U.S. patent application number 13/205808 was filed with the patent office on 2011-12-01 for high-strength discontinuosly-reinforced titanium matrix composites and method for manufacturing the same.
This patent application is currently assigned to ADMA Products, Inc.. Invention is credited to Volodymyr DUZ, Vladimir Moxson, Alexander Shapiro.
Application Number | 20110293461 13/205808 |
Document ID | / |
Family ID | 40346732 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110293461 |
Kind Code |
A1 |
DUZ; Volodymyr ; et
al. |
December 1, 2011 |
High-strength discontinuosly-reinforced titanium matrix composites
and method for manufacturing the same
Abstract
The method for manufacturing high-strength
discontinuously-reinforced titanium matrix composite comprises the
following steps: (a) preparing a basic powdered blend containing
the matrix alloy or titanium powders having a particle size <250
.mu.m for 95% of the powder and powders, which reinforcing matrix
during high-temperature operations, such as blended elemental
reinforcing powders, ceramic powders, intermetallic powders, and/or
powders of complex carbide- and/or boride particles that are at
least partially soluble in the matrix, (b) preparing reinforcing
powders by co-attrition, mechanical alloying, or pre-sintering of
blended elemental powders with each other and graphite, (c) mixing
the basic powdered blend with the Al-V master alloy powder, and
co-attrited, mechanically-alloyed powders, and pre-sintered powders
in the predetermined ratio to obtain a chemical composition of
titanium matrix composite material, (d) compacting the powder
mixture at room temperature by any of room temperature
consolidation process, (e) sintering at the temperature providing
at least partial dissolution of dispersing ceramic and/or
intermetallic powders, (f) high-temperature deformation at the
temperature range of 1500-2300.degree. F. resulting in additional
in-situ formation of re-enforced particulates, and (g) cooling.
Inventors: |
DUZ; Volodymyr; (Hudson,
OH) ; Moxson; Vladimir; (Hudson, OH) ;
Shapiro; Alexander; (Upper Arlington, OH) |
Assignee: |
ADMA Products, Inc.
Twinsburg
OH
|
Family ID: |
40346732 |
Appl. No.: |
13/205808 |
Filed: |
August 9, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11890644 |
Aug 7, 2007 |
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13205808 |
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Current U.S.
Class: |
419/2 ;
419/11 |
Current CPC
Class: |
C22C 1/1084 20130101;
B22F 2998/10 20130101; B22F 2998/10 20130101; C22C 32/0047
20130101; B22F 2999/00 20130101; B22F 2003/175 20130101; B22F
2999/00 20130101; B22F 2003/185 20130101; C22C 1/1084 20130101;
B22F 3/02 20130101; B22F 3/17 20130101; C22C 1/1005 20130101; B22F
3/18 20130101; B22F 3/10 20130101; B22F 3/24 20130101; B22F 3/24
20130101; B22F 3/15 20130101 |
Class at
Publication: |
419/2 ;
419/11 |
International
Class: |
C22C 33/02 20060101
C22C033/02; B22F 3/11 20060101 B22F003/11 |
Claims
1. A method for manufacturing a high-strength discontinuously-rein
(breed titanium matrix composite material comprising the following
steps: (a) preparing a basic powdered blend containing a matrix
alloy or titanium powders having a particle size less than 250
.mu.m for 95% of the powder, and a mixture of the same titanium
powder with a master alloy creating an alloyed titanium matrix, and
powders which reinforce matrix during sintering or forging
operations such as ceramic powders, intermetallic powders, and
powders of complex carbide- and boride particles that are at least
partially soluble in the matrix during the sintering, forging, or
other high temperature operations, such as at least one AlV.sub.2C,
AlTi.sub.2Si.sub.3, AlTi.sub.6Si.sub.3, AlTi.sub.4Si.sub.7,
Al.sub.3B.sub.48Si, VB.sub.2, V.sub.3B.sub.2, V.sub.3B.sub.4,
TiVSi.sub.2, TiVB.sub.4, Ti.sub.2AlC, Ti.sub.3AlC, AlCr.sub.2C,
TiAlV.sub.2, (Ti,V)C, (Ti,V)(B,C), V.sub.2C, V.sub.4C.sub.3,
VSi.sub.2, Ta.sub.3B.sub.4, Ta.sub.3B.sub.2, Ti.sub.2Al(B,C),
TaTiB.sub.4, NbTiB.sub.4, and Al.sub.3U.sub.2C.sub.3, (b) preparing
reinforcing powders by co-attrition, mechanical alloying, or
pre-sintering and grinding of elemental metal powders and graphite,
(c) co-attrition of the basic powdered blend (a) with the Al-V
master alloy powder or mechanically-alloyed powders in the
predetermined ratio to obtain a chemical composition of titanium
matrix composite material, (d) consolidating at room temperature
the powder mixture containing incompletely-formed reinforcing
particles by cold isostatic pressing, die pressing, direct powder
rolling, or other processes. (e) sintering at a temperature
providing at least partial dissolution of dispersing ceramic and/or
intermetallic powders to form the reinforcing particle system after
cooling. (f) high-temperature deformation (forging, rolling, hot
pressing, hot isostatic pressing, and/or others) in a temperature
range of 1500-2300.degree. F., (g) cooling.
2. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein the ceramic and intermetallic hard
particles dispersed in the matrix are selected from the group
consisting of SiC, TiB. TiB.sub.2. Ti.sub.3B.sub.4,
Ti.sub.2B.sub.4C, ZrC, ZrB.sub.2, TaC, TaB, TaB.sub.2,
Ta.sub.3B.sub.2, B.sub.4Si, VB, V.sub.2B, WC, NbC, NbB,
Nb.sub.3B.sub.2, Nb.sub.3B.sub.4, Al.sub.4C.sub.3, Al.sub.4C.sub.3,
AlB.sub.2, TiAl, Ti.sub.3Al, TiAl.sub.3Al.sub.8V.sub.5, VC,
Cr.sub.7C.sub.3, HfC, UC, U.sub.2C.sub.3, and TiCr.sub.2.
3. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein the basic powdered blend is prepared
in the form of elemental powder blend or combination of elemental
powders, graphite, and prealloyed powders blend.
4. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein co-attrition or mechanical alloying
of reinforcing elemental powders is carried out with a partial
addition of the master alloy in an amount up to 30 wt. % of the
weight of reinforcing powders.
5. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein mechanical alloying is carried out
with different dispersion effects, i.e. attrition for different
time to create a particular particle size distribution of
reinforcing particles.
6. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein boron and carbon powders are
preliminary reacted with aluminum or aluminum-vanadium master alloy
at 800-1100.degree. C., then obtained pre-sintered cake is ground
in powder and added into the initial mixture of composite material
components.
7. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein boron carbide and boron silicide
powders are preliminary reacted with titanium powder at
1200-1400.degree. C., then obtained pre-sintered cake is ground in
powder and added into the initial mixture of composite material
components.
8. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein titanium boride and silicon carbide
powders are preliminary reacted with aluminum or aluminum-vanadium
master alloy at 900-1100.degree. C. then obtained pre-sintered cake
is ground in powder and added into the initial mixture of composite
material components.
9. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein carbon powder is introduced in amount
of up to 30 wt. % in the basic powder blend, whereby the carbon is
in the form of graphite, black carbon, or pyrolytic carbon.
10. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein the sintering is carried out at a
temperature of 2300.degree. F. (1260.degree. C.) and higher to
provide complete densification and provide oversaturated solid
solution that will result in a formation of coherent reinforced
carhidic and/or intermetallic particles in the matrix alloy during
the cooling.
11. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein hot pressing, hot isostatic pressing,
or hot rolling are carried out after sintering in any
combination.
12. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein the resulting composite material is
characterized by density over 98% of theoretical value and
discontinued porosity after sintering that makes it possible
forging, hot pressing, hot isostatic pressing, or hot rolling
without any special protective coating, encapsulating, or
canning.
13. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein the resulting composite material
after step (e) has discontinued porosity and density over 98% of
theoretical value.
14. The method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 1, wherein a near-net shape state after forging,
hot pressing, hot isostatic pressing, or hot rolling is performed
without any special protective coating, encapsulating, or canning,
and without finishing of final product by machining and/or chemical
milling.
15. A method for manufacturing a high-strength
discontinuously-reinforced titanium matrix composite material
comprising the following steps: (a) preparing a basic powdered
blend containing a matrix alloy or titanium powders having a
particle size less than 250 .mu.m for 95% of the powder, or a
mixture of the same titanium powder with a master alloy creating an
alloyed titanium matrix, and powders which reinforce matrix during
sintering or forging operations such as ceramic powders,
intermetallic powders, or powders of complex carbide- and boride
particles that are at least partially soluble in the matrix during
the sintering, forging, or other high temperature operations, such
as at least one of AlV.sub.2C, AlTi.sub.2Si.sub.3,
AlTi.sub.6Si.sub.3, AlTi.sub.4Si.sub.7, Al.sub.3B.sub.48Si,
VB.sub.2, V.sub.3B.sub.2, V.sub.3B.sub.4, TiVSi.sub.2, TiVB.sub.4,
Ti.sub.2AlC, Ti.sub.3AlC, AlCr.sub.2C, TiAlV.sub.2, (Ti,V)C,
(Ti,V)(B,C), V.sub.2C, V.sub.4C.sub.3, VSi.sub.2, Ta.sub.3B.sub.4,
Ta.sub.3B.sub.2, Ti.sub.2Al(B,C), TaTiB.sub.4, NbTiB.sub.4, and
Al.sub.3U.sub.2C.sub.3. (b) preparing reinforcing powders by
co-attrition, mechanical alloying, and pre-sintering and grinding
of elemental metal powders and graphite, (c) co-attrition of the
basic powdered blend (a) with the Al-V master alloy powder and
mechanically-alloyed powders in the predetermined ratio to obtain a
chemical composition of titanium matrix composite material, (d)
consolidating at room temperature the powder mixture containing
incompletely-formed reinforcing particles by cold isostatic
pressing, die pressing, direct powder rolling, or other processes.
(e) sintering at a temperature providing at least partial
dissolution of dispersing ceramic and/or intermetallic powders to
form the reinforcing particle system after cooling, (f)
high-temperature deformation (forging, rolling, hot pressing, hot
isostatic pressing, and/or others) in a temperature range of
1500-2300.degree. F. (g) cooling.
16. The method for manufacturing the high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 15, wherein boron or carbon powders are
preliminary reacted With aluminum or aluminum-vanadium master alloy
at 800-1100.degree. C. then the obtained pre-sintered cake is
ground in powder and added into the initial mixture of composite
material components.
17. The method for manufacturing the high-strength
discontinuously-reinforced titanium matrix composite material
according to claim 15, wherein titanium boride or silicon carbide
powders are preliminary reacted with aluminum or aluminum-vanadium
master alloy at 900-1100.degree. C., and then obtained pre-sintered
cake is ground in powder and added into the initial mixture of
composite material components.
Description
[0001] The present application is a Divisional Application of U.S.
application Ser. No 11/890,644 filed on Aug. 7, 2007, the entire
contents of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to sintered titanium metal
matrix composites discontinuously-reinforced with dispersed ceramic
and intermetallic particles such as silicon carbide, titanium
borides, vanadium carbides, titanium aluminides, etc.
BACKGROUND OF THE INVENTION
[0003] Titanium-based or titanium alloy-based metal matrix
composites (TMMC) are of particularly great interest in the
following areas: the aerospace and automotive industries. medical
implants, armor, and chemical-resistant applications due to their
high specific strength, high stiffness, low weight, and relatively
high wear resistance. The titanium or titanium alloy matrix in
these composites are reinforced by fibers or particles which have a
substantially higher hardness and elastic modulus than the matrix
alloy. Reinforcing components should be thoroughly and uniformly
dispersed in the volume of the matrix alloy to achieve the maximum
mechanical properties of the composite material. In addition, the
optimum combination of the mechanical properties of the composite
material depends upon the sizes of the reinforcing particles,
strength of the bond between the hard particles and the matrix
alloy, and the porosity of sintered composite materials.
[0004] Despite more than twenty years of experience in industrial
applications. conventional TMMC are far from perfection and being
used only on a limited basis. The limitation of their usage is
mostly associated with non-optimized combination of mechanical
properties caused by remaining porosity, not uniform chemistry and
distribution of hard particles as well as absence of well developed
and optimized manufacturing processes.
[0005] For example, the method for manufacturing the Ti-6Al-4V/TiC
composite disclosed in the U.S. Pat. No. 5,722,037 provides the low
densities of the resulting material which is only about 93% of the
theoretical value even after vacuum sintering fix 4 hours at
1300.degree. C. The method includes formation of reinforcing TiC
particles in the titanium matrix by chemical reaction with
hydrocarbon gas that is more effective in the porous matrix than in
the dense one.
[0006] In the U.S. Pat. No. 4,731,115 granted to Abkowitz, et al. a
TiC/titanium alloy composite cladding material and process for
manufacturing the same are disclosed, in which blended components
are compacted by cold isostatic pressing and sintered at
2200-2250.degree. F. However, this method does not provide
sufficient density of the material, and to improve the density, the
invention further includes encapsulating the sintered pre-form and
hot isostatic pressing (HIP) at 1650-2600.degree. F. followed by
subsequent forging, rolling. or extruding. This method is not so
cost-effective due to the additional HIP operation and besides of
this, it requires encapsulation, which should be further removed
from the final product by grinding or chemical milling. Moreover,
the HIP process does not permit production of articles with close
tolerances of their sizes. Requirements for encapsulating are
mostly associated with the interconnected porosity. which prevents
full consolidation and creates extensive surface oxidation taking
place during HIP process.
[0007] T. Kaba, et al. (U.S. Pat. No. 5,534,353) proposed
compacting a powdered component blend by cold isostatic pressing,
atomizing the product by melting and spraying, and finally,
sintering the atomized powder by HIP at 1100.degree. C.
(2012.degree. F.). The final product has improved bending strength
at room temperature, but includes expensive process of atomization
in a protective atmosphere. and the components produced by this
process are still exhibit an interconnected porosity. Additional
encapsulating and HIP operation are required for closing this
porosity. which increases cost of manufacturing the components with
acceptable combination of their properties.
[0008] A method for manufacturing titanium matrix composites,
according to the U.S. Pat. No. 5,458,705, is mainly based on the
precipitations of reinforcing particles from the titanium alloy
matrix during the solidification and cooling of the matrix alloy.
This means that this method should include melting and casting of
titanium alloys at the temperature above 1600.degree. C.
(2900.degree. F.) and these high temperatures would destroy the
re-enforcement. The created ceramic particles or intermetallic hard
particles degrade flow rate during casting of molten composite
alloy, creates segregation during casting process and, as a result,
the reinforcing particles are not uniformly distributed in a
resulting TMMC. Degraded flow rate also restricts an ability torn
produce the cast TMMC components with thin cross sections.
[0009] All previous processes for manufacturing the dense titanium
matrix composites consisting of matrix alloy and reinforcing
particles by using powder metallurgy approaches have considerable
drawbacks associated with porosity and non-uniformity of
reinforcing particles distribution which degrade ductility and
strength of the TMMC and restrict applications of these
manufacturing processes. These powder metallurgy processes also
require the expensive high temperature consolidation in capsules to
prevent oxidation due to extensive porosity which in escalate cost
of the manufacturing processes and limit an ability to control the
sizes of finished components.
[0010] A significant difference in (structural and) mechanical
properties between sintered TMMC material and the non-reactive
wrought metal being used for manufacturing the encapsulations
results in non-uniform deformation and stress concentration in
during high temperature formation of the TMMC alloys. Cracks in
various areas of the sintered material observed during the first
cycles of hot deformation are caused by both interconnected
porosity and stress concentration. These cracks restrict
maintaining a reliable and reproducible manufacturing process
during subsequent forging. hot rolling, or other high temperature
deformation.
[0011] Some of the known casting processes to produce TMMC
exhibited limitation in manufacturing the components with thin
cross sections.
[0012] Therefore, it would be desirable to provide (a) a
high-strength and fully-dense titanium matrix composites having
near full density or insignificant closed porosity after sintering
or other high temperature processing of green components, and (b) a
cost-effective method for producing such composites using blended
elemental. powders or combination of pre-alloyed and elemental
metal powder blends, as well. It also requires to apply a low cost
room temperature consolidation processes such as die-pressing,
direct powder rolling, cold iso-static pressing, but the presence
of re-enforced particles restricts applications of these low cost
consolidation processes. A new composition and manufacturing
method, which would improve the application performance of
resulting. materials, as well as eliminate destructive effect of
opened porosity and oxidation so taking place during subsequent
high-temperature processing or eliminate a need for expensive
encapsulation operation is required in order to achieve a near full
density TMMC alloy with acceptable mechanical properties.
[0013] This present invention achieves this goal by using not only
complex carbides and borides as additional reinforcing components
in the Ti/TiC, Ti/TiB2, and Ti/(TiC, TiB2) composite structures but
also formation of reinforcing particles by solid-state chemical
reactions during co-attrition and mechanical alloying of carbide-
and boride-forming elemental powders, which react with each other
and with graphite. The content of carbides in the initial mixture
may be minimized in order to be able to consolidate the components
at room temperature. Usage a co-attrition and mechanical alloying
to produce the alloying additions to the blends has positive effect
because the carbide forming elements are still ductile during room
temperature consolidation. Also, co-attrition, mechanical alloying,
and pre-sintering of blended elemental powders allow to control the
particle size of reinforcing particulates and optimize their
distribution by selecting temperature and time during sintering
operation. Finally, this new approach provides the sintered
structure having the closed porosity with no interconnected voids
at the near full theoretical density, while at the same time, the
composite material exhibits acceptable mechanical properties in the
as-sintered conditions, and/or if the complex shaped parts are
being manufactured by subsequent high temperature deformation,--no
encasing, canning, or encapsulating are required in performing
these additional operations.
OBJECTS OF THE INVENTION
[0014] It is therefore, an object of the invention is to produce a
fully-dense, essentially uniform structure of flat and shaped
titanium metal matrix composite consisting of high-strength and
ductile matrix with uniformly distributed re-enforcing particles of
controlled particle size that provides improved mechanical
characteristics such as fracture toughness. flexure strength,
impact strength, elastic modulus, and wear resistance.
[0015] Another object of this invention is to avoid interconnected
porosity and manufacture the sintered composite material which may
have only closed porosity and near full density after sintering,
e.g., over 98% of the theoretical value.
[0016] Yet, another object of this invention is to produce
near-full density parts from a titanium matrix composite material
that has acceptable mechanical properties without a need for
further hot deformation.
[0017] It is yet another object of this present invention is to
provide a powder metallurgy technique for manufacturing near-net
shape sintered TMMC that can be used as final product in the
as-sintered state or in the state after hot deformation without
secondary operations such as machining, chemical milling, or
others.
[0018] It is yet another additional object of the invention is to
establish a continuous cost-effective process to produce
fully-dense flat and shaped titanium alloy matrix composite parts
with in controlled size tolerances from either blended elemental
powders or from a combination of the pre-alloyed and elemental
powders blend.
[0019] The nature, utility, and features of this invention will be
more apparent from the following detailed description with respect
to preferred embodiments of the invented technology.
SUMMARY OF THE INVENTION
[0020] While the use of a number of manufacturing processes
including sintering and hot deformation has previously been
contemplated in the titanium matrix composite industry, as
mentioned above, the processing limitations related to an ability
to manufacture a near full density composite structure by low cost
room-temperature consolidation, limited process stability,
inability to manufacture the components with controlled sizes when
components with close tolerances are being produced, high
production costs, defective microstructure, porosity, and
insufficient mechanical properties of not fully dense TMMC
articles, established a need for development of the new low cost
manufacturing processes for producing the TMMC with optimized
mechanical properties and improved performance. This invention
overcomes shortcomings in the prior art.
[0021] The goals of the invention are (a) to change the type of
porosity of the sintered semi-product from the interconnecting
porosity to only discontinuous porosity at near full density, e.g.,
over 98% of the theoretical value after sintering, and (b) to
improve mechanical properties at reduced cost of production process
for manufacturing fully-dense titanium matrix composites.
[0022] An attempt was made to produce discontinuously reinforced
TMMC using a blended elemental powder metallurgy approach. A newly
developed process allows uniform distribution of reinforcing
particles in the ductile matrix while improving the bond strength
between the reinforcing particulate and the matrix alloy.
[0023] One novelty of the invention is the use of soluble complex
borides and carbides (such as AlV.sub.2C, AlTi.sub.2Si.sub.3,
AlTi.sub.6Si.sub.3, AlTi.sub.4Si.sub.7, Al.sub.3B.sub.48Si,
VB.sub.2, V.sub.3B.sub.2, V.sub.3B.sub.4TiVSi.sub.2, TiVB.sub.4,
Ti.sub.2AlC, Ti.sub.3AlC, AlCr.sub.2C, TiAlV.sub.2, (Ti,V)C,
(Ti,V)(B,C), V.sub.2C, V.sub.4C.sub.3, VSi.sub.2, Ta.sub.3B.sub.4,
Ta.sub.3B.sub.2, Ti.sub.2Al(B,C), TaTiB.sub.4, NbTiB.sub.4, and/or
Al.sub.3U.sub.2C.sub.3) for the reinforcement of titanium alloy
matrixes along with elemental carbide and boride particles such as
SiC, TIB, TiB.sub.2, Ti.sub.3B.sub.4, Ti.sub.2B.sub.5, B.sub.4C,
ZrC, ZrB.sub.2, TaC, TaB, TaB.sub.2, Ta.sub.3B.sub.2, VB, V.sub.2B,
WC, NbC, NbB, Nb.sub.3B.sub.2, Nb.sub.3B.sub.4, Al.sub.4C.sub.3,
Al.sub.4C.sub.3, AlB.sub.2, TiAl, Ti.sub.3Al, TiAl.sub.3,
Al.sub.3V.sub.5, VC, Cr.sub.7C.sub.3, HfC, UC,U.sub.2C.sub.3,
B.sub.4Si, B.sub.6Si, and/or TiCr.sub.2. Said complex borides and
carbides not only reinforce effectively the matrix titanium alloy,
but also prevent its grain growth during the sintering and
subsequent heat treatment.
[0024] Another novelty of this invention is consolidation of the
blend of matrix and reinforcing powders at room temperature,
whereby the reinforcing particles are not finally formed. The
incompletely formed intermetallic particles are not so brittle as
finally-formed intermetallics that results in effective
consolidation to high degree of green body density, and besides, in
reducing number of defects in the final product. The composite
reinforcing particles are finally formed during the hot stage of
the manufacture: sintering, forging, hot rolling, HIP etc. These
dispersed particles are grown from the solid solution. and
therefore, they are completely compatible with the matrix
microstructure. The resulting microstructure provides significant
gain in strength of produced composite material.
[0025] There are two innovative approaches arc being used in this
invention to produce the particulates for reinforcement. First
approach is preparing the reinforcing powders by co-attrition or
mechanical alloying the reinforcing elemental powders and second
approach is dealing with pre-sintering and grinding the reinforcing
elemental powders. Both approaches allow application of low cost
room temperature consolidation of the particulates for
reinforcement after they are blended either with pure titanium
powder or with titanium powder mixed with master alloys, followed
by sintering operation resulting in near full density TMMC
structures. Actual formation of these TMMC structures is being
created during high temperature processing of green pre-forms, i.e.
in-situ formation of reinforced particulates uniformly distributed
in titanium or titanium alloy matrix alloy.
[0026] The preparation of pre-sintered cakes is being performed at
the temperatures which result in partial formation of the
particulate reinforcement, and the reinforcement is created during
the subsequent high temperature processing such as sintering and/or
high temperature deformation (forging, hot pressing or rolling).
These pre-sintered cakes do not have not finally formed reinforcing
particles in the matrix alloy.
[0027] These cakes are made from boron and/or carbon powders
reacted with aluminum or aluminum-vanadium master alloy at
800-1100.degree. C., boron carbide and boron silicide powders in
reacted with titanium powder at 1200-100.degree. C., and titanium
boride and/or silicon carbide powders are preliminary reacted with
aluminum or aluminum-vanadium master alloy at 900-1100.degree. C.
We discovered that reaction products such as TB.sub.2.
Ti.sub.3SiC.sub.2, and other complex borides. carbides and
silicides have better compatibility with the crystal lattice of
matrix titanium alloys that results in additional strength and
toughness of the composite materials. The formation of such
reinforcing particles as TiB.sub.2. Ti.sub.3SiC.sub.2. and other
complex borides, carbides and silicides occurs during hot treatment
and cooling of the previously green body. Therefore, the complete
size and particle distribution are formed only in final
products.
[0028] The co-attrition or mechanical alloying of the Al-V master
alloy powder with blended elemental carbide-forming elements
co-attrited or mechanically alloyed with graphite powders. as well
as with hard reinforcing particles of above-mentioned ceramics and
intermetallics is among other novelties of this invention.
[0029] A combination of unique properties of (i) high strength and
stiffness at temperatures up to 820.degree. C. (1500.degree.), (ii)
good mechanical properties at room temperature including good
ductility, (iii) improved resistance to matrix cracking. and (iv)
very close controlled tolerances of sizes of the finished parts
which is achieved in the resulting material by forming a
discontinuous porosity of sintered semi-product followed by
effective densification during subsequent high temperature
deformation. Also, as sintered, near full density product may be
high temperature deformed (HIPped, forged, or rolled) without a
need for encapsulation.
[0030] The invented compositions and methods are suitable for the
manufacture of flat or shaped titanium matrix composite articles
having improved mechanical properties such as lightweight plates
and sheets for aircraft and automotive applications, armor plates.
heat-sinking lightweight electronic substrates, bulletproof
structures for vests, partition walls and doors, as well as
sporting goods such as helmets, golf clubs, sole plates, crown
plates, etc.
[0031] The subsequent objects, features, and advantages of our
invented material and process will be clarified by the following
detailed description of the preferred embodiments oldie
invention.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION
[0032] As discussed, the present invention relates generally to the
manufacture of titanium matrix composites that are reinforced by
ceramic and/or intermetallic particles using a combination of
elemental and pre-alloyed powders (obtained by atomization or other
method), elemental metal powder blends, and/or titanium hydrides,
or a combinations thereof (i.e. combination of pre-alloyed,
elemental and/or hydrogenated powders as raw materials).
[0033] Use of preliminary prepared fine powder of Aluminum-Vanadium
master alloy plays a unique role in this process and results in
formation of highly-dense structure developed during sintering and
manufacturing a semi-finished product or finished product having
solely closed discontinuous porosity at density over 98% of the
theoretical value. The co-attrition or mechanical alloying of the
master alloy powder with blended elemental carbide-forming elements
co-attrited or mechanically alloyed with graphite powders, as well
as with hard reinforcing, ceramic and intermetallic particles plays
important role in the formation of fine microstructure of the
resulting composite material with good bonds between the matrix and
reinforcing particles developed during, subsequent sintering of
room temperature consolidated (die pressed, or cold isostatic
pressed or direct powder rolled) green pre-forms. No previously
known methods, mentioned in References, allow producing such
composite structure because they used finally structured, brittle
reinforcing particles in the starting blend. This results in
crushing those brittle particle during both room temperature
consolidation and high-temperature processing (such as forging,
rolling, and hot pressing) creating multiple defects in the
composite material structure such as cracks, voids, and stress
concentrators.
[0034] The addition of complex carbide- and/or silicide particles
that are at least partially soluble in the matrix such as
AlV.sub.2C, AlTi.sub.2Si.sub.3, AlTi.sub.6Si.sub.3,
AlTi.sub.4Si.sub.7, Al.sub.3B.sub.48Si, VB.sub.2, V.sub.3B.sub.2,
V.sub.3B.sub.4, TiVSi.sub.2, TiVB.sub.4, Ti.sub.2AlC, Ti.sub.3AlC,
AlCr.sub.2C, TiAlV.sub.2, (Ti,V)C, (Ti,V)(B,C),
V.sub.2C,V.sub.4C.sub.3, VSi.sub.2, Ta.sub.3B.sub.4,
Ta.sub.3B.sub.2, Ti.sub.2Al(B,C), TaTiB.sub.4, NbTiB.sub.4, and/or
Al.sub.3U.sub.2C.sub.3, UC, U.sub.2C.sub.3, B.sub.4Si, B.sub.6Si,
and/or TiCr.sub.2 dispersed in the matrix in the amount of 5,50
vol. % allows not only control ductility of the matrix during any
hot deformation of the sintered pre-form, but also significantly
improves the effect of particle reinforcement of the resulting
composite material. The above mentioned dispersed particles are
formed "in-situ" after final stages of the composite manufacture:
hot treatment and cooling. In order to reach the effect of full
compatibility of reinforcing particles with matrix alloy, the
process includes following steps:
[0035] (a) preparing a basic powdered blend containing the matrix
alloy or titanium powders having a particle size less than 250
.mu.m for 95% of the powder and powders which reinforce matrix
during sintering or forging operations such as ceramic powders,
intermetallic powders, and/or powders of complex carbide- and/or
boride particles that are at least partially soluble in the matrix
at the sintering or forging temperatures such as AlV.sub.2C,
AlTi.sub.2Si.sub.3, AlTi.sub.6Si.sub.3, Al.sub.3B.sub.48Si,
VB.sub.2, V.sub.3B.sub.2, V.sub.3B.sub.4, TiVSi.sub.2, TiVB.sub.4,
Ti.sub.2AlC, Ti.sub.3AlC, AlCr.sub.2C, TiAlV.sub.2, (Ti,V)C,
(Ti,V)(B,C), V.sub.2C, V.sub.4C.sub.3, VSi.sub.2, Ta.sub.3B.sub.4,
Ta.sub.3B.sub.2, Ti.sub.2Al(B,C), TaTiB.sub.4, NbTiB.sub.4,
Al.sub.3U.sub.2C.sub.3, UC, U.sub.2C.sub.3, B.sub.4Si, B.sub.6Si,
and/or TiCr.sub.2.
[0036] (b) preparing additional reinforcing powders having
controlled particle size by co-attrition, mechanical alloying,
pre-sintering and grinding of elemental powders processed with the
graphite powders,
[0037] (c) mixing the basic powdered blend with the Al-V master
alloy powder and/or mechanically-alloyed reinforcing powders in the
predetermined ratio to obtain a chemical composition of titanium
matrix composite material.
[0038] (d) consolidating at room temperature the powder mixture
containing incompletely-formed reinforcing particles by cold
isostatic pressing, die pressing, direct powder rolling, or other
processes,)
[0039] (e) sintering at the temperature providing at least partial
dissolution of dispersing ceramic and/or intermetallic powders to
form the reinforcing particle system after the cooling,
[0040] (f) high-temperature deformation (forging, rolling, hot
pressing, hot isostatic pressing, and others) in the temperature
range of 1500-2300.degree. F. for further in-situ formation of
re-enforced particulates,
[0041] (g) cooling.
[0042] Complex carbides combine merits of both metals and ceramics.
Like metals, they are resistant to thermal shock, but like
ceramics, they have high strength, hardness. and thermal stability;
Such complex carbides as AlTi.sub.2Si.sub.3, AlTi.sub.6Si.sub.3,
TiVSi.sub.2, TiVB.sub.4, Ti.sub.2AlC, AlCr.sub.2C, TiAlV.sub.2 have
unique compressive plasticity at room temperature and high
temperature that allows plastic deformation of the reinforced
matrix without cracking. When the sintered composite material
pre-form is heated to 1500-1700.degree. F. fear forging or hot
rolling, the complex carbides are partially dissolved in the
matrix, and the matrix alloy being freed of the carbide
reinforcements is easily deformed at these temperatures. We can use
pre-sintering, so that the alloys may be easily subjected to high
temperature deformation, but in the most cases we want to produce
TMMC without any high temperature deformation, i.e. final carbides
and other reinforcing particulates to be formed in-situ during
sintering. Complex boride and carbide powders are manufactured
separately for adding into the basic powder blend. Some of these
phases can be precipitated during cooling after hot deformation and
fix fine grain structure of forged or hot rolled composite
material.
[0043] A novel method for preparation of reinforced composite
structure was used in this invention. The composite components
(especially reinforcing ceramic or intermetallic particles are
prepared by grinding the preliminary reacted pre-sintered cakes.
These cakes are made by:
[0044] (a) heating boron with the powder mixture to temperatures in
the range of 800-100.degree. C. when boron and/or carbon powders
reacted with aluminum or aluminum-vanadium master alloy.
[0045] (b) heating to temperatures in the range of 900-100.degree.
C. when titanium boride and/or silicon carbide powders reacted with
aluminum or aluminum-vanadium master alloy, and
[0046] (c) heating to temperatures in the range of
1200-1400.degree. C. when boron carbide and boron silicide powders
reacted with titanium powder, and
[0047] These pre-sintered cakes are ground for dispersed particles
which are subsequently mixed with the basic elemental powder blend.
We discovered that reaction products such as TiB.sub.2, TiC,
Ti.sub.3SiC.sub.2, and other complex borides. carbides and
silicides have better compatibility with the crystal lattice of
matrix titanium alloys that results in additional strength and
toughness of the composite materials.
[0048] We found that boron carbide B.sub.4C powder reacts with
titanium powder at 1200-1400.degree. C.; with the formation of both
titanium boride phases TiB.sub.2, TiB, and titanium carbide TiC. If
titanium powder is taken in the excessive amount, these reaction
products are synthesized immediately in the contact with titanium
particles that improve the bond between reinforcing horides and
carbides with the main component of the matrix alloy.
[0049] Similar reaction occur between silicon carbide SiC and
titanium with the formation of very effective reinforcing particles
of Ti.sub.3SiC.sub.2.
[0050] The co-attrition or mechanical alloying of the Al-V master
alloy powder with hard reinforcing particles of above-mentioned
ceramics and intermetallics is among other novelties of this
invention.
[0051] The foregoing examples of the invention are illustrative and
explanatory. The exampled are not intended to be exhaustive arid
serve only to show the possibilities of the invented
technology.
EXAMPLE 1
[0052] A TiB.sub.2 and SiC-reinforced titanium composite material
based on the Ti-6Al-4V alloy matrix was manufactured by (a)
preparing a basic powder blend containing titanium powder and
having a particle size .ltoreq.200 mesh (.ltoreq.74 microns) for
95% of the powder, 5% of graphite, 2.5% of dispersing SiC powder.
7.5% of dispersing TiB.sub.2 particles, and 2.5% of dispersing
powders of AlTi.sub.2Si.sub.3, (Ti, V)(B,C), and TiVB.sub.4 complex
intermetallic particles partially soluble in the matrix at
1500-2300.degree. F., (b) co-attrition and mechanical alloying of
the basic blend components to manufacture reinforcing particles of
complex composition and controlled particle size, (c) making a
powder of Al-V master alloy having a particle size of 10 .mu.m and
less, (d) co-attrition of 30% of this master alloy powder with
reinforcing powders of graphite. SiC powder, TiB.sub.2 particles,
and powders of AlTi.sub.2Si.sub.3, (Ti,V)(B,C), and TiVB.sub.4
complex intermetallic particles, (e) mixing the basic powder blend
with the master alloy powder and reinforcing particles at the
weight ratio between titanium powder and master alloy of 9:1 to
obtain a chemical composition of titanium matrix composite
material, (f) compacting the powder mixture at room temperature by
cold isostatic pressing, (g) sintering at 2300.degree. F, (h)
forging at 1600.degree. F., and (i) cooling.
[0053] Sintered semi-product had density 98.9% with closed
discontinuous porosity that allowed to perform the forging
operation in air without encapsulating the sintered pre-firm. The
resulting (TiB.sub.2-SiC)/Ti-6Al-4V composite material has 100%
density, and exhibits improved yield strength at room temperature
and at 930.degree. F. (500.degree. C.).
EXAMPLE 2
[0054] A carbide-reinforced titanium composite material based on
the Ti-6Al-4V alloy matrix was manufactured by (a) preparing a
basic powder blend containing titanium powder having a particle
size .ltoreq.140 mesh (.ltoreq.100 .mu.m) for 95% of the powder, 2%
of graphite, 15% of dispersing SiC powder, and 4% of dispersing
AlV.sub.2C. Ti.sub.2AlC, and V.sub.2C particles partially soluble
in the matrix at 1500-2300.degree. F., (b) co-attrition and
mechanical alloying of the basic blend components to manufacture
reinforcing particles of complex composition and controlled
particle size, (c) making a powder of Al-V master alloy having a
particle size of 10 .mu.m and less, (d) mixing and co-attriting the
basic powder blend with the master alloy powder, at the ratio of
9:1 to obtain a chemical composition of titanium matrix composite
material, (e) compacting the powder mixture at room temperature by
die-pressing, (f) sintering at 2350.degree. F., (g) forging at
1600.degree. F., and (h) cooling.
[0055] Sintered semi-product had a density of 99% with closed
discontinuous porosity that allowed it to carry out forging in open
air without encapsulating (or encasing). The resulting
carbide-reinforced Ti-6Al-4V matrix composite material has 100%
density, and it exhibits improved yield strength at room
temperature and at 930.degree. F. (500.degree. C.), and satisfied
oxidation resistance up to 1470.degree. F. (800.degree. C.).
EXAMPLE 3
[0056] The titanium matrix composite was manufactured using the
same raw materials for Ti-6Al-4V matrix alloy and carbide
reinforcements, and the same mode of sintering as in Example 1. The
final hot deformation was made by hot rolling at 1650.degree. F.
instead of forging.
[0057] The resulting TiC/Ti-6Al-4V. composite material also had
100% density, and exhibited satisfied yield strength at room
temperature and at 930.degree. F. (500.degree. C.).
EXAMPLE 4
[0058] The boride-reinforced titanium composite material based on
the Ti-6Al-4V alloy matrix was manufactured by (a) preparing a
basic powder blend containing titanium powder having a particle
size .ltoreq.200 mesh (.ltoreq.74 microns) for 95% of the powder,
5% of graphite, 12.5% of the dispersing TiB.sub.2 powder, and 2.5%
or the dispersing VB.sub.2, TiVB.sub.4, and NbTiB.sub.4, complex
boride particles partially soluble in the matrix at
1500-2300.degree. F., (b) the TiB.sub.2 powder was prepared by
reacting B.sub.4C powder with titanium powder at 2280.degree. F.
(1250.degree. C.) followed by grinding the pre-sintered cake, (c)
making a powder of Al-V master alloy having a particle size of 10
.mu.m and less. (d) mixing the basic powder blend and co-attriting
with the master alloy powder at the ratio of 9:1 to obtain a
chemical composition of titanium matrix composite material, (e)
compacting the powder mixture at room temperature by cold isostatic
pressing, (f) sintering at 2450.degree. F., and (g) cooling.
[0059] The resulting composite material has density 99.3% of the
theoretical value with closed discontinuous porosity and exhibits
acceptable yield strength at room temperature and at 930.degree.
F., (500.degree. C.). cost-effective plate of this material was
used as final product without hot deformation.
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