U.S. patent application number 10/529291 was filed with the patent office on 2006-05-18 for method and apparatus for producing amorphous alloy sheet, and amorphous alloy sheet produced using the same.
Invention is credited to Chang Kyu Kim, Nack Joon Kim, Dong Geun Lee, Han Sang Lee, Jung Gu Lee, Sunghak Lee, Sung Soo Park, Young Soo Park.
Application Number | 20060102315 10/529291 |
Document ID | / |
Family ID | 36384969 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060102315 |
Kind Code |
A1 |
Lee; Jung Gu ; et
al. |
May 18, 2006 |
Method and apparatus for producing amorphous alloy sheet, and
amorphous alloy sheet produced using the same
Abstract
The present invention provides a method for producing a bulk
amorphous alloy sheet with high quality at low production cost, by
which an alloy melt can be directly transformed into a sheet form
without using other additional processes. The method comprises
preparing a melt containing alloy components; feeding the melt into
a gap defined between two rolls, which rotate in opposite direction
to each other, and each of which is provided with heat exchange
means; and cooling the melt at a cooling rate higher than the
critical cooling rate for transformation of the melt into an
amorphous solid phase, when the melt passes through the gap defined
between the two rolls. The present invention also provides an
apparatus for producing a bulk amorphous alloy sheet with high
quality at low production cost, and a bulk amorphous alloy
sheet.
Inventors: |
Lee; Jung Gu;
(Kyungsangbuk-do, KR) ; Park; Sung Soo;
(Kyungsangbuk-do, KR) ; Lee; Dong Geun;
(Kyungsangbuk-do, KR) ; Kim; Nack Joon;
(Kyungsangbuk-do, KR) ; Park; Young Soo;
(Kyungsangbuk-do, KR) ; Lee; Sunghak;
(Kyungsangbuk-do, KR) ; Kim; Chang Kyu;
(Kyungsangbuk-do, KR) ; Lee; Han Sang;
(Kyungsangbuk-do, KR) |
Correspondence
Address: |
ROTHWELL, FIGG, ERNST & MANBECK, P.C.
1425 K STREET, N.W.
SUITE 800
WASHINGTON
DC
20005
US
|
Family ID: |
36384969 |
Appl. No.: |
10/529291 |
Filed: |
September 26, 2003 |
PCT Filed: |
September 26, 2003 |
PCT NO: |
PCT/KR03/01966 |
371 Date: |
March 25, 2005 |
Current U.S.
Class: |
164/463 ;
148/561; 164/480 |
Current CPC
Class: |
B22D 11/0697 20130101;
B22D 11/0622 20130101; B22D 11/0682 20130101; B22D 11/112 20130101;
C22C 45/001 20130101 |
Class at
Publication: |
164/463 ;
164/480; 148/561 |
International
Class: |
B22D 25/00 20060101
B22D025/00; B22D 11/06 20060101 B22D011/06; C22C 45/00 20060101
C22C045/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2002 |
KR |
10-2002-0058764 |
Aug 22, 2003 |
KR |
10-2003-0058337 |
Claims
1. A method for producing a bulk amorphous alloy sheet, the method
comprising: preparing a melt containing alloy components; feeding
the melt directly into a gap defined between two rolls, which
rotate in opposite direction to each other, and each of which is
provided with heat exchange means; and cooling the melt at a
cooling rate higher than the critical cooling rate for
transformation of the melt into an amorphous solid phase, when the
melt passes through the gap defined between the two rolls, wherein
the rotation rate of the two rolls is in the range of 1 to 10
cm/sec, and the gap between the two rolls is in the range of 0.5 to
20 mm.
2. The method according to claim 1, wherein the step of preparing
the melt is carried out in an inert atmosphere.
3. The method according to claim 1, wherein the heat exchange means
is a circuit for flow of a cooling fluid.
4. The method according to claim 3, wherein the cooling fluid is
cooling water or cooling oil.
5. The method according to claim 1, wherein the two rolls are made
of a copper-based alloy containing material.
6. The method according to claim 1, wherein the temperature of the
melt to be fed into the gap defined between the two rolls is in the
range of 500 to 1,500.degree. C., the surface temperature of the
two rolls is in the range of 15 to 30.degree. C.
7. The method according to claim 1, wherein the two rolls are
arranged in such a manner that an angle defined by the horizontal
and a straight line connecting the respective rotation centers of
the two rolls, is in the range of 0 to 90 degrees.
8. A bulk amorphous alloy sheet prepared by the method according to
claim 1.
9. The bulk amorphous alloy sheet according to claims 8, which has
a thickness of 0.5 to 20 mm.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a 35 U.S.C. .sctn. 371 National Phase
Entry Application from PCT/KR03/001966, filed Sep. 26, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for producing an
amorphous or noncrystalline alloy, and more particularly, to a
method for producing a bulk amorphous alloy sheet.
[0004] 2. Description of the Related Art
[0005] An amorphous alloy is a material that has a liquid
phase-like microstructure with no crystallinity due to disordered
arrangement of atoms, and contains no crystalline imperfections
such as grain boundary and dislocation, unlike a conventional
crystalline alloy. Therefore, an amorphous alloy is a significantly
improved material in terms of mechanical properties such as
strength, magnetic properties, corrosion resistance, and the
like.
[0006] Due to the above-described excellent characteristics, there
have been increasing interests on amorphous alloy materials, in
particular, an amorphous alloy sheet as a new material that can be
used for various purposes in various industrial fields including
the aero-space industry, the nuclear power equipment industry, and
the defense industry. However, despite the demands in various
industrial fields, there have not yet been developments on
efficient and industrially applicable methods for mass-producing an
amorphous alloy sheet.
[0007] As for conventional processes for producing amorphous
alloys, there are die casting and permanent mold casting. However,
die casting and permanent mold casting are inappropriate to
mass-produce amorphous alloy sheets that can be used for various
purposes, as well as are not cost effective.
[0008] A melt spinning process is another conventional method for
the amorphous alloy production. However, since this process is
intended for production of an amorphous alloy material in the form
of an ultra-thin strip of about 0.05 mm or less in thickness, it is
not suitable for production of a bulk amorphous alloy sheet.
[0009] A strip casting process is a process that produces a metal
material into a sheet form. This process has advantages such as
equipment investment cost reduction, low energy consumption, and
high proportion of products relative to raw materials. However, it
has been understood that a conventional strip casting process is
not suitable for production of an amorphous alloy sheet, and thus,
no reports have been made on examples of use of a conventional
strip casting process for production of an amorphous alloy sheet.
Even probabilities that a conventional strip casting process may be
used in production of an amorphous alloy sheet have been
denied.
[0010] Therefore, in order for a bulk amorphous alloy with good
properties to be used for more various purposes in more various
industrial fields, development of a method for mass-producing a
bulk amorphous alloy, in a sheet form with high utility, at low
production cost, is required.
SUMMARY OF THE INVENTION
[0011] The present invention provides a method for producing a bulk
amorphous alloy sheet with high quality at low production cost, by
which an alloy melt can be directly transformed into a sheet form
without using other additional processes.
[0012] The present invention also provides an apparatus for
producing a bulk amorphous alloy sheet with high quality at low
production cost, and a bulk amorphous alloy sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
[0014] FIG. 1 is FIG. 1 is a diagram of a method for producing an
amorphous alloy sheet according to the present invention;
[0015] FIG. 2 is a schematic view of an apparatus for producing an
amorphous alloy sheet according to an embodiment of the present
invention;
[0016] FIG. 3 is a diagram showing transformation of an amorphous
alloy melt into a sheet form that is carried out in two rolls of
the apparatus of FIG. 2;
[0017] FIG. 4 is a diagram showing adjustment of a gap between two
rolls in the apparatus of FIG. 2;
[0018] FIG. 5 is a diagram showing an example of an arrangement
structure of two rolls in the apparatus of FIG. 2 according to an
angle defined by the horizontal and a straight line connecting the
respective rotation centers of the two rolls;
[0019] FIG. 6 is an X-ray diffraction pattern of an amorphous alloy
sheet produced according to Example of the present invention;
and
[0020] FIG. 7 is an optical microphotograph of the microstructure
of an amorphous alloy sheet produced according to Example of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] A method for producing an amorphous alloy sheet according to
the present invention comprises: preparing a melt containing alloy
components; feeding the melt into a gap defined between two rolls,
which rotate in opposite direction to each other, and each of which
is provided with heat exchange means; and cooling the melt at a
cooling rate higher than the critical cooling rate for
transformation of the melt into an amorphous solid phase when the
melt passes through the gap defined between the two rolls.
[0022] An apparatus for producing an amorphous alloy sheet
according to the present invention comprises: a crucible for
receiving a melt containing alloy components, which is provided
with a melt outlet; two rolls, each of which is provided with heat
exchange means to cool the melt at a cooling rate higher than the
critical cooling rate for transformation of the melt into an
amorphous solid phase when the melt passes through a gap defined
between the two rolls; and a connecting channel for passing the
melt from the melt outlet of the crucible to the gap defined
between the two rolls.
[0023] Hereinafter, a method for producing an amorphous alloy sheet
according to the present invention will be described in detail.
FIG. 1 schematically shows a method for producing an amorphous
alloy sheet according to the present invention.
[0024] The step of preparing a melt can be carried out, for
example, using a melting furnace which is provided with heating
means suitable for melting alloy components and with a sealable
crucible.
[0025] The heating means provided in the melting furnace can be
operated in a heating manner such as resistance heating, arc
heating, induction heating, infrared heating, e-beam heating, and
laser heating, but is not limited thereto.
[0026] The step of preparing a melt can be carried out in an inert
or non-inert atmosphere. As for some specific alloys,
non-crystallization requires an inert atmosphere. In this case, it
is preferable to carry out the step of preparing a melt in an inert
atmosphere.
[0027] In a case where the step of preparing a melt is carried out
using the aforementioned melting furnace, an inert atmosphere can
be accomplished by feeding an inert gas into the melting furnace.
Examples of an inert gas to be used herein include helium, neon,
argon, krypton, xenon, radon, nitrogen, or a mixture thereof.
Alternatively, an inert atmosphere can be accomplished by
maintaining the sealable crucible in a vacuum state.
[0028] The step of preparing a melt can also be carried out in
other specific atmospheres required for specific alloys. In this
case, gases required for formation of such specific atmospheres are
fed into the crucible.
[0029] A melt thus prepared is fed into a gap defined between the
two rolls, which rotate in opposite direction to each other, and
each of which is provided with heat exchange means. According to an
embodiment of the present invention, the melting furnace can have a
melt nozzle, which is located to be near the two rolls. The melt is
fed into the gap defined between the two rolls through the melt
nozzle.
[0030] The melt fed into the gap defined between the two rolls is
cooled at a cooling rate higher than the critical cooling rate for
transformation of the melt into an amorphous phase. In order to
accomplish such rapid cooling, the two rolls may be made of a
material with good heat conductivity and may be provided with heat
exchange means. A copper-based alloy material can be used as a good
heat conductive material for the two rolls, but is not limited
thereto. The heat exchange means to be installed in the two rolls
may be, for example, a circuit for flow of a cooling fluid, but is
not limited thereto. The cooling fluid may be cooling water or
cooling oil.
[0031] There are no particular limitations on the diameter and
rotation rate of the two rolls. However, in view of a heat
transfer, a linear velocity at the circumferences of the two rolls
may be in the range of about 1 to 10 cm/sec. Also, there are no
particular limitations on the gap between the two rolls. However,
in view of a heat transfer and/or a thickness of a desired sheet,
the gap between the two rolls may be in the range of about 0.5 to
20 mm. As long as an object of the present invention can be
accomplished, the gap between the two rolls may also be less than
about 0.5 mm or more than about 20 mm. In addition, there are no
particular limitations on the width of the rolls. The width of the
rolls can be appropriately determined depending on the maximum
width of a desired sheet.
[0032] Generally, the critical cooling rate for amorphous phase
formation varies depending on types of alloys. An appropriate
cooling rate for a specific alloy can be realized by adjusting the
circulation rate of a cooling fluid, the rotation rate of the two
rolls, the gap between the two rolls, the temperature of the melt,
etc.
[0033] The melt is cast into an amorphous alloy sheet by the
above-described rapid cooling and then removed away from the rolls.
Due to rolling effect by the two rolls, generation of cracks and
air gaps is prevented, which was identified by X-ray diffraction
and microscope image analysis results.
[0034] In a method of the present invention, if the temperature of
the melt to be fed into the gap defined between the two rolls is
too low, melt feeding is not smoothly carried out, and thus, it is
difficult to produce a sheet. On the other hand, if it is too high,
the melt is not sufficiently cooled even using the two rolls and
the heat exchange means, and thus, it is difficult to produce an
amorphous sheet.
[0035] If the surface temperature of the two rolls is too low, the
melt is not cooled by a uniform proportion, and thus, the loading
of the melt is not smoothly carried out. Furthermore, cracks may be
caused in edges of a formed sheet. On the other hand, if it is too
high, it is difficult to obtain a cooling rate above the critical
cooling rate.
[0036] If the rotation rate of the two rolls is too slow,
solidification of the melt may be completed before an amorphous
solid alloy is completely removed away from the rolls, and thus,
operation of the rolls may be suspended. On the other hand, if it
is too fast, uniform cooling is not sufficiently accomplished, and
thus, it is difficult to produce a sheet with high quality.
[0037] If the gap between the two rolls is too small, it is
difficult to produce a bulk amorphous alloy sheet. Furthermore, due
to excess feeding of the melt, other process factors may be
adversely affected. At the same time, cracks may be caused in edges
of a formed sheet. On the other hand, if it is too large, a sheet
may be formed to an excessive thickness, and thus, a cooling rate
above the critical cooling rate cannot be realized at the center
portion of a sheet. As a result, it is difficult to obtain a
uniform, high quality amorphous alloy.
[0038] By way of an illustrative example, in case of a copper-based
amorphous alloy comprised of 45 to 49 atomic % Cu, 32-34 atomic %
Ti, 10-13 atomic % Zr, 5-7 atomic % Ni, 1-3 atomic % Sn, and 0.5-2
atomic % Si, the temperature of the melt to be fed into the gap
defined between the two rolls may be set to a range of about 500 to
1,500.degree. C., the surface temperature of the two rolls a range
of about 15 to 30.degree. C., the rotation rate of the two rolls a
range of about 1 to 10 cm/sec, and the gap between the two rolls a
range of about 0.5 to 20 mm.
[0039] It should be understood that the method of the present
invention can be applied to all types of alloys capable of being
transformed into an amorphous phase, in addition to the above
copper-based alloy.
[0040] Hereinafter, an apparatus for producing an amorphous alloy
sheet according to the present invention will be described in
detail. The apparatus can be efficiently used in production of an
amorphous alloy sheet according to the above-described method.
[0041] An apparatus for producing an amorphous alloy sheet
according to the present invention comprises: a crucible for
receiving a melt containing alloy components and provided with a
melt outlet; two rolls, each of which is provided with heat
exchange means to cool the melt at a cooling rate higher than the
critical cooling rate for transformation of the melt into an
amorphous solid phase when the melt passes through a gap defined
between the two rolls; and a connecting channel for passing the
melt from the melt outlet of the crucible to the gap defined
between the two rolls.
[0042] FIG. 2 schematically shows an apparatus for producing an
amorphous alloy sheet comprising a crucible 10, a connecting
channel 20, and two rolls 30, according to an embodiment of the
present invention.
[0043] The crucible 10 may be a melting crucible that can control
an atmosphere therein. As shown in FIG. 2, the crucible 10 receives
a melt containing alloy components and is provided with a melt
outlet 18. The crucible 10 also comprises a gas supply unit 16 for
controlling an atmosphere in the crucible 10 and a heating unit 14
for melting alloy components to prepare the melt and maintaining
the temperature of the prepared melt.
[0044] The crucible 10 may further comprise a stopper 12 that can
open and shut the melt outlet 18 to control the release of the
melt.
[0045] The connecting channel 20 may comprise a heating unit 22
that can maintain the temperature of the melt in the connecting
channel 20 while the melt flows from the crucible 10 to the gap
defined between the rolls 30. The connecting channel 20 may further
comprise a gas supply unit 24 that can control an atmosphere in the
connecting channel 20.
[0046] The two rolls 30 may be made of a copper-based alloy
containing material. However, since there are no particular
limitations on a material for the two rolls, the two rolls may also
be made of other types of materials with good heat
conductivity.
[0047] Each of the two rolls 30 may comprise a circuit 32 for flow
of a cooling fluid as the heat exchange means. The cooling fluid
may be cooling water or cooling oil.
[0048] FIG. 3 is a detailed view of the two rolls of FIG. 2 and
schematically shows transformation of the melt into a solid sheet
by cooling when the melt passes through the gap defined between the
two rolls. An alloy melt, which can be transformed into an
amorphous phase, is fed into the gap defined between the two rolls
30 in rotation, then the melt is cooled while being in contact with
the two rolls 30 and cast into a solid sheet. The sheet thus
obtained is removed away from the two rolls 30 by rotation of the
two rolls 30. At this time, in order for the cooling rate of the
melt by contact of it with the two rolls 30 to be higher than the
critical cooling rate for formation of an amorphous phase, the two
rolls 30 is cooled by the heat exchange means. The alloy melt is
strongly pressed by the two rolls 30 to cast into an amorphous
alloy sheet and then is removed away from the two rolls 30.
[0049] If the gap between the two rolls is too small, it is
difficult to produce a bulk amorphous alloy sheet. Furthermore, due
to excess feeding of the melt, other process factors may be
adversely affected. At the same time, cracks may be formed at the
edges of a formed sheet. On the other hand, if it is too large, a
cooling rate above the critical cooling rate cannot be realized in
a center portion of a sheet. As a result, it is difficult to obtain
a uniform, high quality amorphous alloy sheet. In this regard, the
gap between the two rolls 30 may be in the range of about 0.5 to 20
mm. The two rolls may be installed to be spaced apart at a
predetermined distance from each other, or may be installed in such
a way that the gap between the two rolls can be adjusted when
needed. FIG. 4 schematically shows adjustment of a gap between the
two rolls.
[0050] FIG. 5 schematically shows the structure of the two rolls
arranged in such a manner that an angle defined by the horizontal
and a straight line connecting the respective rotation centers of
the two rolls, is in the range of 0 to 90 degrees. The angle may
vary depending on characteristics of a melt such as fluidity. For
example, if the fluidity of a melt is high, the two rolls can be
vertically installed (i.e., the angle is 90 degrees) to smoothly
carry out horizontal supply of a melt and release of a sheet. On
the other hand, if the fluidity of a melt is insufficient, the two
rolls can be horizontally installed (i.e., the angle is 0 degrees)
to smoothly carry out vertical supply of a melt by gravity and
release of a sheet. The two rolls may be installed at a fixed angle
selected from the angle of 0 to 90 degrees or may be installed in
such a way that the angle can be adjusted in the range.
[0051] If the rotation rate of the two rolls is too slow,
solidification of a melt may be completed before an amorphous solid
alloy is completely removed away from the rolls, and thus,
operation of the rolls may be suspended. On the other hand, if it
is too fast, uniform cooling is not sufficiently accomplished, and
thus, it is difficult to produce a sheet with high quality. In this
regard, the two rolls may be installed in such a way to be operated
at a rotation rate of about 1 to 10 cm/sec. To this, the two rolls
may be connected to conventional driving means (not shown).
[0052] Hereinafter, a bulk amorphous alloy sheet according to the
present invention will be described in detail.
[0053] A bulk amorphous alloy sheet according to the present
invention is either a bulk alloy material that consists of fully
amorphous phase or a bulk alloy material that consists of composite
containing amorphous and crystalline phases.
[0054] The term, "bulk sheet" as used herein indicates that an
amorphous alloy of the present invention is processed into a
material which has structural continuity and a relatively large
two- or three-dimensional dimension, not into a thin film (of 100
.mu.m or less in thickness, for example) dimension. For example, an
amorphous alloy sheet of the present invention may have a thickness
of about 0.5 to 20 mm, but is not limited thereto. Also, there are
no particular limitations on the width, length, and shape of an
amorphous alloy sheet of the present invention. Such a bulk
amorphous alloy sheet can be used for various purposes. Also,
attentions have been paid to such a bulk amorphous alloy sheet as a
new material in the whole industrial fields including the nuclear
power equipment industry (metal pipe), the defense industry
(amorphous metal-tungsten composite penetrator), the sports
equipment industry (golf clubs), and the aero-space industry.
[0055] The bulk amorphous alloy sheet according to the present
invention can be produced by the above-mentioned method according
to the present invention.
[0056] The bulk amorphous alloy sheet according to the present
invention may consist of composite containing amorphous and
crystalline phases. In that case, the volume or weight ratio of
amorphous phase to crystalline phase in the composite can be
controlled by varying the process conditions in the above-mentioned
method according to the present invention.
[0057] The bulk amorphous alloy sheet according to the present
invention may typically contain an amorphous phase of about 90% by
volume or more, preferably about 96% by volume or more.
[0058] In experiments of producing an amorphous alloy sheet using
the above-described method and apparatus of the present invention,
amorphous alloy sheets containing an amorphous phase of at least
about 96% by volume, even about 100% by volume were obtained.
Typically, an amorphous alloy sheet of the present invention may
contain an amorphous phase of about 96.0% by volume to about 99.9%
by volume.
[0059] On the other hand, the bulk amorphous alloy sheet according
to the present invention may also contain amorphous phase of about
90% by volume or less.
[0060] There are no particular limitations on alloy compositions to
be used in a method and an apparatus for producing an amorphous
alloy sheet of the present invention, and an amorphous alloy sheet
produced by the method and apparatus. For example, there may be
used amorphous alloy compositions such as
Cu.sub.47Ti.sub.34Zr.sub.11Ni.sub.8 [S. C. Glade, W. L. Johnson: J.
Appl. Phys., vol. 89 (2001) pp. 1573-1579];
Cu.sub.47Ti.sub.33Zr.sub.11Ni.sub.8Si.sub.1 [M. Calin: Scripta
Mater., in press (2003)];
Cu.sub.47Ti.sub.33Zr.sub.11Ni.sub.6Sn.sub.2Si.sub.1 [D. H. Bae, H.
K. Lim, S. H. Kim, D. H. Kim and W. T. Kim: Acta Materialia, vol.
50 (2002) pp. 1749-1759]; Cu.sub.60Zr.sub.30Ti.sub.10,
Cu.sub.60Hf.sub.25Ti.sub.15 [Akihisa Inoue, Wei Zhang, Tao Zhang
and Kei Kurosaka: J. of Non-Crystalline Solids, vol. 304 (2002) pp.
200-209]; Zr.sub.57Nb.sub.5Al.sub.10Cu.sub.15.4Ni.sub.12.6 [H.
Choi-Yim, R. D. Conner, F. Szuecs and W. L. Johnson: Acta
Materialia, vol. 50 (2002) pp. 2737-2745];
Zr.sub.41Ti.sub.14Cu.sub.12Ni.sub.10Be.sub.23 [J. Schroers, R.
Busch, S. Bossuyt and W. L. Johnson: Mater. Sci. & Eng. A.,
vol. 304-306 (2001) pp. 287-291]; and
Zr.sub.65A.sub.7.5Ni.sub.10Cu.sub.12.5Pd.sub.5 [M. Sherif
El-Eskandarany, J. Saida and A. Inoue: Acta Materialia, vol. 51
(2003) pp. 4519-4532].
[0061] Hereinafter, the present invention will be described more
specifically by Example. However, the following Example is provided
only for illustration and thus the present invention is not limited
thereto.
EXAMPLE
[0062] In this Example, a copper-based alloy with its chemical
composition presented in Table 1 was used as a mother alloy. An
apparatus shown in FIG. 2 was used. TABLE-US-00001 TABLE 1 Chemical
composition of mother alloy Elements Cu Ti Zr Ni Sn Si Content
(atomic %) 47 33 11 6 2 1
3 kg of a copper-based mother alloy was loaded into a high purity
graphite crucible and then maintained at a temperature of about
1,400.degree. C. for about 60 minutes to be completely melted into
a liquid phase. A copper-based mother alloy melt thus obtained was
discharged while being maintained at a temperature of about
1,200.degree. C., and then transferred into an inlet between
rolling rolls of the strip casing apparatus
[0063] The rotation rate, surface temperature, and gap of the
rolling rolls were about 2.0 cm/sec, about 20.degree. C., and about
2 mm, respectively. Under these process conditions, amorphous alloy
sheets of 1 m in length, 10 cm in width, and 2 mm in thickness were
prepared.
[0064] The non-crystallinity of the copper-based amorphous alloy
sheets thus prepared was determined by X-ray diffraction analysis
and the result is presented in FIG. 6. As shown in FIG. 6, the
amorphous alloy sheets obtained in Example were in an amorphous
phase that contained the small volume fraction of a crystalline
phase.
[0065] The cross-sections of the copper-based amorphous alloy
sheets obtained in Example were subjected to an optical microscope
image analysis and the resultant cross-sectional microphotograph is
presented in FIG. 7. As shown in FIG. 7, no air gaps or cracks that
may be caused by solidification and contraction of a melt were
observed in the alloy sheets obtained in Example. In addition, the
amount of an amorphous phase in the amorphous alloy sheets was
evaluated. According to the evaluation result, the alloy sheets
obtained in Example contained an amorphous phase of about 96% by
volume or more. Therefore, it was demonstrated that the alloy
sheets obtained in Example are excellent amorphous alloy
sheets.
[0066] As apparent from the above descriptions, a method and an
apparatus for producing an amorphous alloy sheet according to the
present invention is used in production of an amorphous alloy sheet
of high quality, in which the generation of air gaps and cracks is
remarkably reduced.
[0067] According to a method and an apparatus for producing an
amorphous alloy sheet of the present invention, an amorphous alloy
sheet can be directly prepared from a melt without using a separate
process. Therefore, the amorphous alloy sheet, which has very high
industrial applicability, can be produced in large scale and at
very low cost. Consequently, the application range of an amorphous
alloy can be economically extended.
* * * * *