U.S. patent application number 13/828451 was filed with the patent office on 2014-06-19 for high elastic aluminum alloy and method for producing the same.
This patent application is currently assigned to HYUNDAI MOTOR COMPANY. The applicant listed for this patent is HYUNDAI MOTOR COMPANY. Invention is credited to Hoo Dam Lee, Kyung Moon Lee, Hoon Mo Park.
Application Number | 20140170017 13/828451 |
Document ID | / |
Family ID | 50931114 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140170017 |
Kind Code |
A1 |
Park; Hoon Mo ; et
al. |
June 19, 2014 |
HIGH ELASTIC ALUMINUM ALLOY AND METHOD FOR PRODUCING THE SAME
Abstract
Disclosed is an aluminum alloy, including: about 14.about.20 wt
% of Si; about 2.about.7.5 wt % of Ti; about 1.about.3 wt % of B;
and a balance of Al as a main component, wherein wt % are based on
the total weight of the aluminum alloy and wherein a ratio of Ti/B
is about 2.about.2.5:1.
Inventors: |
Park; Hoon Mo; (Seongnam,
KR) ; Lee; Kyung Moon; (Anyang, KR) ; Lee; Hoo
Dam; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HYUNDAI MOTOR COMPANY |
Seoul |
|
KR |
|
|
Assignee: |
HYUNDAI MOTOR COMPANY
Seoul
KR
|
Family ID: |
50931114 |
Appl. No.: |
13/828451 |
Filed: |
March 14, 2013 |
Current U.S.
Class: |
420/548 ;
164/473 |
Current CPC
Class: |
C22C 21/04 20130101;
C22C 1/101 20130101; C22C 47/08 20130101; C22C 26/00 20130101; C22C
2026/002 20130101; C22C 21/02 20130101; B22D 11/003 20130101; C22C
1/026 20130101 |
Class at
Publication: |
420/548 ;
164/473 |
International
Class: |
C22C 21/04 20060101
C22C021/04; B22D 11/00 20060101 B22D011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2012 |
KR |
10-2012-0145787 |
Claims
1. An aluminum alloy, comprising: about 14.about.20 wt % of Si;
about 2.about.7.5 wt % of Ti; about 1.about.3 wt % of B; and a
balance of Al as a main component, wherein wt % are based on the
total weight of the aluminum alloy, and wherein a ratio of Ti/B is
about 2.about.2.5:1.
2. The aluminum alloy of claim 1, wherein the aluminum alloy is
formed by continuous casting.
3. The aluminum alloy of claim 1, wherein the Ti, B and Al
components comprise aluminum mother alloys of Al-(5.about.10 wt
%)Ti and Al-(2.about.10 wt %)B.
4. The aluminum alloy of claim 1, further comprising: about
2.about.7 vol % of CNT.
5. The aluminum alloy of claim 4, wherein the CNT is coated with
one or more metal oxides.
6. A method of manufacturing the aluminum alloy of claim 4,
comprising the steps of: coating CNT with one or more metal oxides;
introducing the CNT into an aluminum molten solution together with
inert gas and stirring to form a mixture; and forming the aluminum
alloy from the mixture using continuous casting.
7. The method of claim 6, wherein the CNT is coated with one or
more metal oxides to a thickness of about 20.about.50 nm.
8. The method of claim 6, wherein the stirring is performed at a
rotation speed of about 500.about.1500 rpm.
9. The method of claim 6, wherein, in the step of forming the
aluminum alloy, the aluminum molten solution is vibrated on a
casting table during the continuous casting before it is injected
into a mold.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims under 35 U.S.C. .sctn.119(a) the
benefit of Korean Patent Application No. 10-2012-0145787 filed Dec.
13, 2012, the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to a high elastic aluminum
alloy, particularly to such an alloy whose elasticity is remarkably
improved by maximizing the formation of a boride compound and
adding CNT thereto, and a method of manufacturing the same.
[0004] 2. Description of the Related Art
[0005] Conventionally, in providing alloys, the various alloy
ingredients are controlled so as to impart desired
characteristics.
[0006] For example, when only silicon (Si) is used to make a high
elastic alloy, the elasticity of the alloy cannot be sufficiently
improved, and the silicon (Si) particles become coarse. As such, it
is difficult to produce a highly elastic alloy because of the
coarse silicon (Si) particles.
[0007] Further, conventional aluminum (Al) composite materials are
expensive, even though they are formed into powder using reinforced
metal compounds or carbon nanotubes (CNTs).
[0008] Further, when powdered reinforced particles are introduced
into a casting process, there are problems of loss, wettability and
dispersity in a molten aluminum (Al) solution. Further, when only
reinforced particles are added to a base alloy without otherwise
improving the base alloy, the amount of reinforced particles must
be increased in order to attain a desired elasticity. This results
in causing several problems, including increased cost, increase
difficulty in control over the process and the like.
[0009] In order to provide alloys with improved elasticity, various
technologies have been developed. For example, such technologies
have included maximizing the formation of a boride compound which
plays an important role in the improvement of elasticity, adding
CNT to a high elastic alloy to thereby increase elasticity,
preventing CNT from being damaged in a high-temperature molten
aluminum solution, and uniformly dispersing the boride compound
formed by the spontaneous reaction with CNT in the aluminum molten
solution.
[0010] Korean Unexamined Patent Application Publication No.
10-2012-0059256 describes "an aluminum casting alloy and a method
of manufacturing the same." It is described in KR 10-2012-0059256 A
that "the present invention relates to an aluminum alloy including
aluminum 81.about.93 wt %, silicon 5.about.13 wt %, titanium
1.about.3 wt % and boron 1.about.3 wt %. The aluminum alloy of the
present invention has high elasticity compared to conventional
aluminum alloys although it does not include expensive materials
such as carbon nanotubes (CNTs) and the like. Further, conventional
aluminum alloys can be applied only to a low-pressure casting
process, whereas the aluminum alloy of the present invention can be
applied to all general casting processes including a high-pressure
casting process."
[0011] However, this technology does not solve the above problems
of loss, wettability and dispersity in a molten aluminum (Al)
solution when powdered reinforced particles are introduced into a
casting process. Further, when the amount of reinforced particles
is increased, this technology does not adequately decrease costs,
process control difficulty or the like.
[0012] It is to be understood that the foregoing description is
provided to merely aid the understanding of the present invention,
and does not mean that the present invention falls under the
purview of the related art which was already known to those skilled
in the art.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention provide a highly elastic
aluminum alloy whose elasticity is remarkably improved by
maximizing the formation of a boride compound and adding CNT
thereto, and a method of manufacturing the same.
[0014] In order to accomplish the above object, an aspect of the
present invention provides an aluminum alloy, including: about
14.about.20 wt % of Si; about 2.about.7.5 wt % of Ti; about
1.about.3 wt % of B; and a balance of Al as a main component,
wherein wt % are based on the total weight of the alloy
composition, and wherein a ratio of Ti/B is about
2.about.2.5:1.
[0015] According to various embodiments, the aluminum alloy is
formed by continuous casting.
[0016] According to various embodiments, the aluminum alloy is
prepared using aluminum mother alloys of Al-(5.about.10 wt %)Ti and
Al-(2.about.10 wt %)B.
[0017] According to various embodiments, the aluminum alloy further
includes about 2.about.7 vol % of CNT.
[0018] According to various embodiments, the CNT is coated with one
or more metal oxide, which can be selected from any known metal
oxides.
[0019] Another aspect of the present invention provides a method of
manufacturing the aluminum alloy, including the steps of: coating
CNT with one or more metal oxides; introducing the CNT into an
aluminum molten solution together with inert gas and stirring the
mixture; and forming the aluminum alloy using continuous
casting.
[0020] According to various embodiments, the CNT is completely
coated with one or more metal oxide to a thickness of about
20.about.50 nm.
[0021] According to various embodiments, the stirring is performed
at a rotation speed of about 500.about.1500 rpm.
[0022] According to various embodiments, in the step of forming the
aluminum alloy, the aluminum molten solution is vibrated on a
casting table during the continuous casting before being injected
into a mold.
[0023] Other aspects and exemplary embodiments of the invention are
discussed infra.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The above and other objects, features and advantages of the
present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0025] FIG. 1 is a graph showing the elasticity of a high elastic
aluminum alloy according to an embodiment of the present
invention;
[0026] FIG. 2 is a schematic view showing a stirring apparatus used
to manufacture a high elastic aluminum alloy according to an
embodiment of the present invention; and
[0027] FIG. 3 is a flowchart showing a method of manufacturing a
high elastic aluminum alloy according to an embodiment of the
present invention.
REFERENCE NUMERALS
[0028] S100: coating
[0029] S200: stirring
[0030] S500: forming
[0031] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various preferred features illustrative of the
basic principles of the invention. The specific design features of
the present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
[0032] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the attached
drawings.
[0034] It is understood that the term "vehicle" or "vehicular" or
other similar term as used herein is inclusive of motor vehicles in
general such as passenger automobiles including sports utility
vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and
the like, and includes hybrid vehicles, electric vehicles, plug-in
hybrid electric vehicles, hydrogen-powered vehicles and other
alternative fuel vehicles (e.g. fuels derived from resources other
than petroleum). As referred to herein, a hybrid vehicle is a
vehicle that has two or more sources of power, for example both
gasoline-powered and electric-powered vehicles.
[0035] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a," "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof. As
used herein, the term "and/or" includes any and all combinations of
one or more of the associated listed items.
[0036] Unless specifically stated or obvious from context, as used
herein, the term "about" is understood as within a range of normal
tolerance in the art, for example within 2 standard deviations of
the mean. "About" can be understood as within 10%, 9%, 8%, 7%, 6%,
5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated
value. Unless otherwise clear from the context, all numerical
values provided herein are modified by the term "about".
[0037] FIG. 1 is a graph showing the elasticity of a high elastic
aluminum alloy according to an embodiment of the present invention,
FIG. 2 is a schematic view showing a stirring apparatus used to
manufacture a high elastic aluminum alloy according to an
embodiment of the present invention, and FIG. 3 is a flowchart
showing a method of manufacturing a high elastic aluminum alloy
according to an embodiment of the present invention.
[0038] According to an exemplary embodiment, the high elastic
aluminum alloy of the present invention includes about 14.about.20
wt % of Si, about 2.about.7.5 wt % of Ti, about 1.about.3 wt % of
B; and a balance of Al as a main component, wherein the wt % are
based on the total weight of the aluminum alloy composition.
According to various embodiments, the ratio of Ti/B is about
2.about.2.5:1.
[0039] According to the present invention, it has been found that
when the aluminum alloy has the above composition and ratio of
Ti/B, the formation of a boride compound that plays an important
role in the improvement of elasticity can be maximized.
[0040] According to various embodiments, in order to maintain the
desired ratio of Ti/B and naturally induce a TiB.sub.2 compound,
the aluminum alloy may be prepared using two aluminum mother
alloys, Al-(5.about.10 wt %)Ti and Al-(2.about.10 wt %)B.
Al-(5.about.10 wt %)Ti includes about 5.about.10 wt % of Ti and
balance of Al as a main constituent. The other aluminum mother
alloy, Al-(2.about.10 wt %)B includes about 2.about.10 wt % of B
and balance of Al as a main constituent.
[0041] Further, when the formation of the boride compound is
maximized using the present method and compositions, the
elasticity, mechanical properties (strength, wear resistance) and
workability of a base alloy can be improved.
[0042] The elastic modulus of conventional aluminum alloy (A390: Si
17 wt %) is about 85 GPa, which is much less than the elastic
modulus of the aluminum alloys in accordance with the present
invention. For example, an aluminum alloy (Al-16Si-2.3Ti-1B) of the
present invention demonstrates an elastic modulus of 102 Gpa, and
another aluminum alloy (Al-20Si-2.3Ti-1B) of the present invention
demonstrates an elastic modulus of about 106 GPa.
[0043] The compositions of the aluminum alloy according to the
present invention and a conventional aluminum alloy, which differ
only in the ratio of Ti and B, are given in Table 1 below.
TABLE-US-00001 TABLE 1 Si Fe Cu Mn Mg Ni Zn Ti B Al Conventional
A390 16-18 0.5 4.0-5.0 0.1 0.45-0.65 -- 0.1 0.2 -- Bal. technology
Invention Invention 14-20 -- -- -- -- -- -- 2-7.5 1-3 Bal. Example
16-18 0.5 4.0-5.0 0.1 0.45-0.65 -- 0.1 2-7.5 1-3 Bal. (A390
applied)
[0044] As shown in Table 1 above, unlike the conventional aluminum
alloy, the aluminum alloy of the present invention includes about
2.about.7.5 wt % of Ti, about 1.about.3 wt % of B and a balance of
Al.
[0045] Further, the results of formation of boride according to
embodiments of the present invention are given in Table 2.
TABLE-US-00002 TABLE 2 Ti:B = 1:1 Ti:B = x:1 Alloy TiB.sub.2 Alloy
TiB.sub.2 Content 1 wt % Al--1Ti--1B 1.45 Al--2.3Ti--1B 3.21 of B 2
wt % A2--1Ti--2B 2.9 Al--4.5Ti--2B 6.3 3 wt % Al--3Ti--3B 4.36
Al--6.7Ti--3B 9.64
[0046] As shown in Table 2, according to the present invention, the
amount of boride is present in the range of 1.45 to 9.64. From the
results, it is preferred to provide the ratio of Ti/B between about
2.about.2.5:1.
[0047] FIG. 1 is a graph showing the elasticity of a high elastic
aluminum alloy according to an embodiment of the present invention.
As demonstrated in the graph of FIG. 1, when the content of TiB2 is
9.64%, the elastic modulus of an aluminum alloy is increased 45%
from 68 GPa to 98.5 GPa.
[0048] The aluminum alloy of the present invention can be formed by
any suitable methods, and is preferably formed by continuous
casting. Continuous casting is a casting method of continuously
injecting molten metal into a mold and solidifying the injected
molten metal. Such casting is generally used to produce
plate-shaped, bar-shaped or line-shaped billets. In the continuous
casting method, a molten solution is poured into the top of a mold
to form an ingot, and the ingot is continuously rapidly cooled and
drawn to produce long billets having a length of several meters to
several tens of meters. When an alloy is made by continuous
casting, the temperature of a tundish (i.e. a broad, open container
with one or more holes in the bottom conventionally used in casting
metals) must be controlled at the time of solidifying a molten
solution (Al--Si--Mg--Cu) because the molten solution may be
changed.
[0049] When the molten solution is charged in the tundish, the
inlet of the tundish is heated to about 650.degree. C. or more to
prevent the molten solution from being solidified by rapid cooling,
and the temperature of the outlet of the tundish is maintained at
about 300.about.350.degree. C. to discharge the molten solution in
a mush state. This procedure is necessary for maintaining the shape
of billets without downwardly flowing the molten solution
continuously injected into the top of the tundish. Continuous
casting exhibits a rapid cooling rate compared to other casting
methods, so this continuous casting is advantageous in increasing
the content of solute atoms and in improving the fineness and
uniformity of the texture of the alloy.
[0050] According to the present invention, elasticity of an alloy
is maximized by adding CNT to a high elastic alloy, by preventing
the CNT from being damaged in a high-temperature molten aluminum
solution, and by uniformly dispersing the boride compound formed by
the spontaneous reaction with CNT in the aluminum molten
solution.
[0051] According to various embodiments, the aluminum alloy may
further include about 2.about.7 vol % of CNT. The CNT may be coated
with one or more metal oxides, which can be selected from any known
metal oxides.
[0052] According to an exemplary embodiment of the present
invention, when 2.3Ti-1B and 5 vol % of CNT were added to Al-16Si,
the final elastic modulus thereof was 112.5 Gpa. Further, when
2.3Ti-1B and 5 vol % of CNT were added to Al-20Si, the final
elastic modulus thereof was 118.5 GPa.
[0053] In this case, it is preferred that the content of CNT be
about 2.about.7 vol %. When CNT is added in an amount of at least 2
vol %, the elastic modulus of the aluminum alloy can be adjusted to
105 GPa, thus obtaining an aluminum alloy having physical
properties equal to those of cast iron. However, when CNT is used
in an amount of more than 7 vol % during casting, there is a
problem in that the CNT is not sufficiently melted and dispersed.
As a result, the thus obtained aluminum alloy is not suitable as a
material for casting.
[0054] FIG. 3 is a flowchart showing a method of manufacturing a
high elastic aluminum alloy according to an embodiment of the
present invention. The method of manufacturing a high elastic
aluminum alloy according to the present invention generally
includes the steps of: coating CNT with metal oxide (S100);
introducing the CNT into an aluminum molten solution together with
inert gas and stirring the mixture (S200); and forming the aluminum
alloy using continuous casting (S500).
[0055] In particular, first, an aluminum molten solution is
prepared that preferably uses aluminum mother alloys of
Al-(5.about.10 wt %)Ti and Al-(2.about.10 wt %)B, wherein the ratio
of Ti/B is adjusted in the range of about 2.about.2.5:1.
[0056] Subsequently, CNT is coated with one or more metal oxides,
such as SiO.sub.2, TiO.sub.2 or the like, to a thickness of about
20.about.50 nm to prevent the CNT from being damaged in the
high-temperature aluminum molten solution (S100). Preferably, the
CNT is completely coated with the one or more metal oxides.
[0057] Subsequently, the coated CNT is introduced into the aluminum
molten solution 10 together with inert gas, and then stirred at a
high rotation speed of about 500.about.1500 rpm, for example, using
a double stirrer 20 shown in FIG. 2, to uniformly disperse the CNT
and the boride compound in the aluminum molten solution 10
(S200).
[0058] Subsequently, thermal insulation and runner transportation
are performed (S300), followed by vibrating the aluminum molten
solution on a casting table during the continuous casting before
injection into a mold (S400). The casting table contributes to the
improvement of uniformity of reinforced particles by vibrating the
aluminum molten solution before it is injected into a mold.
[0059] As such, the uniformity of the high elastic aluminum alloy
can be improved by the rapid cooling rate in continuous casting,
the high-speed rotation of the double stirrer and the vibration of
the aluminum molten solution on the casting table.
[0060] As described above, according to the present invention, the
improvement of elasticity of the aluminum alloy can be maximized by
maximizing the formation of a boride compound and by adding CNT to
the high elastic alloy
[0061] Further, according to the present invention, it is possible
to prevent CNT from being damaged in a high-temperature molten
aluminum solution. Still further, according to the present
invention, the boride compound formed by the spontaneous reaction
with CNT can be uniformly dispersed in the aluminum molten
solution.
[0062] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *