U.S. patent application number 11/544820 was filed with the patent office on 2007-04-12 for titanium boride.
This patent application is currently assigned to International Titanium Powder, LLC. Invention is credited to Adam Benish, Lance Jacobsen.
Application Number | 20070079908 11/544820 |
Document ID | / |
Family ID | 37808330 |
Filed Date | 2007-04-12 |
United States Patent
Application |
20070079908 |
Kind Code |
A1 |
Jacobsen; Lance ; et
al. |
April 12, 2007 |
Titanium boride
Abstract
A titanium metal or a titanium alloy having submicron titanium
boride substantially uniformly dispersed therein and a method of
making same is disclosed. Ti power of Ti alloy powder has dispersed
within the particles forming the powder titanum boride which is
other than whisker-shaped or spherical substantially uniformly
dispersed therein.
Inventors: |
Jacobsen; Lance; (Minooka,
IL) ; Benish; Adam; (US) |
Correspondence
Address: |
HARRY M. LEVY, EMRICH & DITHMAR, LLC.;Suite 2080
125 South Wacker Drive
Chicago
IL
60606
US
|
Assignee: |
International Titanium Powder,
LLC
Lockport
IL
60441
|
Family ID: |
37808330 |
Appl. No.: |
11/544820 |
Filed: |
October 6, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60724166 |
Oct 6, 2005 |
|
|
|
Current U.S.
Class: |
148/421 |
Current CPC
Class: |
C22C 32/0073 20130101;
C22B 34/1295 20130101; C22B 34/1272 20130101; B22F 9/28 20130101;
C22C 14/00 20130101; B22F 3/02 20130101; B22F 9/18 20130101; B22F
3/10 20130101 |
Class at
Publication: |
148/421 |
International
Class: |
C22C 14/00 20060101
C22C014/00 |
Claims
1. A titanium metal or a titanium alloy having submicron titanium
boride substantially uniformly dispersed therein.
2. The titanium alloy of claim 1, wherein Al and V are present in a
minor amount by weight.
3. The titanium alloy of claim 2, wherein Al and V are present at a
total concentration of about 10% by weight.
4. The titanium alloy of claim 3, wherein Al is present at a
concentration of about 6% by weight and V is present at a
concentration of about 4% by weight.
5. The titanium metal or titanium alloy of claim 1, wherein boron
is present up to about 4% by weight.
6. The titanium metal or titanium alloy of claim 1, wherein said
metal or base alloy is a powder and titanium boride is dispersed
within most of the particles forming the powder.
7. The titanium metal or titanium alloy or claim 6, wherein
titanium boride is dispersed within substantially all of the
particles forming the powder.
8. The titanium metal or titanium alloy of claim 1, wherein said
titanium boride is other than whisker-shaped or spherical.
9. The titanium metal or titanium alloy of claim 1, wherein said
titanium or titanium alloy having titanium boride dispersed therein
are consolidated powders.
10. The titanium metal or titanium alloy of claim 1, wherein said
titanium or titanium alloy having titanium boride dispersed therein
is sintered powder.
11. The titanium metal or titanium alloy of claim 1, wherein said
titanium or titanium alloy having titanium boride dispersed therein
is a solid.
12. The titanium metal or titanium alloy of claim 1, wherein the
titanum boride is principally TiB.
13. A Ti powder or a Ti base alloy powder having submicron titanium
boride substantially uniformly dispersed therein, wherein said Ti
powder or Ti base alloy powder and titanium boride are made by the
subsurface reduction of TiCl.sub.4 and a boron halide and other
chlorides and/or halides of the Ti base alloy constituents, if
present, with liquid alkali or alkaline earth metal or mixtures
thereof in a reaction zone.
14. The material of claim 13, wherein the alkali or alkaline earth
metal or mixtures thereof is present in sufficient quantity to
maintain the reduction products below the sintering temperature
thereof away from the reaction zone.
15. The material of claim 14, wherein the alkali metal is sodium
and the alkaline earth metal is magnesium or calcium.
16. The material of claim 15, wherein the liquid metal is present
as a stream.
17. The material of claim 16, wherein the chlorides and/or halides
are introduced into the liquid metal as a gas at sonic velocity or
greater.
18. The material of claim 14, wherein the boron halide is a
chloride.
19. The material claim 18, wherein boron chloride is BCl.sub.3.
20. The material of claim 13, wherein said Ti base alloy contains
Al and V and titanium boride in at least most of the particles
forming the powder.
21. The material of claim 20, wherein titanium boride is in
substantially all of the particles forming the powder.
22. A Ti powder or a Ti base alloy powder having submicron titanium
boride which is other than whisker-shaped or spherical
substantially uniformly dispersed therein.
23. The titanium base alloy powder of claim 22 wherein Al and V are
present in a minor amount by weight.
24. The titanium base alloy powder of claim 23, wherein Al and V
are present at a total concentration of about 10% by weight.
25. The titanium base alloy powder of claim 24, wherein Al is
present at a concentration of about 6% by weight and V is present
at a concentration of about 4% by weight.
26. The titanium powder or titanium base alloy powder of claim 22,
wherein boron is present up to about 4% by weight.
27. The titanium powder or titanium base alloy powder of claim 26,
wherein titanium boride is in at least most of the particles
forming the powder.
28. The titanium powder or titanium base alloy powder of claim 27,
wherein the titanium boride is in substantially all of the
particles forming the powder.
29. The Ti powder or titanium base alloy powder of claim 28,
wherein substantially all of the titanium boride is TiB.
30. A product having an SEM substantially as shown in one or more
of the FIGS. 1-8.
Description
RELATED APPLICATIONS
[0001] This application, pursuant to 37 C.F.R. 1.78(c), claims
priority based on provisional application serial No. 60/724,166
filed Oct. 6, 2005.
BACKGROUND OF THE INVENTION
[0002] Relatively small boron additions to conventional titanium
alloys provide important improvements in strength, stiffness and
microstructural stability. Because boron is essentially insoluble
in titanium at all temperatures of interest, the titanium boride is
formed for even very small boron additions. The density of titanium
boride is nearly equal to those of conventional Ti alloys, but its
stiffness is over four times higher than conventional titanium
alloys. Thus, titanium boride offers significant improvements in
stiffness, tensile strength, creep, and fatigue properties. Since
titanium boride is in thermodynamic equilibrium with titanium
alloys, there are no interfacial reactions to degrade properties at
elevated temperature. Further, because the coefficient of thermal
expansion of titanium boride is nearly equal to values for titanium
alloys, residual stresses are nearly eliminated" Taken from JOM
Article May 2004 "Powder Metallurgy Ti-6Al-4V Alloys: Processing,
Microstructure, and Properties", the entire disclosure of which is
incorporated by reference.
[0003] Currently two approaches appear to be used to accomplish
boron addition; 1) Blended elemental addition of TiB.sub.2 and
solid state reaction to produce the titanium boride which usually
forms as whiskers with a 10 to 1 aspect ratio and 2) Pre-alloyed
powders from a melt process.
[0004] Negatives of the blended elemental approach are the added
effort to blend the powders to obtain a uniform distribution (which
is never perfect) and the added time and temperature it takes the
solid state reaction to transform TiB.sub.2 to TiB (1300 C for 6
hours). Also, this approach has the potential to form larger
Titanium boride particles or have residual titanium boride
particles that adversely affect properties. The titanium boride
whiskers that are formed can lead to anisotropic properties of the
part depending on the type of process used to make the part.
[0005] A negative of the pre-alloyed approach is that it has a
tendency to leave large primary borides in the pre-alloyed
materials that cause low fracture toughness.
[0006] Representative examples of patents related to producing
metal alloys with titanium boride are the Davies et al. U.S. Pat.
No. 6,099,664 issued to Davies et al. Aug. 8, 2000, in which
titanium boride particles in the 1-10 micron size range are
produced in a molten reaction zone. The Blenkinsop et al. U.S. Pat.
No. 6,488,073 issued Dec. 3, 2002 teaches the addition of an alloy
in which tantalum boride or tungsten boride particles are added to
a molten alloy material to form a molten mixture which upon cooling
has the boride distributed therein. Another method of making boride
containing titanium alloys is disclosed in the Abkowitz U.S. Pat.
No. 5,897,830 in which titanium boride powders are mixed with the
powders of various constituents to form a consumable billet which
is thereafter cast or melted to form the article of manufacture.
Each of these processes as described in the above-mentioned patents
has a variety of shortcomings, not the least of which is the
imperfect distribution of the boride as well as the size of the
boride particles.
SUMMARY OF THE INVENTION
[0007] The Armstrong Process as disclosed in U.S. Pat. Nos.
5,779,761, 5,958,106 and 6,409,797, the entire disclosures of which
are herein incorporated by reference appears very unexpectedly to
give uniform distribution of very fine submicron titanium boride
within the Ti or Ti alloy powder. This eliminates the need for
blending and solid state reaction to form titanium boride; it also
eliminates concerns regarding larger particles that can adversely
affect fracture toughness and other mechanical properties. Because
of the fineness of the titanium boride particles and the uniform
distribution in most if not substantially all of the particles
forming the powder, more isotropic mechanical properties may be
achievable. None of the current approaches to boron addition to Ti
powder can achieve this type of distribution of titanium boride,
particularly in the submicron size ranges.
[0008] Accordingly, it is a principal object of the present
invention to provide a titanium metal or a titanium alloy having
submicron titanium boride substantially uniformly dispersed
therein.
[0009] Another object of the invention is to provide a Ti powder or
a Ti base alloy powder having submicron titanium boride
substantially uniformly dispersed therein, wherein the Ti powder or
Ti base alloy powder and titanium boride are made by the subsurface
reduction of TiCl.sub.4 and a boron halide and other chlorides
and/or halides of the Ti base alloy constituents, if present, with
liquid alkali or alkaline earth metal or mixtures thereof in a
reaction zone.
[0010] A further object of the invention is to provide a Ti powder
or a Ti base alloy powder having submicron titanium boride which is
other than whisker-shaped or spherical substantially uniformly
dispersed therein.
[0011] A final object of the invention is to provide a product
having an SEM substantially as shown in one or more of FIGS.
1-8.
[0012] The invention consists of certain novel features and a
combination of parts hereinafter fully described, illustrated in
the accompanying drawings, and particularly pointed out in the
appended claims, it being understood that various changes in the
details may be made without departing from the spirit, or
sacrificing any of the advantages of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For the purpose of facilitating an understanding of the
invention, there is illustrated in the accompanying drawings a
preferred embodiment thereof, from an inspection of which, when
considered in connection with the following description, the
invention, its construction and operation, and many of its
advantages should be readily understood and appreciated.
[0014] FIG. 1 is an SEM of a titanium powder having submicron
titanium boride substantially uniformly dispersed therethrough at a
magnification of 50;
[0015] FIG. 2 is another SEM of a titanium powder having submicron
titanium boride substantially uniformly dispersed therethrough at a
magnification of 50;
[0016] FIG. 3 is a similar SEM of a titanium powder having
submicron titanium boride substantially uniformly dispersed
therethrough at a magnification of 3000;
[0017] FIG. 4 is another SEM of a titanium powder having submicron
titanium boride substantially uniformly dispersed therethrough at a
magnification of 3000;
[0018] FIG. 5 is a titanium base alloy having about 10% total of
aluminum and vanadium with titanium boride with submicron titanium
borides substantially uniformly dispersed throughout the particles
forming the powder at a 40 magnification;
[0019] FIG. 6 is a titanium base alloy having about 10% total of
aluminum and vanadium with titanium boride with submicron titanium
borides substantially uniformly dispersed throughout the particles
forming the powder at a 50 magnification;
[0020] FIG. 7 is a titanium base alloy having about 10% total of
aluminum and vanadium with titanium boride with submicron titanium
borides substantially uniformly dispersed throughout the particles
forming the powder at a 3000 magnification;
[0021] FIG. 8 is a titanium base alloy having about 10% total of
aluminum and vanadium with titanium boride with submicron titanium
borides substantially uniformly dispersed throughout the particles
forming the powder at a 3000 magnification (a different portion of
the same sample as FIG. 7).
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] Using the Armstrong method described in the above three
identified patents and application Ser. No. 11/186,724 filed Jul.
21, 2005, the entire application is herein incorporated by
reference.
[0023] The equipment used to produce the 6/4 alloy with submicron
titanium boride substantially uniformly dispersed therein is
similar to that disclosed in the aforementioned patents disclosing
the Armstrong Process with the exception that instead of only
having a titanium tetrachloride boiler 22 as illustrated in those
patents, there is also a boiler for each constituent of the alloy
connected to the reaction chamber by suitable valves. Boron
addition is from a boiler for BCl.sub.3. The piping acts as a
manifold so that the gases are completely mixed as they enter the
reaction chamber and are introduced subsurface to the flowing
liquid sodium, preferably at least at sonic velocity, as disclosed
in the incorporated patents. Upon subsurface contact with the
liquid metal the halides immediately and completely react
exothermically to form a reaction zone in which the reaction
products are produced. The flowing liquid metal preferably sodium,
sweeps the reaction products away from the reaction zone
maintaining the reaction products at a temperature below the
sintering temperatures of the reaction products. It was determined
during production of the 6/4 alloy that aluminum trichloride is
corrosive and required special materials not required for handling
either titanium tetrachloride or vanadium tetrachloride. Therefore,
Hastelloy C-276 was used for the aluminum trichloride boiler and
the piping to the reaction chamber. The BCl.sub.3 is not as
corrosive as AlCl.sub.3.
[0024] During most of the runs the steady state temperature of the
reactor was maintained at about 400.degree. C. by the use of
sufficient excess sodium. Other operating conditions for the
production of the 6/4 alloy powder with submicron titanium boride
dispersed in most, if not substantially all, of the particles
forming the powder were as follows:
[0025] A device similar to that described in the incorporated
Armstrong patents was used except that a VCl.sub.4 boiler, a
AlCl.sub.3 boiler and a BCl.sub.3 boiler were provided and all
three gases were fed into the line feeding TiCl.sub.4 into the
liquid Na. The typical boiler pressures and system parameters are
listed hereafter in Table 1. TABLE-US-00001 TABLE 1 TiCl4 Boron
Noz. TiCl4 TiCl4 VCl4 AlCl3 Noz. Boron Distill Bake Boron Aluminum
Vanadium Oxygen Dia. Press. Flow Press. Press. Dia. Press. Temp
Temp(C.)/Time Run# Wt % Wt % Wt % Wt % (in) (Kpa) (Kg/min) (Kpa)
(Kpa) (in) (Kpa) (C.) (hrs) NR285 .82 -- -- .485 7/32 540 2.4 -- --
.040 640 575 750/24 .89 .477 .9 .605 .82 .578 NR286 2.21 -- -- .874
7/32 500 2.3 -- -- .040 1400-1600 575 775/24 3.17 .875 3.15 .985
3.18 .969 NR291 .25 7.08 2.84 .346 7/32 500 2.9 640 860 .040 600
575 775/24 .38 6.91 2.5 .494 NR292 2.58 7.46 3.79 1.06 7/32 510 2.2
620 850 .040 1500 575 775/24 2.49 7.72 3.59 1.33 A-308 .71 -- --
.304 7/32 500 2.5 -- -- .040 450-525 575 790/30 .64 .303 A-328 1.24
-- -- .31 5/32 550 1.23 -- -- .040 570 575 790/36 Inlet Na
temperature about 240.degree. C. Reactor Outlet Temperature about
510 C. Na Flowrate about 40 kg/min
[0026] The reactor was generally operated for approximately 250
seconds injecting approximately 11 kg of TiCl.sub.4. The salt and
titanium alloy solids were captured on a wedge wire filter and free
sodium metal was drained away. The product cake containing titanium
alloy, sodium chloride and sodium was distilled at approximately
100 milli-torr at 550 to 575.degree. C. vessel wall temperatures
for 20 hours. Once all the sodium metal was removed via
distillation, the trap was re-pressurized with argon gas and heated
to 750.degree. C. and held at temperature for 48 hours. The vessel
containing the salt and titanium alloy cake was cooled and the cake
was passivated with a 0.7 wt % oxygen/argon mixture. After
passivation, the cake was washed with deionized water and
subsequently dried in a vacuum oven at less than 100.degree. C.
[0027] Table 2 below sets forth a chemical analysis of various runs
for both Ti as well as 6/4 alloy with submicron titanium boride
substantially uniformly dispersed therein from an experimental loop
running the Armstrong Process. As used herein, titanium boride
means principally TiB but does not exclude minor amounts of
TiB.sub.2 or other borides.
[0028] Similarly, the process described herein produces a novel
powder in which most, if not substantially all, of the particles
forming the powder have submicron titanium boride dispersed
therein. While the boride dispersion may not always be perfect in
every particle, the titanium boride is very small, submicron, and
generally uniformly dispersed within the particles forming the
powder, whether the powder is titanium or a titanium alloy.
[0029] As seen from Table 2 below, the sodium levels for 6/4 with
submicron titanium boride are very low while the sodium level for
Ti with submicron titanium boride are somewhat higher, but still
less than commercially pure titanium, without submicron titanium
boride dispersed therein, made by the Armstrong Process, as
described in the incorporated application.
[0030] As stated in the referenced application, the surface area of
the 6/4 alloy compared to the CP titanium, as determined using BET
Specific Surface Area analysis with krypton as the adsorbate is
much larger than the CP titanium. The surface area of the 6/4 alloy
with titanium boride is even greater, that is the alloy powder with
titanium boride was smaller in average diameter and more difficult
to grow into larger particles than Ti alloy without titanium
boride. TABLE-US-00002 TABLE 2 Al % by weight V % by weight B % by
weight Na 9 5 0.0039 10 5 0.0026 8 5 0.001 7 2.2 0.017 8 1.8 0.0086
5.4 5.3 0.0015 7.3 4.7 0.002 14 3 0.018 7.75 5.2 0.009 9.6 6.8
0.0078 13 6.7 0.0092 9.2 0.009 0.014 6 4 0.0018 5.7 3.5 0.0018 5
2.2 0.0018 5.3 3.6 0.0052 7.2 4 0.014 0.82 0.018 0.89 0.023 0.9
0.0047 0.82 0.0028 2.21 0.0047 3.17 0.0076 3.15 0.013 3.2 0.012
7.08 2.84 0.25 0.0025 6.91 2.5 0.38 0.0024 7.46 3.79 2.58 0.0023
7.72 3.59 2.49 0.0077
[0031] The SEMs of FIGS. 1-8 show that the 6/4 powder and/or Ti
powder with submicron titanium boride distributed therein is
"frillier" than the previously made 6/4 powder in the referenced
application. Each of the figures references a run disclosed in
Table 1 and represents samples taken from that run at different
magnifications. As stated in the referenced application and as
reported by Moxson et al., Innovations in Titanium Powder
Processing in the Journal of Metallurgy May 2000, it is clear that
by-product fines from the Kroll or Hunter Processes contain large
amounts of undesirable chlorine which is not present in the CP
titanium powder or alloy made by the Armstrong Process. Moreover,
the morphology of the Hunter and Kroll fines, as previously
discussed, is different from the CP powder or the 6/4 alloy powder
or either with submicron titanium boride therein made by the
Armstrong Process. Neither the Kroll nor the Hunter process has
been adapted to produce 6/4 alloy or any alloy. Alloy powders have
been produced by melting prealloyed stock and thereafter using
either gas atomization or a hydride-dehydride process (MHR). The
Moxson et al. article discloses 6/4 powder made in Tula, Russia and
as seen from FIG. 2 in that article, particularly FIGS. 2c and 2d
the powders made by Tula Hydride Reduction process are
significantly different than those made by the Armstrong Process.
Moreover, referring to the Moxson et al. article in the 1998 issue
of the International Journal of Powder Metallurgy, Vol. 4, No. 5,
pages 45-47, it is seen that the chemical analysis for the
pre-alloy 6/4 powder produced by the metal-hydride reduction (MHD)
process contains exceptional amounts of calcium and also is not
within ASTM specifications for aluminum.
[0032] As is well known in the art, solid objects can be made by
forming 6/4 or CP titanium powders into a near net shapes and
thereafter sintering, see the Moxson et al. article and can also be
formed by hot isostatic pressing, laser deposition, metal injecting
molding, direct powder rolling or various other well known
techniques. Therefore, the titanium alloy powder or titanium powder
with submicron titanium boride dispersed substantially uniformly
therein made by the Armstrong method may be formed into a
consolidated or a consolidated and sintered product or may be
formed into a solid object by well known methods in the art and the
subject invention is intended to cover all such products made from
the powder of the subject invention.
[0033] There has been disclosed herein a titanium metal powder or a
titanium base alloy powder having submicron titanium boride
substantially uniformly dispersed therein.
[0034] The specific titanium alloy of the type set forth wherein Al
and V are present in a minor amount by weight, but preferably ASTM
Grade 5, as well as commercially pure titanium, ASTM Grade 2, both
as disclosed in the incorporated patent application, Table 1
therein, with submicron titanium boride substantially uniformly
dispersed therein have been disclosed, wherein boron is present up
to about 4% by weight. The invention however, includes any weight
of boron added. Preferably, alloys have at least 50% by weight
titanium with titanium boride, preferably TiB, present in any
required amount.
[0035] Any halide may be used in the process, as previously
described, but chlorides are preferred because they are readily
available and less expensive than other halides. Various alkali or
alkaline earth metals may be used, i.e. Na, K, Mg, Ca, but Na is
preferred.
[0036] Solid products are routinely made by a variety of processes
from the powders described herein. Products made from powder
produced by the Armstrong method including BCl.sub.3 introduced
into flowing liquid reducing metal produce superior hardness and
other desirable physical properties are within the scope of this
invention.
[0037] While the invention has been particularly shown and
described with reference to a preferred embodiment thereof, it will
be understood by those skilled in the art that several changes in
form and detail may be made without departing from the spirit and
scope of the invention.
* * * * *