KR100784915B1 - Zirconium / Titanium Based Amorphous Amorphous Alloys - Google Patents

Abstract

The present invention relates to a phase-separated zirconium / titanium based (Zr / Ti based) amorphous alloy, which is represented by the general formula (ZT) _100-ab (A) _a (B) _b , where ZT is Zr and At least one of Ti, (A) is at least one of Y and La, (B) is at least two of Be, Fe, Co, Ni, Cu, Ag, and Nb, and a and b are atomic percent A zirconium / titanium-based anisotropically separated amorphous alloy having an amorphous forming ability having a range of 5 ≦ a ≦ 60 and 20 ≦ b ≦ 80 is provided.

The ideally separated amorphous alloy of the present invention has a phase-separated structure having a very fine connection structure having a nano-sized to easily prepare an amorphous matrix nanocomposite by selectively nanocrystallizing the abnormally separated composition through selective heat treatment or control of cooling rate. Can be.

Ideal Separation, Zirconium / Titanium Based, Amorphous Alloys

Description

Zr / Ti-based Two Phase Metallic Glasses

        1 is an X-ray diffraction analysis result of the Ti-Y-Zr-Be-Ni-Cu-based anisotropic amorphous alloy of the present invention.

        Figure 2 is a differential thermal analysis of the Ti-Y-Zr-Be-Ni-Cu-based aberrant separation amorphous alloy and the comparative alloy of the present invention.

        FIG. 3 is a transmission electron microscope analysis of a nano-crystallized specimen in which only the Y-based phase-separated amorphous region was selectively heat treated with Ti-Y-Zr-Be-Ni-Cu-based anisotropically separated amorphous alloy for 30 seconds at 600 K. FIG. The result is.

The present invention relates to a phase-separated zirconium / titanium-based (Zr / Ti-based) amorphous alloy, and more particularly, to a large mixing through the intrinsic properties and thermodynamic considerations of member elements in amorphous formation in Zr / Ti-based alloys having excellent amorphous forming ability The present invention relates to a zirconium / titanium-based amorphous alloy capable of abnormally separating amorphous crystals during solidification by adding an element having a thermal difference and at the same time adding a third alloying element having excellent amorphous forming ability.

In general, the metal has a crystal structure at room temperature and may be called an aggregate of microcrystals. When these crystalline metals are heated to a liquid state and quenched at a high cooling rate of 10 ⁵ to 10 ⁶ K / sec or more, the atoms do not have a regular arrangement and show a disordered arrangement when solidified. This condition is called amorphous. Because amorphous alloys have a new atomic arrangement different from crystalline alloys, there are many excellent properties that cannot be obtained in crystalline alloys, such as high strength and wide elastic limit regions, excellent corrosion properties, electromagnetic properties, and unique chemicals. Exhibit properties. In particular, recent studies have shown that alloys that precipitate nanocrystalline phases in amorphous bases through partial crystallization of amorphous phases have good mechanical properties, soft magnetism, and hard magnetism that cannot be obtained in both amorphous and crystalline alloys. And excellent catalytic properties. These superior properties are a new concept of material with great potential for industrial application, in line with the extreme properties of the materials required in modern industrial societies. Thus, amorphous alloys and nanocrystalline alloys have been studied until recently with much interest.

In the biphasic amorphous alloys developed to date, several limited compositional zones of Zr-La-Al-Cu-Ni, Y-Ti-Al-Co, and Ni-Nb-Y alloys have been developed by rapid solidification using melt spinners. Only phase separation has been reported. These results indicate that aberrant separation amorphousization requires a higher cooling rate for amorphousization than conventional single phase amorphous alloys, and also has a limitation in the composition of the alloying components.

Particularly, except for some cases, the conventional phase-separated amorphous alloy as described above has a limited crystallization behavior of the main composition of each phase-separated composition in a narrow temperature range, thereby selectively depositing the nanocrystalline phase in the amorphous interior.

In order to overcome this limitation, in the present invention, a Zr-based or Ti-based bulk amorphous alloy, which has been reported to have excellent amorphous forming ability, is added to solidify by adding an element having a large amount of mixed heat through intrinsic properties and thermodynamic considerations of member elements. Separation amorphization was made possible, and due to the crystallization behavior that is clearly separated by the intrinsic crystallization temperature difference of each main element, 1) easy production of composites through nanocrystallization, 2) multi-stage molding in the subcooled liquid region corresponding to each amorphous It is an object of the present invention to provide a zirconium / titanium-based biphasic amorphous alloy with improved properties.

In order to achieve this object, according to the invention, it is represented by the general formula (ZT) _100-ab (A) _a (B) _b , wherein ZT is at least one of Zr and Ti, and (A) is Y and La (B) is at least two of Be, Fe, Co, Ni, Cu, Ag, and Nb, and a and b have atomic ratios of 10 ≦ a ≦ 60 and 20 ≦ b ≦ 80. Provided is a zirconium / titanium-based anisotropically separated amorphous alloy having excellent amorphous forming ability.

For the reason of element selection in the present invention, first, elements with different crystallization temperature ranges having a large amount of mixed heat with the main elements Zr and Ti were group A (Y, La), and Zr, Ti, and A Elements that have a negative mixed heat with the elements of the group to have excellent amorphous forming ability were group B (Be, Fe, Co, Ni, Cu, Ag and Nb).

On the other hand, the addition of the semi-metal element group Al, Si, and Sn elements known to contribute to the improvement of the amorphous formation ability when added in the Zr-based amorphous alloy may further increase the amorphous formation ability.

In the present invention, the mixed heat relationship of the pair of elements forming the immiscible region is as follows.

Zr-Y: 15 kJ / mole, Ti-Y: 9 kJ / mole

Zr-La: 13 kJ / mole, Ti-La: 20 kJ / mole

In the present invention, the reason for composition limitation is that when group A elements having a positive mixed heat relationship are added less than 10%, thermodynamic instability is formed because a miscibility gap, which is an immiscible region, is formed between the two elements. On the other hand, when added in excess of 60%, there is a problem that the amorphous forming ability is rather sharply reduced due to the excessive amount of elements with a positive mixing heat.

In addition to the abnormal separation of the main elements, the amorphous formation ability acts as an important factor for abnormal separation, so the rule of thumb for improving the amorphous formation ability is generally (1) multicomponent system of three or more components, and 2) large atomic radius of 12% or more among members. The elements of group B were selected in consideration of the difference in size, 3) composed of elements with negative mixing heat, 4) conditions near the deep process composition for stabilization of liquid phase, and only one element was added or 20 If it is added less than%, it violates the confusion theory, which is the concept of improving amorphous forming ability through multi-component system, and if it is added more than 80%, it is separated abnormally based on the thermodynamic relationship between group A and B. Is a thermodynamically unstable state in which a solubility gap (which is an immiscible region between elements) is formed, and the amount of the main element is small, Is reduced, the role of the main striking element is clearly not get a separate crystallization temperature interval.

 As previously discussed, (Zr, Ti), group A, and group B elements can be abnormally amorphous, but if necessary, such as Al, Si, and Sn, which are known to help improve amorphous forming ability in Zr or Ti based amorphous alloys. It is also possible to add more semimetallic elements. The addition of these elements can contribute to the abnormal separation amorphous by improving the amorphous forming ability of the abnormally separated Zr or Ti-based amorphous alloy. However, when these elements are added in excess of 20%, a large change is caused in the amorphous forming ability combination consisting of (Zr, Ti) -A-group-B group elements, thereby reducing the amorphous forming ability.

 On the other hand, according to the research results of the present inventors, when Zr is substituted using Hf, which exhibits similar behavior when substituted in an amorphous alloy system with a group element such as Zr, the role of Zr in forming an amorphous alloy and It has been found that, by playing a similar role, similar heterogeneous amorphization behavior can be obtained in the same composition range.

Example

Hereinafter, the present invention will be described in detail with reference to Examples.

(Production of specimen)

1. Manufacturing of master alloy

In the present invention, (Zr, Ti), Group A (Y, La), Group B (Be, Fe, Co, Ni, Cu, Ag, respectively, having a purity of 99.8% to 99.99% in order to obtain a mother alloy having a desired alloy composition. , And Nb) elements were subjected to Arc dissolution under high purity argon (99.99%) gas atmosphere.

In addition, in order to eliminate segregation of the alloying component during arc melting, the sample was repeatedly dissolved while inverting the sample.

2. Preparation of Specimen Using Melt Spinning Method

The prepared master alloy was prepared using a ribbon spinning specimen using a melt spinning method with a relatively high cooling rate (10 ⁴ -10 ⁶ K / s).

Specifically, the mother alloy was first charged into a quartz tube, the vacuum degree of the chamber was about 10 ⁻⁴ Torr, and then dissolved by high frequency induction heating in an argon atmosphere of about 7-9 kPa. At this time, the molten metal is maintained in the quartz tube due to the surface tension, and after the master alloy is completely dissolved, the quartz tube is rapidly lowered before the reaction with the quartz tube occurs, and about 50 kPa of argon gas is injected into the quartz tube. By spraying the molten metal to the surface of the Cu roll (wheel surface velocity: ~ 40 m / s) rotating at a high speed to prepare a ribbon-shaped specimen having a thickness of about 30μm, width of about 2mm.

3. Fabrication of Specimen Using Injection Casting

In the present invention, the bulk specimens were prepared by injection casting with varying cooling rates using the prepared mother alloy copper molds of various diameters. The master alloy was filled with high-purity argon in a high vacuum state, filled with a high temperature induction melted in an argon atmosphere, and then filled in a copper mold which is cooled by water through a constant injection pressure, thereby molding a rod-shaped specimen having a constant length of 50 mm.

Analysis of the amorphous alloy composition of the present invention prepared by the above method was performed as follows.

Psalm Analysis

1. Transmission Electron Microscope Analysis

Transmission electron microscopy (TEM) analysis was performed to observe the phase separation of the bulk amorphous alloy. After mechanically polishing the specimen prepared by injection casting, the specimen was prepared by ion milling. The angle between the ion beam and the specimen surface was polished by varying 4-8 ° using ion milling.

Under this condition, using a JEM 2000EX, a bright field image (BF image: Bright Field image) and a limited field diffraction pattern (SADP) were obtained at an acceleration voltage of 200 kV.

2. Differential Thermal Analysis

In general, differential scanning calorimeter-Perkin Elmer (DSC7) is used to evaluate the thermodynamic properties associated with the glass transition temperature (T _g ) and crystallization temperature (T _x ) of the amorphous phase.

In this experiment, a sample was put in a copper pan and placed in a platinum holder. An empty pan was used as a reference. In order to prevent oxidation of the specimen, the temperature range of 373-953K was measured under high purity (99.999%) argon atmosphere, and DSC analysis was carried out by loading approximately 20 mg of sample and 40K / min (0.667 K / min) under 99.99% purity argon atmosphere. It carried out at the constant temperature increase rate of s).

3. X-ray Diffraction Analysis

In order to confirm that the prepared specimen was amorphous, the sample was irradiated with an X-ray diffractometer (M18XHF ²² -SRA, monochromatic Cu K radiation). X-ray diffraction analysis was conducted under conditions of 50 kV and current of 200 mA for Cu target (λ = 1.5406, Ka ₁ line) tube voltage. X-ray diffraction spectra were obtained with a 0.02 ° interval at a rate of 4 ° / min in the scan range of 20 ° -80 ° by the method of continuous scanning.

In general, in the case of amorphous specimens, a wide diffraction pattern without a crystal pick can be obtained in an X-ray diffraction analysis experiment. In the present invention, unlike a typical amorphous alloy, a diffraction pattern regarding two amorphous phases overlaps because of an abnormal amorphous alloy. It was confirmed that the diffraction angle has a relatively large area.

The above results are shown in Table 1.

(Unit: Kelvin) division    Alloy composition (at%) T _g 1 T _x 1 T _g 2 T _x 2 Manufacture / Form   Example One Ti _33.75 Zr ₁₂ Y _11.25 Be ₂₂ Ni ₁₀ Cu ₁₁ - 526 646 703 M / DA 2 Ti _27.5 Zr ₁₀ Y _27.5 Be ₁₈ Ni ₈ Cu ₉ - 542 625 682 M / DA 3 Ti ₂₀ Zr ₂₁ Y ₂₀ Be ₂₀ Ni ₁₀ Cu ₉ 510 545 627 675 M / DA 4 Zr _28.5 La _32.5 Ni _11.3 Cu _12.7 Nb ₅ - 458 - 632 M / DA 5 Zr ₃₅ La ₃₀ Cu _17.5 Ni ₁₀ Al _7.5 419 453 636 678 M / DA 6 Zr ₃₀ La _27.5 Cu _12.5 Ni ₁₀ Co _3.5 Al _16.5 461 523 684 723 I / DA   Comparative Example One Ti ₅₅ Zr ₁₀ Be ₁₈ Ni ₈ Cu ₉ - - 629 667 M / SA 2 Zr ₆₅ Cu _17.5 Ni ₁₀ Al _7.5 - - 645 748 M / SA 3 Zr ₁₀ Y ₆₅ Be ₁₀ Ni ₁₀ Cu ₅ 515 560 - - M / SA 4 Zr ₄₀ Ti ₁₁ Y ₈ Be ₂₅ Cu ₈ Ni ₈ - - 628 674 M / SA 5 Zr ₅ Y ₇ Ni ₆₃ Ag ₂₅ - - - - M / Cryst. 6 Zr _55.9 Ta ₈ Cu _18.6 Al _7.5 Ni ₁₀ - - 700 783 I / Comp. 7 Ti ₁₅ Zr ₁₈ Y ₂₀ Ni ₁₀ Cu ₁₀ Si ₂₂ Sn ₅ - - - - M / Cryst.

Where M = Melt-spinning Method, I = Injection casting Method,

       SA = single amorphous phase, DA = aberrant separation amorphous phase, Cryst. = Determined, Comp. = Composite (SA + Cryst.)

As shown in Table 1, the alloys of Examples 1 to 6 of the present invention undergo Two Distinguishable Phase Amorphous (DA) during solidification. In addition, the amorphous forming ability of such a phase-separated amorphous alloy is more dependent on the cooling rate conditions than a single amorphous alloy, but in the case of Zr-La-Cu-Ni-Co-Al-based amorphous alloy of Example 6 of the present invention, 10- Abnormal amorphousness is also possible through injection casting with a cooling rate as small as 100 K / s.

In particular, as can be seen in Zr ₃₀ La _27.5 Cu _12.5 Ni ₁₀ Co _3.5 Al _16.5 of Example 6, the appropriate addition of the Al element improves the respective amorphous forming ability which is ideally separated in the Zr- or Ti-based amorphous alloy. It can be seen that abnormal amorphousization is possible up to the bulk form.

That is, the alloy Zr _28.5 La _32.5 Ni _11.3 Cu _12.7 Nb ₅ of Example 4 may be prepared as an abnormal separation amorphous by the melt spinning method, but was not found distinct glass transition temperature of the separated amorphous during differential thermal analysis. However, in the case of Zr ₃₅ La ₃₀ Cu _17.5 Ni ₁₀ Al _7.5 of Example 5 to which the Al element was partially added, the separated amorphous had a distinct glass transition behavior and a wide supercooled liquid region, so that the separated amorphous had a relatively good amorphous forming ability and thus was stable, ideally separated amorphous. You can see that paint is possible.

In particular, it can be seen that, in the maximum case, as in Example 6, it is possible to manufacture in bulk by injection casting by appropriate combination of elements such as Al, Si, Sn and the like.

On the other hand, Comparative Examples 1 and 2 are cases in which the elements of group A are not added, and since the immiscible region is not formed due to the absence of elements with positive mixing heat, a simple Zr-, Ti-based single phase amorphous (SA: Single Phase Amorphous alloy is shown.

When the element of group A of the comparative example 2 is not added, addition of Al element related to the improvement of amorphous forming ability is also meaningless.

In Comparative Example 3, when more than 60% of the elements of Group A were added, Zr- (or Ti-) elements were quantitatively insufficient to form an immiscible region between Group A and Zr- (or Ti-) elements. An example is shown in which a single amorphous (SA) alloy is formed based on elements of group A.

In Comparative Example 4, the abnormal separation between the elements is performed, but in the case of the composition mainly composed of group A element, which has relatively low amorphous forming ability compared to Zr- (or Ti-), due to the small amount of group B, it is separated from the process composition and precipitated as crystal phase. For example, Zr- (or Ti-) amorphous and group A crystalline phases are precipitated in a composite form.

Comparative Example 5 is quantitatively insufficient to form an immiscible region between group A and Zr- (or Ti-) elements when more than 60% of the elements of group B are added. It can be said that the element that has the relation of mixing heat is added, which violates the rule of experience of amorphous formation ability.

In Comparative Example 6, in the case where the elements of group A are added with elements other than the relation of the present invention, Ta is in a positive mixed heat relationship (Zr-Ta: 3 kJ / mole), but mixed with other members In the thermal relationship (Cu-Ta: 2kJ / mole), the Ta element is isolated during solidification, and thus, the composite is manufactured in the form of precipitation of a crystalline phase mainly containing a Ta phase in a single amorphous consisting of the remaining elements.

Elements such as Al, Si, and Sn are generally added to improve amorphous forming ability in Cu-based amorphous alloys, but do not need to be added for abnormal separation, but when added in small amounts, glass forming ability (GFA) is improved. It plays a role in contributing to aberrant separation amorphous. However, when added in excess of 20%, as can be seen in Comparative Example 7 shows a negative role in the correlation between the existing elements, the ability to form amorphous decreases rapidly, it shows that the amorphous phase is not obtained through quench solidification.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is an X-ray diffraction analysis of the Ti-Y-Zr-Be-Ni-Cu-based anisotropic amorphous alloy of the present invention. Each amorphous alloy has a halo diffraction pattern detected at its own fixed position by the atomic radius difference of the principal element. In the case of Y and Ti alloys, as shown schematically in FIG. The pattern relating to the Ti phase is detected in the high angular region.

As can be seen in FIG. 1, in the case of the anisotropically separated alloy of the present invention, two hollow patterns are detected by overlapping, so that a wider hollow pattern of 18-20 degrees may be provided than a single amorphous phase. This characteristic can be clearly seen as the Ti-related peak (peak) as shown in (c) (Ti: Y = 3: 1) of FIG.

2 is a differential thermal analysis of the Ti-Y-Zr-Be-Ni-Cu-based aberrant separation amorphous alloy of the present invention. As can be seen, the anisotropically separated amorphous alloys of the present invention are each Y-rich amorphous during continuous heating by anisotropically separated into in situ (In-situ) during solidification according to the crystallization temperature range depending on the main element It can be seen that the crystallization and Ti-rich amorphous phase crystallization behavior is clearly separated.

FIG. 3 is a transmission electron microscope analysis result of a specimen in which the Ti-Y-Zr-Be-Ni-Cu-based anisotropic amorphous alloy was heat-treated at 600 K for 30 seconds to selectively nanocrystallize the Y-based phase-separated amorphous region. . As can be seen, in the case of the anisotropically separated amorphous alloy of the present invention, several nm to several tens of tens of tens of nm of the amorphous phase of the present invention is selectively crystallized through the Y-based amorphous crystallization, which is crystallized at a low temperature range according to the crystallization temperature range depending on the element. It can be seen that the nanocomposite can be easily made by allowing the Y-rich crystal phase of nm to be nanocrystallized. In general, the formation of amorphous is closely related to the critical cooling rate, it is thought that it is possible to make this type of nanocomposite by controlling the cooling rate during manufacturing in addition to heat treatment. In particular, recent studies have shown that the alloys in which the nanocrystalline phases are deposited on the amorphous base through partial crystallization of the amorphous phase have excellent properties that could not be obtained in the complete amorphous alloy and the crystalline alloy. The production of nanocomposites is expected to suggest new concepts for manufacturing nanocomposites.

As described above, in the case of the zirconium / titanium-based alloy which can be abnormally amorphous according to the present invention, the following effects are provided.

1) Through the thermodynamic approach, it is possible to produce an amorphous alloy in which an amorphous phase is separated by an in-situ method with an excellent amorphous forming ability.

2) In the amorphous alloy of the present invention, the phase separation mechanism is a concept contrary to the general rule of thumb for amorphous formation, and provides a criterion for designing an amorphous material with a new concept different from the rule of thumb proposed previously. In addition, the remaining additive element and composition region should meet the rule of thumb on the improvement of amorphous forming ability. Based on the combination of these two concepts, the development of the ideal bulk amorphous alloy using phase separation in other alloy systems will be based on the present invention. It can be done easily.

3) The phase-separated amorphous alloy of the present invention has a phase-separated structure having a very fine connection structure having a nano-size, so that the amorphous matrix-based nanocomposite can be easily nanocrystallized by selectively nanocrystallizing the separated composition through selective heat treatment or control of cooling rate. It can manufacture.

4) The phase-separated amorphous alloy of the present invention exhibits a stable supercooled liquid region in both amorphous phases, thereby enabling multi-stage deformation behavior in the supercooled liquid region. Specifically, the conventional supercooled liquid region using superplasticity of amorphous material is mainly used for processing materials through micro-forming such as MEMS. In the alloy of the present invention, the abnormally separated amorphous phase is supercooled for each amorphous phase. In the case of having a separate liquid region, it is possible to transform the amorphous matrix into a composite form after partial nanocrystallization by the appearance of a secondary supercooled liquid region, which may be applied to a new processing method of the nanocomposite.

Claims (6)

Represented by the general formula (ZT) _100-ab (A) _a (B) _b , ZT is at least one of Zr and Ti, (A) is at least one of Y and La, (B) is at least two of Be, Fe, Co, Ni, Cu, Ag, and Nb, a, b is a zirconium / titanium-based ideal separation amorphous alloy having an excellent amorphous forming ability, characterized in that the atomic percentage in the range of 10≤a≤60, 20≤b≤80. The zirconium / titanium-based ideal separation amorphous alloy of claim 1, wherein the amorphous alloy further comprises at least one of Al, Si, and Sn in an amount of 20 atomic percent or less with respect to the total alloy composition. The method of claim 1, wherein the amorphous alloy is a zirconium / titanium-based ideal separation amorphous alloy with excellent amorphous forming ability, characterized in that by substituting a portion of Zr of the constituent component with Hf. According to claim 1, wherein ZT is Zr and Ti, A is Y, B is Be, Cu, Ni, zirconium / titanium-based anisotropic amorphous alloy having excellent amorphous forming ability, characterized in that. According to claim 1 or 2, wherein A is Y, B is Cu, Ni is excellent zirconium / titanium-based ideal separation amorphous alloy, characterized in that the amorphous forming ability. According to claim 1 or 2, wherein A is La, B is Cu, Ni, Co is zirconium / titanium-based ideal separation amorphous alloy with excellent amorphous forming ability, characterized in that.

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