U.S. patent application number 13/169210 was filed with the patent office on 2012-12-27 for forging of glassy aluminum-based alloys.
This patent application is currently assigned to UNITED TECHNOLOGIES CORPORATION. Invention is credited to Venkatarama K. Seetharaman, Thomas J. Watson.
Application Number | 20120328472 13/169210 |
Document ID | / |
Family ID | 45930616 |
Filed Date | 2012-12-27 |
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United States Patent
Application |
20120328472 |
Kind Code |
A1 |
Watson; Thomas J. ; et
al. |
December 27, 2012 |
FORGING OF GLASSY ALUMINUM-BASED ALLOYS
Abstract
A forged devitrified aluminum alloy of forging devitrified
aluminum alloys having a desired shape. The alloy is forged in a
plane strain forging die with the axis of extrusion being parallel
to the direction of forging. The alloy is then forged in a product
forming forging die having a desired shape such that the original
axis of extrusion is aligned with the axis of the forging die
resulting in the desired shape
Inventors: |
Watson; Thomas J.; (South
Windsor, CT) ; Seetharaman; Venkatarama K.; (Rocky
Hill, CT) |
Assignee: |
UNITED TECHNOLOGIES
CORPORATION
Hartford
CT
|
Family ID: |
45930616 |
Appl. No.: |
13/169210 |
Filed: |
June 27, 2011 |
Current U.S.
Class: |
420/550 ;
72/352 |
Current CPC
Class: |
F05D 2300/173 20130101;
C22F 1/04 20130101; C22C 1/002 20130101; F05D 2230/25 20130101;
B21J 1/006 20130101; B21K 3/04 20130101; B21C 23/002 20130101; C21D
2201/03 20130101; C22C 21/00 20130101 |
Class at
Publication: |
420/550 ;
72/352 |
International
Class: |
C22C 21/00 20060101
C22C021/00; B21J 5/02 20060101 B21J005/02 |
Claims
1. A method of forging devitrified aluminum alloys, comprising the
steps of: selecting a devitrified aluminum alloy billet having an
axis of extrusion; placing the billet in a plane strain forging die
so the axis of extrusion is parallel to the direction of forging;
forging the billet in the plane strain forging die to elongate the
billet in the horizontal direction; removing the billet and placing
it in a blocker die or series of blocker dies having a desired
shape such that the original axis of extrusion is aligned with the
axis of the forging die; and forging the billet in the product
forging final die to produce a forged billet having a desired
shape.
2. The method of claim 1, wherein the plane strain forging die and
product forging die during forging the billet is maintained at a
temperature from about 500.degree. F. to about 800.degree. F.
(260.degree. C. to 426.7.degree. C.).
3. The method of claim 2, wherein the temperature ranges from about
675.degree. F. to about 750.degree. F. (357.2.degree. C. to
398.9.degree. C.) during forging the billet.
4. The method of claim 1, wherein the plane strain forging is done
at a press speed of from about 0.001 inches per second to 0.1
inches per second.
5. The method of claim 1, wherein the billet during forging the
billet is maintained at a temperature from about 500.degree. F. to
about 800.degree. F. (260.degree. C. to 426.7.degree. C.).
6. The method of claim 5, wherein the temperature ranges from about
700.degree. F. to about 750.degree. F. (371.1.degree. C. to
398.9.degree. C.) during forging the billet.
7. The method of claim 1, wherein the devitrified aluminum alloy is
an aluminum based alloy containing from 3 to 18.5 atomic percent
nickel and 3 to 14.0 atomic percent yttrium.
8. A method of forging devitrified aluminum alloys, comprising the
steps of: selecting a devitrified aluminum alloy billet having an
axis of extrusion; placing the billet in a plane strain forging die
so the axis of extrusion is parallel to the direction of forging;
forging the billet in the plane strain forging die at a temperature
of the die from about 500.degree. F. to about 800.degree. F.
(260.degree. C. to 426.7.degree. C.) to elongate the billet in the
horizontal direction while maintaining the temperature of the
billet at a temperature from about 500.degree. F. to about
800.degree. F. (260.degree. C. to 426.7.degree. C.).; removing the
billet and placing it in a blocker die or series of blocker dies
having a desired shape such that the original axis of extrusion is
aligned with the axis of the forging die; and forging the billet in
the product forging final die at a temperature of the die from
about 500.degree. F. to about 800.degree. F. (260.degree. C. to
426.7.degree. C.) to produce a forged billet having a desired
shape.
9. The method of claim 8, wherein the temperature of the die ranges
from about 675.degree. F. to about 750.degree. F. (357.2.degree. C.
to 398.9.degree. C.) during plane strain forging the billet.
10. The method of claim 8, wherein the plane strain forging is done
at a press speed of from about 0.001 inches per second to 0.1
inches per second.
11. The method of claim 8, wherein the temperature of the billet
ranges from about 700.degree. F. to about 750.degree. F.
(371.1.degree. C. to 398.9.degree. C.) during plane strain forging
the billet.
12. The method of claim 8, wherein the devitrified aluminum alloy
is an aluminum based alloy containing from 3 to 18.5 atomic percent
nickel and 3 to 14.0 atomic percent yttrium.
13. A forged devitrified aluminum alloy made according to the
method of clam 8.
14. A forged devitrified aluminum alloy of forging devitrified
aluminum alloys having a desired shape, comprising: a devitrified
aluminum alloy billet having an axis of extrusion; the alloy being
forged in a plane strain forging die so the axis of extrusion is
parallel to the direction of forging; the billet being elongated in
the horizontal direction; and the billet further being forged in a
product forming forging die having a desired shape such that the
original axis of extrusion is aligned with the axis of the forging
die resulting in the desired shape.
15. The forged devitrified aluminum alloy of claim 14, wherein the
plane strain forging die and the product forging during forging the
billet is maintained at a temperature from about 500.degree. F. to
about 800.degree. F. (260.degree. C. to 426.7.degree. C.).
16. The forged devitrified aluminum alloy of claim 15, wherein the
temperature ranges from about 675.degree. F. to about 750.degree.
F. (357.2.degree. C. to 398.9.degree. C.) during plane strain
forging the billet.
17. The forged devitrified aluminum alloy of claim 14, wherein the
plane strain forging is done at a press speed of from about 0.001
inches per second to 0.1 inches per second.
18. The forged devitrified aluminum alloy of claim 14, wherein the
billet during forging the billet is maintained at a temperature
from about 500.degree. F. to about 800.degree. F. (260.degree. C.
to (426.7.degree. C.).
19. The forged devitrified aluminum alloy of claim 18, wherein the
temperature ranges from about 700.degree. F. to about 750.degree.
F. (371.1.degree. C. to 398.9.degree. C.) during plane strain
forging the billet.
20. The forged devitrified aluminum alloy of claim 14, wherein the
devitrified aluminum alloy is an aluminum based alloy containing
from 3 to 18.5 atomic percent nickel and 3 to 14.0 atomic percent
yttrium.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is related to the following co-pending
applications that are filed on even date herewith and are assigned
to the same assignee: DIFFUSION BONDING OF GLASSY ALUMINUM-BASED
ALLOYS, Ser. No. ______, Attorney Docket No.
PA0009506U-U73.12-665KL; MASTER ALLOY PRODUCTION FOR GLASSY
ALUMINUM-BASED ALLOYS, Ser. No. ______, Attorney Docket No.
PA0009509U-U73.12-666KL; EXTRUSION OF GLASSY ALUMINUM-BASED ALLOYS,
Ser. No. ______, Attorney Docket No. PA0009510U-U73.12-667KL; and
PRODUCTION OF ATOMIZED POWDER FOR GLASSY ALUMINUM-BASED ALLOYS,
Ser. No. ______, Attorney Docket No. PA0009512U-U73.12-668KL. All
referenced incorporated herein.
BACKGROUND
[0002] Aluminum alloys are important in many industries. Glassy
Al-based alloys and their devitrified derivatives are currently
being considered for applications in the aerospace industry. These
alloys involve the addition of rare earth and transition metal
elements. These alloys have high strength and, when processed
appropriately, have high ductility.
[0003] One of the key requirements for high ductility is control of
the second phase size during thermomechanical processing; in this
case, forging extruded billet into various forged shapes.
[0004] When pure Al or Al-based alloys are forged, the alloys are
heated, such as to 700.degree. F. to 800.degree. F., and are forged
at high press speeds. There is normally no concern for adiabatic
heating because the alloys are usually heat-treatable. In a heat
treatment, they are solutionized, quenched and aged to a desired
temper after forging.
[0005] Al-based alloys such as Al--Y--Ni--Co alloys are devitrified
glass-forming aluminum alloys that derive their strength from a
nanometer-sized grain structure and nanometer-sized intermetallic
second phase or phases. Examples of such alloys are disclosed in
co-owned U.S. Pat. Nos. 6,974,510 and 7,413,621, the disclosures of
which are incorporated herein by reference in their entirety.
[0006] However, devitrified derivatives of glassy aluminum alloys
have nanocrystalline microstructures that have mechanical
properties that cannot be obtained when starting out with powder in
the crystalline state. Standard forging practices will destroy the
nanocrystalline microstructure and the important properties are
lost.
SUMMARY
[0007] The invention involves the forging of extruded billet, or
forging mults, in a direction whose axis is parallel to the axis of
extrusion that formed the alloy billet. The alloy itself is a
devitrified derivative of glassy aluminum alloys such as those
described in the above identified patents.
[0008] Of particular use are aluminum based alloys containing from
3 to 18.5 atomic percent nickel and 3 to 14.0 atomic percent
yttrium.
[0009] The alloy billet is textured and has an axis of extrusion in
which the microstructure is aligned. Forging in this direction
changes the microstructure to give maximum strength, and also
causes the plate phases within the subject alloys to become
randomly oriented, resulting in improved ductility.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic view of an alloy billet inserted in a
cylinder.
[0011] FIG. 2 is a schematic view of a forging die.
[0012] FIG. 3 is a schematic view of the cylinder and billet of
FIG. 1 inserted into the die of FIG. 2.
[0013] FIG. 4 is a schematic view of the die of FIG. 3 with the
billet just below the lip of the die.
[0014] FIG. 5 is a schematic view of the use of a punch inserted
into the die and billet of FIG. 4.
[0015] FIG. 6 is a schematic view of the billet after forging in
FIG. 5.
[0016] FIG. 7 is a schematic view of the billet after being
extracted from the die of FIG. 6.
[0017] FIG. 8 is a schematic view of the extracted billet of FIG. 7
inserted into a forging die such that the forging direction is
parallel to the axis of extrusion.
[0018] FIG. 9 is a schematic view of a part produced by the forging
in FIG. 8.
DETAILED DESCRIPTION
[0019] An alloy billet 11 that, for example, is 4 inches in
diameter and 36 inches tall, is potted in a two inch diameter
cylinder 13 of aluminum alloy 6061 or other such metals, as shown
in FIG. 1. Billet 11 may be formed from any devitrified aluminum
alloy, such as an aluminum based alloy containing from 3 to 18.5
atomic percent nickel and 3 to 14.0 atomic percent yttrium.
[0020] Cylinder 13 with billet 11 is then put in a steel plane
strain die 15 in FIGS. 2 and 3, where die 15 is wider than cylinder
13. Billet 11 is aligned so that its extrusion axis 17 will be
parallel to the axis of forging in plane strain forge die 15 and is
just below the lip 15a of die 15, as seen in FIG. 4.
[0021] In FIG. 5, punch 19 is inserted into die 15 and plane strain
forges billet 11 into the shape shown in FIG. 6. In this process, a
maximum amount of work is placed in the direction of extrusion,
axis 17. At the same time, billet 11 is elongated in the horizontal
direction so as to prepare billet 11 for further processing to form
a useful part such as an airfoil.
[0022] FIG. 7 shows the elongated billet 11 after it is removed
from die 15. Billet 11 is then placed in a forging die 21, shown in
FIG. 8 for forming an airfoil. Such forging dies could include
blocker dies and a final forging die. Again, the forging is done in
the direction of extrusion axis 17. Airfoil 23 is the result of
forging in die 21.
[0023] During extrusion to form billet 11, the plate phases
(Al.sub.23Ni.sub.6Y.sub.4 and Al.sub.19Ni.sub.5Y.sub.3) that give
the alloy its strength, become aligned with the extrusion direction
17. This leads to low ductility in the extrusion direction and even
lower ductility in the transverse direction. When forged parallel
to the direction of extrusion, axis 17, the plate phases become
randomly oriented and smaller in size. This leads to more uniform
flow during plastic deformation, resulting in improved
ductility.
[0024] To provide for the retention of the nano-scale
microstructure during forging, the temperature of the forged
product must be controlled. This is accomplished through careful
control of the temperature of the dies and the billet. The
temperature of the dies typically ranges from 500.degree. F. to
about 800.degree. F. (260.degree. C. to 426.7.degree. C.). For more
control, this temperature is maintained from about 675.degree. F.
to about 750.degree. F. (357.2.degree. C. to 398.9.degree. C.)
during forging the billet. The billet temperature is also
controlled to be at a temperature from about 500.degree. F. to
about 800.degree. F. (260.degree. C. to (426.7.degree. C.). Again,
more control will use a temperature range from about 700.degree. F.
to about 750.degree. F. (371.1.degree. C. to 398.9.degree. C.)
during forging the billet. During forging, adiabatic heating is
controlled by controlling the press speed. Good results have been
attained at a press speed of from about 0.001 inches per second to
0.1 inches per second.
[0025] Once the product has been formed, normal finish operations
are performed. In the airfoil of FIG. 9, the forging path resulted
in high yield strength and high ductility perpendicular to the
chord direction for a blade. This is important for bird strike
capability.
[0026] While the invention has been described with reference to an
exemplary embodiment(s), it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment(s) disclosed, but that the invention will
include all embodiments falling within the scope of the appended
claims.
* * * * *