U.S. patent application number 09/800985 was filed with the patent office on 2001-10-18 for aluminum-copper clad member, method of manufacturing the same, and heat sink.
This patent application is currently assigned to Showa Aluminum Corporation. Invention is credited to Copeland, David, Osame, Yasuhiro, Tasaki, Seiji, Ushioda, Shunta, Yamanoi, Tomoaki, Yamauchi, Terukazu.
Application Number | 20010030039 09/800985 |
Document ID | / |
Family ID | 26587198 |
Filed Date | 2001-10-18 |
United States Patent
Application |
20010030039 |
Kind Code |
A1 |
Copeland, David ; et
al. |
October 18, 2001 |
Aluminum-copper clad member, method of manufacturing the same, and
heat sink
Abstract
An aluminum-copper clad member includes an aluminum-base member,
a copper-base member and an insertion member made of pure aluminum
or JIS A1xxx series aluminum alloy. The aluminum-base member and
the copper-base member are clad via the insertion member. A heat
sink includes a heat radiation portion made of aluminum-base
material and provided with a plurality of tongue-like fins formed
by skiving a surface layer of one side of the heat radiation
portion and a thermal diffusion portion made of copper-base
material and joined to the other side of the heat radiation portion
via an insertion member made of pure aluminum or JIS A1xxx series
aluminum alloy.
Inventors: |
Copeland, David; (Oyamashi,
JP) ; Ushioda, Shunta; (Yukishi, JP) ;
Yamauchi, Terukazu; (Oyamashi, JP) ; Osame,
Yasuhiro; (Oyamashi, JP) ; Yamanoi, Tomoaki;
(Osaka, JP) ; Tasaki, Seiji; (Oyamashi,
JP) |
Correspondence
Address: |
Vasilios D. Dossas
NIRO, SCAVONE, HALLER & NIRO
Suite 4600
181 West Madison Street
Chicago
IL
60602
US
|
Assignee: |
Showa Aluminum Corporation
|
Family ID: |
26587198 |
Appl. No.: |
09/800985 |
Filed: |
March 7, 2001 |
Current U.S.
Class: |
165/104.26 ;
165/104.21; 165/185; 257/E23.103; 257/E23.109 |
Current CPC
Class: |
H01L 23/3672 20130101;
B21J 5/068 20200801; F28F 21/085 20130101; F28F 21/084 20130101;
H01L 2924/0002 20130101; F28F 21/089 20130101; H01L 23/3736
20130101; F28F 3/048 20130101; H01L 2924/0002 20130101; H01L
2924/00 20130101 |
Class at
Publication: |
165/104.26 ;
165/104.21; 165/185 |
International
Class: |
F28D 015/00; F28F
007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2000 |
JP |
2000-66807 |
Mar 10, 2000 |
JP |
2000-66942 |
Claims
What is claimed is:
1. An aluminum--copper clad member, comprising: an aluminum-base
member; a copper-base member; and an insertion member made of pure
aluminum or JIS A1xxx series aluminum alloy, wherein said
aluminum-base member and said copper-base member are clad via said
insertion member.
2. The aluminum--copper clad member as recited in the claim 1,
wherein said copper-base member is made of oxygen free copper or
phosphorus processed deoxidized copper.
3. A method of manufacturing an aluminum--copper clad member, said
method comprising the steps of: joining an insertion member made of
pure aluminum or JIS A1xxx series aluminum alloy to a copper-base
member by a cold rolling to obtain a joined two members; joining an
aluminum-base member to said insertion member by a cold rolling or
a hot rolling to obtain a joined three members; and heat treating
said joined two members before joining said aluminum-base member to
said insertion member by a cold rolling or a hot rolling, or heat
treating said joined three members after joining said aluminum-base
member to said insertion member by a cold rolling or a hot
rolling.
4. The method of manufacturing an aluminum--copper clad member as
recited in claim 3, wherein a roll-working rate of said insertion
member is set to 30% or more.
5. The method of manufacturing an aluminum--copper clad member as
recited in claim 3, wherein a roll-working rate of said
aluminum-base member is set to 40% or more.
6. The method of manufacturing an aluminum--copper clad member as
recited in claim 4, wherein a roll-working rate of said
aluminum-base member is set to 40% or more.
7. The method of manufacturing an aluminum--copper clad member as
recited in claim 3, wherein said step of heat treating is performed
at from 200 to 400.degree. C.
8. The method of manufacturing an aluminum--copper clad member as
recited in claim 4, wherein said step of heat treating is performed
at from 200 to 400.degree. C.
9. The method of manufacturing an aluminum--copper clad member as
recited in claim 5, wherein said step of heat treating is performed
at from 200 to 400.degree. C.
10. A heat sink, comprising: a heat radiation portion made of
aluminum-base material and provided with a plurality of tongue-like
fins formed by skiving a surface layer of one side of said heat
radiation portion; and a thermal diffusion portion made of
copper-base material and joined to the other side of said heat
radiation portion in a closely fitted manner.
11. The heat sink as recited in the claim 10, wherein said thermal
diffusion portion is a flat plate.
12. The heat sink as recited in the claim 10, wherein said thermal
diffusion portion includes a heat exchanging medium chamber inside
thereof.
13. The heat sink as recited in the claim 12, wherein said heat
exchanging medium chamber is provided with wicks formed on an inner
wall thereof.
14. A heat sink, comprising: a heat radiation portion made of
aluminum-base material and provided with a plurality of tongue-like
fins formed by skiving a surface layer of one side of said heat
radiation portion; and a thermal diffusion portion made of
copper-base material and joined to the other side of said heat
radiation portion via an insertion member made of pure aluminum or
JIS A1xxx series aluminum alloy.
15. The heat sink as recited in the claim 14, wherein said thermal
diffusion portion is a flat plate.
16. The heat sink as recited in the claim 14, wherein said thermal
diffusion portion includes a heat exchanging medium chamber inside
thereof.
17. The heat sink as recited in the claim 16, wherein said heat
exchanging medium chamber is provided with wicks formed on an inner
wall thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an aluminum-copper clad
member suitably used as, for example, a heat exchanger, a radiator,
a heat pipe and a heat sink, and also relates to a manufacturing
method thereof. Furthermore, the present invention relates to a
heat sink, and more specifically to, a heat sink suitably used for
cooling exothermic devices installed in various electric
apparatuses.
[0003] 2. Description of Related Art
[0004] Heat exchangers, radiators, heat pipes and heat sinks are
widely used in the industrial fields of electric devices,
communication apparatuses and transport apparatuses such as
automobiles and airplanes. They are required to be not only
excellent in heat transfer performance but also light in weight and
small in size. Thus, various improvements have been made from the
view points of materials and configurations.
[0005] As for the view point of materials, in place of copper-base
material which is excellent in heat transfer performance and
thermal diffusion performance but defective in weight,
aluminum-base material, which is light in weight and excellent in
heat transfer performance ranked next to copper, is widely
used.
[0006] In an aluminum heat exchanger used in the field of electric
device industries, various improvements including an increasing of
the cooling area and the thickness of components are made in order
to improve heat transfer performance thereof. However, since such
an aluminum heat exchanger has been remarkably improved in size,
weight and performance, it becomes difficult to further improve the
heat transfer performance by increasing the cooling area and the
thickness of components. Furthermore, in cases where water is used
as operation fluid for heat pipes, there are such drawbacks that
the heat pipe performance of aluminum heat exchanger deteriorates
due to non-condensing gases generated therein.
[0007] From the view point of configuration, in a heat sink, for
example, a number of thin-plate like fins are integrally formed on
a heat radiation board to increase the heat radiation area. Such a
heat sink, which is usually an aluminum extruded article, is
advantageous to an electric device, such as a computer having a
number of exothermic devices, for quickly discharging heat
generated by the exothermic devices. In the heat sink of the
aforementioned shape, in order to improve the heat radiation
performance, it is important to increase the heat radiation area.
In order to increase the heat radiation area, it is necessary to
increase the number of fins, decrease the fin thickness, narrow the
fin intervals and increase the fin height. It is, however,
difficult to manufacture the heat sink of such a fin shape due to
restrictions of extrusion technology.
[0008] Moreover, since improving the fin functions is not
sufficient to enhance the heat radiation performance of the heat
sink, it is necessary to improve the thermal diffusion function of
the heat sink substrate to be attached to an exothermic device. The
thermal diffusion function can be improved by increasing the
thickness of the substrate. However, since the installation space
of a heat sink is limited due to the miniaturization of the whole
apparatus in which the heat sink is installed, an increased
thickness of the substrate results in a decreased fin height, which
in turn decreases the heat radiation area. Moreover, increasing the
thickness of the substrate contradicts decreasing the weight of the
apparatus.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide an
aluminum-copper clad member which is excellent in heat radiation
performance and suitably used for a heat sink or the like.
[0010] It is another object of the present invention to provide a
method of manufacturing the aluminum-copper clad member.
[0011] It is still another object of the present invention to
provide a heat sink which is capable of improving the heat
radiation performance without increasing the size and/or
weight.
[0012] According to one aspect of the present invention, an
aluminum-copper clad member comprises an aluminum-base member, a
copper-base member and an insertion member made of pure aluminum or
Japanese Industrial Standard (hereinafter referred to as "JIS") JIS
A1xxx series aluminum alloy, wherein the aluminum-base member and
the copper-base member are clad via the insertion member. According
to the aluminum-copper clad member, since the aluminum-base member
and the copper-base member are clad via the insertion member made
of pure aluminum or JIS A1xxx series aluminum alloy which is easily
clad to the copper-base member even in a cold rolling, oxidization
of the copper-base member and generation of compounds between
different materials can be decreased, resulting in high joining
strength.
[0013] It is preferable that the copper-base member is made of
oxygen free copper or phosphorus processed deoxidized copper. In
this case, the generation of oxides is effectively restrained,
resulting in excellent joining strength of the clad member.
[0014] In the aforementioned aluminum-copper clad member, since the
clad member has lightness of aluminum and heat transfer
performance, thermal diffusion performance and corrosion resistance
of copper, when used as heat exchanger material, it is possible to
realize a heat transfer performance exceeding that of aluminum
while restraining the weight increase as compared to a copper heat
sink. Moreover, corrosion resistance equivalent to copper can be
obtained by applying the aforementioned clad member such that the
copper-base member constitutes an easy-to-corrode portion.
[0015] According to another aspect of the present invention, a
method of manufacturing an aluminum-copper clad member includes the
steps of: joining an insertion member made of pure aluminum or JIS
A1xxx series aluminum alloy to a copper-base member by a cold
rolling to obtain a joined two members; joining an aluminum-base
member to the insertion member by a cold rolling or a hot rolling
to obtain a joined three members; and heat treating the joined two
members before joining the aluminum-base member to the insertion
member by a cold rolling or a hot rolling, or heat treating the
joined three members after joining the aluminum-base member to the
insertion member by a cold rolling or a hot rolling.
[0016] According to this method, even if the joining of the
copper-base member and the insertion member to be directly
connected thereto is performed by a cold rolling, high joining
strength therebetween can be obtained, resulting in excellent
joining of the copper-base member and the aluminum-base member.
Moreover, since the aforementioned clad member is obtained through
rolling steps, it is possible to manufacture the aluminum-copper
clad member having a wide width and a long length. Therefore, a
heat exchanger member, which requires lightness, good heat transfer
performance, good corrosion resistance and large surface area, can
be manufactured.
[0017] In the aforementioned method, it is preferable that a
roll-working rate of the insertion member is set to 30% or more.
Furthermore, it is preferable that a roll-working rate of the
aluminum-base member is set to 40% or more. In cases where the
roll-working rate of the insertion member is set to 30% or more,
and/or the roll-working rate of the aluminum-base member is set to
40% or more, excellent joining strength can be obtained.
[0018] Furthermore, it is preferable that the heat treating is
performed at from 200.degree. C. to 400.degree. C. This also
enhances the joining strength.
[0019] According to still another aspect of the present invention,
a heat sink includes a heat radiation portion made of aluminum-base
material and provided with a plurality of tongue-like fins formed
by skiving a surface layer of one side of the heat radiation
portion; and a thermal diffusion portion made of copper-base
material and joined to the other side of the heat radiation portion
in a closely fitted manner.
[0020] In the aforementioned heat sink, since it includes a heat
radiation portion made of aluminum-base material and provided with
a plurality of tongue-like fins formed by skiving a surface layer
of one side of the heat radiation portion and a thermal diffusion
portion made of copper-base material and joined to the other side
of the heat radiation portion in a closely fitted manner, when used
as heat exchanger material, it is possible to realize a heat
transfer performance exceeding that of aluminum while restraining
the weight increase as compared to a copper heat sink. Especially,
since the thermal diffusion portion in contact with the heat
radiation portion is made of a copper-base member, an excellent
cooling effect can be obtained without increasing the volume of the
heat sink while maintaining the conventional fin height. Therefore,
the heat sink is suitably used as a heat sink in the electric
device having a limited installation space.
[0021] In the aforementioned heat sink, it is preferable that the
thermal diffusion portion is a flat plate. In this case, the heat
sink can be manufactured easily.
[0022] Furthermore, it is preferable that the thermal diffusion
portion includes a heat exchanging medium chamber inside thereof
and that the heat exchanging medium chamber is provided with wicks
formed on an inner wall thereof. In cases where the thermal
diffusion portion includes the heat exchanging medium chamber
inside thereof, the heat sink can be used as a heat pipe and the
thermal diffusion performance and heat radiation performance can be
further improved.
[0023] Furthermore, since the thermal diffusion portion is formed
by corrosion resistant copper-base material, it is possible to use
water as heat exchange medium.
[0024] In cases where the heat exchanging medium chamber is
provided with wicks formed on an inner wall thereof, since the
circulation of heat exchange medium is enhanced within the chamber
due to the capillary phenomenon, the thermal diffusion performance
and the heat radiation performance can be further improved.
[0025] According to still yet another aspect of the present
invention, a heat sink includes a heat radiation portion made of
aluminum-base material and provided with a plurality of tongue-like
fins formed by skiving a surface layer of one side of the heat
radiation portion; and a thermal diffusion portion made of
copper-base material and joined to the other side of the heat
radiation portion via an insertion member made of pure aluminum or
JIS A1xxx series aluminum alloy. In this heat sink, oxidization of
the copper-base member and generation of the compounds between the
different materials are restrained at the time of junction,
resulting in high joining strength. Moreover, this heat sink also
has outstanding lightness, heat transfer performance, thermal
diffusion performance and corrosion resistance.
[0026] In the aforementioned heat sink, it is preferable that the
thermal diffusion portion is a flat plate. In this case, the heat
sink can be manufactured easily. Furthermore, it is preferable that
the thermal diffusion portion includes a heat exchanging medium
chamber inside thereof and that the heat exchanging medium chamber
is provided with wicks formed on an inner wall thereof. In cases
where the thermal diffusion portion includes the heat exchanging
medium chamber inside thereof, the heat sink can be used as a heat
pipe and the thermal diffusion performance and heat radiation
performance can be further improved.
[0027] Furthermore, since the thermal diffusion portion is formed
by corrosion-resistant copper-base material, it is possible to use
water as heat exchange medium.
[0028] In cases where the heat exchanging medium chamber is
provided with wicks formed on an inner wall thereof, since the
circulation of heat exchange medium is enhanced within the chamber
due to the capillary phenomenon, the thermal diffusion performance
and the heat radiation performance can be further improved.
[0029] Other objects and the features of the present invention will
be apparent from the following detailed description of the
invention with reference to the attached drawings. BRIEF
DESCRIPTION OF THE DRAWINGS
[0030] The present invention will be more fully described and
better understood from the following description, taken with the
appended drawings, in which:
[0031] FIG. 1 is a cross sectional view of an aluminum-copper clad
member according to the present invention;
[0032] FIG. 2 is a cross sectional view of a cooling tube made of
the aluminum-copper clad member shown in FIG. 1;
[0033] FIG. 3 is a perspective view showing a test heat sink;
[0034] FIG. 4 is a cross sectional view showing an example A of a
heat sink according to the present invention;
[0035] FIG. 5 is an explanatory view showing the manufacturing
process of the heat sink of the example A;
[0036] FIG. 6 is an explanatory view showing another manufacturing
processes of the heat sink of the example A;
[0037] FIG. 7 is a perspective view showing an example B of a heat
sink according to the present invention;
[0038] FIG. 8 is an explanatory view showing the manufacturing
process of the heat sink of the example B;
[0039] FIG. 9 is an explanatory view showing another manufacturing
processes of the heat sink of the example B;
[0040] FIG. 10 is a cross sectional view showing an example C of a
heat sink according to the present invention;
[0041] FIG. 11 is a cross sectional view showing an elevation view
and manufacturing process of an example D of a heat sink according
to the present invention;
[0042] FIG. 12 is a cross sectional view showing an example E of a
heat sink according to the present invention; and
[0043] FIG. 13 is a cross sectional view showing an example F of a
heat sink according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Aluminum--Copper Clad Member
[0045] As shown in FIG. 1, the aluminum--copper clad member 1
according to the present invention includes an aluminum-base member
11, a copper-base member 13 and an insertion member 12. The
insertion member 12 is made of pure aluminum or JIS A1xxx series
aluminum alloy and interposed between the copper-base member 13 and
the aluminum-base member 11.
[0046] The composition of the aforementioned aluminum-base member
11 is not specifically limited. As the aluminum-base member 11, for
example, high-grade pure aluminum, aluminum or its aluminum alloy
of JIS A1xxx series, Al--Cu series alloy of JIS A2xxx series,
Al--Mn series alloy of JIS A3xxx series, Al--Si series alloy of JIS
A4xxx series, Al--Mg series alloy of JIS A5xxx series, Al--Si--Mg
series alloy of JIS A6xxx series, Al--Zn--Mg--Cu series alloy and
Al--Zn--Mg series alloy of JIS A7xxx series, etc., can be used
widely.
[0047] The composition of the aforementioned copper-base member 13
is not specifically limited. It is recommended to use oxygen free
copper or phosphorus processed deoxidized copper as the copper-base
member because they can restrain generation of oxides or compounds
with aluminum.
[0048] As for the insertion member 12, it is necessary to use pure
aluminum which is easily joined by a cold rolling to the
copper-base member 13 as different metal material, or JIS A1xxx
series aluminum alloy with few added elements. It is specifically
recommended that the insertion member 12 is made of a high-grade
pure aluminum of 99.90% purity, or an aluminum alloy of purity more
than that of JIS A1050 alloy among JIS A1xxx series aluminum
alloys.
[0049] By using the aforementioned insertion member 12, the
insertion member can be joined by a cold rolling with high joining
strength. Generally, between the aluminum-base member 11 and the
copper-base member 13, thermal resistance arises due to the
difference in thermal conductivity. However, the thermal resistance
can be reduced by interposing pure aluminum or JIS A1xxx series
aluminum alloy having higher thermal conductivity among
aluminum-base materials as the aforementioned insertion member
12.
[0050] Method of Manufacturing the Aluminum--Copper Clad Member
[0051] The aforementioned aluminum--copper clad member 1 is
manufactured by, for example, the following method.
[0052] First, the insertion member 12 is joined to the copper-base
member 13 by a cold rolling. Since the insertion member 12 is made
of pure aluminum or JIS A1xxx series aluminum alloy, it is small in
modification resistance and excellent in joining performance to the
copper-base member 13 by a cold rolling. Moreover, since the
insertion member 12 is joined to the copper-base member 13 by a
cold rolling, oxidization of the copper-base member 13 and the
generation of compounds with the ingredients of the insertion
member 12 are restrained. Thus, the causes for deteriorating the
joining strength can be eliminated. Although the cold roll-working
rate is desirable to be 30% or more in order to obtain sufficient
joining strength, when it exceeds 70%, there is a possibility that
the materials may break due to the work hardening. More preferably,
the roll-working rate is from 40% to 70%.
[0053] Next, the aluminum-base member 11 is joined to the insertion
member 12 by a cold rolling or a hot rolling. In this rolling,
since the surface of the copper-base member 13 is already covered
with the insertion member 12 to be intercepted from atmosphere, a
hot rolling or a cold rolling may be performed. In order to
securely adhere the aluminum-base member 11 to the insertion member
12, the roll-working rate is preferably set to 40% or more
depending on the required final thickness. In cases of performing a
hot rolling, it is preferable that the rolling temperature is set
to from 100 to 350.degree. C. and that the hot rolling is performed
immediately after reaching the target temperature so as not to grow
compound phase at the interface between the copper-base member 13
and the insertion member 12. In this rolling, since both the
insertion member 12 and the aluminum-base member 11 are aluminum,
they are firmly joined each other, which results in a secure
joining of the aluminum-base member 11 and the copper-base member
13 via the insertion member 12.
[0054] In the aforementioned series of joining steps, the joined
two members are heat treated before joining the aluminum-base
member 11 to the insertion member 12 to securely join the
copper-base member 13 and the insertion member 12. Alternatively,
after joining the aluminum-base member 11 on the insertion member
12, the joined three members are heat treated to securely joining
the aluminum-base member 11, the insertion member 12 and the
copper-base member 13. In order to suppress the growth of compounds
at the interface between the copper-base member 13 and the
insertion member 12 and to obtain high joining strength
therebetween, it is preferable to perform the aforementioned heat
treatment within the temperature range of from 200 to 400.degree.
C. It is preferable to perform the aforementioned heat treatment at
the temperature of from 220 to 300.degree. C. Moreover, it is
preferable to perform the heat treatment within one hour so as not
to grow compounds. When the thickness of the compounds layer is
controlled to 10 .mu.m or less by adjusting the heat treatment
conditions, a further improved joining condition can be
obtained.
[0055] It is possible to manufacture a securely joined
aluminum--copper clad member by heat treating the joined two
members before joining the aluminum-base member 11 to the insertion
member 12, or the joined three members after joining the
aluminum-base member 11 to the insertion member 12. However, in
cases where the aluminum-base member 11 is joined on the insertion
member 12 by a cold rolling, the heat treatment is preferably
subjected to the joined three members after joining the
aluminum-base member 11 to the insertion member 12.
[0056] Since the aforementioned aluminum--copper clad member 1
according to the present invention has lightness of aluminum and
heat transfer performance, thermal diffusion performance and
corrosion resistance of copper, the clad member can be suitably
used as heat exchanger materials.
[0057] For example, the aluminum--copper clad member 1 can be
manufactured into a heat exchanging tube 2 as shown in FIG. 2. In
this heat exchanging tube 2, when the copper-base member 13 is
located inside the tube, refrigerant contacts the copper-base
member 13 which is excellent in corrosion resistant. This enhances
not only the heat transfer performance but also the corrosion
resistance. Moreover, the aluminum--copper clad member 1 can also
be manufactured into a heat sink with a plurality of tongue-like
fins which will be detailed.
EXAMPLE
[0058] The aluminum--copper clad member and the method of
manufacturing the clad member according to the present invention
will be detailed below.
[0059] As the aforementioned copper-base member 13, an oxygen free
copper board and a phosphorus processed deoxidized copper board,
each of which is 8 mm in thickness, 100 mm in width and 150 mm in
length, were prepared.
[0060] As the aforementioned insertion member 12, three kinds of
99.999% purity aluminum plates 94 mm width and 150 mm length with
different thickness, i.e., 0.1 mm thickness, 0.5 mm thickness and
1.0 mm thickness, were prepared.
[0061] As the aforementioned aluminum-base member 11, JIS A1100 or
JIS A6063 aluminum plate 100 mm width and 200 mm length with
different thickness, i.e., 2.0 mm thickness, 5.0 mm thickness, 10.0
mm thickness and 15.0 mm thickness, were prepared.
[0062] The combination of the aforementioned members are shown in
Table 1.
[0063] In manufacturing the clad member, the insertion member 12
was placed on the copper-base member 13, and then they are
subjected to a cold rolling at the roll-working rate shown in Table
1 to join them.
[0064] Subsequently, the joined members 12 and 13 according to the
example Nos. 1-13 were held for 1 hour at the temperature shown in
Table 1 to perform a middle heat treatment. On the other hand, the
joined members according to the examples of the inventive example
Nos. 14-17 were proceeded to the following process without being
subjected to the middle heat treatment.
[0065] Next, the aluminum-base member 11 shown in Table 1 was put
on the insertion member 12 of the aforementioned joined member and
subjected to a cold rolling or a hot rolling at 500.degree. C. at
the roll-working rate shown in Table 1 to join them.
[0066] Furthermore, as for the example Nos. 14-17 to which the
middle heat treatment was not executed, they were held at the
temperature shown in Table 1 for 1 hour to perform a final heat
treatment.
[0067] The examples Nos. 1-13 to which the middle heat treatment
was executed, were not subjected to the final heat treatment.
[0068] On the other hand, as for the clad member according to the
comparative example Nos. 1-4 with no insertion member, the clad
members were manufactured by performing a hot rolling an
aluminum-base member and a copper-base member at the temperature
and the roll-working rate shown in Table 1.
[0069] The joining rate and the joining strength of these clad
members were evaluated. The joining rate was evaluated by an
ultrasonic inspection. The joining rate (%) was calculated as
follows: the joining rate (%)=(non-joined area/measured
area).times.100. The joining strength was evaluated by falling the
test piece onto an iron floor 20 times from the height of 1.5 m,
and cracks or destructions of the test piece was examined. These
evaluation results are shown in Table 1.
1TABLE 1 (Manufacturing conditions and Evaluation) Insertion Middle
Aluminum-base Hot/Cold member Cold roll- heat member roll- Final
heat Joining Clad member (Pure Al) working treatment
Material/Thickness working treatment rate Joining No. Cupper-base
member Thickness(mm) rate(%) (.degree. C.) (mm) rate (%) (.degree.
C.) (%) strength Example 1 Oxygen free copper 0.1 42 250 A1100/2.0
Heat/58 -- 100 No crack 2 Oxygen free copper 0.5 45 300 A1100/5.0
Heat/58 -- 100 No crack 3 Phosphorus processed 0.5 55 350
A6063/10.0 Cold/50 -- 100 No crack deoxidized copper 4 Oxygen free
copper 0.5 59 400 A1100/10.0 Heat/45 -- 100 No crack 5 Phosphorus
processed 1.0 65 300 A6063/10.0 Cold/58 -- 100 No crack deoxidized
copper 6 Oxygen free copper 1.0 68 350 A1100/2.0 Cold/58 -- 100 No
crack 7 Phosphorus processed 1.0 68 400 A6063/10.0 Heat/55 -- 100
No crack deoxidized copper 8 Phosphorus processed 1.0 68 200
A6063/10.0 Heat/53 -- 100 No crack deoxidized copper 9 Oxygen free
copper 0.5 65 250 A6063/15.0 Cold/50 -- 100 No crack 10 Phosphorus
processed 0.5 65 350 A6063/150 Cold/50 -- 100 No crack deoxidized
copper 11 Oxygen free copper 0.5 65 350 A6063/15.0 Heat/58 -- 100
No crack 12 Phosphorus processed 0.5 65 400 A1100/5.0 Heat/58 --
100 No crack deoxidized copper 13 Oxygen free copper 10 60 350
A6063/10.0 Heat/50 -- 100 No crack 14 Oxygen free copper 1.0 68 --
A1100/2.0 Cold/58 350 100 No crack 15 Phosphorus processed 1.0 65
-- A6063/100 Cold/58 300 100 No crack deoxidized copper 16 Oxygen
free copper 0.5 65 -- A6063/15.0 Cold/50 350 100 No crack 17
Phosphorus processed 0.5 55 -- A6063/10.0 Cold/50 300 100 No crack
deoxidized copper Comparative 1 Oxygen free copper No insertion
member A1100/10.0 Heat/49 50 Destroyed example 2 Oxygen free copper
A6063/100 Heat/58 60 Cracks 3 Phosphorus processed A6063/10.0
Heat/59 70 Destroyed deoxidized copper 4 Phosphorus processed
A1100/10.0 Heat/58 95 Cracks deoxidized copper
[0070] Furthermore, the heat transfer performance of the test heat
sink 20 shown in FIG. 3 manufactured by the aluminum--copper clad
members according to the example Nos. 2, 8 and 16 and the non-clad
aluminum alloy member having the same thickness as the
aforementioned clad members, were compared and evaluated.
[0071] The aforementioned test heat sink 20 was prepared by cutting
out the aforementioned clad member into a plate of 80 mm width (W)
and 60 mm depth (D) and forming three rows of tongue-like fins 22
of 30 mm height (FH) at the fin pitch (FP) of 2 mm. The copper-base
member side constitutes a plate-like base portion 21. As for the
test heat sink 20 made of the non-clad aluminum alloy member, the
test heat sink 20 was prepared by cutting out the aforementioned
non-clad aluminum alloy member into the same size as the
aforementioned clad member and forming the same tongue-like fins 22
as in the aforementioned clad member on one surface. The other side
constitutes a plate-like base portion 21.
[0072] As shown in FIG. 3, a heat source 23 was attached to the
rear central portion of the base portion 21 of each test heat sink
20 in a close-fitted manner. Then, the test heat sink 20 was heated
by the heat source 23 and, at the same time, cooled by blowing air
of 2 m/sec wind velocity onto the test heat sink from the upper
side of the fins. In this state, the temperature of the right above
portion 24 of the heat source 23, the temperature of the cooling
air, and the input heat quantity (w) of the heat source 23 were
measured respectively, and the thermal resistance (R) of each test
heat sink was calculated by the following formula (f1) for
evaluating the heat transfer performance
R=(Te-Tair)/Q (f1)
[0073] wherein R is a thermal resistance (.degree. C./w) of the
heat sink, Te is a temperature (.degree. C.) at the right above
portion 24 of the heat source 23, Tair is a temperature (.degree.
C.) of the cooling air, Q is an input heat quantity(w) of the heat
source 23.
[0074] The evaluated results are shown in Table 2.
2TABLE 2 Thermal transfer performance of Al-Cu clad member and
non-clad member Thermal resistance Test No. Test piece R(.degree.
C./W) I Clad member (Example No. 2) 0.510 Oxygen free copper-A1100
Middle heat treatment A1100 member (non-clad) 0.667 II clad member
(Example No. 8) 0.534 phosphorus processed deoxidized copper-A6063
Middle heat treatment A6063 (non-clad) 0.682 III clad member
(Example No. 16) 0.528 Oxygen free copper-A6063 Final heat
treatment A6063 member (non-clad) 0.682
[0075] From the results shown in Table 1, as for the
aluminum--copper clad member in which the insertion member was
interposed, it is confirmed that different metal members are firmly
joined at the whole surface thereof to have high joining strength.
Moreover, from the results shown in Table 2, it is also confirmed
that each aluminum--copper clad member is excellent in heat
transfer performance exceeding the heat transfer performance of
aluminum without causing deterioration of heat transfer performance
due to the joined portions.
[0076] Heat Sink
[0077] FIGS. 4-11 show the examples A-D of heat sinks according to
the present invention, each of which consists of a
thermal-diffusion portion of aluminum-base material and a heat
radiation portion of copper-base material.
[0078] Moreover, FIGS. 12-13 show examples E-F of heat sinks
according to the present invention, each of which is made of the
aforementioned aluminum--copper clad member 1. Each of these heat
sinks consists of a heat-radiation portion of aluminum-base
material and a thermal diffusion portion of copper-base material
joined to the heat-radiation portion via an insertion member. The
shape and the manufacturing method of each heat sink will be
explained as follows.
[0079] Embodiment A
[0080] The heat sink 31 shown in FIG. 4 consists of a heat
radiation portion 41 having a number of tongue-like fins 42 on one
surface side thereof and a plate shaped thermal diffusion portion
51 joined to the other side of the heat radiation portion 41.
[0081] As shown in FIG. 5, the heat sink 31 is manufactured by
joining a plate-shaped aluminum-base member 43 and a plate-shaped
copper-base member 51 and then forming tongue-like fins 42 on the
aluminum plate 43.
[0082] In the aforementioned manufacturing process, since both the
members are flat plates, the joining method may be any one of
well-known methods including a rolling method, a friction joining
method, an ultrasonic joining method and a brazing method.
Moreover, the tongue-like fins 42 may be formed by a well known
method.
[0083] As shown in FIG. 6, the heat sink 31 can also be
manufactured by forming tongue-like fins 42 on the aluminum plate
to obtain a heat radiation portion 41, and then joining the heat
radiation portion 41 onto a copper-base plate 51. In this case, the
joining of the heat radiation portion 41 and the thermal diffusion
portion 51 must be performed by a method other than a rolling
method.
[0084] It is preferable that the thickness of the aluminum plate 43
before forming the tongue-like fins 42 is from 1 mm to 10 mm. If
the fin height is less than 1 mm, the fin height becomes lower,
resulting in decreased heat radiation performance. On the other
hand, even if the fin height exceeds 10 mm, it does not contribute
to form thinner and higher tongue-like fins 42.
[0085] Moreover, it is preferable that the thickness of the
plate-shaped copper-base member constituting a thermal diffusion
portion 51 is from 1.5 mm to 8 mm so as to secure the excellent
thermal diffusion performance as a plate-shaped thermal diffusion
portion and to avoid excessive weight.
[0086] Embodiment B
[0087] The heat sink 32 shown in FIG. 7 consists of a heat
radiation portion 41 having a number of tongue-shaped fins 42
formed on one surface thereof and a thermal diffusion portion 61
joined to the other side of the heat radiation portion 41. The
thermal diffusion portion 61 has a hollow chamber 62 for heat
exchanging medium. This heat sink 32 can be served as a heat pipe
by vacuuming the chamber 62 and filling the vacuumed chamber with
heat exchange medium such as water.
[0088] The heat sink 32 can be manufactured by joining the heat
radiation portion 41 manufactured by forming the tongue-shaped fins
42 on the aluminum plate and the thermal diffusion portion 61
having a hollow portion, as shown in FIG. 8. Alternatively, the
tongue-shaped fins 42 may be formed after joining the two members
as shown in FIG. 5. Alternatively, as shown in FIG. 9, the similar
heat exchanging chamber 32' can be manufactured by joining a
copper-base member 65 having a U-shaped cross-section to the heat
sink 31 obtained by joining the plate-shaped thermal diffusion
portion 51 and the heat radiation portion 41 as shown in FIG. 4. In
this case, the plate-shaped thermal diffusion portion 51 and the
copper-base member 65 of a U-shaped cross-section constitute the
thermal diffusion portion 64.
[0089] In this embodiment, the joining method of the heat radiation
portion 41 and the thermal diffusion portion 61, the joining method
of the heat radiation portion 41 and the U-shaped member 65, the
forming method of the tongue-shaped fins 42, and the size of the
heat radiation portion 41 are the same as in the example A. Since
the thermal diffusion portion 61 and 64 of the heat sink 32 and 32'
functions as a heat pipe, the thermal diffusion performance and the
heat radiation performance of the thermal diffusion portion 61 and
64 will be increased. Therefore, the thickness of the thermal
diffusion portion 61 and 64 may be thinner than that of the
plate-shaped thermal diffusion portion 51. The thickness is
preferably from 1.2 mm to 5 mm. Since the thermal diffusion portion
61 is made of copper-base material, it is excellent in corrosion
resistance, and water can be used as heat exchanging medium.
[0090] Embodiment C
[0091] FIG. 10 shows a heat sink according to an embodiment C. This
heat sink 33 has a thermal diffusion portion 66 which functions as
a heat pipe like the heat sink 32 according to the embodiment B.
However, this heat sink 33 is different from the aforementioned
heat sink 32 in that wicks are formed in the inner wall of the heat
exchanging medium chamber 63. Thus, forming wicks by attaching a
wire net or sintering copper powder to the inner wall of the heat
exchanging medium chamber 63 enhances the circulation of the heat
exchange medium within the chamber, resulting in improved
performance of the heat pipe due to the capillary phenomenon, which
improves the thermal diffusion performance and the heat radiation
performance of the heat sink.
[0092] Embodiment D
[0093] FIG. 11 shows a heat sink 34 having a heat pipe 73 embedded
in the thermal diffusion portion 71. In the heat pipe 73, heat
exchange medium 72 is enclosed.
[0094] In the heat sink 32 and 33 of the aforementioned embodiments
B and C, the thermal diffusion portion 61 and 66 itself constitutes
a heat pipe. The heat pipe is formed by vacuuming air and
introducing heat exchanging medium after the assembly of each
members. Thus, the opening for vacuuming air or introducing heat
exchanging medium is exposed to the outer surface of the heat
sink.
[0095] On the other hand, in the heat sink 34 of this embodiment,
after introducing heat exchange medium through an opening and
closing the opening to complete a heat pipe 73, the heat pipe 73 is
assembled in the state that this heat pipe 73 is embedded in the
thermal diffusion portion 71, and then the tongue-shaped fins 42
are formed. Therefore, the heat pipe 73 is surrounded by the
thermal diffusion portion 71 and cannot be seen from the
outside.
[0096] The heat sink 34 can be manufactured by, for example, the
process shown in FIG. 11.
[0097] That is, the completed heat pipe 73 is loaded into the
dented portion 75 of the outer shell member 74. The dented portion
75 has an inner shape corresponding to the outside shape of the
heat pipe 73. Therefore, the heat pipe 73 is closely fitted in the
dented portion 75. Thereafter, the outer shell member 74 in which
the heat pipe 73 is loaded is joined, for example, to the heat sink
31 in which the plate-shaped thermal diffusion portion 51 and the
heat radiation portion 41 as shown in FIG. 6 are joined. This
heat-pipe-embedded-type heat sink 34 has high reliability since the
previous prepared reliable heat pipe is used.
[0098] Embodiment E
[0099] FIG. 12 shows a heat sink including a heat radiation portion
81 on which tongue-shaped fins 42 are formed, a thermal diffusion
portion 82 to be attached to a heating element and an insertion
member 12 interposed between the heat radiation portion 81 and the
thermal diffusion portion 82 to join them. This heat sink 35 is
manufactured by forming tongue-shaped fins 42 on the surface of the
aluminum-base member 11 of the previously manufactured
aluminum--copper clad member 1. The copper-base member 13
constitutes a plate-shaped thermal diffusion portion 82 as it is.
The preferable thickness of each part before machining is the same
as the embodiment A.
[0100] The heat sink 35 is excellent in thermal diffusion
performance and light in weight like the embodiment A. Moreover,
since the heat radiation portion 81 and the thermal diffusion
portion 82, which are different metal materials, are joined via the
insertion member 12, the joining strength is excellent.
[0101] Embodiment F
[0102] FIG. 13 shows a heat sink 36 with a heat exchanging medium
chamber 84 formed in the thermal diffusion portion 83. In this heat
sink 36, the heat exchanging medium chamber 84 is formed by joining
a copper-base member 65 of a U-shaped cross-section to the heat
sink 35 of the embodiment E. The copper-base member 13 and the
U-shaped member 65 in this clad member 1 constitutes a thermal
diffusion portion 83. The preferable thickness of each part before
machining is the same as the embodiment B.
[0103] The heat sink 36 is excellent in thermal diffusion
performance and light in weight like the embodiment B. Moreover,
since the heat radiation portion 81 and the thermal diffusion
portion 83, which are different metal materials, are joined via the
insertion member 12, the joining strength is excellent.
[0104] Furthermore, in the heat sink 36, wicks may be provided to
the inner wall of the heat exchanging medium chamber 84 like the
heat sink 33 shown in FIG. 10.
[0105] In the aforementioned heat sinks 31, 32, 32', 33, 34, 35 and
36, the composition of the aluminum-base member constituting the
heat radiation portion 41 and 81 is not specifically limited. For
example, high-grade pure aluminum, aluminum or its aluminum alloy
of JIS A1xxx series, Al--Cu series alloy of JIS A2xxx series,
Al--Mn series alloy of JIS A3xxx series, Al--Si series alloy of JIS
A4xxx series, Al--Mg series alloy of JIS A5xxx series, Al--Si--Mg
series alloy of JIS A6xxx series, Al--Zn--Mg--Cu series alloy and
Al--Zn--Mg series alloy of JIS A7xxx series, etc., can be used.
Among the aforementioned materials, JIS A6xxx series alloy can be
recommended in consideration of forming the tongue-shaped fins.
[0106] Moreover, the composition of the copper-base member
constituting the thermal-diffusion portion 51, 61, 62, 65, 66, 71,
82 and 83 is not specifically limited. For example, tough pitch
copper, oxygen-free copper or phosphorus processed deoxidized
copper can be used. Among the aforementioned materials, oxygen free
copper or phosphorus processed deoxidized copper can be recommended
in consideration of controlling the generation of oxides or
aluminum compounds when joining to the heat radiation portion 41
which is different in metal material.
[0107] Moreover, in the embodiments E-F, as the aforementioned
insertion member 12, it is recommended to use high-grade pure
aluminum of 99.90% purity or more, and JIS A1050 alloy among JIS
A1xxx series aluminum as in the insertion member in an
aforementioned aluminum--copper clad member.
[0108] The present invention claims priorities based on Japanese
Patent Applications Nos. 2000-66807 filed on Mar. 10, 2000 and
2000-66942 filed on Mar. 10, 2000, the content of which is
incorporated hereinto by reference in its entirety.
[0109] The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intent, in the use of such terms and expressions, of
excluding any of the equivalents of the features shown and
described or portions thereof, but it is recognized that various
modifications are possible within the scope of the invention
claimed.
* * * * *