CN115852274B - A method for improving room temperature tensile plasticity of Zr-based amorphous alloys - Google Patents

Abstract

The invention discloses a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy. The method uses hot and cold cycles to improve the nanoscale structural non-uniformity in the amorphous alloy, and then uses a high-frequency vibration indenter to inflate the amorphous alloy. Micron-scale non-uniform structural arrays are prepared on the surface. Activate more rheological units in amorphous alloys at the nanoscale, further hinder the expansion of the main shear bands in the plastic deformation of amorphous alloys through the micron-scale non-uniform structural array, and promote the generation of composite shear bands. Under the multi-coupling effect of the micron-scale heterogeneous structure and its stress field, the room temperature tensile plasticity of the micro-nano composite heterogeneous structure amorphous alloy is improved. This invention has important application value in promoting the application of high-performance amorphous alloys as structural materials.

Description

A method for improving room temperature tensile plasticity of Zr-based amorphous alloys

Technical field

The invention relates to a method for improving the room temperature tensile plasticity of a Zr-based amorphous alloy. It improves the room temperature tensile plasticity of the amorphous alloy by preparing a micro-nano composite non-uniform structure in the amorphous alloy, and belongs to the technical field of high-performance metal materials.

Background technique

The long-range disordered microstructure of amorphous alloys brings many excellent performance properties, such as high strength, high hardness and high wear resistance. It is a new type of structural material with broad application prospects. Due to its unique energy state, amorphous alloys also exhibit superior soft magnetic properties, higher catalytic activity and better corrosion resistance, making them valuable for practical engineering applications in the field of functional materials. Therefore, the engineering application prospects and important theoretical value of amorphous alloys have attracted widespread attention from scientific researchers, and have become a research hotspot integrating materials, physics, chemistry, mechanics and energy.

Different from the plastic deformation mechanism dominated by traditional crystalline alloys through dislocations, twinning, and phase transformations, under uniaxial tensile load at room temperature, the deformation of amorphous alloys is highly localized on a microscopic scale and highly localized on a macroscopic scale. It manifests as rapid expansion along the main shear zone, causing the system to exhibit catastrophic brittle fracture. The lack of room temperature tensile plasticity severely restricts the engineering application of amorphous alloys as high-performance structural materials and has become a bottleneck for the development of this field. Therefore, the plastic deformation mechanism of amorphous alloys and the improvement of room temperature tensile plasticity are important and difficult topics in the field of amorphous alloy mechanics.

There are two main methods to improve the room temperature tensile plasticity of amorphous alloys: composition optimization and microstructure control. The use of N+ ion irradiation increases the disorder and free volume content near the surface of the Cu-based amorphous alloy, and at the same time causes a phase transformation from B2 CuZr to B19'CuZr martensite, which improves the tensile plasticity of the amorphous alloy. However, this method will cause partial crystallization of the sample. By appropriately doping elements such as oxygen and boron in amorphous alloys, partial covalent bonds can be contributed to the system, and the resulting more obvious structural heterogeneity can significantly improve the tensile plasticity of amorphous alloys without loss. its yield strength. However, this method will reduce the glass-forming ability of the amorphous alloy and make the preparation process more complicated. Using thermoplastic molding and die-casting, a metallic glass sample with a regular micro-scale hole array was developed. By regulating the size and spatial distribution of the hole array, controllable tensile ductility was achieved. However, this method will have a greater impact on the overall mechanical properties of the material, and the strength and stability of the structure will be reduced. Amorphous alloys have metastable structures and atomic cluster configurations, which have a great impact on the plasticity of amorphous alloys. However, how to control this non-uniform structure is still a challenge. Therefore, it is of great significance to explore a simple and easy method to control the microscopic heterogeneous structure of amorphous alloys and thereby improve the room temperature tensile plasticity of amorphous alloys.

Contents of the invention

Purpose of the invention: The purpose of the invention is to provide a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy.

Technical solution: a method of the present invention for improving the room temperature tensile plasticity of Zr-based amorphous alloy. The method improves the room temperature tensile plasticity of the amorphous alloy by preparing a micro-nano composite non-uniform structure. The micro-nano composite non-uniform structure It is obtained by preparing a micron-scale non-uniform structure array on the surface of an amorphous alloy material with a non-uniform structure.

Through the above technical solution, the present invention uses hot and cold cycles to change the nanoscale structural non-uniformity in the amorphous alloy, and then uses a high-frequency vibrating indenter to prepare a micron-scale non-uniform structural array on the surface of the amorphous alloy. Activate more rheological units in the crystalline alloy, further hinder the expansion of the main shear band in the plastic deformation of the amorphous alloy through the micron-scale inhomogeneous structure array, and promote the generation of composite shear bands. In the nano- and micron-scale inhomogeneous structures Under the action of multiple couplings of stress fields, the room temperature tensile plasticity of micro-nano composite non-uniform structure amorphous alloys is improved.

As a further improvement of the above solution, the atomic percentage range of the components of the amorphous alloy material is as follows: Cu: 10-20%; Ni: 10-20%; Al: 10-20%; Ti: 2-5%, the rest The amount is Zr.

As a further improvement of the above solution, the method specifically includes the following steps:

Step 1: Prepare the bulk amorphous alloy material by vacuum melting the alloy solution and spray-casting it into a liquid nitrogen-cooled copper mold, followed by rapid cooling;

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with a higher degree of non-uniformity;

Step 3: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material, thereby obtaining a Zr-based amorphous alloy with a micro-nano composite non-uniform structure.

As a further improvement of the above solution, the step one includes the following steps:

(1) Weigh the corresponding elemental element raw materials according to the chemical formula of the amorphous alloy;

(2) Mix the weighed elemental element raw materials and put them into a vacuum arc melting furnace for multiple meltings. After cooling, an alloy ingot with uniform composition is obtained;

(3) Under vacuum conditions, the alloy ingot obtained in step (2) is melted into an alloy molten liquid and sprayed into a liquid nitrogen-cooled copper mold. Compared with traditional water-cooled copper mold cooling, the liquid nitrogen-cooled copper mold has better The cooling rate of the molten metal is higher, and amorphous alloy materials with higher rheological unit content can be obtained, that is, amorphous alloys with higher degree of non-uniformity;

(4) Process the amorphous alloy material prepared in step (3) into a tensile sample.

As a further improvement of the above solution, the second step includes the following steps:

(1) Place the amorphous alloy material into liquid nitrogen and keep it warm for 5-10 minutes to fully cool the sample;

(2) Take out the sample and put it into a container with a water temperature of 30-60°C for 5-10 minutes to fully heat the sample;

(3) Repeat the above steps (1) and (2) alternately 10-30 times.

Due to the intrinsic non-uniformity in the amorphous alloy structure, the local structure has different expansion and contraction rates during the above-mentioned hot and cold cycle treatment. After multiple hot and cold cycles, the structural non-uniformity of the amorphous alloy can be further improved.

As a further improvement of the above solution, the third step includes the following steps:

(1) The amorphous alloy material is fixed on a high-frequency vibration platform. Within the elastic deformation stress range, a hemispherical indenter is used to apply high-frequency loads on the upper and lower surfaces of the amorphous alloy within the micron range. The non-crystalline alloy material is changed through energy input. The energy state and microstructure of crystalline alloys can be controlled to control the non-uniform structure within the micron region of amorphous alloys;

(2) Use a high-precision two-dimensional moving slide to design different micron-scale arrays on the upper and lower surfaces of the amorphous alloy material. For the designed array lattice, repeat steps (1) in sequence to prepare micron-scale arrays on the surface of the amorphous alloy material. Non-uniform structural array.

As a further improvement of the above solution, in step (1), the load applied by the hemispherical indenter is 40-60% of the yield strength of the amorphous alloy material, so that the amorphous alloy material is in the elastic deformation zone.

As a further improvement of the above solution, in step (1), the diameter of the contact area between the hemispherical indenter and the amorphous alloy material is 50-200 μm, the array point spacing is twice the diameter of the contact area, and the array shape is square.

As a further improvement of the above solution, in step (1), the vibration frequency of the high-frequency vibration platform is 100-10000 Hz, and the vibration amplitude is 20-50 μm.

As a further improvement of the above solution, in step (2), the vibration loading time of each array point is 0.1-1 second.

The present invention prepares nano- and micron-scale micro-nano composite non-uniform structures in amorphous alloy materials through hot and cold cycles and high-frequency vibration, activating more rheological units at the nano-scale, and through the non-uniform structure at the micron scale. The array hinders the expansion of the main shear bands during plastic deformation of amorphous alloy materials, promotes the generation of composite shear bands, and improves the room temperature tensile strength of amorphous alloys under the multiple coupling effects of nano- and micron-scale non-uniform structures and their stress fields. Plasticity. The processing method provided by this invention has important application value in promoting the application of high-performance amorphous alloys as structural materials.

Beneficial effects: Compared with the existing technology, the present invention has the following significant advantages:

(1) Through a convenient and simple process, the room temperature tensile plasticity of amorphous alloys can be improved, and specific parts of amorphous alloy materials can be precisely targeted;

(2) The high-frequency vibration loading load is within the elastic deformation range of the amorphous alloy material, does not change the macrostructure of the material, and does not lose the stability, strength and other properties of the amorphous alloy material components;

(3) Avoid the impact of element addition on the glass forming ability of the amorphous alloy system, and the treatment process does not require a heat treatment process, which will not cause crystallization of the amorphous alloy material, and at the same time achieve an energy-saving effect.

Description of the drawings

Figure 1 is a schematic diagram of a technical solution for improving the room temperature tensile plasticity of amorphous alloys through the preparation of micro-nano composite heterogeneous structures: (a) A schematic diagram of the preparation of amorphous alloy materials and their microstructure through spray casting rapid solidification method; (b) The effect of hot and cold cycles Schematic diagram of promoting the evolution of nano-scale non-uniform structures in amorphous alloys; (c) Schematic diagram of the controllable preparation of micron-scale non-uniform structural arrays in amorphous alloys under the action of high-frequency vibration; (d) Schematic diagram of tensile plasticity testing of amorphous alloy materials.

Figure 2 shows the X-ray diffraction patterns of the as-cast amorphous alloy and the amorphous alloy after preparation and processing of micro-nano composite heterogeneous structure.

Figure 3 shows the room temperature tensile stress-strain curves of the cast amorphous alloy and the amorphous alloy after the micro-nano composite heterogeneous structure preparation process.

Detailed ways

The technical solution of the present invention will be further described below with reference to the accompanying drawings.

In the embodiment of the present invention, a universal testing machine is used to conduct a room temperature uniaxial tensile test of the Zr-based amorphous alloy material until the amorphous alloy material is broken, the sample size and experimental data are recorded, the engineering stress-strain curve is obtained, and the amorphous alloy material is calculated. Room temperature tensile plasticity data of alloy materials to evaluate the room temperature tensile plasticity of materials treated with different processes.

Example 1

This embodiment provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy, which includes the following steps:

Step 1. Prepare the bulk amorphous alloy material by vacuum melting the alloy solution and spray-casting it into a liquid nitrogen-cooled copper mold. After rapid cooling, according to the chemical formula of the amorphous alloy material, weigh the corresponding weight of elemental elements and heat them in a vacuum electric arc furnace. Melting, a homogeneous alloy ingot with the atomic composition of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ is obtained. Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy molten liquid was sprayed into a copper mold cooled by liquid nitrogen. After rapid cooling, a thickness of 1 mm and a width of 5 mm was prepared. Amorphous alloy sheet of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ . Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with higher structural non-uniformity:

The amorphous alloy tensile sample was placed in liquid nitrogen and incubated for 10 minutes, and then the sample was taken out and placed in a container with a water bath temperature of 40°C for 10 minutes. The hot and cold cycle was alternately repeated 30 times.

Step 3: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material:

The amorphous alloy tensile sample is fixed on a high-frequency vibration platform, and a hemispherical indenter is used to apply loads to the upper and lower surfaces of the amorphous alloy material respectively. The load value is 40% of the yield strength of the amorphous alloy material, so that the sample is in the elastic deformation zone. , the diameter of the contact area between the hemispherical indenter and the sample is 50μm, the array point spacing is 100μm, the array shape is square, the high-frequency vibration load frequency is 10000Hz, the amplitude is 20μm, and the high-frequency vibration loading time of each array point is 1 second. For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the cast amorphous alloy material and the amorphous alloy without micro-nano composite heterogeneous structure preparation and treatment. The loading speed was 1×10 ^-5 s ^-1 , obtain the stress-strain curve, and calculate the tensile plasticity and yield strength of the cast amorphous alloy and the processed amorphous alloy.

The X-ray diffraction patterns of the as-cast amorphous alloy and the amorphous alloy after preparation and treatment with micro-nano composite heterogeneous structure are shown in Figure 2. From the figure, it can be seen that the prepared as-cast material and the processed material are both amorphous. state structure. Figure 3 shows the room temperature tensile stress-strain curve of the cast amorphous alloy and the amorphous alloy prepared and processed with micro-nano composite heterogeneous structure. It can be seen that the cast amorphous alloy sample has brittle fracture and no plastic deformation. After treatment The final amorphous alloy sample showed a certain degree of tensile plasticity, and the plastic deformation reached 0.69%.

From the above results, it can be concluded that the room temperature tensile plasticity of Zr amorphous alloy can be significantly improved through the preparation process of micro-nano composite heterogeneous structure.

Example 2

This embodiment provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy, which includes the following steps:

Step 1: Prepare the bulk amorphous alloy material by vacuum melting the alloy solution and spray-casting it into a liquid nitrogen-cooled copper mold, followed by rapid cooling:

According to the chemical formula of amorphous alloy materials, the corresponding weight of elemental elements is weighed and melted in a vacuum arc furnace to obtain a uniform alloy ingot with the atomic composition of Zr ₅₅ Cu ₁₀ Ni ₂₀ Al ₁₀ Ti ₅ . Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy molten liquid was sprayed into a copper mold cooled by liquid nitrogen. After rapid cooling, a thickness of 1 mm and a width of 5 mm was prepared. Zr ₅₅ Cu ₁₀ Ni ₂₀ Al ₁₀ Ti ₅ amorphous alloy sheet. Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with higher structural non-uniformity:

Put the amorphous alloy tensile sample into liquid nitrogen and keep it incubated for 5 minutes. Then take out the sample and put it into a container with a water bath temperature of 60°C and keep it incubated for 5 minutes. Repeat the hot and cold cycle alternately 10 times.

Step 3: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material:

The amorphous alloy tensile sample is fixed on a high-frequency vibration platform, and a hemispherical indenter is used to apply load on the upper and lower surfaces of the amorphous alloy material respectively. The load value is 60% of the yield strength of the amorphous alloy material, so that the sample is in the elastic deformation zone. , the diameter of the contact area between the hemispherical indenter and the sample is 200μm, the array point spacing is 400μm, the array shape is square, the high-frequency vibration load frequency is 100Hz, the amplitude is 50μm, and the high-frequency vibration loading time of each array point is 0.1 seconds. For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the cast amorphous alloy material and the amorphous alloy without micro-nano composite heterogeneous structure preparation and treatment. The loading speed was 1×10 ^-5 s ^-1 , obtain the stress-strain curve, and calculate the tensile plasticity and yield strength of the cast amorphous alloy and the processed amorphous alloy. The treated amorphous alloy sample showed a certain degree of tensile plasticity, and the plastic deformation reached 0.57%.

From the above results, it can be concluded that the room temperature tensile plasticity of Zr amorphous alloy can be significantly improved through the preparation process of micro-nano composite heterogeneous structure.

Example 3

This embodiment provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy, which includes the following steps:

Step 1. Prepare the bulk amorphous alloy material by vacuum melting the alloy solution and spray-casting it into a liquid nitrogen-cooled copper mold. After rapid cooling, according to the chemical formula of the amorphous alloy material, weigh the corresponding weight of elemental elements and heat them in a vacuum electric arc furnace. Melting, a homogeneous alloy ingot with an atomic composition of Zr ₅₅ Cu ₁₀ Ni ₁₀ Al ₂₀ Ti ₅ is obtained. Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy molten liquid was sprayed into a copper mold cooled by liquid nitrogen. After rapid cooling, a thickness of 1 mm and a width of 5 mm was prepared. Zr ₅₅ Cu ₁₀ Ni ₁₀ Al ₂₀ Ti ₅ amorphous alloy sheet. Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with higher structural non-uniformity:

The amorphous alloy tensile sample was placed in liquid nitrogen and incubated for 8 minutes, and then the sample was taken out and placed in a container with a water bath temperature of 30°C for 7 minutes. The hot and cold cycle was alternately repeated 20 times.

Step 3: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material:

The amorphous alloy tensile sample is fixed on a high-frequency vibration platform, and a hemispherical indenter is used to apply loads to the upper and lower surfaces of the amorphous alloy material respectively. The load value is 50% of the yield strength of the amorphous alloy material, so that the sample is in the elastic deformation zone. , the diameter of the contact area between the hemispherical indenter and the sample is 100μm, the array point spacing is 200μm, the array shape is square, the high-frequency vibration load frequency is 1000Hz, the amplitude is 300μm, and the high-frequency vibration loading time of each array point is 0.5 seconds. For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the as-cast amorphous alloy material and the amorphous alloy without micro-nano composite heterogeneous structure preparation and treatment. The loading speed was 1×10 ^-5 s ^-1 , obtain the stress-strain curve, and calculate the tensile plasticity and yield strength of the cast amorphous alloy and the processed amorphous alloy. The treated amorphous alloy sample showed a certain degree of tensile plasticity, and the plastic deformation reached 0.63%.

From the above results, it can be concluded that the room temperature tensile plasticity of Zr amorphous alloy can be significantly improved through the preparation process of micro-nano composite heterogeneous structure.

Comparative example 1

This comparative example provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy. Compared with Example 1, the difference is that the cooling method for preparing the amorphous alloy in step one is a water-cooled copper mold, which specifically includes the following steps:

Step 1. Prepare bulk amorphous alloy materials through vacuum melting, spray casting and cooling: According to the chemical formula of amorphous alloy materials, weigh the corresponding weight of elemental elements and melt them in a vacuum arc furnace to obtain the atomic composition of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al Homogeneous alloy ingot of ₁₀ Ti ₂ . Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy melt was sprayed into a water-cooled copper mold. After cooling, Zr ₅₈ with a thickness of 1mm and a width of 5mm was prepared. Amorphous alloy sheet of Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ . Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with higher structural non-uniformity:

The amorphous alloy tensile sample was placed in liquid nitrogen and incubated for 10 minutes, and then the sample was taken out and placed in a container with a water bath temperature of 40°C for 10 minutes. The hot and cold cycle was alternately repeated 30 times.

Step 3: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material:

The amorphous alloy tensile sample is fixed on a high-frequency vibration platform, and a hemispherical indenter is used to apply load on the upper and lower surfaces of the amorphous alloy material respectively. The load value is 40% of the yield strength of the amorphous alloy material, so that the sample is in the elastic deformation zone. , the diameter of the contact area between the hemispherical indenter and the sample is 50μm, the array point spacing is 100μm, the array shape is square, the high-frequency vibration load frequency is 10000Hz, the amplitude is 20μm, and the high-frequency vibration loading time of each array point is 1 second. For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the as-cast amorphous alloy material and the amorphous alloy without micro-nano composite heterogeneous structure preparation and treatment. The loading speed was 1×10 ^-5 s ^-1 , obtain the stress-strain curve, and calculate the tensile plasticity and yield strength of the cast amorphous alloy and the processed amorphous alloy. The treated amorphous alloy sample showed a certain degree of tensile plasticity, and the plastic deformation reached 0.34%.

From the above results, it can be concluded that for Zr-based amorphous alloys prepared by cooling water-cooled copper molds, the room temperature tensile plasticity of Zr amorphous alloys can be improved by the micro-nano composite heterogeneous structure preparation process, but the improvement is not as good as that of liquid nitrogen-cooled copper. Zr-based amorphous alloy prepared by mold.

Comparative example 2

This comparative example provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy. Compared with Example 1, the difference is that the processing step of step three is not used, and only steps one and two are used to process the amorphous alloy. Specifically, It includes the following steps:

Step 1. Prepare bulk amorphous alloy material through vacuum melting, spray casting and rapid cooling:

According to the chemical formula of amorphous alloy materials, the corresponding weight of elemental elements is weighed and melted in a vacuum arc furnace to obtain a uniform alloy ingot with the atomic composition of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ . Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy molten liquid was sprayed into a copper mold cooled by liquid nitrogen. After rapid cooling, a thickness of 1 mm and a width of 5 mm was prepared. Amorphous alloy sheet of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ . Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Improve the nanoscale structural non-uniformity in the bulk amorphous alloy material through hot and cold cycles to obtain an amorphous alloy material with higher structural non-uniformity:

The amorphous alloy tensile sample was placed in liquid nitrogen and incubated for 10 minutes, and then the sample was taken out and placed in a container with a water bath temperature of 40°C for 10 minutes. The hot and cold cycle was alternately repeated 30 times.

For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the as-cast amorphous alloy material and the amorphous alloy after only thermal and cold cycle treatment. The loading speed was 1×10 ^-5 s ^{- 1.} Obtain the stress-strain curve and calculate the tensile plasticity and yield strength of the cast amorphous alloy and the processed amorphous alloy. The treated amorphous alloy sample showed brittle fracture, and the tensile plasticity was close to 0. From the above results, it can be concluded that the room temperature tensile plasticity of Zr amorphous alloy cannot be improved only through hot and cold cycles.

Comparative example 3

This comparative example provides a method for improving the room temperature tensile plasticity of Zr-based amorphous alloy. Compared with Example 1, the difference is that the processing step of Step 2 is not used, and only Steps 1 and 3 are used to process the amorphous alloy. Specifically, It includes the following steps:

Step 1. Preparation of bulk amorphous alloy materials through vacuum melting, spray casting and rapid cooling: According to the chemical formula of amorphous alloy materials, weigh the corresponding weight of elemental elements and melt them in a vacuum arc furnace to obtain the atomic composition of Zr ₅₈ Cu ₂₀ Ni ₁₀ Homogeneous alloy ingot of Al ₁₀ Ti ₂ . Under Ar gas protective atmosphere, the alloy ingot was induction remelted in a quartz tube, and then the alloy molten liquid was sprayed into a copper mold cooled by liquid nitrogen. After rapid cooling, a thickness of 1 mm and a width of 5 mm was prepared. Amorphous alloy sheet of Zr ₅₈ Cu ₂₀ Ni ₁₀ Al ₁₀ Ti ₂ . Use 2000# sandpaper to polish the sample to a thickness of 300 μm, use mechanical polishing to improve the surface quality of the amorphous alloy material, and use wire EDM or laser cutting to prepare the amorphous alloy tensile sample.

Step 2: Prepare a micron-scale non-uniform structure array on the surface of the amorphous alloy material:

The amorphous alloy tensile sample is fixed on a high-frequency vibration platform, and a hemispherical indenter is used to apply load on the upper and lower surfaces of the amorphous alloy material respectively. The load value is 40% of the yield strength of the amorphous alloy material, so that the sample is in the elastic deformation zone. , the diameter of the contact area between the hemispherical indenter and the sample is 50μm, the array point spacing is 100μm, the array shape is square, the high-frequency vibration load frequency is 10000Hz, the amplitude is 20μm, and the high-frequency vibration loading time of each array point is 1 second.

For the samples after the above treatment, a universal tensile testing machine was used to conduct a room temperature quasi-static tensile test on the cast amorphous alloy material and the amorphous alloy after only micron-scale non-uniform structure array preparation. The loading speed was 1× 10 ^{- 5} s ^-1 , obtain the stress-strain curve, and calculate the tensile plasticity and yield strength of the as-cast amorphous alloy and the amorphous alloy after only micron-scale non-uniform structure array preparation. The amorphous alloy sample that was only processed to prepare the micron-scale non-uniform structural array showed a certain degree of tensile plasticity, but the tensile plastic deformation was only 0.16%. From the above results, it can be concluded that only the preparation of micron non-uniform structural arrays through high-frequency vibration can only slightly improve the room temperature tensile plasticity of Zr amorphous alloy.

Through the above examples and comparative examples, it can be proved that the preparation of micron non-uniform structural arrays only through a single hot and cold cycle and high-frequency vibration cannot significantly improve the room temperature tensile plasticity of Zr-based amorphous alloys. Under the conditions of using liquid nitrogen cooling copper mold spray casting to prepare amorphous alloys with a high degree of non-uniformity, the nanoscale structural non-uniformity in the amorphous alloys is improved through hot and cold cycles, and the high-frequency vibration of the indenter is further used to form the amorphous alloys. Micron-scale non-uniform structural arrays are prepared on the alloy surface to activate more rheological units at the nano-scale, and hinder the expansion of the main shear bands during plastic deformation through the micron-scale non-uniform structural arrays and promote the generation of composite shear bands. Under the multiple coupling effect of nano- and micron-scale heterogeneous structures and their stress fields, the room temperature tensile plasticity of micro-nano composite heterogeneous structure amorphous alloys can be significantly improved.

The above examples are only preferred embodiments of the present invention and do not limit the scope of protection of the present invention. All modifications, combinations, partial combinations and substitutions based on the design ideas of this case fall within the scope of protection of this case. .

Claims (8)

1. The method for improving room-temperature stretch plasticity of the Zr-based amorphous alloy is characterized by improving room-temperature stretch plasticity of the amorphous alloy by preparing a micro-nano composite non-uniform structure, wherein the micro-nano composite non-uniform structure is obtained by preparing a micrometer-scale non-uniform structure array on the surface of an amorphous alloy material with a nanometer-scale non-uniform structure; the method specifically comprises the following steps:

firstly, preparing a block amorphous alloy material by vacuum smelting alloy solution and spray casting the alloy solution into a liquid nitrogen cooling copper mold and rapidly cooling the alloy solution;

step two, improving the nano-scale structural non-uniformity in the bulk amorphous alloy material through cold and hot circulation to obtain an amorphous alloy material with higher structural non-uniformity;

preparing a micrometer non-uniform structure array on the surface of the amorphous alloy material to obtain Zr-based amorphous alloy with a micro-nano composite non-uniform structure;

the third step comprises the following steps:

(1) Fixing an amorphous alloy material on a high-frequency vibration platform, applying high-frequency load to the upper and lower surfaces of the amorphous alloy within a micrometer region by adopting a hemispherical pressure head within the elastic deformation stress range, and changing the energy state and microstructure of the amorphous alloy through energy input so as to realize the regulation and control of the non-uniform structure within the micrometer region of the amorphous alloy;

(2) And (3) designing different micrometer-scale arrays on the upper surface and the lower surface of the amorphous alloy material by utilizing a high-precision two-dimensional moving sliding table, and sequentially repeating the step (1) for the designed array lattice to prepare the micrometer-scale non-uniform structure array on the surface of the amorphous alloy material.

2. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein the amorphous alloy material comprises the following components in atomic percent: cu:10-20%; ni:10-20%; al:10-20%; ti:2-5%, the balance being Zr.

3. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein said step one comprises the steps of:

(1) Weighing corresponding elemental raw materials according to the chemical formula of the amorphous alloy;

(2) Mixing the weighed elemental raw materials, putting the mixture into a vacuum arc melting furnace for smelting for a plurality of times, and cooling to obtain alloy ingots with uniform components;

(3) Under the vacuum condition, melting the alloy cast ingot obtained in the step (2) into alloy solution, spraying the alloy solution into a copper mold cooled by liquid nitrogen, and rapidly cooling to obtain an amorphous alloy material with high rheological unit content;

(4) And (3) processing the amorphous alloy material prepared in the step (3) into a stretched sample.

4. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein said step two comprises the steps of:

(1) Placing the amorphous alloy material into liquid nitrogen for heat preservation for 5-10 minutes, and fully cooling the sample;

(2) Taking out the sample, placing the sample into a container with the water temperature of 30-60 ℃ for heat preservation for 5-10 minutes, and fully heating the sample;

(3) And (5) repeating the step (1) and the step (2) for 10-30 times alternately.

5. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein in step (1), the hemispherical indenter is loaded by 40-60% of the yield strength of the amorphous alloy material, so that the amorphous alloy material is in an elastic deformation zone.

6. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein in the step (1), a hemispherical indenter and an amorphous alloy material contact area diameter is 50-200 μm, an array point pitch is 2 times the contact area diameter, and an array shape is square.

7. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein in said step (1), the vibration frequency of the high frequency vibration platform is 100-10000Hz and the vibration amplitude is 20-50 μm.

8. The method for improving room temperature stretch plasticity of a Zr-based amorphous alloy according to claim 1, wherein in said step (2), the vibration loading time per array point is 0.1-1 sec.