U.S. patent application number 11/603374 was filed with the patent office on 2009-08-20 for high elevated temperature strength nano aluminum-matrix-composite alloy and the method to make the same.
This patent application is currently assigned to DWA Technologies, Inc.. Invention is credited to William C. Harrigan, JR., Jack Y. Peng, Raymond L. Stanish.
Application Number | 20090208362 11/603374 |
Document ID | / |
Family ID | 40955298 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090208362 |
Kind Code |
A1 |
Harrigan, JR.; William C. ;
et al. |
August 20, 2009 |
High elevated temperature strength nano aluminum-matrix-composite
alloy and the method to make the same
Abstract
A novel and unique nano aluminum-matrix-composite alloy that has
higher strength between room temperature and 200 degrees C. than
those of prior art aluminum alloys and prior art
aluminum-matrix-composites. The composite alloy has improved
fatigue resistance, wear resistance, a lower coefficient of thermal
expansion and higher modules than prior art aluminum alloys.
Inventors: |
Harrigan, JR.; William C.;
(Northridge, CA) ; Stanish; Raymond L.; (Garden
Grove, CA) ; Peng; Jack Y.; (Westlake Village,
CA) |
Correspondence
Address: |
ROZSA LAW GROUP LC
18757 BURBANK BOULEVARD, SUITE 220
TARZANA
CA
91356-3346
US
|
Assignee: |
DWA Technologies, Inc.
|
Family ID: |
40955298 |
Appl. No.: |
11/603374 |
Filed: |
November 22, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60739190 |
Nov 23, 2005 |
|
|
|
Current U.S.
Class: |
420/534 ;
420/528 |
Current CPC
Class: |
C22C 21/14 20130101;
C22C 32/00 20130101; C22C 21/16 20130101 |
Class at
Publication: |
420/534 ;
420/528 |
International
Class: |
C22C 21/14 20060101
C22C021/14; C22C 21/16 20060101 C22C021/16 |
Claims
1. A nano aluminum-matrix-composite alloy comprising: high strength
at high temperature, high wear resistance, low coefficient of
thermal expansion and high modules, with a matrix phase, a nano
phase and a modular phase, wherein said matrix phase consists of a
weight percent of the matrix phase of 1.0 to 5.0 percent copper,
0.8 to 2.0 percent magnesium, maximum 0.5 percent manganese, 0.01
to 1.5 percent iron, 0.01 to 1.4 percent nickel, 0.1 to 1.2 percent
silicon, 0.01 to 0.12 percent titanium, a maximum of 0.05 percent
of other elements, and the remainder being aluminum.
2. (canceled)
3. The nano aluminum-matrix-composite alloy in accordance with
claim 1, wherein said nano phase comprises a weight percent of the
matrix phase of 0.2 to 5 percent nano aluminum oxide.
4. The nano aluminum-matrix-composite alloy in accordance with
claim 1, wherein said modular phase comprises a weight percent of
the nano aluminum matrix composite alloy of 10 to 30 percent
micro-size ceramic.
5. The nano aluminum-matrix-composite alloy in accordance with
claim 1, wherein said micro size ceramic has an average particle
size of 3 to 30 microns and is selected from the group comprising
silicon carbide, aluminum oxide, boron carbide and titanium
carbide.
6. The nano aluminum-matrix-composite alloy in accordance with
claim 1, which is produced by a powder metallurgy process.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to high strength aluminum alloys and
aluminum-matrix-composites for high temperature applications.
[0003] 2. Description of Related Art
[0004] Aluminum alloys and aluminum-matrix-composites that have
high strength at elevated temperature are very useful in aerospace
applications and internal engines. In Addition, high elevated
temperature strength, high fatigue resistance, high modulus, high
wear resistance, low coefficient of thermal expansion are also
important for some high temperature applications, such as engine
pistons.
[0005] It is has been known for several decades that alloys of the
Al--Cu--Mg--Fe--Ni type have higher elevated temperature strength
and creep resistance than Al--Cu--Mg alloys with the same Cu and Mg
content. First used in the form of cast, die-formed or forged
pieces, alloys of this type were adapted for production of
high-strength sheet metals and were used, in particular, for the
fuselage of the Concorde supersonic aircraft. These alloys are also
used for pistons in racing engines. They correspond to the Aluminum
Association designation 2618, and contain the alloying elements as
listed in Table 1.
[0006] A piston of an internal gasoline engine must operate for
long times at temperatures approaching 200 .degree. C. Elevated
temperature tensile tests conducted on alloys that have been
exposed for 100 hours at the test temperature are a means of
assessing the suitability of an alloy to perform well as a piston.
The typical yield strengths of 2618 aluminum alloy at elevated
temperature after 100 hour exposure to temperature are listed in
Table 2. To prevent recrystallization, up to 0.25% Mn and 0.25%
Zr+Ti has also been added to 2618 as grain refiner. Such variant is
registered under the designation 2618A. 2618A improves yield
strength at room temperature to 400 Mpa.
[0007] The alloy 2618, now used for over 20 years, essentially has
a creep resistance compatible with the flight conditions of a
supersonic aircraft, but its resistance to crack propagation or
fatigue resistance is somewhat insufficient, requiring increased
inspection of the fuselage. For the purpose of preparing a
successor to the Concorde, a modification of the alloy 2618 was
sought in order to improve its resistance to crack propagation.
Thus, French patent FR 2279852 in the name of CEGEDUR PECHINEY
proposes an aluminum alloy with a reduced iron and nickel content,
which has the following alloying elements (% by weight):
[0008] Cu: 1.8-3;
[0009] Mg: 1.2-2.7;
[0010] Si: <0.3;
[0011] Fe: 0.1-0.4; and
[0012] Ni and Co, where Ni+Co=0.1-0.4 and
[0013] (Ni+Co)/Fe: 0.9-1.3.
[0014] The alloy can also contain Zr, Mn, Cr, V or Mo contents
lower than 0.4%, and possibly Cd, In, Sn or Be contents of at least
0.2% each, a Zn content of at least 8% or an Ag content of at least
1%. This alloy results in a substantial improvement in the fracture
toughness factor which represents resistance to crack propagation.
Conversely, the results of creep tests at temperatures of
100.degree. C. and 175.degree. C. are entirely comparable to those
of 2618.
[0015] Bechet in U.S. Pat. No. 5,738,735 proposes a new alloy which
has a composition of (% by weight):
[0016] Cu: 2.0-3.0;
[0017] Mg. 1.5-2.1;
[0018] Mn: 0.3-0.7;
[0019] Si: 0.3-0.6;
[0020] Fe: <0.3;
[0021] Ni: <0.3;
[0022] Ti: <0.15;
[0023] Other elements: <0.05 each and 0.15 total; and
[0024] Balance Al.
[0025] The alloy can also include a silver content of less than 1%,
and in this case, this element can partially substitute for the
silicon; the total Si+0.4Ag must be between 0.3 and 0.6%.
Preferably, the Cu content is between 2.5 and 2.75% and the Mg
content is between 1.55 and 1.8%.
[0026] The combination of these various modifications, namely the
limitation of the iron and nickel, the increase in the silicon
content and the presence of manganese, leads to an unexpected
increase in creep resistance relative to the alloy 2618 and to an
alloy such as that described in French patent FR 2279852. Note that
the fine grained recrystallized structure of light sheet metals
represents the most unfavorable condition for creep resistance,
particularly for strain under stress, due to the localized strain
at the grain boundaries. However this type structure is good for
strength properties.
[0027] The room temperature yield strength of Bechet's alloy
described in U.S. Pat. No. 5,738,735 is average 419 MPa at T6 heat
treatment condition, which is little higher than 2618A. However,
the creep resistance of the Bechet's alloy is superior to the 2618A
at 100 and 150.degree. C.
[0028] Good elevated temperature tensile property is not enough for
engine piston of lightweight aluminum alloy. A piston that has
coefficient of thermal expansion (CTE) close to the CTE of engine
cylinder liner made of steel significantly improves engine
performance, reduces emission and fuel consumption. Aluminum alloys
have a CTE of about 23 PPM/.degree. C., which is too big comparing
to about 13 PPM/.degree. C. of steel. High silicon aluminum alloys
were developed to reduce CTE of aluminum pistons, such as 380, 390,
and 4032. All high silicon alloys have lower tensile strengths than
2618 and Bechet's alloy as show in Table 3. Alloys 380, 390 and
Nansa-398 are for cast pistons. Like 2618 alloy 4032 is for forge
pistons.
[0029] The higher silicon, the lower CTE and the higher wear
resistance. However, high silicon aluminum alloys have low tensile
strengths and low ductility. The CTE of high silicon alloys is
still too high for high-performance engine pistons. All aluminum
alloys, including all high temperature alloy and high silicon
alloys have low fatigue resistance. In order to further reduce CTE
and increase fatigue resistance, aluminum-matrix-composites
containing 17% to 25% ceramic reinforcement phase have been
introduced to piston application.
[0030] The composition of two aluminum-matrix-composites,
2009/SiC/17.5p and 6092/SiC/25p, are listed in Table 4. They
contain 17.5 and 25 volume percent silicon carbide ceramic powder.
Their elevated temperature strength and CTE are shown in Table
5.
[0031] 2009/SiC/17.5p and 6092/SiC/25p aluminum-matrix-composites
have higher strength at 200.degree. C. than silicon aluminum alloys
but still lower than 2618 alloy. They can have lower CTE than
silicon alloys and still maintain good toughness. The fatigue
resistance of aluminum alloys decrease with stress cycles.
Aluminum-matrix-composite can have infinite fatigue life for load
under fatigue stress. Table 6 compares the fatigue test data of
2009/SiC/25p at T4 condition with 2024-Al at T42 condition. The
composition of 2009 matrix is similar to 2024 composition. The data
shows that aluminum-matrix-composites have fatigue resistance of up
to 100 times of aluminum alloy.
[0032] Peng et al. in U.S. patent application Ser. No. 10/738,275
provided a manufacturing method of three-phase nano aluminum matrix
composites. The first phase is aluminum alloy matrix phase. The
second is a nano aluminum oxide phase that enhances the strength of
the matrix. The third is the micro-ceramic phase that has higher
modulus than aluminum oxide and contributes the stiffness
enhancement to the composite. This micro ceramic phase also reduces
the thermal expansion of the composites and increases the wear
resistance. For simplification, the aluminum alloy matrix phase is
called as matrix-phase, the nano aluminum oxide phase is called as
nano-phase and the high modulus ceramic phase is referred to as
modulus-phase. The nano-phase and the modulus-phase are uniformly
distributed throughout the matrix to form the nano composite alloy
that has high strength and high modulus. Using the three-phase
method can significantly improve the strength of an aluminum alloy
at room temperature but does not necessarily increase the elevated
temperature strength. The present invention specifically addresses
the increased elevated temperature strength necessary for high
temperature applications.
SUMMARY OF THE INVENTION
[0033] It is an object of the present invention to create a novel
and unique nano aluminum-matrix-composite alloy ("NAMC-alloy") that
has higher strength between room temperature and 200.degree. C.
than those of prior-art aluminum alloys and prior-art
aluminum-matrix-composites.
[0034] It is another object of the present invention to a novel and
unique high temperature strength NAMC-alloy that has higher fatigue
resistance than that of prior-art aluminum alloys.
[0035] It is still another object of the present invention to a
novel and unique high-temperature strength NAMC-alloy that has
higher wear-resistance than that of prior-art aluminum alloys.
[0036] It is still another object of the present invention to a
novel and unique high-temperature strength NAMC-alloy that has
lower coefficient of thermal expansion than that of prior-art
aluminum alloys.
[0037] It is still another object of the present invention to a
novel and unique high-temperature strength NAMC-alloy that has
higher modulus than that of prior-art aluminum alloys.
[0038] It is still another object of the present invention to a
novel and unique high-temperature strength NAMC-alloy that can be
extruded, rolled, forged and machined into products.
DETAILED DESCRIPTION OF INVENTION
[0039] The present invention provides a novel and unique
three-phase NAMC-alloy that contains a novel aluminum matrix phase
(matrix-phase), a nano aluminum oxide phase (nano-phase) and a
micro ceramic modulus phase (modulus-phase). The nano-phase
enhances the elevated temperature strength of the matrix-phase.
Therefore the resulted aluminum-matrix-composite has high strength
between room temperature and 200.degree. C., high modulus, low CTE,
high wear resistance, high fatigue resistance. The new high
temperature strength aluminum-matrix-composite alloy can be
extrude, rolled, forged and machined into finished product.
[0040] The novel composition of aluminum matrix, the percentage of
nano-phase and the percentage of modulus phase is listed in Table
7. The nano-phase percentage of aluminum oxide is determined by the
average particle size of aluminum powder and the powder
manufacturing process. Peng et al in U.S. patent application Ser.
No. 10/738,275 provided detail method of controlling the percentage
of the nano aluminum oxide in aluminum powder. The micron-size
ceramic can be micron-size of silicon carbide particles, aluminum
oxide particles, boron carbide particles and titanium carbide
particles. The ceramic particle size is average 3-30 microns.
Silicon carbide is preferred for high thermal conductivity. The
powder matrix phase containing aluminum oxide on every aluminum
particle is uniformly blended with the micron-size ceramic powder.
The blended powder is produced into billet by standard powder
metallurgy process.
Example 1
[0041] An aluminum matrix of powder alloy containing 2.3% copper,
1.6% Magnesium, 0.35% silicon, 1.4% iron, 1.0% nickel and 1.2%
aluminum oxide was blended with 25% of average 7 micron silicon
carbide powder. The blended powder was vacuum hot pressed into a
356 mm diameter by 356 mm long billet. This billet was extruded to
95 mm diameter rod. The rod was turned to 89 mm diameter and
re-extruded to a 17 mm diameter rod for testing. Tensile sample
blanks were cut from the 17 mm rod and were heat treated to a peak
strength condition by solution treatment of 530.degree. C. for 2
hours, water quench and age for 2 hours at 200.degree. C. Tensile
samples were then machined from the heat-treated blanks. Additional
blanks were heat treated to the peak strength condition and then
heated to various temperatures for 100 hours before being machined
into test samples. The exposure and test temperatures were 150, 175
and 200.degree. C. These data are shown in Table 8.
Example 2
[0042] An aluminum matrix of powder alloy containing 4.0% copper,
1.5% magnesium, 0.5% silicon and 0.8% aluminum oxide was blended
with 20% silicon carbide. The blended powder is made into an 89 mm
diameter billet by vacuum hot pressing. The billet is extruded to a
13 mm diameter rod. Tensile sample blanks were cut from the 13 mm
rod and were heat treated to a peak strength condition by solution
treatment of 530.degree. C. for 2 hours, water quench and age for 2
hours at 200.degree. C. Tensile samples were then machined from the
heat-treated blanks. Additional blanks were heat treated to the
peak strength condition and then heated to various temperatures for
100 hours before being machined into test samples. The exposure and
test temperatures were 150 and 200.degree. C. These data are shown
in Table 9.
[0043] The tensile data in Table 8 and 9 show that the new nano
aluminum-matrix-composites alloy has significantly higher strength
from room temperature to 200.degree. C. than prior art of high
temperature aluminum alloys and aluminum-matrix-composites.
TABLE-US-00001 TABLE 1 2618 alloying elements (% by weight) Cu Mg
Fe Ni Ti Si Al 1.9-2.7 1.3-1.8 0.9-1.3 0.9-1.2 0.04-0.1 0.10-0.25
Balance
TABLE-US-00002 TABLE 2 Yield strength of 2618 after 100 hour
exposure to temperature Test Temperature (.degree. C.) Room T. 100
150 200 Yield Strength (MPa), 324 310 302 254 T6 Teat Treatment
TABLE-US-00003 TABLE 3 Yield strengths of high Silicon alloys after
100 hour exposure to temperature Si CTE Yield Strength (Mpa) Level
Elongation (PPM/ at Test Temperature Alloy (%) at R.T. (%) .degree.
C.) Room T. 150.degree. C. 200.degree. C. 380, F 8.5 3 21.5 165 165
152 390, T5 17 1 18.2 210 195 165 NASA 16 0.4 18.8 235 221 198 398,
T5 4032, T6 12 9 20.2 315 290 182
TABLE-US-00004 TABLE 4 Composites of 2009/SiC/17.5p and
6092/SiC/25p Aluminum- Ceramic Matrix- Composition of Aluminum
Matrix (weight % of the Matrix, Al: Balance) (wt % of Total)
Composites Cu Mg Mn Fe Si Ti Zn Other, Each SiC 2009/SiC/17.5p
3.8-4.9 1.2-1.8 0.3-0.9 0.3 Max 0.5 Max 0.05 Max 0.25 Max 0.05 Max
17 6092/SiC/25p 0.7-1.0 0.8-1.2 0.15 Max 0.3 Max 0.4-0.8 0.15 Max
0.25 Max 0.05 Max 25
TABLE-US-00005 TABLE 5 Yield Strengths of
Aluminum-Matrix-Composites after Exposure for 100 Hours at Test
Temperature Elongation CTE Yield Strength (MPa) at Test Temperature
Alloy at R. T. (%) (PPM/.degree. C.) Room T. 150.degree. C.
200.degree. C. 2009/SiC/17.5p, 8 18 330 295 210 T4 6092/SiC/25p, 3
17.5 427 375 245 T6
TABLE-US-00006 TABLE 6 Fatigue test data for 2024-A1 and
2009/SiC/25p AMC. 2009/SiC/25p, T4 2024, T42 (Mill HNBK 5F) Average
Cycles to Stress Cycles to Stress Failure (MPa) Failure (MPa)
10,000,000 250 350,000 228 309,000,000 200 1,000,000 207
376,000,000 175 3,500,000 172 10,000,000 155 Data for fully
reversed loading, R = -1.
TABLE-US-00007 TABLE 7 Composition of the NAMC-alloy of present
invention Nano-phase Modulus-phase Composition of Aluminum Matrix
(weight % of the Matrix-Phase) (wt % Matrix-phase) (wt % of
NAMC-alloy) Cu Mg Mn Fe Ni Si Ti Other, Each Al Al.sub.2O.sub.3
Micro-ceramic 1.0-5.0 0.8-2.0 0.5 Max. 0.01-1.5 0.01-1.4 0.1-1.2
0.01-0.12 0.05 Max Balance 0.2-5 5-30
TABLE-US-00008 TABLE 8 Tensile test data for Example 1 NAMC-alloy
at temperatures from room temperature to 200.degree. C. after 100
hour exposure. Test Temperature Room T. 150.degree. C. 175.degree.
C. 200.degree. C. Yield Strength (MPa) 442 454 351 260 Ultimate
Strength (MPa) 589 518 400 302 Elongation (%) 5.1 5.0 7.7 10.3
TABLE-US-00009 TABLE 9 Tensile test data for Example 2 NAMC-alloy
at room temperatures and 200.degree. C. after 100 hour exposure.
TEST TEMPERATURE R. T. 150.degree. C. 200.degree. C. Yield Strength
(MPa) 500 454 286 Ultimate Strength (MPa) 531 518 318 Elongation
(%) 10 5.0 11.8
[0044] Defined in detail, the present invention is a nano
aluminum-matrix-composite alloy comprising: high strength at high
temperature, high wear-resistance, low coefficient of thermal
expansion and high modules, with a matrix phase, a nano phase and a
modular phase.
[0045] Of course the present invention is not intended to be
restricted to any particular form or arrangement, or any specific
embodiment, or any specific use, disclosed herein, since the same
may be modified in various particulars or relations without
departing from the spirit or scope of the claimed invention
hereinabove shown and described of which the apparatus or method
shown is intended only for illustration and disclosure of an
operative embodiment and not to show all of the various forms or
modifications in which this invention might be embodied or
operated.
* * * * *