U.S. patent application number 16/233405 was filed with the patent office on 2019-07-04 for die casting aluminum alloy, production method of die casting aluminum alloy, and communications product.
The applicant listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Banghong HU, Xiaorui LIU, Naier MENG.
Application Number | 20190203324 16/233405 |
Document ID | / |
Family ID | 65010463 |
Filed Date | 2019-07-04 |
United States Patent
Application |
20190203324 |
Kind Code |
A1 |
LIU; Xiaorui ; et
al. |
July 4, 2019 |
DIE CASTING ALUMINUM ALLOY, PRODUCTION METHOD OF DIE CASTING
ALUMINUM ALLOY, AND COMMUNICATIONS PRODUCT
Abstract
Embodiments of the present disclosure provide a die casting
aluminum alloy, including constituents with the following mass
percentages: silicon: 4.0% to 10.0%; magnesium: 0.2% to 1.0%;
copper: .ltoreq.0.1%; manganese: .ltoreq.0.1%; zinc: .ltoreq.0.1%;
ferrum: .ltoreq.1.3%; titanium: .ltoreq.0.2%; inevitable
impurities: .ltoreq.0.15%; and the rest: aluminum. The die casting
aluminum alloy has a high heat-conducting property, good
formability, high corrosion resistance, and a good mechanical
property. This can resolve a prior-art problem that forming and
heat dissipation requirements of a communications product with a
complex structure, high heat flux density, and large power cannot
be met at the same time because it is difficult for a die casting
aluminum alloy to have both a high heat-conducting property and
good formability. The embodiments of the present disclosure further
provide a production method of the die casting aluminum alloy and a
communications product.
Inventors: |
LIU; Xiaorui; (Shenzhen,
CN) ; MENG; Naier; (Shenzhen, CN) ; HU;
Banghong; (Shenzhen, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Shenzhen |
|
CN |
|
|
Family ID: |
65010463 |
Appl. No.: |
16/233405 |
Filed: |
December 27, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22F 1/043 20130101;
C22C 1/026 20130101; C22F 1/04 20130101; C22C 21/02 20130101; B22D
21/007 20130101; C22C 21/04 20130101 |
International
Class: |
C22C 21/04 20060101
C22C021/04; B22D 21/00 20060101 B22D021/00; C22F 1/043 20060101
C22F001/043; C22C 1/02 20060101 C22C001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 29, 2017 |
CN |
201711468332.2 |
Claims
1. A die casting aluminum alloy, consisting of constituents with
the following mass percentages: silicon: 4.0% to 10.0%; magnesium:
0.2% to 1.0%; copper: .ltoreq.0.1%; manganese: .ltoreq.0.1%; zinc:
.ltoreq.0.1%; ferrum: .ltoreq.1.3%; titanium: .ltoreq.0.2%;
impurities: .ltoreq.0.15%; and remainder: aluminum.
2. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the silicon is 5.5% to 6.5%.
3. The die casting aluminum alloy according to claim 2, wherein the
mass percentage of the silicon is 5.8% to 6.3%.
4. The die casting aluminum alloy according to claim 2, wherein the
mass percentage of the silicon is 5.7%.
5. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the silicon is 4.3% to 5.0%.
6. The die casting aluminum alloy according to claim 5, wherein the
mass percentage of the silicon is 4.4% to 4.8%.
7. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the silicon is 6.5% to 7.5%.
8. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the magnesium is 0.3% to 0.8%.
9. The die casting aluminum alloy according to claim 8, wherein the
mass percentage of the magnesium is 0.4% to 0.7%.
10. The die casting aluminum alloy according to claim 9, wherein
the mass percentage of the magnesium is 0.5% to 0.6%.
11. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the copper is 0.001% to 0.05%.
12. The die casting aluminum alloy according to claim 11, wherein
the mass percentage of the copper is 0.01% to 0.03%.
13. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the manganese is 0.001% to 0.006%.
14. The die casting aluminum alloy according to claim 13, wherein
the mass percentage of the manganese is 0.002% to 0.004%.
15. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the zinc is 0.001% to 0.02%.
16. The die casting aluminum alloy according to claim 15, wherein
the mass percentage of the zinc is 0.001% to 0.008%.
17. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the ferrum is 0.3% to 1.0%.
18. The die casting aluminum alloy according to claim 17, wherein
the mass percentage of the ferrum is 0.5% to 0.7%.
19. The die casting aluminum alloy according to claim 1, wherein a
mass percentage of the titanium is 0.001% to 0.06%.
20. The die casting aluminum alloy according to claim 19, wherein
the mass percentage of the titanium is 0.01% to 0.03%.
21. The die casting aluminum alloy according to claim 1, wherein a
total mass percentage of elements other than the aluminum in the
die casting aluminum alloy is less than 10%.
22. The die casting aluminum alloy according to claim 21, wherein
the total mass percentage of the elements other than the aluminum
in the die casting aluminum alloy is 5.0% to 8.0%.
23. The die casting aluminum alloy according to claim 1, wherein
phases inside an organization structure of the die casting aluminum
alloy comprise a hypoeutectic .alpha.-Al phase, a eutectic
.alpha.-Al phase, a eutectic Si phase, and an intermetallic
compound, wherein the intermetallic compound is distributed at a
grain boundary location or is precipitated in the hypoeutectic
.alpha.-Al phase and the eutectic .alpha.-Al phase, and wherein the
intermetallic compound comprises an Mg.sub.2Si phase.
24. The die casting aluminum alloy according to claim 1, wherein a
coefficient of thermal conductivity of the die casting aluminum
alloy is 170 W/(mK) to 195 W/(mK).
25. The die casting aluminum alloy according to claim 1, wherein a
Brinell hardness of the die casting aluminum alloy is 60 HBW to 80
HBW, a tensile strength of the die casting aluminum alloy is 170
MPa to 220 MPa, a yield strength of the die casting aluminum alloy
is greater than or equal to 100 MPa, and an elongation rate of the
die casting aluminum alloy is greater than or equal to 2%.
26. A method for producing a die casting aluminum alloy, the method
comprising: providing raw materials based on constituents of a die
casting aluminum alloy, and performing heat treatment at any
temperature within 180.degree. C. to 375.degree. C. after casting,
to obtain a die casting aluminum alloy, the die casting aluminum
alloy consisting of constituents with the following mass
percentages: silicon: 4.0% to 10.0%; magnesium: 0.2% to 1.0%;
copper: .ltoreq.0.1%; manganese: .ltoreq.0.1%; zinc: .ltoreq.0.1%;
ferrum: .ltoreq.1.3%; titanium: .ltoreq.0.2%; impurities:
.ltoreq.0.15%; and remainder: aluminum.
27. The method according to claim 26, wherein the casting is
performed through liquid die casting, semi-solid die casting,
vacuum die casting, investment casting, gravity casting, or squeeze
casting.
28. The method according to claim 26, wherein a time for the heat
treatment is 0.2 hours to 8 hours.
29. A communications product, comprising: a housing; and a power
supply circuit located in the housing; a functional circuit located
in the housing, wherein the power supply circuit supplies power to
the functional circuit, and the housing is obtained through casting
by using a die casting aluminum alloy consisting of constituents
with the following mass percentages: silicon: 4.0% to 10.0%;
magnesium: 0.2% to 1.0%; copper: .ltoreq.0.1%; manganese:
.ltoreq.0.1%; zinc: .ltoreq.0.1%; ferrum: .ltoreq.1.3%; titanium:
.ltoreq.0.2%; and impurities: .ltoreq.0.15%; and remainder:
aluminum.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Chinese Patent
Application No. 201711468332.2, filed on Dec. 29, 2017, which is
hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to the field of aluminum
alloy material technologies, and in particular, to a die casting
aluminum alloy, a production method of the die casting aluminum
alloy, and a communications product.
BACKGROUND
[0003] With the development of a 4G/5G communications technology, a
communications product constantly strives for large power,
miniaturization, and lightness. Consequently an increasingly high
requirement is imposed on a heat dissipation capability of a die
casting material of the communications product. Currently, a
commonly used die casting material of the communications product is
mainly a die casting aluminum alloy. However, common thermal
conductivity of a die casting aluminum alloy in the communications
product industry is 90 W/(mK) to 150 W/(mK), and a requirement of a
future product with high heat flux density and large power cannot
be met. In addition, a communications die-casting fitting is
usually in a complex structure with a large quantity of complex
thin-wall heat sink fins, higher and lower bosses, and deep-cavity
structures, and has relatively large dimensions. A heat sink fin
layout of a future heat sink is to be denser and thinner, and a fin
shape is to be more complex. Therefore, a requirement on casting
fluidity of the die casting material of the communications product
is to be higher. Fluidity of an aluminum-silicon (Al--Si) series
die casting aluminum alloy commonly used in a current industry
increases as content of silicon increases, and the fluidity is the
best in a eutectic composition, but thermal conductivity of the
alloy decreases at the same time. Therefore, it is difficult to
have both a high heat-conducting property and good formability.
[0004] Therefore, currently, to develop a die casting aluminum
alloy with both a high heat-conducting property and good
formability has become an urgent need in the communications
industry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is an example method for producing a die casting
aluminum alloy.
[0006] FIG. 2 is an example communications product.
SUMMARY
[0007] In view of this, a first aspect of embodiments of the
present disclosure provides a die casting aluminum alloy that has
both a high heat-conducting property and good formability, to
resolve a prior-art problem that forming and heat dissipation
requirements of a communications product with a complex structure,
high heat flux density, and large power cannot be met at the same
time because it is difficult for a die casting aluminum alloy to
have both a high heat-conducting property and good formability.
[0008] Specifically, the first aspect of the embodiments of the
present disclosure provides the die casting aluminum alloy,
including constituents with the following mass percentages:
[0009] silicon: 4.0% to 10.0%;
[0010] magnesium: 0.2% to 1.0%;
[0011] copper: .ltoreq.0.1%;
[0012] manganese: .ltoreq.0.1%;
[0013] zinc: .ltoreq.0.1%;
[0014] ferrum: .ltoreq.1.3%;
[0015] titanium: .ltoreq.0.2%.
[0016] in the embodiments of the present disclosure, content of the
silicon in the die casting aluminum alloy is controlled within 4.0%
to 10.0% to improve thermal conductivity of the aluminum alloy and
ensure formability of the aluminum alloy, content of elements such
as the magnesium is also properly controlled so that the aluminum
alloy has a mechanical property and corrosion resistance, and total
content of other elements in the aluminum alloy other than aluminum
is relatively low, to ensure that the aluminum alloy has a
relatively high heat-conducting property; and
[0017] inevitable impurities: .ltoreq.0.15%; and the rest: the
aluminum.
[0018] In the first aspect of the present disclosure, a mass
percentage of the silicon is 5.5% to 6.5%.
[0019] In the first aspect of the present disclosure, the mass
percentage of the silicon is 5.8% to 6.3%.
[0020] In the first aspect of the present disclosure, the mass
percentage of the silicon is 5.7%.
[0021] In the first aspect of the present disclosure, a mass
percentage of the silicon is 4.3% to 5.0%.
[0022] In the first aspect of the present disclosure, the mass
percentage of the silicon is 4.4% to 4.8%.
[0023] In the first aspect of the present disclosure, a mass
percentage of the silicon is 6.5% to 7.5%.
[0024] In the first aspect of the present disclosure, a mass
percentage of the magnesium is 0.3% to 0.8%.
[0025] In the first aspect of the present disclosure, the mass
percentage of the magnesium is 0.4% to 0.7%.
[0026] In the first aspect of the present disclosure, the mass
percentage of the magnesium is 0.5% to 0.6%.
[0027] In the first aspect of the present disclosure, a mass
percentage of the copper is 0.001% to 0.05%.
[0028] In the first aspect of the present disclosure, the mass
percentage of the copper is 0.01% to 0.03%.
[0029] In the first aspect of the present disclosure, a mass
percentage of the manganese is 0.001% to 0.006%.
[0030] In the first aspect of the present disclosure, the mass
percentage of the manganese is 0.002% to 0.004%.
[0031] In the first aspect of the present disclosure, a mass
percentage of the zinc is 0.001% to 0.02%.
[0032] In the first aspect of the present disclosure, the mass
percentage of the zinc is 0.001% to 0.008%.
[0033] In the first aspect of the present disclosure, a mass
percentage of the ferrum is 0.3% to 1.0%.
[0034] In the first aspect of the present disclosure, the mass
percentage of the ferrum is 0.5% to 0.7%.
[0035] In the first aspect of the present disclosure, a mass
percentage of the titanium is 0.001% to 0.06%.
[0036] In the first aspect of the present disclosure, the mass
percentage of the titanium is 0.01% to 0.03%.
[0037] A total mass percentage of elements other than the aluminum
in the die casting aluminum alloy in the present disclosure is less
than 10%.
[0038] The total mass percentage of the elements other than the
aluminum in the die casting aluminum alloy in the present
disclosure is 5.0% to 8.0%.
[0039] Phases inside an organization structure of the die casting
aluminum alloy include a hypoeutectic .alpha.-Al phase, a eutectic
.alpha.-Al phase, a eutectic Si phase, and an intermetallic
compound, the intermetallic compound is distributed at a grain
boundary location or is precipitated in the hypoeutectic .alpha.-Al
phase and the eutectic .alpha.-Al phase, and the intermetallic
compound includes an Mg.sub.2Si phase. When the constituents of the
die casting aluminum alloy further include an element Fe and an
element Cu, the intermetallic compound further includes an
Al.sub.3Fe phase, an Al.sub.2Cu phase, and a ternary compound
Al--Si--Fe phase.
[0040] In the present disclosure, a coefficient of thermal
conductivity of the die casting aluminum alloy is 170 W/(mK) to 195
W/(mK).
[0041] In the present disclosure, Brinell hardness of the die
casting aluminum alloy is 60 HBW to 80 HBW, tensile strength is 170
MPa to 220 MPa, yield strength is greater than or equal to 100 MPa,
and an elongation rate is greater than or equal to 2%.
[0042] The die casting aluminum alloy provided in the first aspect
of the embodiments of the present disclosure has both a high
heat-conducting property and good formability, also has high
corrosion resistance, a good mechanical property, and low costs,
and can meet forming and heat dissipation requirements of a
communications product with a complex structure.
[0043] A second aspect of the embodiments of the present disclosure
provides a production method of a die casting aluminum alloy,
including the following steps:
[0044] providing raw materials based on constituents of a die
casting aluminum alloy, and performing heat treatment at any
temperature within 180.degree. C. to 375.degree. C. after casting,
to obtain a die casting aluminum alloy, where the die casting
aluminum alloy includes constituents with the following mass
percentages: silicon: 4.0% to 10.0%; magnesium: 0.2% to 1.0%;
copper: .ltoreq.0.1%; manganese: .ltoreq.0.1%; zinc: .ltoreq.0.1%;
ferrum: .ltoreq.1.3%; titanium: .ltoreq.0.2%; inevitable
impurities: .ltoreq.0.15%; and the rest: aluminum.
[0045] The foregoing heat treatment process may be at a constant
temperature, or may be at a non-constant temperature. In some
implementations, a temperature may be selected from 180.degree. C.
to 375.degree. C. to perform heat treatment. In other
implementations, a plurality of temperatures may be separately
selected from 180.degree. C. to 375.degree. C. as heat treatment
temperatures at a plurality of heat treatment stages.
[0046] In the production method in the present disclosure, the
casting is performed through liquid die casting, semi-solid die
casting, vacuum die casting, investment casting, gravity casting,
or squeeze casting.
[0047] In the production method in the present disclosure, time for
the heat treatment is 0.2 h to 8 h.
[0048] A process of the production method provided in the second
aspect of the present disclosure is simple, and the produced die
casting aluminum alloy has both a high heat-conducting property and
good formability, and also has high corrosion resistance and a good
mechanical property.
[0049] A third aspect of the embodiments of the present disclosure
provides a communications product, including a housing and a power
supply circuit and a functional circuit that are located in the
housing, where the power supply circuit supplies power to the
functional circuit, and the housing is obtained through casting by
using the die casting aluminum alloy according to the first aspect
of the embodiments of the present disclosure.
[0050] The communications product provided in the third aspect of
the embodiments of the present disclosure has a high
heat-conducting property, good formability, high corrosion
resistance, and a mechanical property, and can meet a design
requirement for high density and large power.
DESCRIPTION OF EMBODIMENTS
[0051] Embodiments of the present disclosure are described below
with reference to some specific implementations of the present
disclosure.
[0052] As a communications product constantly strives for large
power, miniaturization, and lightness, the industry imposes an
increasingly high requirement on a heat dissipation capability of a
die casting material of the communications product. Currently, a
commonly used die casting material of the communications product is
mainly a die casting aluminum alloy. However, common thermal
conductivity of a die casting aluminum alloy in the communications
product industry is 90 W/(mK) to 150 W/(mK), and a requirement of a
future product with high heat flux density and large power cannot
be met. In addition, a communications die-casting fitting is
usually in a complex structure with a large quantity of complex
thin-wall heat sink fins, higher and lower bosses, and deep-cavity
structures, and has relatively large dimensions. A heat sink fin
layout of a future heat sink is to be denser and thinner, and a fin
shape is to be more complex. Therefore, a requirement on casting
fluidity of the die casting material of the communications product
is to be higher. Fluidity of an Al--Si series die casting aluminum
alloy commonly used in a current industry increases as content of
silicon increases, and the fluidity is the best in a eutectic
composition, but thermal conductivity of the alloy decreases at the
same time. Therefore, it is difficult to have both a high
heat-conducting property and good formability. In view of this,
currently, to develop a die casting aluminum alloy with both a high
heat-conducting property and good formability has become an urgent
need in the communications industry. In addition, because
communications products are used in a diversity of environments and
are often in relatively poor environments, such as seawater, acid
rain, and an environment with alternate high and low temperatures,
and it needs to be ensured that the communications products are
maintenance-free, the die casting aluminum alloy needs to have both
relatively high corrosion resistance and a mechanical property.
[0053] Specifically, an embodiment of the present disclosure
provides a die casting aluminum alloy that has both a high
heat-conducting property and good formability. The die casting
aluminum alloy includes constituents with the following mass
percentages:
[0054] silicon: 4.0% to 8.0%;
[0055] magnesium: 0.2% to 1.0%;
[0056] copper: .ltoreq.0.1%;
[0057] manganese: .ltoreq.0.1%;
[0058] zinc: .ltoreq.0.1%;
[0059] ferrum: .ltoreq.1.3%;
[0060] titanium: .ltoreq.0.2%; and
[0061] inevitable impurities: .ltoreq.0.15%; and the rest:
aluminum.
[0062] According to the high heat-conductive casting aluminum alloy
provided in this embodiment of the present disclosure, the
constituents of the alloy are determined by comprehensively
considering contribution of each chemical element to an integrated
performance index (including thermal conductivity, fluidity,
corrosion resistance, hardness, strength, and the like) of the
alloy, and with a joint effect of various elements of the foregoing
specific content, different types of performance are balanced, and
a stable crystal structure is formed, so that a die casting
aluminum alloy with good integrated performance is obtained.
[0063] Phases inside an organization structure of the die casting
aluminum alloy in this embodiment of the present disclosure include
a hypoeutectic .alpha.-Al phase, a eutectic .alpha.-Al phase, a
eutectic Si phase, and an intermetallic compound, and the
intermetallic compound is distributed at a grain boundary location
or is precipitated in the .alpha.-Al phases. The phase means
uniform and continuous components having a same chemical
composition, a same atom aggregation state, and a same atom
property, and different phases are separated by an interface. The
intermetallic compound is a compound including a metal and a metal,
or a metal and a metalloid. Specifically, in a crystal structure of
the die casting aluminum alloy in the present disclosure, the
intermetallic compound mainly includes an Mg.sub.2Si phase. When
the constituents of the die casting aluminum alloy further include
an element Fe and an element Cu, the intermetallic compound further
includes an Al.sub.3Fe phase, an Al.sub.2Cu phase, a ternary
compound Al--Si--Fe phase, and the like. The ferrum, the copper,
the magnesium, the manganese, the zinc, and the titanium are
partially solidly dissolved in the hypoeutectic .alpha.-Al phase
and the eutectic .alpha.-Al phase in a form of atoms. The
Al.sub.2Cu phase and the Mg.sub.2Si phase are uniformly dispersed
and distributed.
[0064] Adding of the element silicon (Si) can improve casting
fluidity of an Al--Si series alloy, and in the alloy, Si and Al
form an (.alpha.-Al+Si) eutectic phase. This is a main reason why
casting fluidity of the aluminum-silicon alloy is improved.
However, thermal conductivity of the alloy decreases as content of
Si increases. For example, thermal conductivity of an aluminum
alloy with a Japanese designation ADC12 (in which content of
silicon is 9.6% to 12%) is only 95 W/(mK). This is because a large
amount of Si in the Al--Si alloy exists mainly in a form of primary
Si or eutectic Si or is solidly dissolved in an Al matrix, and
consequently the thermal conductivity of the alloy greatly
decreases. Therefore, to obtain relatively high thermal
conductivity, Si needs to be controlled at lower content. In
consideration of both fluidity and thermal conductivity, in this
embodiment of the present disclosure, a mass percentage of the
silicon is controlled within 4.0% to 8.0%. Further, in an
implementation of the present disclosure, the mass percentage of
the silicon is specifically controlled within 5.5% to 6.5%, and is
further 5.8% to 6.3%, or 5.7%, or 6.0%. In another implementation
of the present disclosure, the mass percentage of the silicon is
specifically controlled within 4.3% to 5.0%, and is further 4.4% to
4.8%, or 4.5%, or 4.7%. In other implementations of the present
disclosure, the mass percentage of the silicon may alternatively be
6.5% to 7.5%, and is further 7.0%.
[0065] The element magnesium (Mg) is a main strengthening element
in the aluminum-silicon alloy. Mg and Si form the Mg.sub.2Si phase
that is uniformly dispersed and distributed in the organization
structure of the alloy and performs a dispersion strengthening
function. The dispersion strengthening means a material
strengthening effect achieved by organizing and mixing a plurality
of phases. The dispersion strengthening is essentially using
dispersed ultra-fine particles to hinder dislocation motion,
thereby improving a mechanical property of a material at a high
temperature. When it is ensured that a weight ratio of Mg to Si
meets Mg/Si<1.73, higher content of the element Mg leads to a
better mechanical property of the alloy. However, excessive
elements Mg lead to an increase in a grain quantity and an increase
in a grain boundary quantity of the grains. The grain boundary is
an interface between grains with a same structure and different
orientations, in other words, a contact interface between grains.
At the crystal boundary, atom arrangement is in transition from one
orientation to another. The atom arrangement is in a transition
state at the crystal boundary. Consequently, a heat conduction path
loses continuity at the crystal boundary, and finally thermal
conductivity of a material decreases. Therefore, in consideration
of both the mechanical property and the thermal conductivity, in an
implementation of the present disclosure, a mass percentage of the
element Mg is controlled within 0.2% to 1.0%. Further, in an
implementation of the present disclosure, the mass percentage of
the magnesium is 0.3% to 0.8%, and is further 0.4% to 0.7% or 0.5%
to 0.6%.
[0066] The element copper (Cu) is also a main strengthening element
in the aluminum-silicon alloy. Cu and Al form the Al.sub.2Cu phase
that is uniformly dispersed and distributed in the organization
structure of the alloy and performs a dispersion strengthening
function. Because solidly dissolved copper has a high cathode
effect on the alloy, a copper ion that enters a liquid corrosion
dielectric solution is re-plated on a surface of the aluminum alloy
in a state of a fine metallic copper grain, to form activity and
even large galvanic corrosion, thereby reducing corrosion
resistance of the alloy. Specifically, the solidly dissolved copper
and a metal that is in the alloy and that has different potential
from that of the copper form a micro battery when there is the
corrosion dielectric solution. The copper acts as a cathode, and
another metal with relatively negative potential acts as an anode.
In a battery reaction, the copper ion in the corrosion dielectric
solution is reduced to metallic copper and the metallic copper is
deposited on a surface of the aluminum alloy, thereby accelerating
electrochemical corrosion. Therefore, for obtaining superior
corrosion resistance, content of the copper needs to be controlled
to control content of solidly dissolved copper, so as to reduce
galvanic corrosion. In an implementation of the present disclosure,
a mass percentage of the element Cu is controlled to be less than
or equal to 0.1%. Further, in an implementation of the present
disclosure, the mass percentage of the copper is 0.001% to 0.05%,
and further, the mass percentage of the copper is 0.003% to 0.005%,
or 0.008% to 0.01%, or 0.01% to 0.03%, or 0.02% to 0.05%, or 0.03%
to 0.04%. In another implementation of the present disclosure, the
mass percentage of the copper is 0.07% to 0.1%, and is further
0.08% to 0.09%.
[0067] The element ferrum (Fe) forms a needle-like brittle phase in
the die casting aluminum alloy. Existence of the Fe splits a
matrix, it is likely to cause stress concentration around the
brittle phase, and a fatigue crack or static load fracture occurs
on the alloy, thereby reducing a mechanical property of the alloy.
Therefore, content of Fe is limited to some extent. However,
excessively low content of Fe leads to an increase in a mold
sticking risk during casting, and the element Fe has relatively
small impact on thermal conductivity. Therefore, after
comprehensive consideration, a mass percentage of the element Fe is
controlled to be less than or equal to 1.3% in this embodiment of
the present disclosure. In an implementation of the present
disclosure, the mass percentage of the ferrum is 0.3% to 1.0%, and
is further 0.5% to 0.7%, or 0.7% to 0.9%, or 0.8% to 1.0%. In an
implementation of the present disclosure, the mass percentage of
the ferrum may alternatively be 0.2% to 0.4%, or 0.25% to 0.45%, or
1.1% to 1.2%.
[0068] Adding of the element manganese (Mn) may improve a
mechanical property and corrosion resistance of the
aluminum-silicon alloy. However, Mn has relatively large impact on
thermal conductivity at the same time, and reduces a
heat-conducting property of the alloy. Therefore, a content range
of the element Mn may be specifically determined based on the
content of the element Fe, and is specifically controlled to be
less than or equal to 0.1% in this embodiment of the present
disclosure. In an implementation of the present disclosure, a mass
percentage of the manganese is 0.001% to 0.006%, and is further
0.002% to 0.003%. In other implementations of the present
disclosure, a mass percentage of the manganese may alternatively be
0.004% to 0.005%, or 0.008% to 0.01%, or 0.012% to 0.05%, or 0.04%
to 0.06%, or 0.07% to 0.08%.
[0069] In an aluminum alloy casting process, the element titanium
(Ti) preferentially reacts with Al to form an Al.sub.3Ti grain
refiner that can convert .alpha.-Al grains from a thick branch
shape into fine and uniform equiaxed grains, so that strength and
plasticity of the aluminum alloy are improved, but a
heat-conducting property of a material is reduced at the same time.
The Al.sub.3Ti grain refiner has an excellent refinement effect,
improves surface quality of castings so that the castings obtain
fine equiaxed grains, especially reduces casting cold shuts and
eliminates a trichite and a columnar crystal, and can effectively
overcome casting cracks and improve a casting appearance. The
equiaxed grains are grains with a relatively small grain dimension
difference in all orientations. Therefore, in comprehensive
consideration of thermal conductivity and a mechanical property
during actual production, in this embodiment of the present
disclosure, a mass percentage of the titanium is controlled to be
less than or equal to 0.2%. Further, in an implementation of the
present disclosure, the mass percentage of the titanium is 0.001%
to 0.06%, and is further 0.001% to 0.003%, or 0.01% to 0.03%, or
0.004% to 0.005%, or 0.008% to 0.01%, or 0.012% to 0.05%, or 0.04%
to 0.06%. In another implementation of the present disclosure, the
mass percentage of the titanium is greater than 0 and less than
0.001%. In other implementations of the present disclosure, the
mass percentage of the titanium may alternatively be 0.07% to 0.08%
or 0.1% to 0.15%.
[0070] In an implementation of the present disclosure, a mass
percentage of the zinc is specifically 0.001% to 0.02%, and is
further 0.001% to 0.008%. In another implementation of the present
disclosure, a mass percentage of the zinc is greater than 0 and
less than or equal to 0.001%. In other implementations of the
present disclosure, a mass percentage of the zinc may alternatively
be 0.03% to 0.06%, or 0.07% to 0.08%, or 0.09% to 0.1%.
[0071] In an implementation of the present disclosure, because an
increase in an impurity element leads to reduction in thermal
conductivity of a material, in this embodiment of the present
disclosure, content of the inevitable impurity elements is
controlled to be less than or equal to 0.15%.
[0072] In a specific implementation of the present disclosure, the
die casting aluminum alloy includes constituents with the following
mass percentages: silicon: 5.8% to 6.3%; magnesium: 0.3% to 0.4%;
copper: <0.1%; manganese: <0.08%; zinc: <0.02%; ferrum:
0.2% to 0.68%; titanium: <0.02%; inevitable impurities:
.ltoreq.0.15%; and the rest: aluminum.
[0073] In another specific implementation of the present
disclosure, the die casting aluminum alloy includes constituents
with the following mass percentages: silicon: 5.7%; magnesium:
0.33%; copper: 0.1%; manganese: 0.001%; zinc: <0.001%; ferrum:
0.58%; titanium: <0.001%; inevitable impurities: .ltoreq.0.15%;
and the rest: aluminum.
[0074] Adding of each element to pure metal aluminum leads to
reduction in orderly arrangement of a crystal lattice of a
material, and leads to lattice distortion and limited periodic
motion of electrons, and a heat-conducting property and electrical
conductivity of the material are reduced. Therefore, in an
implementation of the present disclosure, for obtaining a
relatively high heat-conducting property, a total mass percentage
of elements other than the aluminum in the die casting aluminum
alloy is controlled to be less than 10%, and is further controlled
within 5.0% to 8.0%, or within 5.5% to 7.5%, or within 6.0% to
6.5%.
[0075] In an implementation of the present disclosure, with a
comprehensive effect of specific content of specific elements, a
coefficient of thermal conductivity of the die casting aluminum
alloy reaches 170 W/(mK) to 195 W/(mK), Brinell hardness is 60 HBW
to 80 HBW, tensile strength is 170 MPa to 220 MPa, yield strength
is greater than or equal to 100 MPa, and an elongation rate is
greater than or equal to 2%.
[0076] The tensile strength is a critical value at which a metal is
in transition from uniform plastic deformation to
local-concentrated plastic deformation, and is also a maximum
bearing capability of the metal in a case of static stretching. The
tensile strength indicates resistance to maximum uniform plastic
deformation of a material, and deformation of a tensile sample is
uniform and consistent before the tensile sample bears maximum
tensile stress. However, after the maximum tensile stress is
exceeded, a necking phenomenon starts to occur on the metal, to be
specific, concentrated deformation occurs. The yield strength is a
yield limit when a yield phenomenon occurs on a metal material, in
other words, stress that resists microplastic deformation. For a
metal material on which no apparent yield phenomenon occurs, it is
specified that a stress value corresponding to residual deformation
of 0.2% is used as a yield limit of the metal material, and is
referred to as a conditional yield limit or conditional yield
strength. The elongation rate is an index for describing plastic
performance of a material, and is a percentage of a ratio of total
deformation .DELTA.L of a gauge section after tensile fracture of a
sample to an original gauge length L.
[0077] The die casting aluminum alloy provided in this embodiment
of the present disclosure has a high heat-conducting property, good
formability, high corrosion resistance, and a mechanical property,
can be applied to a harsh outdoor environment, can be used for
forming complex thin-wall castings (such as a heat sink) to meet a
design requirement for high density and large power, and can be
specifically used in fields such as a mobile phone, a notebook
computer, a communications device industry, an automobile, and
civil hardware. More specifically, an embodiment of the present
disclosure provides a communications product, including a housing
and a power supply circuit and a functional circuit that are
located in the housing, where the power supply circuit supplies
power to the functional circuit, and the housing is obtained
through casting by using the die casting aluminum alloy provided in
the embodiments of the present disclosure. The communications
product may be a heat sink. Certainly, in the communications
product, another component that can use an aluminum alloy part may
also be obtained through casting by using the die casting aluminum
alloy in the embodiments of the present disclosure, such as a
handle, a maintenance cavity cover, a guide rail, a rotating shaft,
and a supporting kit.
[0078] Correspondingly, an embodiment of the present disclosure
further provides a production method of a die casting aluminum
alloy, including the following steps:
[0079] S10. Provide raw materials based on constituents of a die
casting aluminum alloy, and perform casting through liquid die
casting, semi-solid die casting, vacuum die casting, investment
casting, gravity casting, or squeeze casting.
[0080] S20. Perform heat treatment within 180.degree. C. to
375.degree. C. after casting and cooling, to obtain a die casting
aluminum alloy, where the die casting aluminum alloy includes
constituents with the following mass percentages: silicon: 4.0% to
8.0%; magnesium: 0.2% to 1.0%; copper: .ltoreq.0.1%; manganese:
.ltoreq.0.1%; zinc: .ltoreq.0.1%; ferrum: .ltoreq.1.3%; titanium:
.ltoreq.0.2%; inevitable impurities: .ltoreq.0.15%; and the rest:
aluminum.
[0081] In the present disclosure, in step S10, all the liquid die
casting, the semi-solid die casting, the vacuum die casting, the
investment casting, the gravity casting, and the squeeze casting
are existing conventional processes. Raw materials and process
parameters required for each process are not specially limited in
the present disclosure, and only need to be selected and set
according to an industry requirement and an actual requirement.
[0082] In the present disclosure, in step S20, further, a
temperature for the heat treatment is 200.degree. C. to 300.degree.
C. or 240.degree. C. to 280.degree. C. A heat treatment process may
be at a constant temperature, or may be at a non-constant
temperature. Optionally, time for the heat treatment is 0.2 h to 8
h, and further, the time for the heat treatment is 1 h to 5 h or 2
h to 6 h. The heat treatment in the present disclosure can
strengthen the alloy, and can not only improve a mechanical
property (such as strength, hardness, and an elongation rate) of
the alloy, but also improve physical performance (including
density, conductivity, and thermal conductivity) and
electrochemical performance (including solid solution potential) of
castings. An alloy element more easily leads to reduction in the
conductivity and the thermal conductivity of the alloy when
existing in a form of a solid solution in comparison with being
combined with another element to form an intermetallic compound.
Therefore, heat treatment is even needed during production of a
high heat-conductive and electricity-conductive component. After
low-temperature heat treatment of 180.degree. C.-375.degree. C. in
the present disclosure, a point defect of the alloy such as a
vacancy or a solidly dissolved atom can be reduced. Specifically,
at a relatively low heat treatment temperature in the present
disclosure, the vacancy may be transferred from an interior of a
material to a surface of the alloy and escapes, thereby reducing
lattice distortion of the alloy, and greatly improving thermal
conductivity of the alloy without reducing a mechanical property of
the alloy. In addition, a dispersion strengthening phase (such as
Mg.sub.2Si or Al.sub.2Cu) is precipitated from a solid solution,
thereby reducing content of a solidly dissolved atom, so that
strength and electrical conductivity of the alloy are optimized. In
the die casting aluminum alloy of the present disclosure, most
elements Mg and Cu are precipitated in a form of dispersion
strengthening phases: Mg.sub.2Si and Al.sub.2Cu, and only a very
small quantity of the elements exist inside an .alpha.-Al phase in
a form of a solidly dissolved atom.
[0083] Phases inside an organization structure of the die casting
aluminum alloy produced in this embodiment of the present
disclosure include a hypoeutectic .alpha.-Al phase, a eutectic
.alpha.-Al phase, a eutectic Si phase, and an intermetallic
compound, and the intermetallic compound is distributed at a grain
boundary location or is precipitated in the .alpha.-Al phase. The
intermetallic compound mainly includes an Al.sub.3Fe phase, an
Al.sub.2Cu phase, an Mg.sub.2Si phase, a ternary compound
Al--Si--Fe phase, and the like. The ferrum, the copper, the
magnesium, the manganese, the zinc, and the titanium are partially
solidly dissolved in the hypoeutectic .alpha.-Al phase and the
eutectic .alpha.-Al phase in a form of atoms. The Al.sub.2Cu phase
and the Mg.sub.2Si phase are uniformly dispersed and
distributed.
[0084] In an implementation of the present disclosure, a mass
percentage of the silicon is specifically controlled within 5.5% to
6.5%, and is further 4.3% to 4.8% or 4.4% to 5.0%. In other
implementations of the present disclosure, a mass percentage of the
silicon may alternatively be 4.5% to 5.0%, or 6.0% to 7.0%, or 6.5%
to 7.5%.
[0085] In an implementation of the present disclosure, a mass
percentage of the magnesium is 0.3% to 0.7%, and is further 0.4% to
0.5% or 0.6% to 0.8%.
[0086] In an implementation of the present disclosure, a mass
percentage of the copper is 0.001% to 0.05%. In another
implementation of the present disclosure, a mass percentage of the
copper is 0.08% to 0.1%. In other implementations, a mass
percentage of the copper may alternatively be 0.003% to 0.005%, or
0.008% to 0.01%, or 0.02% to 0.05%, or 0.04% to 0.06%.
[0087] In an implementation of the present disclosure, a mass
percentage of the ferrum is 0.3% to 1.0%, and is further 0.5% to
0.7%. In an implementation of the present disclosure, a mass
percentage of the ferrum may alternatively be 0.25% to 0.45%, or
0.7% to 0.9%, or 1.1% to 1.2%, or 0.8% to 1.0%.
[0088] In an implementation of the present disclosure, a mass
percentage of the manganese is 0.001% to 0.006%, and is further
0.002% to 0.003%. In other implementations of the present
disclosure, a mass percentage of the manganese may alternatively be
0.004% to 0.005%, or 0.008% to 0.01%, or 0.012% to 0.05%, or 0.04%
to 0.06%, or 0.07% to 0.08%.
[0089] In an implementation of the present disclosure, a mass
percentage of the titanium is 0.001% to 0.003%. In another
implementation of the present disclosure, a mass percentage of the
titanium is greater than 0 and less than 0.001%.
[0090] In an implementation of the present disclosure, a mass
percentage of the zinc is specifically 0.001% to 0.008%.
[0091] In another implementation of the present disclosure, a mass
percentage of the zinc is greater than 0 and less than or equal to
0.001%.
[0092] In a specific implementation of the present disclosure, the
die casting aluminum alloy includes constituents with the following
mass percentages: silicon: 5.8% to 6.3%; magnesium: 0.3% to 0.4%;
copper: <0.1%; manganese: <0.08%; zinc: <0.02%; ferrum:
0.2% to 0.68%; titanium: <0.02%; inevitable impurities:
.ltoreq.0.15%; and the rest: aluminum.
[0093] In another specific implementation of the present
disclosure, the die casting aluminum alloy includes constituents
with the following mass percentages: silicon: 5.7%; magnesium:
0.33%; copper: 0.1%; manganese: 0.001%; zinc: <0.001%; ferrum:
0.58%; titanium: <0.001%; inevitable impurities: .ltoreq.0.15%;
and the rest: aluminum.
[0094] A process of the production method of the die casting
aluminum alloy provided in this embodiment of the present
disclosure is simple, and the produced die casting aluminum alloy
has a high heat-conducting property, good formability, high
corrosion resistance, and a good mechanical property.
[0095] The embodiments of the present disclosure are further
described below by using a plurality of embodiments.
Embodiment 1
[0096] A die casting aluminum alloy includes constituents with the
following mass percentages: silicon: 5.8% to 6.3%; magnesium: 0.3%
to 0.4%; copper: <0.1%; manganese: <0.08%; zinc: <0.02%;
ferrum: 0.2% to 0.68%; titanium: <0.02%; inevitable impurities:
.ltoreq.0.15%; and the rest: aluminum.
[0097] A production method of a complex thin-wall communications
housing that is obtained through die casting by using the die
casting aluminum alloy with the constituents in this embodiment
includes the following steps:
[0098] Based on the constituents of the foregoing die casting
aluminum alloy, a pure aluminum A00 aluminum ingot (whose purity is
99.7%), a pure magnesium ingot, an AlSi26 intermediate alloy, an
AlFe20 intermediate alloy, and the like are used as raw materials,
melting, semi-solid slurrying, and semi-solid die casting are
performed on the raw materials, and after cooling, 180.degree. C.
to 375.degree. C. heat treatment is performed for 0.2 to 8 hours,
to obtain the thin-wall communications housing.
Embodiment 2
[0099] A die casting aluminum alloy includes constituents with the
following mass percentages: silicon: 5.7%; magnesium: 0.33%;
copper: 0.1%; manganese: 0.001%; zinc: <0.001%; ferrum: 0.58%;
titanium: <0.001%; inevitable impurities: .ltoreq.0.15%; and the
rest: aluminum.
[0100] A complex thin-wall communications housing is obtained in
the manner in Embodiment 1 of the present disclosure through die
casting by using the die casting aluminum alloy with the
constituents in this embodiment.
Embodiment 3
[0101] A die casting aluminum alloy includes constituents with the
following mass percentages: silicon: 4.7%; magnesium: 0.33%;
copper: <0.1%; manganese: <0.05%; zinc: <0.01%; ferrum:
0.58%; titanium: <0.1%; inevitable impurities: .ltoreq.0.15%;
and the rest: aluminum.
[0102] A complex thin-wall communications housing is obtained in
the manner in Embodiment 1 of the present disclosure through die
casting by using the die casting aluminum alloy with the
constituents in this embodiment.
Embodiment 4
[0103] A die casting aluminum alloy includes constituents with the
following mass percentages: silicon: 4.5%; magnesium: 0.46%;
copper: <0.1%; manganese: <0.1%; zinc: <0.001%; ferrum:
0.4% to 0.58%; titanium: .ltoreq.0.1%; inevitable impurities:
.ltoreq.0.15%; and the rest: aluminum.
[0104] A complex thin-wall communications housing is obtained in
the manner in Embodiment 1 of the present disclosure through die
casting by using the die casting aluminum alloy with the
constituents in this embodiment.
Effect Embodiment
[0105] To provide strong support for beneficial effects brought by
the technical solutions in the embodiments of the present
disclosure, the following product performance tests are
provided:
[0106] A comparison test is performed on the die casting aluminum
alloys in Embodiment 1 to Embodiment 4 of the present disclosure
and an ADC12 alloy in terms of thermal conductivity, formability,
and a mechanical property (including hardness, tensile strength,
yield strength, and an elongation rate). A result is as
follows:
1. Thermal Conductivity
[0107] A thermal conductivity test is performed on the die casting
aluminum alloys in Embodiment 1 to Embodiment 4 of the present
disclosure and the ADC12 alloy, and the thermal conductivity test
is performed by using a laser flash method (ASTM E 1461-01). Sample
dimensions are .PHI.12.7 mm.times.(2 to 4) mm. For heat, refer to
ISO 11357 and ASTM E1269. For density, refer to ISO 1183-1:2004. A
thermal conductivity result of each alloy is shown in Table 1.
TABLE-US-00001 TABLE 1 Comparison between thermal conductivity of
alloys Alloy designation Thermal conductivity (w/m k) ADC12 95
Embodiment 1 185 Embodiment 2 190 Embodiment 3 182 Embodiment 4
180
[0108] It may be learned from the result in Table 1 that the die
casting aluminum alloy in the embodiments of the present disclosure
has a better heat-conducting property than that of the ADC12
aluminum alloy, and can meet a heat dissipation requirement of a
communications product with a complex structure, high heat flux
density, and large power.
2. Formability
[0109] Die casting is separately performed on three types of
alloys: the alloys in Embodiment 1 and Embodiment 2 of the present
disclosure and the ADC12 alloy, to obtain a complex thin-wall
communications housing. When formability of the alloy is poor, a
short shot defect is likely to occur on a thin-wall heat sink fin.
According to existing statistics, 30 die-casting fittings are
continuously produced by using each alloy. Statistical results of
maximum physical dimensions of each short shot feature on 25 heat
sink fins of the die-casting fittings are shown in Table 2. The
maximum physical dimensions (R) are described in three categories:
0.5 mm.ltoreq.R.ltoreq.1.0 mm, or 1.0 mm<R.ltoreq.3 mm, or
R>3 mm.
TABLE-US-00002 TABLE 2 Statistics of short shot features of
different alloy die-casting fittings Short shot Total quantity:
Short shot Short shot Alloy defect 0.5 mm .ltoreq. quantity: 1.0 mm
< quantity: designation quantity R .ltoreq. 1.0 mm R .ltoreq. 3
mm R > 3 mm ADC12 201 90 90 21 Embodiment 1 205 124 65 16
Embodiment 2 220 102 103 15
3. Corrosion Resistance
[0110] A corrosion resistance test is performed on the die casting
aluminum alloys in Embodiment 1 to Embodiment 4 of the present
disclosure. Corrosion resistance of the die casting aluminum alloy
is compared with that of an existing alloy, and a result is shown
in Table 3. The corrosion resistance of the alloy is indicated by
using a corrosion rate. A test method for the corrosion rate
complies with the standard GB/T19292.4 and the standard GB/T 16545,
and sample dimensions are 120 mm.times.100 mm.times.5 mm. For
eliminating an edge effect, an edge of a corrosion rate test sample
is wrapped with an adhesive tape. After 1440 h of a neutral salt
spray test, an average corrosion rate is calculated by using a
weight change before and after salt spray.
TABLE-US-00003 TABLE 3 Comparison between corrosion rates of alloys
Alloy designation Corrosion rate (mg/(dm.sup.2 .times. d)) ADC12
34.0 Embodiment 1 4.5 Embodiment 2 4.3 Embodiment 3 5.0 Embodiment
4 4.6
4. Mechanical Property
[0111] Die casting is separately performed on the alloys in
Embodiment 1 and Embodiment 2 of the present disclosure and the
ADC12 alloy, to obtain a complex thin-wall communications housing.
A standard tensile mechanical test piece is cut from a product
according to a GB/T 228 requirement, and the mechanical property is
tested on a tensile testing machine. A result is shown in Table
4.
TABLE-US-00004 TABLE 4 Mechanical properties of alloys Yield Alloy
Tensile strength strength Elongation Hardness designation (MPa)
(MPa) rate (%) (HBW) ADC12 260 .gtoreq.100 0.7 92 Embodiment 1 210
136 4.6 79 Embodiment 2 199 132 4.0 70
[0112] FIG. 1 is an example method for producing a die casting
aluminum alloy. The method includes: providing raw materials based
on constituents of a die casting aluminum alloy (step 102), and
performing heat treatment at any temperature within 180.degree. C.
to 375.degree. C. after casting, to obtain a die casting aluminum
alloy, the die casting aluminum alloy consisting of constituents
with the following mass percentages: silicon: 4.0% to 10.0%;
magnesium: 0.2% to 1.0%; copper: .ltoreq.0.1%; manganese:
.ltoreq.0.1%; zinc: .ltoreq.0.1%; ferrum: .ltoreq.1.3%; titanium:
.ltoreq.0.2%; impurities: .ltoreq.0.15%; and remainder: aluminum
(step 104).
[0113] FIG. 2 is an example communications product 200. The
communications product 200 includes a housing 202. A power supply
circuit 204 and a functional circuit 206 are located in the housing
202. The power supply circuit supplies power to the functional
circuit, and the housing is obtained through casting by using a die
casting aluminum alloy consisting of constituents with the
following mass percentages: silicon: 4.0% to 10.0%; magnesium: 0.2%
to 1.0%; copper: .ltoreq.0.1%; manganese: .ltoreq.0.1%; zinc:
.ltoreq.0.1%; ferrum: .ltoreq.1.3%; titanium: .ltoreq.0.2%;
impurities: .ltoreq.0.15%; and remainder: aluminum.
[0114] It can be learned from the foregoing descriptions that the
die casting aluminum alloy obtained in the embodiments of the
present disclosure has both a high heat-conducting property and
good formability, and also has high corrosion resistance and a good
mechanical property, thereby resolving a prior-art problem that a
heat dissipation requirement of a communications product with high
heat flux density and large power cannot be met because a
heat-conducting property of a die casting aluminum alloy is poor.
Therefore, the following problems can be effectively avoided: a low
yield rate of die-casting fittings, severe burn-in caused due to
heat emission of a product, corrosion in a harsh environment such
as a coastal area, assembling difficulties caused by an
insufficient mechanical property, or severe deformation in wind
load.
* * * * *