CN108504966B

CN108504966B - Cobalt-based bulk amorphous alloy and preparation method thereof

Info

Publication number: CN108504966B
Application number: CN201810593726.9A
Authority: CN
Inventors: 郭胜锋; 赖利民; 何然干; 丁凯露
Original assignee: Southwest University
Current assignee: Southwest University
Priority date: 2018-06-11
Filing date: 2018-06-11
Publication date: 2020-03-20
Anticipated expiration: 2038-06-11
Also published as: CN108504966A

Abstract

The invention relates to a cobalt-based bulk amorphous alloy and a preparation method thereof in the field of amorphous alloys. The component of the bulk amorphous alloy is Co_x‑Mo_y‑B_zX, y and z are atomic percentWherein 59. ltoreq. x.ltoreq.67, 17. ltoreq. y.ltoreq.28, 11. ltoreq. z.ltoreq.19 and x + y + z =100, such as Co₆₄Mo₂₂B₁₄，Co₅₉Mo₂₈B₁₃And the like. The block amorphous alloy has the characteristics of ultrahigh strength, high amorphous forming capability, good thermal stability, corrosion resistance, soft magnetic performance and the like, does not contain elements such as rare and noble metals Ta, Nb and the like, has low preparation cost, and is suitable for application fields such as high-strength metal structural members, corrosion-resistant and wear-resistant coatings, magnetic components and parts.

Description

Cobalt-based bulk amorphous alloy and preparation method thereof

Technical Field

The invention belongs to the field of amorphous alloy materials, and mainly relates to a novel ternary cobalt-based bulk amorphous alloy and a preparation method thereof. In particular to a ternary bulk amorphous alloy with ultrahigh strength, high amorphous forming capability, excellent corrosion resistance and good soft magnetic property.

Background

The amorphous alloy has a unique structure with long-range disorder and short-range order of atomic arrangement, so that the amorphous alloy has extremely high strength and hardness, good wear resistance and processability and excellent corrosion resistance. Amorphous three-dimensional size larger than 1mm is generally called as bulk amorphous alloy, and among numerous bulk amorphous alloys, cobalt-based bulk amorphous alloy has higher strength, good corrosion resistance and soft magnetic property. However, the cobalt-based amorphous alloy developed in the early stage has relatively low forming ability, and the product thereof mainly exists in the form of thin strip, filament, and the like. Until 2000, Co was developed in Inoue et al₄₀Fe₂₂Nb₆Zr₂B₃₀After the bulk amorphous alloy with the diameter of 1mm (Materials transformations Jim, 2000, 41 (9): 1256-. Subsequently, introducing trace element Er into cobalt-based amorphous alloy by Men et al in 2006, Co with critical dimension as high as 10mm was developed₄₈Cr₁₅Mo₁₄C₁₅B₆Er₂Bulk amorphous alloys (journal of materials research, 2006, 21 (4): 958-.

In order to further improve the mechanical property of the cobalt-based bulk amorphous, a Co-Ta-B bulk amorphous system (Journal of Materials research, 2011, 26 (16): 2072 and 2079) was developed in 2011, and the fracture strength of the Co-Ta-B bulk amorphous system is as high as 6GPa, but the plasticity of the Co-Ta bulk amorphous system is only 0.5%, so that the engineering application and further development of the Co-Ta-B bulk amorphous system are severely limited. 2012 of the yearShenbaolong et al (Co)_1-xFe_x)₆₈B_21.9Si_5.1Nb₅(intermellics 23 (2012) 63-67) amorphous alloy, the room temperature plasticity is improved to a certain extent, and 1.3% plastic strain is reached. However, the strength of such alloys is overall reduced. Then, a Co-Nb-B amorphous alloy system (Journal of Non-Crystalline solids, 386 (2014) 121-123) is continuously developed, the highest strength of the Co-Nb-B amorphous alloy system reaches 5200MPa, the Co-Nb-B amorphous alloy system has high amorphous forming capability, the critical dimension reaches 2mm, and the plasticity is greatly improved. However, cobalt-based bulk amorphous alloys developed at present often contain rare and precious metals, such as Ta, Nb, etc., which limits the development space and application space to some extent. Therefore, the cobalt-based bulk amorphous alloy material with high strength, low cost, good corrosion resistance and soft magnetic property is developed, and has important theoretical research value and practical application significance.

Disclosure of Invention

In view of this, the present invention aims to: (1) providing a brand new ternary ultrahigh-strength cobalt-based bulk amorphous alloy and a preparation method thereof; (2) the cobalt-based bulk amorphous alloy material prepared by the method has the advantages of ultrahigh strength, high amorphous forming capability, excellent corrosion resistance, good soft magnetic property and the like; (3) the cobalt-based bulk amorphous alloy system with lower cost is developed without rare and noble metals such as Ta and Nb which are commonly used in the high-strength cobalt-based bulk amorphous alloy system at present.

In order to achieve the purpose, the invention provides the following technical scheme:

the cobalt-based bulk amorphous alloy is characterized in that the cobalt-based bulk amorphous alloy contains Co_x-Mo_y-B_zIn the system, x, y and z are atomic percent, x is more than or equal to 59 and less than or equal to 67, y is more than or equal to 17 and less than or equal to 28, and z is more than or equal to 11 and less than or equal to 19. The cobalt-based bulk amorphous alloy consists of a single amorphous phase, and the critical diameter of the cobalt-based bulk amorphous alloy is 1-2 mm; the cobalt-based bulk amorphous alloy has the fracture strength of 4.8-5.4 GPa and the plastic deformation of 4%; the corrosion current density of the cobalt-based bulk amorphous alloy in a 3.5% NaCl solution is 3.94 mu A/cm²~7.55μA/cm²(ii) a The glass transition temperature of the cobalt-based bulk amorphous alloy is 818-847K.

The preparation method of the cobalt-based bulk amorphous alloy comprises the following steps:

(1) weighing three high-purity raw materials of Co, Mo and B according to the components of the cobalt-based bulk amorphous alloy, and polishing surface oxide skins of metal Co and metal Mo to ensure that the purity of each raw material is higher than 99.9%.

(2) Firstly, putting the prepared raw materials into a vacuum electric arc furnace; then vacuumizing to 4X 10^-3Below Pa, then filling argon at 0.05MPa, continuing to vacuumize to 4X 10^-3Below Pa, filling argon of 0.2 MPa; then smelting for five to seven times under the argon protective atmosphere with the purity of 99.999 percent to ensure that the alloy components are uniform and obtain a master alloy ingot; and finally, completely melting the master alloy ingot, and obtaining a sample rod of the cobalt-based bulk amorphous alloy through a water-cooling copper mold rapid solidification technology.

Further, the purity of the three high-purity raw materials of Co, Mo and B in the step (1) is more than 99.9%.

Further, the sample rod of the cobalt-based bulk amorphous alloy is obtained through the water-cooling copper mold rapid solidification technology in the step (2).

The invention has the beneficial effects that: the glass has a critical dimension of 1-2 mm, a fracture strength of 4.8 GPa-5.4 MPa, good room temperature plasticity and a high glass transition temperature; in addition, in a NaCl solution with the mass fraction of 3.5%, the corrosion resistance is low in current density and wide in passivation region, and the corrosion resistance is good; does not contain rare and noble metals such as Nb, Ta and the like which are commonly used in the high-strength cobalt-based bulk amorphous alloy system at present, and Co_x-Mo_y-B_zThe cost is lower; the preparation method of the bulk amorphous alloy adopts the smelting process of a vacuum arc furnace, and then uses the water-cooling copper mold rapid solidification technology to prepare the bulk amorphous alloy sample rod, and the preparation process is simple.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 shows Co of example 1₆₄Mo₂₂B₁₄XRD pattern of bulk amorphous alloy.

FIG. 2 shows Co of example 1₆₄Mo₂₂B₁₄Compressive stress strain curve of bulk amorphous alloy

FIG. 3 shows Co of example 1₆₄Mo₂₂B₁₄Bulk amorphous alloy potentiodynamic polarization curve.

FIG. 4 shows Co of example 2₅₉Mo₂₈B₁₃XRD pattern of bulk amorphous alloy.

FIG. 5 shows Co of example 2₅₉Mo₂₈B₁₃Bulk amorphous alloy potentiodynamic polarization curve.

FIG. 6 shows Co of example 3₅₉Mo₂₄B₁₇、Co₆₀Mo₂₆B₁₄、Co₆₅Mo₂₄B₁₁DTA (transformation-induced plasticity) diagram of bulk amorphous alloy.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

Preparation of Co₆₄Mo₂₂B₁₄Bulk amorphous

(1) According to Co₆₄Mo₂₂B₁₄Three high-purity raw materials of Co, Mo and B are weighed according to the components of the cobalt-based bulk amorphous alloy, and the oxide skin on the surfaces of metal Co and metal Mo is polished to ensure that the purity of each raw material is higher than 99.9 percent.

Co obtained in example 1₆₄Mo₂₂B₁₄Analyzing the bulk amorphous alloy bar by X-ray diffraction (XRD)Co as shown in FIG. 1₆₄Mo₂₂B₁₄The result of the XRD pattern of the bulk amorphous alloy shows that the bulk amorphous alloy has a typical diffuse scattering peak package of an amorphous material and has no obvious crystal peak, and the component can be shown to be composed of a single amorphous phase within the XRD precision range, and the amorphous critical dimension of the component is 2mm in diameter.

Co obtained in example 1₆₄Mo₂₂B₁₄The bulk amorphous alloy bar is analyzed by a compression mechanics experiment, such as Co shown in figure 2₆₄Mo₂₂B₁₄The compressive stress strain curve of the bulk amorphous alloy shows that Co₆₄Mo₂₂B₁₄The fracture strength of the bulk amorphous alloy is 5250MPa, and the plastic strain is about 4%.

Co obtained in example 1₆₄Mo₂₂B₁₄Electrochemical experiments are carried out on the block amorphous alloy bar in NaCl solution with the mass fraction of 3.5%, and Co is shown in figure 3₆₄Mo₂₂B₁₄The potentiodynamic polarization curve diagram of the bulk amorphous alloy shows that Co₆₄Mo₂₂B₁₄The bulk amorphous alloy has obvious passivation region, belongs to uniform corrosion, and has the corrosion current density of about 7.55 mu A/cm²。

Example 2

Preparation of Co₅₉Mo₂₈B₁₃Bulk amorphous

(1) According to Co₅₉Mo₂₈B₁₃Three high-purity raw materials of Co, Mo and B are weighed according to the components of the cobalt-based bulk amorphous alloy, and the oxide skin on the surfaces of metal Co and metal Mo is polished to ensure that the purity of each raw material is higher than 99.9 percent.

Co obtained in example 2₅₉Mo₂₈B₁₃The bulk amorphous alloy rod was analyzed by X-ray diffraction (XRD), Co shown in FIG. 4₅₉Mo₂₈B₁₃The XRD pattern of the bulk amorphous alloy shows that the result shows a typical diffuse scattering peak package of the amorphous material, wherein no obvious crystal peak appears, and the component can be shown to be composed of a single amorphous phase within the XRD precision range, and the maximum amorphous forming size of the component is 1.5mm in diameter.

Co obtained in example 2₅₉Mo₂₈B₁₃Electrochemical experiments are carried out on the block amorphous alloy bar in NaCl solution with the mass fraction of 3.5%, and Co is shown in figure 5₅₉Mo₂₈B₁₃The potentiodynamic polarization curve diagram of the bulk amorphous alloy shows that Co₅₉Mo₂₈B₁₃The bulk amorphous alloy presents a remarkable passivation interval and belongs to typical uniform corrosion, and the corrosion current density is about 3.94 mu A/cm²。

Example 3

Preparation of Co₅₉Mo₂₄B₁₇、Co₆₀Mo₂₆B₁₄、Co₆₅Mo₂₄B₁₁Bulk amorphous alloy

(1) According to Co₅₉Mo₂₄B₁₇、Co₆₀Mo₂₆B₁₄、Co₆₅Mo₂₄B₁₁Three high-purity raw materials of Co, Mo and B are weighed according to the components of the cobalt-based bulk amorphous alloy, and the oxide skin on the surfaces of metal Co and metal Mo is polished to ensure that the purity of each raw material is higher than 99.9 percent.

1mm in diameter obtained in example 3Co₅₉Mo₂₄B₁₇、Co₆₀Mo₂₆B₁₄、Co₆₅Mo₂₄B₁₁DTA analysis of the three amorphous alloys, Co as shown in FIG. 6₅₉Mo₂₄B₁₇、Co₆₀Mo₂₆B₁₄、Co₆₅Mo₂₄B₁₁The DTA curve of the bulk amorphous alloy shows that the series of cobalt-based bulk amorphous alloys have remarkable glass transition and crystallization phenomena, the glass transition temperature Tg is 818-847K, the crystallization initial temperature Tx is 911-920K, and the cobalt-based bulk amorphous alloys have extremely high thermal stability.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. The cobalt-based bulk amorphous alloy is characterized in that the cobalt-based bulk amorphous alloy contains Co_x-Mo_y-B_zIn the system, x, y and z are atomic percent, wherein x is more than or equal to 59 and less than or equal to 67, y is more than or equal to 17 and less than or equal to 28, and z is more than or equal to 13 and less than or equal to 19; the cobalt-based bulk amorphous alloy consists of a single amorphous phase, and the critical amorphous forming diameter of the cobalt-based bulk amorphous alloy is 1-2 mm; the cobalt-based bulk amorphous alloy has the fracture strength of 4.8-5.4 GPa and the plastic deformation of 4%; the corrosion current density of the cobalt-based bulk amorphous alloy in a 3.5% NaCl solution is 3.94 mu A/cm²~7.55μA/cm²(ii) a The glass transition temperature of the cobalt-based bulk amorphous alloy is 818-847K;

(1) weighing three high-purity raw materials of Co, Mo and B according to the components of the cobalt-based bulk amorphous alloy, and polishing surface oxide skins of metal Co and metal Mo to ensure that the purities of the metal Co, the metal Mo and the simple substance B are higher than 99.9%;

(2) firstly, the prepared raw materials are put into vacuumAn electric arc furnace; then vacuumizing to 4X 10^-3Below Pa, then filling argon at 0.05MPa, continuing to vacuumize to 4X 10^-3Below Pa, filling argon of 0.2 MPa; then smelting for five to seven times under the argon protective atmosphere with the purity of 99.999 percent to ensure that the alloy components are uniform and obtain a master alloy ingot; and finally, completely melting the master alloy ingot, and obtaining a sample rod of the cobalt-based bulk amorphous alloy through a water-cooling copper mold rapid solidification technology.