U.S. patent application number 14/762772 was filed with the patent office on 2015-12-10 for metal composite comprising aligned precipitate and preparation method therefor.
The applicant listed for this patent is KOREA INSTITUTE OF MACHINERY & MATERIALS. Invention is credited to Seung Zeon HAN.
Application Number | 20150354048 14/762772 |
Document ID | / |
Family ID | 48866864 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150354048 |
Kind Code |
A1 |
HAN; Seung Zeon |
December 10, 2015 |
METAL COMPOSITE COMPRISING ALIGNED PRECIPITATE AND PREPARATION
METHOD THEREFOR
Abstract
The present invention provides a metal composite with an
oriented precipitate, in which a solid solution is created by
performing solution treatment or homogenization on an alloy, a
discontinuous cellular precipitate or lamellar precipitate of 40%
or more per unit area of 500 .mu.m.times.500 .mu.m is forcibly
created by aging and oriented by plastic working. The present
invention provides a method of manufacturing a metal composite with
an oriented precipitate which includes: a material preparing step
of preparing a molded alloy; a solid solution creating step of
creating a solid solution by performing heat treatment on the alloy
in a single phase area; a precipitate forcible-creating step of
creating a cellular precipitate or a lamellar precipitate of 40% or
more per unit area of 500 .mu.m.times.500 .mu.m by aging the alloy
containing the solid solution; and a precipitate orienting step of
orienting the precipitate by performing plastic working on the
alloy containing the precipitate.
Inventors: |
HAN; Seung Zeon;
(Changwon-si, Gyeongsangnam-do, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOREA INSTITUTE OF MACHINERY & MATERIALS |
Yuseong-gu Daejeon |
|
KR |
|
|
Family ID: |
48866864 |
Appl. No.: |
14/762772 |
Filed: |
February 14, 2013 |
PCT Filed: |
February 14, 2013 |
PCT NO: |
PCT/KR2013/001163 |
371 Date: |
July 22, 2015 |
Current U.S.
Class: |
148/686 ;
148/414 |
Current CPC
Class: |
C22F 1/002 20130101;
C22C 9/06 20130101; C22F 1/08 20130101 |
International
Class: |
C22F 1/08 20060101
C22F001/08; C22C 9/06 20060101 C22C009/06; C22F 1/00 20060101
C22F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2013 |
KR |
10-2013-0006993 |
Claims
1. A metal composite with an oriented precipitate, wherein a solid
solution is created by performing solution treatment or
homogenization on an alloy, a discontinuous cellular precipitate or
lamellar precipitate of 40% or more per unit area of 500
.mu.m.times.500 .mu.m is forcibly created by aging, and the
forcibly created precipitate is oriented by plastic working.
2. A metal composite with an oriented precipitate, wherein a solid
solution is created by performing solution treatment or
homogenization on an alloy, a discontinuous cellular precipitate or
lamellar precipitate of 40% or more per unit area of 630
.mu.m.times.480 .mu.m is forcibly created by aging, and the
forcibly created precipitate is oriented by plastic working.
3. A metal composite with an oriented precipitate, wherein a solid
solution is created by performing solution treatment or
homogenization on an alloy, a discontinuous cellular precipitate or
lamellar precipitate is forcibly created by aging, and the forcibly
created precipitate is oriented by plastic working to have a length
of 2.01 .mu.m or more per unit area of 3.5 .mu.m.times.1.5 .mu.m in
a copper base.
4. The metal composite of claim 1, wherein the oriented precipitate
has a length to diameter aspect ratio of 100 or more.
5. The metal composite of claim 4, wherein the alloy that became
the solid solution is rapidly cooled by water quenching or cooled
by air.
6. The metal composite of claim 5, wherein the aging is performed
for three hours or more.
7. The metal composite of claim 6, wherein precipitation-promoting
metal is added in the solution treatment or homogenization
process.
8. The metal composite of claim 7, wherein the
precipitation-promoting metal includes any one of titanium (Ti) or
vanadium (V).
9. A method of manufacturing a metal composite with an oriented
precipitate, the method comprising: a material preparing step of
preparing a molded alloy;/a solid solution creating step of
creating a solid solution by performing heat treatment on the alloy
in a single phase area; a precipitate forcible-creating step of
creating a cellular precipitate or a lamellar precipitate of 40% or
more per unit area of 500 .mu.m.times.500 .mu.m by aging the alloy
containing the solid solution; and a precipitate orienting step of
orienting the precipitate by performing plastic working on the
alloy containing the precipitate.
10. A method of manufacturing a metal composite with an oriented
precipitate, the method comprising: a material preparing step of
preparing a molded alloy; a solid solution creating step of
creating a solid solution by performing heat treatment on the alloy
in a single phase area; a precipitate forcible-creating step of
creating a cellular precipitate or a lamellar precipitate of 40% or
more per unit area of 630 .mu.m.times.480 .mu.m by aging the alloy
containing the solid solution; and a precipitate orienting step of
orienting the precipitate by performing plastic working on the
alloy containing the precipitate.
11. A method of manufacturing a metal composite with an oriented
precipitate, the method comprising: a material preparing step of
preparing a molded alloy; a solid solution creating step of
creating a solid solution by performing heat treatment on the alloy
in a single phase area; a precipitate forcible-creating step of
creating a cellular precipitate or a lamellar precipitate by aging
the alloy containing the solid solution; and a precipitate
orienting step of orienting the precipitate to have a length of 2.0
.mu.m or more per unit area of 3.5 .mu.m.times.1.5 .mu.m in a
copper base by performing plastic working on the alloy containing
the precipitate.
12. The method of any one of claim 9 wherein
precipitation-promoting metal including any one of titanium (Ti)
and vanadium (V) is added in the material preparing step.
13. The method of claim 12, wherein the solid solution creating
step is a process of performing heating within a temperature range
of above the lowermost temperature where a single phase is
maintained in the state diagram and below the melting
temperature-7.5.times.X (X is wt % of an added component other than
copper base) of a copper base phase for two hours or more.
14. The method of claim 12, wherein the solid solution creating
step is a process of performing heating within a temperature range
of above the lowermost temperature where a single phase is
maintained in the state diagram and below the melting
temperature-7.5 .times.X (X is wt % of an added component other
than copper base) of a copper base phase for two hours or more.
15. The method of claim 14, wherein the alloy is a copper alloy and
(Ni+Si), which is X, is 4.8 to 7.5 wt %.
16. The metal composite of claim 2, wherein the oriented
precipitate has a length to diameter aspect ratio of 100 or
more.
17. The metal composite of claim 3, wherein the oriented
precipitate has a length to diameter aspect ratio of 100 or
more.
18. The method of claim 10 wherein precipitation-promoting metal
including any one of titanium (Ti) and vanadium (V) is added in the
material preparing step.
Description
TECHNICAL FIELD
[0001] The present invention relates to a metal composite with an
oriented precipitate and a method of manufacturing the same, and
more particularly, to a metal composite with an oriented
precipitate that has improved strength and electric conductivity by
forcibly creating a precipitate through aging after creating a
solid solution, which is created by selectively adding
precipitation-promoting metal to an alloy and performing solution
treatment or homogenization, and by orienting the forcibly created
precipitate through plastic working, and a method of manufacturing
the metal composite.
BACKGROUND ART
[0002] Due to high electric conductivity, copper is widely used in
electric/electronic circuits, but as information communication
parts have become highly integrated and reduced in weight, copper
is exposed to high current and voltage when it is used in
electric/electronic circuits.
[0003] Furthermore, when it is used as a conductive material, it is
further exposed to a severe environment, so high strength and
electric conductivity and excellent thermal stability are
required.
[0004] That is, copper alloys are used for connectors,
accumulators, or connectors for connecting a controller to various
electric parts, actuators, and sensors in vehicles equipped with
increased electric devices and it is strongly required to downsize
these connectors.
[0005] In particular, connectors disposed close to an engine are
exposed to the heat and vibration of the engine, and when a large
amount of current is applied to the connectors, the connectors
generate heat and increase the temperature to a high level.
Accordingly, those connectors require high reliability under such
environments.
[0006] Accordingly, as a material of copper alloy connectors used
in common vehicles, a Cu--Fe--P alloy (Korean Patent No.
10-0997560) or a Cu--Mg--P alloy (Korean Patent No. 10-0417756)
have been disclosed. The strength of the former alloy is improved
by precipitating a Fe--P compound based on the addition of both of
Fe and P.
[0007] Furthermore, there have been proposed an alloy of which
mobility resistance is improved by adding Zn (Japanese Patent
Application Publication No. 168830) and an alloy of which
mitigation of stress resistance is improved by adding Mg (Japanese
Patent Application Publication No. 358033).
[0008] The latter alloy is improved in tensile strength, electric
conductivity, and mitigation of stress resistance by improving
strength and creeping characteristic by adding Mg and P.
[0009] As described above, copper alloys can improve its electric
conductivity, thermal stability, and strength by adding various
components.
[0010] However, various components that are added to copper alloys
make electric conductivity and strength opposite to each other.
[0011] That is, when the strength is increased, the electric
conductivity is decreased, and when the electric conductivity is
increased, a microstructure changes and strength decreases.
SUMMARY OF INVENTION
Technical Problem
[0012] An object of the present invention is to provide a metal
composite with an oriented precipitate that has improved strength
and electric conductivity by forcibly creating a precipitate
through aging after creating a solid solution, which is created by
selectively adding precipitation-promoting metal to an alloy and
performing solution treatment or homogenization, and by orienting
the forcibly created precipitate through plastic working, and a
method of manufacturing the metal composite.
Solution to Problem
[0013] In order to achieve the object, the present invention
provides a metal composite with an oriented precipitate, in which a
solid solution is created by performing solution treatment or
homogenization on an alloy, a discontinuous cellular precipitate or
lamellar precipitate of 40% or more per unit area of 500
.mu.m.times.500 .mu.m is forcibly created by aging, and the
forcibly created precipitate is oriented by plastic working.
[0014] The present invention provides a metal composite with an
oriented precipitate, in which a solid solution is created by
performing solution treatment or homogenization on an alloy, a
discontinuous cellular precipitate or lamellar precipitate of 40%
or more per unit area of 630 .mu.m.times.480 .mu.m is forcibly
created by aging, and the forcibly created precipitate is oriented
by plastic working.
[0015] The present invention provides a metal composite with an
oriented precipitate, in which a solid solution is created by
performing solution treatment or homogenization on an alloy, a
discontinuous cellular precipitate or lamellar precipitate is
forcibly created by aging, and the forcibly created precipitate is
oriented by plastic working to have a length of 2.0 .mu.m or more
per unit area of 3.5 .mu.m.times.1.5 .mu.m in a copper base.
[0016] The oriented precipitate has a length to diameter aspect
ratio of 100 or more.
[0017] The alloy that became the solid solution is rapidly cooled
by water quenching or cooled by air.
[0018] The aging is performed for three hours or more.
[0019] Precipitation-promoting metal is added in the solution
treatment or homogenization process.
[0020] The precipitation-promoting metal includes any one of
titanium (Ti) and vanadium (V).
[0021] The present invention provides a method of manufacturing a
metal composite with an oriented precipitate which includes: a
material preparing step of preparing a molded alloy; a solid
solution creating step of creating a solid solution by performing
heat treatment on the alloy in a single phase area; a precipitate
forcible-creating step of creating a cellular precipitate or a
lamellar precipitate of 40% or more per unit area of 500
.mu.m.times.500 .mu.m by aging the alloy containing the solid
solution; and a precipitate orienting step of orienting the
precipitate by performing plastic working on the alloy containing
the precipitate.
[0022] The present invention provides a method of manufacturing a
metal composite with an oriented precipitate which includes: a
material preparing step of preparing a molded alloy; a solid
solution creating step of creating a solid solution by performing
heat treatment on the alloy in a single phase area; a precipitate
forcible-creating step of creating a cellular precipitate or a
lamellar precipitate of 40% or more per unit area of 630
.mu.m.times.480 .mu.m by aging the alloy containing the solid
solution; and a precipitate orienting step of orienting the
precipitate by performing plastic working on the alloy containing
the precipitate.
[0023] The present invention provides a method of manufacturing a
metal composite with an oriented precipitate which includes: a
material preparing step of preparing a molded alloy; a solid
solution creating step of creating a solid solution by performing
heat treatment on the alloy in a single phase area; a precipitate
forcible-creating step of creating a cellular precipitate or a
lamellar precipitate of 40% or more per unit area of 630
.mu.m.times.480 .mu.m by aging the alloy containing the solid
solution; and a precipitate orienting step of orienting the
precipitate to have a length of 2.0 .mu.m or more per unit area of
3.5 .mu.m.times.1.5 .mu.m in a copper base by performing plastic
working on the alloy containing the precipitate.
[0024] In the material preparing step, precipitation-promoting
metal including any one of titanium (Ti) and vanadium (V) is
added.
[0025] The solid solution creating step is a process of performing
heating within a temperature range of above the lowermost
temperature where a single phase is maintained in the state diagram
and below the melting temperature-7.5.times.X (X is wt % of an
added component other than copper base) of a copper base phase for
two hours or more.
[0026] The precipitate forcible-creating step is performed at a
temperature below 47.times.X (X is wt % of an added component other
than copper base)+melting temperature of a copper base
phase.times.0.4(K, absolute temperature).
[0027] The alloy is a copper alloy and (Ni+Si), which is X, is 4.8
to 7.5wt %.
Advantageous Effects of Invention
[0028] The present invention relates to a metal composite with an
oriented precipitate that can function as a reinforcing material of
a composite by artificially orienting an artificially created
precipitate through plastic working.
[0029] Accordingly, electric conductivity and strength are
improved.
[0030] Furthermore, it is possible to adjust the amount of
precipitate by selectively adding precipitation-promoting
metal.
BRIEF DESCRIPTION OF DRAWINGS
[0031] FIG. 1 is a picture of microstructures, obtained by an
optical microscope, of a continuous precipitate and a discontinuous
precipitate before plastic working in a metal composite with an
oriented precipitate according to the present invention.
[0032] FIG. 2 is a picture of a microstructure obtained by a
transmission electron microscope, enlarging the portion A of FIG.
1.
[0033] FIG. 3 is a picture of a microstructure, obtained by a
transmission electron microscope, of a metal composite with an
oriented precipitate according to the present invention.
[0034] FIG. 4 is a diagram comparing changes in hardness and
electric conductivity before/after aging in a metal composite with
an oriented precipitate according to the present invention.
[0035] FIG. 5 is a flowchart illustrating a method of manufacturing
a metal composite with an oriented precipitate according to the
present invention.
[0036] FIG. 6 is a schematic diagram illustrating a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0037] FIG. 7 is a Cu--Ni.sub.2Si two-phase diagram for examining
temperatures to be applied in a step of creating a solid solution
and a step of forcibly creating a precipitate in a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0038] FIG. 8 is a picture of a microstructure in a comparative
example aged without a step of creating a solid solution in a
method of manufacturing a metal composite with an oriented
precipitate according to the present invention.
[0039] FIG. 9 is a picture of a microstructure after a step of
creating a solid solution and a step of forcibly creating a
precipitate in a method of manufacturing a metal composite with an
oriented precipitate according to the present invention.
[0040] FIG. 10 is a picture of a microstructure in plastic working
on a comparative example where slow cooling has been applied in a
step of creating a solid solution in a method of manufacturing a
metal composite with an oriented precipitate according to the
present invention.
[0041] FIG. 11 is a picture of a microstructure in plastic working
on an embodiment where rapid cooling has been applied in a step of
creating a solid solution in a method of manufacturing a metal
composite with an oriented precipitate according to the present
invention.
[0042] FIG. 12 is a picture of a microstructure in a comparative
example without a step of creating a solid solution in a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0043] FIG. 13 is a picture of a microstructure in an embodiment
with a step of creating a solid solution in a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0044] FIG. 14 is a picture of a microstructure in a comparative
example where slow cooling has been performed without
precipitation-promoting metal in a step of creating a solid
solution in a method of manufacturing a metal composite with an
oriented precipitate according to the present invention.
[0045] FIG. 15 is a picture of a microstructure in an embodiment
where rapid cooling has been performed with precipitation-promoting
metal in a step of forcibly creating a precipitate in a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0046] FIG. 16 is a picture of a microstructure in heat treatment
at 500.degree. C. after hot rolling on the comparative example of
FIG. 14.
[0047] FIG. 17 is a picture showing a change in the microstructure
according to heat treatment temperature and time change in the
embodiment of FIG. 15.
[0048] FIGS. 18 and 19 are graphs showing changes in area ratios of
discontinuous precipitation after a step of forcibly creating a
precipitate in a method of manufacturing a metal composite with an
oriented precipitate according to the present invention.
[0049] FIG. 20 is a picture of a microstructure, obtained by an
electron microscope, in a preferred embodiment that has undergone a
step of forcibly creating a precipitate in a method of
manufacturing a metal composite with an oriented precipitate
according to the present invention.
[0050] FIG. 21 is a picture of a microstructure when a step of
forcibly creating a precipitate (up) and a step of orienting a
precipitate (down) in a comparative example without a step of
creating a solid solution.
[0051] FIG. 22 is a picture comparing microstructure before/after a
step of orienting precipitate in a method of manufacturing a metal
composite with an oriented precipitate according to the present
invention.
[0052] FIG. 23 is a graph comparing mechanical properties
before/after a step of orienting precipitates employing a drawing
process in a comparative example and a preferred embodiment.
[0053] FIG. 24 is a graph comparing mechanical properties
before/after a step of orienting precipitates employing a rolling
process in a comparative example and a preferred embodiment.
[0054] FIG. 25 is a graph comparing the test results of FIG. 23
step by step.
DESCRIPTION OF EMBODIMENTS
[0055] A metal composite 20 with a discontinuous cellular
precipitate or a lamellar precipitate according to the present
invention is described hereafter with reference to FIGS. 1 to
3.
[0056] The terms and words used in the present specification and
claims should not be interpreted as being limited to typical
meanings or dictionary definitions, but should be interpreted as
having meanings and concepts relevant to the technical scope of the
present invention based on the rule according to which an inventor
can appropriately define the concept of the term to describe most
appropriately the best method he or she knows for carrying out the
invention.
[0057] Therefore, the configurations described in the embodiments
and drawings of the present invention are merely the most
preferable embodiments and do not represent all of the technical
spirit of the present invention. Thus, the present invention should
be construed as including all the changes, equivalents, and
substitutions included in the spirit and scope of the present
invention at the time of filing this application.
[0058] FIGS. 1 and 2 are pictures of microstructures, obtained by
an optical microscope, of a continuous precipitate and a
discontinuous precipitate before plastic working, with FIG. 2 being
the enlarged picture of portion A in FIG. 1, in a metal composite
with an oriented precipitate according to the present invention and
FIG. 3 is a picture of a microstructure, obtained by a transmission
electron microscope, of a metal composite 20 with an oriented
precipitate according to the present invention.
[0059] The present invention provides a metal composite 20 that has
improved strength and electric conductivity by providing a
composite type strengthening effect by creating and artificially
orienting a precipitate of a cellular or lamellar structure that
reduces mechanical strength in metal.
[0060] That is, the metal composite 20 of the present invention was
achieved by artificially creating a precipitate in an alloy 10, as
in FIGS. 1 and 2, and artificially orienting the precipitate, as in
FIG. 3.
[0061] The precipitate may be a discontinuous cellular precipitate
or a continuous lamellar precipitate and, for the plastic working,
various processes such as drawing, rolling, and extruding may be
selected.
[0062] FIG. 4 is a chart comparing changes in hardness and electric
conductivity before/after aging in the metal composite 20 with an
oriented precipitate according to the present invention.
[0063] As shown in the figure, precipitation-promoting metal 10 for
increasing the amount of a precipitation may be added to the alloy
in the process of manufacturing the metal composite 20.
[0064] The precipitation-promoting metal is titanium (Ti) or
vanadium (V) and a copper alloy was selected in a preferred
embodiment of the present invention.
[0065] Since the precipitation-promoting metal is selectively
added, electric conductivity or strength can be artificially
adjusted.
[0066] The length to diameter aspect ratio of a precipitate,
artificially created by aging for more than three hours before
plastic working, is 100 or more and a discontinuous precipitate
area of 40% or more of the entire area of the alloy 10 is formed,
so as to improve strength and electric conductivity.
[0067] According to the present invention, it is possible to
forcibly create a discontinuous cellular precipitate or lamellar
precipitate of 40% or more per unit area of 500 .mu.m.times.500
.mu.m through aging after creating a solid solution by performing
solution treatment or homogenization on the alloy 10 and it is also
possible to create a discontinuous cellular precipitate or a
continuous lamellar precipitate of 40% or more per unit area of 630
.mu.m.times.480 .mu.m.
[0068] Furthermore, it is possible to orient the forcibly created
precipitate to have a length of 2.0 .mu.m or more per unit area of
3.5 .mu.m.times.1.5 .mu.m in a copper base through plastic
working.
[0069] A method of manufacturing the metal composite 20 is
described hereafter with reference to FIG. 5.
[0070] FIG. 5 is a flowchart illustrating a method of manufacturing
the metal composite 20 with an oriented precipitate according to
the present invention.
[0071] As shown in the figure, the method of manufacturing the
metal composite 20 of the present invention includes a material
preparing step (S100) of preparing a molded alloy 10, a solid
solution creating step (S200) of creating a solid solution by
thermally treating the alloy 10 in a one phase area, a precipitate
forcible-creating step (S300) of creating a cellular precipitate or
a lamellar precipitate by aging the alloy 10 containing the solid
solution, and a precipitate orienting step (S400) of orienting the
precipitate by performing plastic working on the alloy 10
containing the precipitate.
[0072] The material preparing step (S100) is a process of preparing
an alloy (see FIGS. 5 and 6), in which the precipitation-promoting
metal described above may be selectively prepared.
[0073] In detail, the alloy 10, which is a copper alloy containing
Ni--Si in an embodiment of the present invention, is a mold formed
by any one of rolling, drawing, and extruding and contains a
residual precipitate.
[0074] The precipitation-promoting metal includes any one of
titanium (Ti) and vanadium (V).
[0075] The weight percent (wt %) of (Ni+Si), which is the sum of
nickel (Ni) and silicon (Si), is limited to 81% or more of the
highest solid solubility to the entire weight of the alloy 10, that
is, 4.8 to 7.5wt % and the balance is copper (Cu) and other
unavoidable impurities.
[0076] The precipitation-promoting metal is selectively included,
and titanium (Ti) of 0.025 to 0.24wt % or vanadium (V) of 0.028 to
0.086wt % may be included.
[0077] After the material preparing step (S100), the solid solution
creating step (S200) is performed. The solid solution creating step
(S200) is a process for removing a residual precipitation, and when
precipitation-promoting metal is included in the material preparing
step (S100), the solution solubility may be low.
[0078] The solid solution creating step (S200) is a process of
heating the alloy 10 and the precipitation-promoting metal at a
predetermined temperature or more and the preferred temperature in
the solid solution creating step (S200) is preferably 950.degree.
C. or more for the copper-based alloy and under 1084 (melting point
of pure copper)-7.5.times.X.
[0079] X is the weight percent (wt %) of (Ni+Si) described above,
1084-7.5.times.X where a liquid state is not produced and
950.degree. C. or more that is the highest solid solution limit
temperature where a solid solution can be produced are preferable
for the Cu--Ni--Si, Cu--Ni--Si--Ti, Cu--Ni--Si--V alloy 10 that is
an embodiment of the present invention.
[0080] That is, referring to FIG. 7, in the Cu--Ni--Si,
Cu--Ni--Si--Ti, or Cu--Ni--Si--V alloy 10 that is an embodiment,
not a single phase, but a multiple phase is produced 950.degree. C.
or less, so a discontinuous precipitate is not created.
[0081] After the solid solution creating step (S200), the
discontinuous precipitate forcible-creating step (S300) is
performed.
[0082] The precipitate forcible-creating step (S300) is a process
of creating a discontinuous cellular precipitate or a discontinuous
lamellar precipitate in the alloy 10, and in an embodiment of the
present invention, when water quenching or air cooling is performed
and precipitation-promoting metal was added after the solid
solution creating step (S200), aging was performed for two or more
hours, and when precipitation-promoting metal was not added, aging
was performed for five or more hours, thereby forcibly creating a
discontinuous precipitate.
[0083] That is, FIGS. 8 and 9 are pictures of microstructures in a
comparative example and an embodiment employing different ways of
cooling in the solid solution creating step (S200). It was slowly
cooled in a furnace in the comparative example, whereas it was
rapidly cooled in the embodiment.
[0084] Accordingly, it can be seen that a precipitate having a
normal shape was created in the comparative example, but a
discontinuous precipitate was created in the embodiment.
[0085] FIG. 10 is a picture of a microstructure in plastic working
on a comparative example in which slow cooling was performed in the
solid solution creating step (S200) in the method of manufacturing
the metal composite with an oriented precipitate according to the
present invention and FIG. 11 is a picture of a microstructure in
plastic working on an embodiment in which rapid cooling was
performed in the solid solution creating step (S200) in the method
of manufacturing the metal composite with an oriented precipitate
according to the present invention.
[0086] As in these figures, a precipitate was not oriented in the
comparative example in which slow cooling was performed in a
furnace, but in the embodiment in which rapid cooling was performed
in the solid solution creating step (S200), it can be seen that the
precipitate was oriented in the processing direction in the
precipitate orienting step (S400).
[0087] Accordingly, it is preferable to perform rapid cooling using
water quenching or air cooling in the solid solution creating step
(S200).
[0088] After the solid solution creating step (S200), the
precipitate forcible-creating step (S300) is performed. The
precipitate forcible-creating step (S300) is a step for increasing
the amount of a precipitate formed in the alloy 10 in the solid
solution creating step (S200), and aging was performed in an
embodiment of the present invention.
[0089] Microstructures before/after the precipitate
forcible-creating step (S300) are comparatively described with
reference to FIGS. 12 to 19.
[0090] First, as in FIGS. 12 and 13, a small area of discontinuous
precipitate area was created in a comparative example in which slow
cooling was performed in a furnace in the solid solution creating
step (S200), but in an embodiment where the solid solution creating
step (S200) was preferably performed, it can be seen that the area
of a discontinuous precipitate expanded even if the precipitate
forcible-creating step (S300) was performed for the same amount of
time as the comparative example.
[0091] The contents of components in the comparative example and
the embodiments were as in the following Table 1.
TABLE-US-00001 TABLE 1 Item Cooling type Cu Ni Si Comparative Slow
Bal. 5.98 wt % 1.43 wt % example cooling Embodiment Rapid Bal. 5.98
wt % 1.43 wt % cooling
[0092] As in FIGS. 14 and 15, it can be seen that the discontinuous
precipitate area was wider when precipitation-promoting metal was
included than when precipitation-promoting metal was not included,
even if the precipitate forcible-creating step (S300) was performed
for the same amount of time.
[0093] FIG. 14 is a picture of a microstructure in a comparative
example in which precipitation-promoting metal was not added and
slow cooling was performed in the solid solution creating step
(S200) in the method of manufacturing a metal composite 20 with an
oriented precipitate according to the present invention and FIG. 15
is a picture of a microstructure in an embodiment in which
precipitation-promoting metal was added and rapid cooling was
performed in the solid solution creating step (S200) in the method
of manufacturing a metal composite 20 with an oriented precipitate
according to the present invention, in which microstructures after
the solid solution creating step (S200) and the precipitate
forcible-creating step (S300) was finished, when vanadium (V) was
added in the material preparing step (S100) are shown, and it could
be seen that formation of a discontinuous precipitate was promoted
in the same way as titanium (Ti).
[0094] FIG. 16 is a picture of a microstructure in a heat treatment
of 500.degree. C. after hot rolling in the comparative example of
FIG. 14, and FIG. 17 is a picture showing changes in a
microstructure according to changes in heat treatment temperature
and length of time in the embodiment of FIG. 15.
[0095] When heating was performed at 400.degree. C. in the
precipitate forcible-creating step (S300), as in FIG. 17, a
discontinuous precipitate was not created even though six hours
passed, but when heating was performed at 450.degree. C. and
500.degree. C., a precipitate began to increase from the point of
time when one hour passed.
[0096] On the other hand, in the comparative example, a precipitate
was not created even though heating was performed at 500.degree. C.
for seven hours, as in FIG. 16.
[0097] The microstructure did not show a large change in the
comparative example before the precipitate forcible-creating step
(S300), as in FIGS. 14 and 16, but in the embodiment, it could be
seen that the discontinuous precipitate increased with the lapse of
time, as in FIGS. 15 and 17.
[0098] In the comparative example, when vanadium (V) or titanium
(Ti) not added, a small amount of discontinuous precipitate was
formed even though the precipitate forcible-creating step (S300)
was performed for a long time, the result being opposite to the
preferred embodiment.
[0099] FIGS. 18 and 19 are graphs showing changes in area ratios in
discontinuous precipitation after the precipitate forcible-creating
step (S300) in the method of manufacturing a metal composite 20
with an oriented precipitate according to the present
invention.
[0100] That is, the figures provide graphs for analyzing the amount
of creation of a precipitate when X, which is weight percent (wt %)
of (Ni+Si), was changed, in which it can be seen that when X, which
is the weight percent (wt %) of (Ni+Si), is included over 4.81wt %
to the entire weight of the alloy 10, a discontinuous precipitate
or a lamellar precipitate occupied an area of 40% or more.
[0101] However, when X, which is the weight percent (wt %) of
(Ni+Si), is less than 4.81wt %, a discontinuous precipitate having
an area of 40% or more was not created.
[0102] Accordingly, it is preferable that X, which is the weight
percent (wt %) of (Ni+Si), is in the range of 4.8 to 7.5wt % in the
state diagram shown in FIG. 7. Furthermore, it is possible to
estimate from the state diagram that all of precipitated alloys
show the same phenomenon, so the same phenomenon occurs in an alloy
containing 81% of the highest solution solubility.
[0103] Based on the embodiment described above, as the result of
performing the precipitate forcible-creating step (S300) at
500.degree. C., as in FIG. 20, a discontinuous cellular precipitate
was created and the length to diameter aspect ratio of the lamellar
precipitate was 100 or more.
[0104] Based on the test result described above, the temperature
(.degree. C.) for the discontinuous forcible creating step (S300)
is 47.times.X+260.degree. C(533K) or less and has this
relationship.
[0105] Furthermore, the temperature (.degree. C.) for the solid
solution creating step (S200) is 1084-7.5.times.X and 950.degree.
C. or more, which is the highest soluble limit where a solid
solution can be created and has this relationship.
[0106] The discontinuous precipitate is created from 0.4.times.the
melting point (K, absolute temperature) of copper-based metal or
more where dispersion starts, so a discontinuous precipitate is
forcibly created in the area in the state diagram shown in FIG. 7
from the relationship with additional components other than the
base metal proposed in the present invention.
[0107] The precipitate orienting step (S400) is performed after the
discontinuous precipitate forcible-creating step (S300). The
precipitate orienting step (S400) is a process for artificially
orienting a discontinuous precipitate or a discontinuous lamellar
precipitate formed inside in accordance with the embodiment
described above.
[0108] That is, in an embodiment of the present invention, rolling,
drawing, or extruding was employed in the precipitate orienting
step (S400), FIG. 11 is a picture of a microstructure of the metal
composite 20 manufactured by rolling (upper) and drawing (lower) in
FIG. 11, and it can be seen that discontinuous precipitates are
arranged in parallel in the metal composite 20 manufactured in
accordance with a preferred embodiment of the present
invention.
[0109] Microstructures of a comparative example and an embodiment
are compared hereafter with reference to FIGS. 21 and 22.
[0110] FIG. 21 is a picture of a microstructure when a precipitate
orienting step was performed in a comparative example without the
solid solution creating step (S200) and FIG. 22 is a picture
comparing microstructures before/after the precipitate orienting
step (S400) in the method of manufacturing the metal composite 20
with an oriented precipitate according to the present
invention.
[0111] In the comparative example shown in FIG. 21, the precipitate
orienting step (S400) was performed on an alloy where a precipitate
was not created in the precipitate forcible-creating step (S300)
since the solid solution creating step (S200) was not performed.
Thus, it can be seen that the orientation of the microstructure is
very different from the embodiment (the lower picture in FIG. 22)
where the precipitate orienting step (S400) was performed after a
solid solution was created (the upper picture in FIG. 22).
[0112] The difference in whether there is orientation of
microstructures considerably depends on mechanical properties, as
in FIGS. 23 and 24.
[0113] FIG. 23 is a graph comparing mechanical properties
before/after the precipitate orienting step (S400) where drawing
was employed in a comparative example and a preferred embodiment,
and FIG. 24 is a graph comparing mechanical properties before/after
the precipitate orienting step (S400) where rolling was employed in
a comparative example and a preferred embodiment.
[0114] First, referring to FIG. 23, in the embodiment where aging
was finished, it shows strength of 500 MPa or less, which is lower
than 600 MPa, which is the strength of the comparative example.
[0115] However, it can be seen that the increases in strength are
very different in the comparative example and the embodiment
employing drawing in the precipitate orienting step (S400).
[0116] That is, the strength was 600 MPa before drawing, but it
slightly increased to 800 MPa after drawing in the comparative
example, but in the embodiment, the strength was about 500 MPa
before drawing, but it increased close to 1100 MPa after drawing.
Accordingly, it can be seen that the strength of the alloy 10 is
higher in the embodiment than the comparative example after the
precipitate orienting step (S400).
[0117] Accordingly, it can be seen that a precipitate can function
as a reinforcing material by forcibly creating a precipitate
through the precipitate forcible-creating step (S300) and then
forcibly orienting the precipitate.
[0118] FIG. 24 shows an example when rolling was used in the
precipitate forcible-creating step (S400), in which the strength
was 600 MPa before rolling in the comparative example, which is
higher than 550 MPa, which is the strength in the embodiment, but
after the precipitate forcible-creating step (S400) was performed,
the strength was less than 800 MPa in the comparative example, but
the strength in the preferred embodiment of the present invention
was 900 MPa, so an effect of increasing strength according to
orientation of a precipitate could be seen.
[0119] FIG. 25 is a graph comparing the test result of FIG. 23 in
each stage, in which effects of increasing strength in each process
are shown sequentially in the upward direction starting from the
bottom.
[0120] As in the figure, the comparative example and the embodiment
show the same strength of 200 MPa in the state of the alloy 10, but
the strength of the comparative example increased to 430 MPa, which
is higher than the strength of the embodiment, after the solid
solution creating step (S200) and the precipitate forcible-creating
step (S300).
[0121] However, after the precipitate forcible-creating step
(S400), the strength increased by 190 MPa in the comparative
example, the strength in the embodiment increased by 480 MPa, which
shows an effect of increasing strength of 290 MPa in comparison to
the comparative example.
[0122] That is, since discontinuous precipitates are arranged in
parallel in the metal composite 20 manufactured in accordance with
a preferred embodiment of the present invention, it can be seen
that the mechanical properties were considerably increased in
comparison to the mechanical properties of the metal composite 20
manufactured in accordance with a common manufacturing method.
[0123] The scope of the present invention is not limited to the
embodiments described above and many other modifications based on
the present invention may be achieved by those skilled in the art
within the scope of the present invention.
[0124] For example, titanium was used as precipitation-promoting
metal in an embodiment of the present invention, but vanadium may
also be used.
INDUSTRIAL APPLICABILITY
[0125] The present invention relates to a metal composite with an
oriented precipitate functioning as a reinforcing material for a
composite by artificially orienting a precipitate, which is
artificially created, through plastic working, and a method of
manufacturing the metal composite, so electric conductivity and
strength are improved. Furthermore, if necessary, it is possible to
artificially adjust the amount of precipitate by selectively adding
precipitation-promoting metal, so it can be used in various fields
by adjusting electrical and mechanical properties.
* * * * *