CN102373388A - Cobalt iron base block body metal glass with super-large super-cooling interval and preparation method thereof - Google Patents

Abstract

The invention discloses a cobalt-iron-based bulk metallic glass with an ultra-large supercooling interval, the molecular formula of which is Co _a Fe _b Nb _c M _d B _e , wherein M is one of the five elements Dy, Y, Tb, Er and Gd Any one, a, b, c, d, e is the molar content of atoms, 24≤a≤56, 6≤b≤38, 4≤c≤8, 0<d≤5, 26≤e≤31, And a+b+c+d+e=100. The cobalt-iron-based bulk metallic glass has strong amorphous forming ability and super-large width of the supercooled liquid phase region, and its value can exceed 100K, and even reach 130K. At the same time, it has ultra-high strength and excellent soft magnetic properties, and its raw materials are relatively It is cheap, so it is a bulk metallic glass with excellent comprehensive properties, and has broad application prospects in the fields of micro precision devices and magnetic functional materials.

Description

Cobalt-iron-based bulk metallic glass with super-large supercooling interval and preparation method thereof

technical field

The invention belongs to the field of amorphous alloys, and in particular relates to a cobalt-iron-based bulk metallic glass with a super-large supercooling interval and a preparation method thereof.

Background technique

In modern society, traditional metal materials and glass materials are one of the most widely used materials in human production and life. Metallic materials are characterized by excellent mechanical properties, electrical and thermal conductivity, and some metallic materials also exhibit excellent magnetic properties. However, the manufacturing process of metal parts is relatively complicated, especially the processing and manufacturing of high-strength and miniature precision metal devices is more difficult.

Glass materials above the softening temperature are easily deformed after being pressurized, and the shape remains unchanged after cooling down or pressure disappearing. Combined with various forming methods such as blowing, drawing, pressing, casting, and sinking, glass materials can be made into various solid and hollow products, and can also be made into devices with complex shapes and strict dimensions by welding and powder sintering. The disadvantages of glass materials are also obvious: first, the fracture strength of glass materials is generally smaller than that of metal materials; second, glass is a typical brittle material with defects on the surface and inside, and it is easy to crack cracks under the action of external forces and environmental media. are greatly restricted.

In the early 1960s, Duwez et al. invented metallic glass (W.Klement, R.H. Wilens, and P.Duwez, Nature., 181(1960) 869-870). Conventional metal alloys are all crystalline structures, that is, the arrangement of atoms is a long-range ordered lattice structure. The atomic arrangement of metallic glasses (amorphous alloys) is long-range disordered. Compared with traditional oxide glass, the bonding between atoms in metallic glass is a metal bond, so it retains the relevant characteristics of metal materials, such as good electrical properties (such as electrical conductivity) and mechanical properties of general metal materials, and it also has the same Superplasticity in the supercooled liquid phase region like oxide glasses, that is, metallic glasses can be precisely pressed and formed in the supercooled liquid phase region while maintaining the original material properties, but this cannot be done for crystalline metal alloys. In a certain sense, metallic glass has the characteristics of both metal and glass materials. At the same time, due to the unique long-range disordered and short-range ordered structure, metallic glass has excellent properties that traditional crystalline alloy materials do not have, such as: high fracture Strength, hardness, low elastic modulus, high wear resistance, excellent corrosion resistance, and excellent soft magnetic properties (such as Fe-based, Co-based or Ni-based metallic glasses). Therefore, metallic glasses have shown broad application potential in many fields and aroused great interest.

However, the subsequently developed metallic glass alloy systems, due to their generally weak amorphous formation ability, require extremely high cooling rates (greater than 10 ⁶ K/s) during preparation, and most of the obtained metallic glasses are low-dimensional materials, such as: thin Tapes, filaments, fine powder, etc. Due to the shape limitation, many excellent properties of metallic glass materials cannot be fully utilized in practical applications. Moreover, the supercooled liquid phase region of these metallic glasses is too narrow, and it is difficult to exert the behavioral characteristics of metallic glasses in the supercooled liquid phase region. If the three-dimensional size of metallic glass can reach millimeter level, it is called "bulk metallic glass" or "bulk amorphous alloy". In the 1990s, bulk metallic glasses without noble metal elements were developed. As a kind of amorphous solid, bulk metallic glass, like traditional oxide glass, has the ability of superplastic processing in the supercooled liquid phase region.

The supercooled liquid region width ΔT is a measure of the superplastic formability of bulk metallic glasses. The larger the ΔT value, the higher the thermal stability of the supercooled liquid, and the bulk metallic glass can be superplastically formed at a wider temperature and longer time range.

In addition, with the development of life science, biological science and information technology, more and more micro devices are required. These micro-devices not only have strict requirements on size, but more importantly, require components to have good mechanical properties. Using conventional crystal materials and traditional processing techniques, it is difficult to meet the requirements of high strength, corrosion resistance and wear resistance at the same time. As mentioned above, bulk metallic glasses not only have good superplastic forming ability in supercooled liquid phase region, but also have excellent mechanical properties, which makes bulk metallic glasses have broad application prospects in the field of micro precision devices. In addition, ferromagnetic bulk metallic glasses also have excellent soft magnetic properties, such as high magnetic permeability, low coercive force and high-frequency loss, and at the same time have high mechanical strength and wear and corrosion resistance. Therefore, Fe-based and Co-based bulk metallic glass materials are also suitable for applications in high-performance magnetic sensors, high-frequency switching power supplies, high-frequency transformers, and core materials for transformers.

So far, the developed Fe-based and Co-based bulk metallic glasses exhibit high fracture strength and hardness, but the small width and critical dimension of the supercooled liquid phase region restrict their application in the field of superplastic forming . Some noble metal-based bulk metallic glasses, such as Pd, Pt, or Au-based metallic glass alloys, although they exhibit strong amorphous-forming ability and have a wide supercooled liquid region, there is a good supercooled liquid region. Plasticity and precision forming ability, but the high cost of raw materials limits its application in the engineering field.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art above, and to provide a cobalt-iron-based bulk metallic glass, which has strong amorphous forming ability and wide supercooled liquid phase region, and has ultrahigh Strength and excellent soft magnetic properties, and its raw materials are relatively cheap, and can be applied in the field of micro precision devices and magnetic functional materials.

The technical solution adopted by the present invention to achieve the above technical purpose is: a cobalt-iron-based bulk metallic glass with a super-large supercooling interval, and its molecular formula is:

Co _a Fe _b Nb _c M _d B _e

Among them, M is any one of the five elements Dy, Y, Tb, Er and Gd, a, b, c, d, e are the molar content of atoms, 24≤a≤56, 6≤b≤38, 4 ≤c≤8, 0<d≤5, 26≤e≤31, and a+b+c+d+e=100;

The preparation method of the cobalt-iron-based bulk metallic glass of the present invention comprises the following steps:

Step 1: Dosing according to the elemental composition and the molar content of atoms in the following molecular formula,

Co _a Fe _b Nb _c M _d B _e

Among them, M is any one of the five elements Dy, Y, Tb, Er and Gd, a, b, c, d, e are the molar content of atoms, 24≤a≤56, 6≤b≤38, 4 ≤c≤8, 0<d≤5, 26≤e≤31, and a+b+c+d+e=100;

Step 2: In an electric arc furnace with an argon atmosphere, mix and melt the ingredients in step 1, and obtain a master alloy ingot after cooling;

Step 3: Using the existing metal mold casting method, re-melting the master alloy ingot obtained in step 2, and using the copper mold casting method to obtain a rod-shaped or plate-shaped bulk metallic glass.

Preferably, the purity of Co, Fe, Nb, M and B elements is not lower than 99.5wt%.

The cobalt-iron-based bulk metallic glass provided by the present invention has the following advantages:

1) It has strong amorphous forming ability, and can produce larger-sized amorphous alloys at a very low cooling rate, and its size can reach up to 4.0mm in each dimension.

2) It has a super-large width of the supercooled liquid phase region, and its value can exceed 100K, even reach 130K, which can make it obtain a longer processing time before crystallization occurs, and is suitable for industrial mass production.

3) It has good superplastic forming processability in the supercooled liquid phase region, and has the same precision press forming characteristics as oxide glass and plastic.

4) It has a relatively high glass transition temperature, and the glass transition temperature is greater than 865K, which can keep the mechanical properties of the material stable at a relatively high working temperature.

5) It has excellent mechanical properties, the compressive fracture strength at room temperature can reach 4830MPa, and the Vickers hardness value of most components exceeds 1200.

6) It has excellent soft magnetic properties, the coercive force is between 0.84 and 3.43A/m, and the effective magnetic permeability (1A/m, 1kHz) can reach up to 20100.

In addition, the raw material of the cobalt-iron-based bulk metallic glass provided by the present invention is relatively cheap, so it is a bulk metallic glass with excellent comprehensive performance, and has broad application prospects in the fields of micro precision devices and magnetic functional materials.

Description of drawings

Fig. 1 is the DSC curve chart of the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ amorphous rod sample with a diameter of 3 mm prepared in Example 1;

Fig. 2 is the X-ray diffraction pattern of the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ amorphous rod sample with a diameter of 3 mm prepared in Example 1;

Fig. 3 is a high-resolution electron microscope image and the corresponding selected area diffraction pattern of the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ amorphous rod sample with a diameter of 3 mm prepared in Example 1;

Fig. 4 is the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ amorphous rod sample prepared in Example 1 with a diameter of 2 mm under different temperature conditions, and the stress-strain curve measured by compression test;

Fig. 5 is the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ 2 mm amorphous rod sample prepared in Example 1 with a diameter of 3 mm and the indentation morphology of the Vickers hardness test;

Fig. 6 is a photo of a coin pattern printed on the surface of a (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ non-wafer sample prepared in Example 1;

Fig. 7 is a photo of the mesh pattern printed on the surface of the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ non-wafer sample prepared in Example 1;

Fig. 8 is the hysteresis loop at room temperature of the (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ amorphous ribbon sample prepared in Example 1;

Fig. 9 is a physical photograph of (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ amorphous rod samples with diameters of 3mm and 4mm prepared in Example 2, and an amorphous material sample with a size of 17mm×10mm×1mm;

Fig. 10 is the X-ray diffraction pattern of the (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ amorphous rod sample with a diameter of 4 mm prepared in Example 2;

Fig. 11 is a DSC curve of the (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ amorphous rod sample with a diameter of 4 mm prepared in Example 2.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention, but do not limit it in any way.

Example 1:

In this example, the molecular formula of the cobalt-iron-based bulk metallic glass is (Co _0.5 F _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ , and its preparation method is as follows:

Co, Fe, Nb, Dy and B components with a raw material purity of not less than 99.5wt% are prepared in a molar ratio of 31:31:6:2:30, mixed and smelted in an electric arc furnace with an argon atmosphere 3 to 4 times, after cooling, the ingot of (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ master alloy is obtained; The alloy melt was pressed into a copper mold to obtain bulk metallic glass amorphous rod samples with a composition of (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ , a diameter of 2mm and 3mm, and a size of 17mm×10mm ×1mm non-wafer sheet sample.

The above bulk metallic glass amorphous samples were tested as follows:

热学参数由耐弛404C高温DSC测定；采用FEI公司Tecnai F20型号透射电子显微镜分析样品的内部显微结构。X-ray diffraction (XRD) was used to analyze the structure of the sample, differential calorimetry scanning analysis (DSC) and high-resolution transmission electron microscopy (HRTEM) were used to observe the structure. In this embodiment, the X-ray diffractometer produced by Bruker AXS Company is specifically adopted, a copper target is used, and the incident wavelength λ is

The thermal parameters were measured by the relaxation resistance 404C high-temperature DSC; the internal microstructure of the sample was analyzed by the Tecnai F20 transmission electron microscope of FEI Company.

Test the mechanical properties of the samples at room temperature, when heated, and the imprinting processing performance in the supercooled zone. The UTM5105 electronic universal testing machine is used for testing. The test strain rate is 5×10 ^-4 s ^-1 , and Hitach's S-4800 field emission scanning is used. Dianjing observed and analyzed the indentation.

The Vickers microhardness of the test sample was measured by using a Vickers microhardness tester (model MH5) at room temperature, under the condition of 1000g load and holding pressure for 10s.

Using the annealed amorphous strip to test the soft magnetic properties of the material, the preparation of the amorphous strip adopts the Edmund Bühler single-roller induction melting strip equipment produced in Germany, the working atmosphere is high-purity argon, and the thickness of the prepared thin strip is about 25μm, about 1mm wide. In order to remove the internal stress of the amorphous strips during the preparation process, all test strips were annealed at 50°C for 300s under vacuum condition _Tg . The saturation magnetization in the soft magnetic properties is measured by a Lake shore 7410 vibrating sample magnetometer (VSM), the coercive force is measured by a DC soft magnetic BH loop measuring instrument BHS-40 produced by Riken, and the effective permeability is measured by an Agilent 4294A Impedance Analyzer Determination.

The test results are as follows:

(1) Figure 1 is a differential scanning calorimetry (DSC) curve diagram of an amorphous sample with a diameter of 3mm, and its heating rate is 0.67K/s; it can be known from Figure 1 that its glass transition temperature (T _g ) , the crystallization initiation temperature (T _x ), and the width (ΔT) of the liquid phase in the supercooled zone are 898K, 1028K and 130K, respectively.

(2) Figure 2 is the X-ray diffraction pattern of an amorphous sample with a diameter of 3mm. In the figure, only the diffusion peaks representing the amorphous phase appear, but there are no diffraction peaks corresponding to the crystal phase, which proves that the alloy is completely amorphous state; using a high-resolution electron microscope to observe microscopic selection is more sensitive than X-ray diffraction. Figure 3 is a high-resolution electron microscope image of the sample and the corresponding selected area diffraction pattern, which shows that the structure of the sample is disordered and only shows a single amorphous structure.

(3) Figure 4 shows the stress-strain curves of an amorphous sample with a diameter of 2 mm measured by compression test at a temperature range from room temperature to 923K. The figure shows that the amorphous sample is brittle at room temperature, and breaks after the elastic strain reaches about 2%, with a corresponding strength of 4750MPa; and at a temperature of 923K, its brittleness turns into superplasticity, corresponding to a yield strength of Only 90MPa. The photo of the sample in the figure shows that the uncompressed sample size is 4mm high and 2mm in diameter, and the compressed size is about 0.6mm thick and 4.26mm in diameter. The sample was compressed to 15% of the original height without cracking, which shows that the The alloy not only has super high strength but also has excellent superplastic deformation ability in the supercooled region. FIG. 5 is the indentation appearance of the Vickers hardness test of the amorphous sample, and the corresponding Vickers hardness is 1237.

(4) Figure 6 is a photo of the coin pattern printed on the sample by superimposing a non-wafer material with a thickness of about 1mm on top of the coin, heating it to 923K, and holding it under a stress of 100MPa for 30 seconds. The left picture is the printed non-wafer, The picture on the right is the actual coin. Fig. 7 is a photo of the mesh pattern printed on the surface of the non-wafer sample, which shows that the bulk metallic glass material has excellent imprintability and viscous deformability.

(5) The soft magnetic properties of the amorphous sample prepared in this example are also excellent, and Fig. 8 is the room temperature hysteresis loop of the amorphous thin ribbon sample. The corresponding saturation magnetization is 0.52T. The coercive force is 1.80A/m measured by the B-H loop measuring instrument, and the effective magnetic permeability (1A/m, 1kHz) is obtained under the condition of 1kHz frequency and magnetic field strength of 1A/m by the impedance analyzer. for 12500.

The above experimental results show that the cobalt-iron-based bulk metallic glass with the molecular formula (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ has a strong amorphous-forming ability and an ultra-wide supercooled liquid region at 130K, as well as ultra-high Strength and excellent soft magnetic properties, so it can be used in the fields of micro precision devices and magnetic functional materials.

Example 2:

In this example, the molecular formula of the cobalt-iron-based bulk metallic glass is (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ , and its preparation method is basically the same as in Example 1, specifically as follows:

Co, Fe, Nb, Dy and B components with a raw material purity of not less than 99.5wt% are prepared in a molar ratio of 30.5:30.5:6:3:30, mixed and smelted in an electric arc furnace with an argon atmosphere 3 to 4 times, after cooling, the ingot of (Co _0.5 Fe _0.5 ) ₆₂ Nb ₆ Dy ₂ B ₃₀ master alloy is obtained; The alloy melt was pressed into a copper mold to obtain bulk metallic glass amorphous rod samples with a composition of (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ , a diameter of 3mm and 4mm, and a size of 17mm×10mm ×1mm non-wafer sheet sample.

The same method and equipment as in Example 1 were used to test the bulk metallic glass amorphous sample.

Fig. 9 is a photo of the prepared (Co _0.5 Fe _0.5 ) ₆₁ Nb ₆ Dy ₃ B ₃₀ amorphous rod samples with diameters of 3mm and 4mm, and the amorphous sheet samples with a size of 17mm×10mm×1mm.

Fig. 10 is an X-ray diffraction pattern of an amorphous rod sample with a diameter of 4mm. In the figure, only the diffuse peaks representing the amorphous phase appear, which can prove that the alloy is completely amorphous.

Figure 11 is the thermal analysis DSC curve of an amorphous rod sample with a diameter of 4 mm, its glass transition temperature (T _g ), crystallization onset temperature (T _x ), and the width of the liquid phase in the supercooled zone (ΔT) respectively for 899K, 1007K and 108K.

The tested mechanical properties and soft magnetic parameters are listed in Table 1 below.

Embodiment 3～23:

Similar to Example 1, the molecular formulas of the alloy components of the cobalt-iron-based bulk metallic glasses in Examples 3 to 23 are the molecular formulas shown in the following table, respectively. Its preparation method is basically the same as Example 1. The same method and equipment as in Example 1 were used to test the above bulk metallic glass amorphous samples respectively. The critical dimensions, thermodynamic parameters, mechanical properties and soft magnetic properties of the tested samples are shown in Table 1.

The symbols in Table 1 have the following meanings:

D——sample diameter under the experimental conditions; T _g ——glass transition temperature; ΔT——supercooled liquid zone width; T _{1 ——} liquidus temperature; σ——compression fracture strength; Vickers hardness; H _c —coercivity; μ _e —effective permeability (1A/m, 1kHz); M _s —saturation magnetization.

Table 1: Alloy composition, critical size, thermodynamic parameters, mechanical properties and soft magnetic properties of cobalt-iron-based bulk metallic glass samples in Examples 1-23

It can be concluded from the above table that the cobalt-iron-based bulk metallic glass with the alloy composition in the table has a strong amorphous forming ability and an ultra-wide supercooled liquid phase region, as well as ultra-high strength and excellent soft magnetic properties, so it is A metallic glass material with excellent comprehensive properties can be applied to the fields of micro precision devices and magnetic functional materials, and has broad application prospects.

The embodiments described above have described the technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. All within the scope of the principles of the present invention Any modifications and improvements made should be included within the protection scope of the present invention.

Claims (3)

1. ferro-cobalt bast block metal glass with very large super cooling region, it is characterized in that: the molecular formula of described ferro-cobalt bast block metal glass is:

Co _aFe _bNb _cM _dB _e

Wherein, M is any one in Dy, Y, Tb, Er and five kinds of elements of Gd, and a, b, c, d, e are the molar content of atom, 24≤a≤56,6≤b≤38,4≤c≤8,0＜d≤5,26≤e≤31, and a+b+c+d+e=100.

2. the preparation method with ferro-cobalt bast block metal glass of very large super cooling region is characterized in that: comprise the steps:

Step 1: the molar content according to the elementary composition and atom in the following molecular formula is prepared burden,

Co _aFe _bNb _cM _dB _e

Wherein, M is any one in Dy, Y, Tb, Er and five kinds of elements of Gd, and a, b, c, d, e are the molar content of atom, 24≤a≤56,6≤b≤38,4≤c≤8,0＜d≤5,26≤e≤31, and a+b+c+d+e=100;

Step 2: in the electric arc furnace of argon atmospher,, obtain mother alloy ingot after the cooling with the batch mixes in the step 1, melting;

Step 3: adopt existing permanent mold casting method,, adopt copper mold casting method to make bar-shaped or the en plaque block metal glass with the mother alloy ingot refuse that step 2 obtains.

3. the preparation method with ferro-cobalt bast block metal glass of very large super cooling region according to claim 2 is characterized in that: the purity of described Co, Fe, Nb, M and B element is more than 99.5wt%.

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