be
selected for a variety of properties including, but not limited to,
tensile strength, yield strength, hardness, toughness, percent
elongation, percent reduction, Young's modulus, and the like. For
example, the composition of the metal alloy of first component 18
and second component 20 and/or the heat treatment process
corresponding to first component 18 may be selected for any
properties of either of the heat-treated metal alloy and/or the
non-heat-treated metal alloy. As one example in which deposit 14 is
a barrier coating, first component 18 may be selected for high
hardness. As another example in which deposit 14 is a repair joint,
first component 18 may be selected for high ductility/elongation,
high toughness, and/or high tensile strength. Properties of first
component 18 and second component 20, such as tensile strength,
elongation, and yield strength, may be measured using test methods
such as, for example, ASTM E8 Standard Test Methods for Tension
Testing of Metallic Materials, such as for samples that include
first component 18 and/or second component 20, individually or as a
blended cold-spray deposit.
[0025] In some examples, first component 18 includes a hardened
metal alloy formed from a hardening process. For example, hardening
may increase tensile strength and ductility (i.e., elongation) of
the metal alloy, such that deposit 14 that includes first component
18 may have a greater toughness than deposits that do not include a
hardened component; reduce hardness of the metal alloy; create a
more stable metal alloy that may age less in service; and/or modify
surface properties of the first particles that form first component
18, which may change behaviors of the metal alloy within the bulk
of deposit 14. In some examples, first component 18 includes at
least one of a precipitation hardened metal alloy, a quenched
hardened metal alloy, or a tempered metal alloy. In some examples,
a tensile strength of first component 18 is at least about twice as
high as a tensile strength of second component 20, such as at least
about 5 times higher. For example, hardened aluminum may have a
tensile strength of about 20,000 PSI or higher, while non-hardened
aluminum may have a tensile strength of about 4000 PSI. In some
examples, a percent elongation of first component 18 is at least
about 50% higher than a percent elongation of second component 20.
For example, hardened aluminum may have a percent elongation of
about 4-8%, while a non-hardened aluminum may have a percent
elongation of about 2-4%.
[0026] As a result of incorporation of both first component 18 and
second component 20, deposit 14 may have bulk properties derived
from first component 18 and second component 20 that are different
from properties of first component 18 or second component 20
individually. For example, while first component 18 may have
improved properties such as tensile strength and ductility as
compared to second component 20, first component 18 may have
increased brittleness, which may increase susceptibility to
cracking. However, second component 20 may moderate these
properties, such that deposit 14 may have values of bulk properties
that are between the individual properties of either first
component 18 or second component 20. A volume ratio of first
component 18 and second component 20 may be selected to achieve a
particular set of properties derived from a relative volume of
first component 18 and a volume of second component 20. In some
examples, a volume percentage of first component 18 in deposit 14
is between about 1% and about 99%, such as between about 10% and
about 90%, or between about 30% and about 70%.
[0027] First component 18 and second component 20 may be
distributed throughout deposit 14 in various concentrations and
distributions. For example, due to incremental deposition of first
and second particles during cold spraying, distribution (e.g.,
parallel or normal to surface 16 of substrate 12) of first
component 18 and second component 20 may be adjusted temporally
and/or spatially. In some examples, first component 18 and second
component 20 may be distributed substantially homogenously
throughout deposit 14, such that deposit 14 may have relatively
uniform bulk properties. In some examples, first component 18 and
second component 20 may be non-homogeneously distributed throughout
deposit 14, such that deposit 14 may have non-uniform bulk
properties. For example, a concentration of first component 18 may
be higher in a first portion of deposit 14, such as near surface
16, than a second portion of deposit 14 to provide properties that
may be more suitable for the corresponding portion.
[0028] In some examples, in addition to incorporating the metal
alloy of first component 18 and second component 20, deposit 14 may
include other components that provide alternative or additional
functionality to deposit 14. For example, deposit 14 may include
the metal alloy as a first composition and may include another
composition, such as another metal, metal alloy, or ceramic, as a
third component. For example, the second composition may include
various properties that complement first component 18 and/or second
component 20.
[0029] In the example of FIG. 1A, regions of deposit 14
corresponding to first component 18 and second component 20 are
illustrated as having a similar size. For example, a substantially
uniform size may correspond to more uniform grain boundaries.
However, in some examples, regions of deposit 14 corresponding to
first component 18 and second component 20 may have different
sizes. FIG. 1B is a conceptual cross-sectional view of an example
article 10B including a deposit that includes a first component and
a second component. As illustrated in FIG. 1B, deposits
corresponding to first component 18 and second component 20 may
have different sizes. Such different sized deposits of first
component 18 and second component 20 may result from different
sized first and second particles. In some instances, different size
particles may change a behavior of deposit 14 under load. For
example, without being limited to any particular theory, second
component 20 may have smaller deposits of first component 18 at an
interface of deposits of second component 20 and first component 18
boundary. These different sizes of the deposits may impact
deformation at the boundaries when under load, such that the
smaller deposits may lock the boundary and reduce deformation at
the boundary.
[0030] Articles described herein may be produced using cold spray
deposition systems. FIG. 2 is a conceptual and schematic block
diagram of an example system 30 for forming deposit 14 using cold
spraying. System 30 is configured to form deposit 14 on substrate
12 by cold spraying first particles and second particles of a metal
alloy on at least a portion of surface 16 of substrate 12. System
30 may include an enclosure 42, which encloses a stage 44, a cold
spray gun 32, a first material source 34, a second material source
36, and a gas source 38. System 30 may further include a computing
device 40, which is communicatively connected to stage 44, cold
spray gun 32, first material source 34, second material source 36,
and gas source 38.
[0031] Article 10 is positioned within enclosure 42. Enclosure 42
may substantially enclose (e.g., enclose or nearly enclose) stage
44, cold spray gun 32, first material feed 34, second material feed
36, gas source 38, and article 10. Enclosure 42 may maintain a
desired atmosphere (e.g., an atmosphere that is substantially inert
to the materials from which deposit 14 is formed) around substrate
12 and deposit 14 during the cold spray technique. In some
examples, stage 44 may be configured to selectively position and
restrain article 10 in place relative to stage 44 during formation
of deposit 14. In some examples, stage 44 is movable relative to
cold spray gun 32. For example, stage 44 may be translatable and/or
rotatable along at least one axis to position article 10 relative
to cold spray gun 32. Similarly, in some examples, cold spray gun
32 may be movable relative to stage 44 to position cold spray gun
32 relative to article 10. In some examples, system 30 may not
include enclosure 42 and stage 44. For example, system 30 may
include a portable device configured to cold spray the heat-treated
and non-heat-treated metal alloy particles in situ, such as during
a repair. In such examples, system 30 may include temporary
containment as enclosure 42.
[0032] First material source 34 and second material source 36 may
each be configured to supply first particles and second particles,
respectively, to cold spray gun 32. Each material source 34 and 36
may include, for example, a hopper or other container containing
first particles and second particles, respectively. In some
examples, material sources 34 and 36 may each include a pneumatic
hopper operatively coupled to gas source 38, such that gas source
38 enables material sources 34 and 36 to feed the first particles
and second particles, respectively, to cold spray gun 32. Computing
device 40 may be communicatively coupled to first material source
34 and second material source 36 to control a rate of flow of first
particles and second particles, respectively, from material sources
34 and 36 to cold spray gun 32 via a material feed. For example,
computing device 40 may control a valve or a feeder system of the
material feed. In addition to first material source 34 and second
material source 36, system 30 may include other material sources,
such as for a second composition. While shown as separate
equipment, in some examples, first material source 34 and second
material source 36 may be the same equipment. For example, first
particles and second particles may be pre-mixed prior to being fed
into cold spray gun 32.
[0033] The first particles and second particles may have properties
corresponding to localized properties of first component 18 and
second component 20, respectively, of deposit 14, as described in
FIG. 1A above. For example, the first particles may be selected to
provide deposit 14 with particular properties resulting from a
particular heat treatment including, but not limited to, tensile
strength, yield strength, hardness, toughness, percent elongation,
percent reduction, Young's modulus, and the like. In some examples,
the first particles include at least one of a precipitation
hardened metal alloy, a quenched hardened metal alloy, or a
tempered metal alloy. In some examples, a tensile strength of the
first particles is at least about 10% greater than a tensile
strength of the second particles. In some examples, a percent
elongation of the first particles is at least about 10% greater
than a percent elongation of the second particles.
[0034] The first particles and second particles may include any
suitable particle size. For example, the size range of the first
and second particles may be between about 1 micrometer (.mu.m) and
about 50 .mu.m, such as between about 5 .mu.m and about 20 .mu.m.
The size range of the first and second particles may be selected to
achieve a selected impact velocity, e.g., a velocity of the
particles when impacting surface 16. In some examples, an average
size of the first particles and the second particles may be
different.
[0035] Gas source 38 may be configured to accelerate the first and
second particles from first material source 34 and second material
source 36, respectively. Gas source 38 may include, for example, a
source of helium, nitrogen, argon, or other substantially inert
gas, which may function as carrier of the particles. Gas source 38
may be fluidically coupled to a gas feed, which may control a flow
rate and/or pressure of gas delivered to cold spray gun 32. In some
examples, the gas feed may include a heater to heat the gas. The
pressure of the gas in gas source 38 may be sufficient to achieve
supersonic velocities of the gas and/or particles at the outlet of
a nozzle. In some examples, the pressure of the gas may be between
about 0.1 megapascals (MPa) and about 2 MPa, such as between about
0.5 MPa and about 1.5 MPa. In some examples, the supersonic
velocities may be between about 500 meters per second (m/s) to
about 1000 m/s.
[0036] Cold spray gun 32 may be configured to entrain the first
particles from first material source 34 and the second particles
from second material source 36 in the flow of gas from gas source
38 through a nozzle. The nozzle may accelerate the gas and
plurality of particles to high velocities. The resultant high
velocity particle stream 48 may be directed toward surface 16 of
substrate 12. Without limiting the description to a specific
theory, the high velocity of the plurality of particles may be
sufficient to cause plastic deformation of the particles upon
impact with surface 16 of substrate 12. This process may be
repeated as particles attach to surface 16 and/or other attached
particles defining a build surface 46 of deposit 14.
[0037] System 30 may be configured to control relative movement of
high velocity particle stream 48 with respect to surface 16 of
substrate 12 and/or build surface 46. For example, directing high
velocity particle stream 48 toward substrate 12 may result in
deposition of the plurality of particles on surface 16 of substrate
12 and/or build surface 46. As illustrated in FIG. 2, the first
particles and the second particles may accumulate to form deposit
14. For example, high velocity particle stream 48 may be moved over
surface 16 and/or build surface 46 until a sufficient amount of the
heat-treated metal alloy and the non-heat-treated metal alloy has
accumulated to define, at least roughly, deposit 14. For example,
excess metal alloy may be deposited to form a structure with larger
dimensions than a final structure of deposit 14, then excess metal
alloy may be machined away to define deposit 14. Although not
illustrated in FIG. 2, system 30 may also include a milling device
or machining device configured to remove deposited metal alloy to
define a final shape of deposit 14.
[0038] Computing device 40 may include, for example, a desktop
computer, a laptop computer, a tablet, a workstation, a server, a
mainframe, a cloud computing system, or the like. Computing device
40 may include or may be one or more processors or processing
circuitry, such as one or more digital signal processors (DSPs),
general purpose microprocessors, application specific integrated
circuits (ASICs), field programmable logic arrays (FPGAs), or other
equivalent integrated or discrete logic circuitry. Accordingly, the
term "processor," as used herein may refer to any of the foregoing
structure or any other structure suitable for implementation of the
techniques described herein. In addition, in some examples, the
functionality of computing device 40 may be provided within
dedicated hardware and/or software modules.
[0039] Computing device 40 is configured to control operation of
system 30, including, for example, stage 44, cold spray gun 32,
material sources 34 and 36, and/or gas source 38. Computing device
40 may be configured to control operation of stage 44 and/or cold
spray gun 32 to position article 10 relative to cold spray gun 32.
For example, as described above, computing device 40 may control
stage 44 and/or cold spray gun 32 to translate and/or rotate along
at least one axis to position article 10 relative to cold spray gun
32.
[0040] Computing device 40 may control at least one of the feed
rate of the first particles from first material source 34, second
particles from second material source 36, pressure from gas source
38, flow rate of the gas from gas source 38, the movement of high
velocity particle stream 48 relative to article 10, a distance
between cold spray gun 32 and build surface 46, the angle of the
high velocity particle stream relative to build surface 46, and a
width of overlap between adjacent passes of the high velocity
particle stream and the velocity of cold spray gun 32 relative to
build surface 46. Computing device 40 may control at least one of
these parameters to control an amount of material, such as
heat-treated metal alloy and non-heat-treated metal alloy, added to
article 10 at a given time and location and/or to control
metallurgical properties of the added material. In some examples,
cold spray gun 32 may be scanned (e.g., translated) relative to
deposit 14, and deposit 14 will include a general shape
corresponding to the scanned path.
[0041] The articles described herein may be formed using any
suitable technique. FIG. 3 is a flow diagram illustrating an
example technique for forming deposit 14 on surface 16 of substrate
12 that includes cold spraying first particles and second particles
of a metal alloy. The technique of FIG. 3 will be described with
concurrent reference to article 10 of FIG. 1A and system 30 of FIG.
2. In other examples, other systems may be used to perform the
technique of FIG. 3, the technique of FIG. 3 may be used to form
other composite components, or both.
[0042] In some examples, the technique illustrated in FIG. 3 may
optionally include preparing substrate 12 (50). Preparing substrate
12 may include any process or series of processes to prepare
surface 16 of substrate 12 for deposition of deposit 14. In some
examples, preparing substrate 12 may include forming substrate 12.
For example, forming substrate 12 may include forging, casting, or
performing other metallurgy techniques to define a shape of
substrate 12. In some examples, preparing substrate 12 may include
surface preparation of surface 16, such as, for example, abrading
surface 16 and/or coating surface 16 with a coating configured to
improve bonding of deposit 14 or to improve mechanical properties
or chemical properties of article 10, such as one or more thermal
barrier coatings or environmental barrier coatings. In some
examples, preparing substrate 12 may include treatment of a crack,
chip, discontinuity, or other damaged feature for repair by deposit
14. For example, one or more surfaces of a crack may be smoothed,
roughened, or otherwise treated to improve deposition or bonding of
deposit 14 to the surface of the crack.
[0043] In some examples, the technique illustrated in FIG. 3 may
optionally include selecting, by system 30, a composition of
heat-treated particles and non-heat-treated particles (52). The
composition of first particles and second particles in high
velocity particle stream 48 may include a relative composition
(e.g., a ratio) of the first and second particles. In some
examples, computing device 40 may hold constant the composition of
the first particles and second particles throughout the cold spray
deposition process, such as for a deposit having substantially
homogenous properties, while in other examples, computing device 40
may vary the composition of the first particles and the second
particles during the cold spray deposition process, such as for a
deposit having a spatially varying composition. For example,
computing device 40 may receive, such as from a user input, a
desired composition of deposit 14. The desired composition may
represent a relative composition of first component 18, second
component 20, and/or any other composition in resulting article
10.
[0044] The technique illustrated in FIG. 3 includes cold spraying,
by system 30, heat-treated particles and non-heat-treated particles
on to at least a portion of surface 16 of substrate 12 (54). As
discussed above in reference to FIG. 1A, cold spraying involves
using cold spray gun 32 and gas source 38 to accelerate first
particles from first material source 34 and second particles from
second material source 36 toward surface 16 of substrate 12 without
melting the first and second particles. The first and second
particles may contact surface 16 at velocities sufficient to cause
plastic deformation of the particles and result in attachment or
bonding of the particles to surface 16 and/or other attached
particles defining build surface 46. In some examples, cold
spraying includes high pressure cold spraying. For example, gas
source 38 and material sources 34 and 36 may include pressurization
systems to pressurize each of gases, first particles, and second
particles.
[0045] In some examples, the technique illustrated in FIG. 3 may
optionally include, after cold spraying the first and second
particles to form first component 18 and second component 20,
machining the deposited first component 18 and second component 20
to define deposit 14 (56). For example, forming deposit 14 may
include cold spraying excess first component 18 and second
component 20 on to surface 16, then machining away the excess first
component 18 and second component 20. Machining away the excess
first component 18 and second component 20 may enable system 30 to
form deposit 14 including more complex geometries, with increased
precision (e.g., within predetermined tolerances), or both compared
to a technique without machining.
[0046] Various examples have been described. These and other
examples are within the scope of the following claims.
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