KR102456026B1 - Apparatus for measurement of glass forming ability and measurement methods of using the same - Google Patents

Abstract

a mold formed in a disk shape by combining an upper mold and a lower mold, the mold having a cavity including a central injection space into which the molten metal is injected and an amorphous formation space formed around the injection space; and a rotating part for rotating the mold so that centrifugal force is applied to the molten metal, wherein the cross-sectional width of the amorphous forming space has a gradient that gradually decreases toward the edge. A measurement method is provided.

Description

Amorphous forming ability measuring apparatus and amorphous forming ability measuring method using the same {Apparatus for measurement of glass forming ability and measurement methods of using the same}

The present invention relates to an apparatus for measuring amorphous formation ability and a method for measuring amorphous formation ability using the same, and has high reproducibility and low variation according to researchers, so reliability can be increased, and amorphous formation ability capable of deriving the maximum diameter of an amorphous alloy at an arbitrary cooling rate It relates to a measuring device and a method for measuring amorphous formation ability using the same.

Metallic glass alloy and amorphous alloy refer to a metal material having a disordered structure in a liquid state without crystallographically regular periodicity even at room temperature. Metal-based vitreous alloys and amorphous alloys can be said to have very superior properties such as tensile strength, hardness, corrosion resistance, abrasion resistance, and Young's modulus compared to metals having a general crystal structure.

However, the metal-based glassy alloy or the amorphous alloy has a critical thickness that can maintain the amorphous phase throughout the sample depending on the alloy composition. The critical thickness with 100% amorphous phase even at room temperature is determined by the cooling rate in the process of solidification from a liquid state to a solid state. define. The amorphous forming ability controlling factors include the glass transition temperature (T _g ), the crystallization initiation temperature (T _x ), the characteristic temperature of the amorphous material such as the melting point (T _m ), the difference in the atomic size of the alloy components, and the viscosity of the supercooled liquid phase. .

In general, the amorphous formation ability of bulk amorphous alloys can be compared with each other through the critical cooling rate (Rc), and since it is difficult to measure the exact critical cooling rate by a simple method, it is relatively easy to measure the maximum diameter (thickness) of the bulk amorphous alloy. through the amorphous formation ability. Therefore, there is a need for an apparatus capable of measuring the amorphous forming ability of a metallic glassy alloy or an amorphous alloy, which is known in Japanese Patent Registration No. 3925564.

A device such as the above patent may be generally shown as in FIG. 1 . 1 shows a conventional amorphous forming ability measuring apparatus, a molten metallic glassy alloy or a molten metal 10a is injected into a pure copper mold 20 having a hollow portion in a conical or cylindrical shape under an inert gas atmosphere of argon. The vacuum pump 30 connected to the hollow part of the pure copper mold 20 forms the inside of the hollow part at a negative pressure, so that the molten metal-based glassy alloy or the molten metal 10a is injected. The molten metal-based vitreous alloy or the molten metal 10a is cooled with injection due to the pure copper mold 20 and formed into a conical or cylindrical metallic vitreous alloy or an amorphous alloy. That is, the amorphous forming ability is measured by manufacturing a rod or conical type test piece 10 for each thickness with respect to a trace alloy of several grams (g) by suction casting using the pure copper mold 20 . Measurement of the amorphous forming ability as described above may not be possible when the specimen is 1 mm or less. In addition, international standards for standard process conditions for the measurement of amorphous forming ability are insufficient, so there is no international standard for this so far. Therefore, although measurement methods are being studied in the relevant field, the above methods have limitations in that the measurement process is cumbersome and reproducible, and the reliability is low because deviations may occur depending on the researcher.

Japanese Patent No. 3925564 (Registration Date: 2007.03.09) Korean Patent Registration No. 10-0631466 (Registration Date: September 27, 2006)

The technical problem to be achieved by the present invention is to provide an amorphous-forming ability measuring apparatus and amorphous-forming ability measuring method using the same, which can simultaneously manufacture specimens of various thicknesses, have high reproducibility, and have low variation according to researchers, thereby increasing reliability.

In addition, the technical problem to be achieved by the present invention is that it is possible to derive the maximum diameter (thickness) of a metallic glassy alloy or an amorphous alloy at an arbitrary cooling rate, and an amorphous forming ability measuring device capable of increasing accuracy and an amorphous forming ability measuring method using the same purpose is to provide.

The object of the present invention is not limited to the object mentioned above, and other objects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description.

In order to solve the above problem, the present invention is formed in a disk shape by combining an upper mold and a lower mold, and includes an injection space in the center into which molten metal is injected and an amorphous formation space formed around the injection space. ) having a mold; and a rotating part that rotates the mold so that centrifugal force is applied to the molten metal, wherein the cross-sectional width of the amorphous forming space has an inclination gradient that gradually decreases toward the edge. .

The amorphous-forming ability measuring device includes: a dissolving unit for dissolving the master alloy to measure the amorphous-forming ability; and an injection unit positioned between the dissolving unit and the mold to inject the molten metal into the mold.

The mold may change a rotation angular velocity, a radius of the cavity, and an inclination gradient angle of the cavity according to the type of the molten metal.

The cavity may have an inclination gradient in which the cross-sectional width of the implantation space gradually decreases toward the edge, and the inclination gradient angle of the implantation space may be greater than the inclination gradient angle of the amorphous formation space.

In addition, in order to solve the above problem, the present invention is formed in a disk shape by combining an upper mold and a lower mold, and having a cavity including a central injection space and an amorphous formation space formed around the injection space. pouring the molten metal into the mold; rotating the mold so that a centrifugal force is applied to the molten metal, and cooling the mold through the mold while the molten metal is introduced into the amorphous formation space by the centrifugal force caused by the rotation; manufacturing an amorphous metal whose thickness is continuously changed to correspond to the amorphous formation space according to the inclination gradient of the amorphous formation space whose cross-sectional width gradually decreases toward the edge; And it can provide a method for measuring the ability to form amorphous, characterized in that for detecting the thickness at which crystallization starts in the prepared amorphous metal specimen.

Rotating the mold may include rotating the mold by changing the rotation angular velocity or changing the radius of the cavity and the inclination gradient angle of the cavity according to the type of the molten metal.

The cavity may have an inclination gradient in which the cross-sectional width of the implantation space gradually decreases toward the edge, and the inclination gradient angle of the implantation space may be greater than that of the amorphous formation space.

The amorphous forming ability measuring apparatus and the amorphous forming ability measuring method using the same according to an embodiment of the present invention have a high reproducibility by simultaneously manufacturing specimens of various thicknesses by having a mold part that rotates with a slope gradient, and the variation according to the researcher is low, so the reliability can be increased. there are advantages to In addition, it is possible to derive the maximum diameter of the metallic glass alloy or an amorphous alloy from the specimen at any cooling rate, there is an effect of increasing the accuracy.

1 is a view showing a conventional amorphous forming ability measuring apparatus and a photograph showing a specimen;
2 is a perspective view showing an amorphous forming ability measuring apparatus according to an embodiment of the present invention;
3 is a cross-sectional view showing a mold of an amorphous forming ability measuring device according to an embodiment of the present invention and a perspective view showing a specimen;
4 is a cross-sectional view showing a specimen manufactured by an amorphous forming ability measuring device according to an embodiment of the present invention;
5 is a process flow diagram illustrating a method for measuring an amorphous formation ability according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the length, thickness, etc. of layers and regions may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

1 is a view showing a conventional amorphous forming capacity measuring apparatus and a photograph showing a specimen, FIG. 2 is a perspective view showing an amorphous forming capacity measuring apparatus according to an embodiment of the present invention, and FIG. 3 is an amorphous forming capacity measuring apparatus according to an embodiment of the present invention A cross-sectional view showing a mold of the and a perspective view showing a specimen, FIG. 4 is a cross-sectional view showing a specimen manufactured by an amorphous forming ability measuring device according to an embodiment of the present invention, and FIG. 5 is a process showing an amorphous forming capacity measuring method according to an embodiment of the present invention It is a flow chart.

2 to 4, in the amorphous forming ability measuring apparatus 100 according to an embodiment of the present invention, the upper mold 131 and the lower mold 133 are combined to form a disk shape, and the molten metal 10a is injected. a mold 130 having a cavity 135 including a central injection space 135a and an amorphous formation space 135b formed around the injection space 135a; and a rotating part for rotating (R) the mold so that centrifugal force is applied to the molten metal 10a. Furthermore, the amorphous forming ability measuring device 100 includes a dissolving unit 110 for dissolving the master alloy 10b to measure the amorphous forming ability; and an injection unit 120 positioned between the dissolving unit 110 and the mold 130 to inject the molten metal 10a into the mold 130 . Here, it is self-evident that the injection into the cavity 135 of the mold may include all metal materials required to measure the amorphous forming ability.

In addition, the cross-sectional width d of the amorphous forming space 135b has a gradient that gradually decreases toward the edge, and the molten metal 10a flows into the amorphous forming space 135b due to the centrifugal force. Amorphous metal that is cooled through the mold 130 and whose thickness continuously changes corresponding to the amorphous formation space 135b is manufactured, and the thickness at which crystallization starts in the manufactured amorphous metal specimen 11 is detected and amorphized It may be to find the maximum thickness.

In detail, the melting unit 110 is heated to melt the crucible 112 in which the master alloy 10b is located, and the master alloy 10b located in the crucible 112 by being located around the crucible 112 . It may include means 114, for example, the heating means 114 may apply an induction coil.

The molten metal 10a may be injected into the cavity 135 of the mold. That is, the molten metal 10a may be injected into the injection space 135a at the center of the cavity 135 formed in a disk shape by combining the upper mold 131 and the lower mold 133, and the mold 130 is Centrifugal force is applied to the mold 130 by a rotating part (not shown) that rotates, so that the molten metal 10a may be filled in the amorphous formation space 135b formed around the injection space 135a. For example, 100 to 3000 g of the molten metal 10a may be injected into the cavity 135, and the upper mold 131 and the lower mold 133 are made of pure copper with high thermal conductivity to speed up the cooling rate. can

When the mold 130 rotates (R) by the rotating part, centrifugal force is generated, and the molten metal 10a can be filled to the edge of the mold 130 by the centrifugal force, that is, into the amorphous formation space 135b. have. The centrifugal force acting on each position of the mold 130 is defined as F = m ² r (where F = centrifugal force, m = mass, ω = angular velocity, r = distance from the center of the mold to each position], where the angular velocity is Since the centrifugal force acting can be arbitrarily controlled by increasing or increasing the radius of the mold, accurate amorphous forming ability can be measured even for an amorphous alloy having poor amorphous forming ability.

In this case, the cavity 135 has an inclination gradient in which the cross-sectional width of the injection space 135a gradually decreases toward the edge, and the inclination gradient angle θ of the injection space 135a is the amorphous formation space 135b. ) may be larger than the inclination gradient angle. Therefore, the molten metal 10a located in the injection space 135a can be made more smoothly without being caught in the filling of the amorphous formation space 135b by centrifugal force.

The molten metal 10a filled up to the amorphous forming space 135b by centrifugal force is cooled from the area in contact with the upper and lower molds, so that the amorphous alloy specimen 11 can be molded. That is, the metal 10a dissolved by the centrifugal force is rapidly filled in the amorphous formation space 135b and can be cooled as quickly as possible, and can be cooled faster than the known critical cooling rate, so that the maximum thickness that can produce amorphous is can be derived The evaluation of the degree of amorphous forming ability of an alloy having a specific composition generally indicates a relative value according to the cooling rate of a given rapid cooling process. Such amorphous formation ability depends on the composition of the alloy and the cooling rate, and in general, the cooling rate is inversely proportional to the casting thickness. .

In this case, in the present invention, unlike the prior art, it can be cast and molded in the form of a plate (10 in FIG. 3) having a conical cross-section, not a rod form, and the gap between the upper mold 131 and the lower mold 133 ( d), that is, the amorphous alloy specimen 11 molded according to the cross-sectional width d of the amorphous formation space 135b may have a cross-sectional shape having a slope gradient having a thickness of 100 μm to 5000 μm.

Therefore, in the case of a specimen of 1 mm or less, unlike the prior art in which it is impossible to measure the amorphous forming ability, the amorphous forming capacity measuring apparatus 100 of the present invention has the advantage of reproducibly measuring up to the micrometer unit. In addition, since the amorphous alloy specimen 11 has a cross section in which a draft angle is formed up to the circumferential end of the amorphous forming space 135b, it can be seen that specimens having various thicknesses are manufactured depending on the location, which can prevent the occurrence of deviations according to researchers. There is an advantage in that the maximum thickness of the amorphous alloy can be derived according to an arbitrary cooling temperature of the amorphous alloy, and the reliability of the measurement result can be increased.

The mold 130 applies centrifugal force to the molten amorphous alloy filled in the amorphous forming space 135b of the upper mold 131 and the lower mold 133 to increase the filling efficiency, thereby adjusting the height of the solidified amorphous alloy specimen and For uniform cooling, it may be rotated with a centrifugal force of 50 to 100 times the gravity acceleration. If it is less than 50 times the gravitational acceleration, the centrifugal force is low, so that it is not densely filled in the fine gap (d) of 100 μm, a discontinuous solidified layer is formed on the surface, and a non-uniformly cooled and solidified specimen can be obtained. It is preferable to have the above centrifugal force because the driving of the rotating part that rotates the mold 130 may be overloaded, and vibrations may be excessively generated, which causes a problem of preventing filling.

Furthermore, the mold 130 may change the rotational angular velocity of the mold 130, the radius of the cavity 135, and the inclination gradient angle of the cavity 135 according to the type of metal for which the amorphous forming ability is to be measured. have. The molten metal 10a injected into the mold 130 is cooled from the region in contact with the mold 130 and a specimen 11 can be formed, the rotation angular velocity of the mold 130, the radius of the cavity 135, By changing the inclination gradient angle of the cavity 135, specimens of various thicknesses are formed under different cooling conditions according to the type of the amorphous alloy, and there is an advantage in that the maximum thickness of the amorphous alloy can be derived at an arbitrary cooling rate.

Here, the cooling rate can be obtained by measuring the dendrite arm spacing (DAS) of the crystalline alloy. The lamellar spacing in the lamellar tissue satisfies λ ² R = C (C is a constant), and the cooling rate can be obtained by measuring the lamellar spacing using the Jackson-Hunt method. By observing the prepared specimen of the amorphous alloy with an optical microscope or an electron microscope, it is possible to determine whether or not grains are formed, so that the maximum thickness of amorphization can be found. In this case, the method of measuring the cooling rate may be obtained by measuring the dendrite arm spacing (DAS) of a crystalline alloy rather than an amorphous alloy.

4 is a cross-sectional view showing a specimen manufactured by an amorphous forming ability measuring device according to an embodiment of the present invention, where a is a portion showing the boundary between an amorphous phase and a crystalline phase, and b is a critical thickness determined to be amorphous, and the thickness at this time can be called Rc (maximum amorphous section thickness or diameter) value. Therefore, the degree of amorphous formation ability can be expressed through the Rc value.

2 to 5 , in the method for measuring amorphous forming ability according to an embodiment of the present invention, the upper mold 131 and the lower mold 133 are combined to form a disk shape, and the central injection space 135a and the injection space The molten metal 10a may be injected (S120) into the mold 130 having the cavity 135 including the amorphous formation space 135b formed on the periphery of the 135a. Here, it can be said that the injection into the mold 130 may include all metal materials that require measurement of the amorphous forming ability.

For example, 100 to 3000 g of the molten metal 10a may be injected into the cavity 135, and the upper mold 131 and the lower mold 133 are made of pure copper with high thermal conductivity to speed up the cooling rate. can

Next, the rotating part rotates the mold 130 so that centrifugal force is applied to the molten metal 10a, and the molten metal 10a by the centrifugal force caused by the rotation flows into the amorphous forming space 135b into the mold. It may be cooled (S130) through (130).

Rotating the mold 130 may be rotating with a centrifugal force 50 to 100 times greater than the gravitational acceleration. That is, for depth control and uniform cooling of the molten metal 10a filled in the gap d, which is the amorphous formation space 135b of the upper mold 131 and the lower mold 133, the mold 130 is gravity It may be rotating with a centrifugal force of 50 to 100 times the acceleration. If it is less than 50 times the gravitational acceleration, the centrifugal force is low, so that the molten amorphous alloy is not densely filled in the fine gap (d) of 100 μm. If it exceeds, it is preferable to have the centrifugal force, because it may overload the driving of the rotating part that rotates the mold 130 and cause a problem of excessively generating vibration, which prevents filling.

Further, rotating the mold 130 may change the rotation angular velocity according to the type of the molten metal 10a, or change the radius of the cavity 135 or the inclination angle of the cavity 135. Mold ( 130) may be rotated. The molten metal 10a injected into the mold 130 is cooled from a region in contact with the mold 130 , and the specimen 10 may be formed. In this case, by changing the rotation angular velocity of the mold 130, the radius of the cavity 135, and the inclination gradient angle of the cavity 135, specimens of various thicknesses are subjected to different cooling conditions according to the type of the molten metal 10a. It can be formed by cooling, whereby the maximum diameter of the amorphous alloy can be derived at an arbitrary cooling rate, and the accuracy of deriving the critical cooling rate calculated thereafter can be increased.

That is, according to the inclination gradient of the amorphous formation space 135b in which the cross-sectional width d gradually decreases toward the edge, an amorphous metal whose thickness is continuously changed corresponding to the amorphous formation space 135b may be manufactured. In this case, the cavity 135 has an inclination gradient in which the cross-sectional width of the injection space 135a gradually decreases toward the edge. It may be larger than the inclination gradient angle. Accordingly, the molten metal 10a located in the injection space 135a is made more smoothly without being caught in the filling of the amorphous formation space 135b by centrifugal force, so that an amorphous metal having a continuous thickness can be manufactured.

Next, the thickness at which crystallization starts in the prepared amorphous metal specimen may be detected ( S140 ). In addition, it is possible to calculate the maximum thickness of amorphization from the arbitrary cooling rate (S150). Detecting the thickness at which crystallization starts in the amorphous metal specimen may be obtained by observing the prepared amorphous alloy specimen with an optical microscope or an electron microscope to determine whether crystal grains are formed. For example, the prepared amorphous metal specimen 11 may be formed in the form of a cross-section having a gradient having a thickness of 100 μm to 5000 μm.

The amorphous forming ability measuring apparatus and the amorphous forming ability measuring method using the same according to an embodiment of the present invention have a high reproducibility by simultaneously manufacturing specimens of various thicknesses by having a mold part that rotates with a slope gradient, and the variation according to the researcher is low, so the reliability can be increased. there are advantages to In addition, there is an effect that can derive the maximum diameter (thickness) of the metallic glass alloy or amorphous alloy at any cooling rate from the specimen.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be done.

100; Amorphous forming ability measuring device
110; melting part
112; Crucible
114; heating means
120; injection part
130; Mold
131; upper mold
133; lower mold
135; cavity
11; Amorphous alloy specimen

Claims (7)

delete delete delete delete injecting the molten metal into a mold formed in a disk shape by combining the upper mold and the lower mold and having a cavity including a central injection space and an amorphous formation space formed around the injection space;
rotating the mold so that a centrifugal force is applied to the molten metal, and cooling the mold through the mold while the molten metal is introduced into the amorphous formation space by the centrifugal force caused by the rotation;
manufacturing an amorphous metal whose thickness is continuously changed to correspond to the amorphous formation space according to the inclination gradient of the amorphous formation space whose cross-sectional width gradually decreases toward the edge; and
A method for measuring amorphous formation ability, characterized in that the thickness at which crystallization starts in the prepared amorphous metal specimen is detected.
6. The method of claim 5,
Rotating the mold, changing the rotation angular velocity according to the type of the molten metal or rotating the mold in which the radius of the cavity and the inclination gradient angle of the cavity are changed.
6. The method of claim 5,
The cavity has an inclination gradient in which the cross-sectional width of the injection space gradually decreases toward the edge, and the inclination gradient angle of the injection space is greater than the inclination gradient angle of the amorphous formation space.

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