A method for preparing a homogeneous layered hetero-metallic material

Abstract

The application discloses a preparation method of a homogeneous layered heterogeneous metal material and belongs to the field of metal material preparation. The preparation method is as follows: (1) polishing and cleaning a deformed metal plate or rod material with fibrous structure as raw material; (2) fixing two raw materials on a clamp, aligning and closely contacting end faces; (3) under a protective gas, passing a pulse current to the end face and simultaneously applying a pressure, under the synergistic effect of electricity-heat-force, welding the end face of the metal plate or rod material to realize metallurgical bonding; (4) controlling the weld width and spacing to obtain a homogeneous layered heterogeneous metal material with different layer thicknesses; and (5) annealing the homogeneous layered heterogeneous metal material to eliminate internal stress. The application realizes reliable metallurgical bonding of the end face of the metal plate or rod material under the coupling effect of electricity, heat and force, can flexibly control the distribution and proportion of microstructures in the heterogeneous material, avoids using conventional large plastic deformation methods, and is higher in flexibility of product size and shape.

Description

Technical Field

[0001] This invention belongs to the field of metal material preparation, and specifically relates to a method for preparing homogeneous layered heterogeneous metal materials. Background Technology

[0002] Heterogeneous metallic materials (referred to as "heterogeneous metals") can overcome the traditional inverse relationship between strength and plasticity in metallic materials, exhibiting an excellent balance between strength and plasticity. Heterogeneous structures are composed of heterogeneous regions with significantly different mechanical properties, specifically including bimodal structures, harmonic structures, layered structures, and gradient nanostructures. During deformation, numerous soft / hard interfaces or soft / hard transition interfaces coordinate deformation, generating additional back stress reinforcement. Simultaneously, a large strain gradient is generated near the soft / hard interfaces, and the increased strain within the soft regions leads to a gradual increase in back stress, resulting in significant back stress work hardening. This allows the matrix to acquire good plasticity, ultimately achieving a good balance between strength and plasticity.

[0003] Currently, the preparation techniques for homogeneous layered heterogeneous metallic materials are generally divided into two categories: 1) Locally controlled deformation of soft-phase coarse-grained metals to form layered heterogeneous single-metal materials, such as the preparation of layered heterogeneous pure copper by die extrusion and the preparation of layered heterogeneous metal sheets by local deformation and rolling with a spherical rolling head. 2) First, the metal material is subjected to large deformation to form hard regions of nanocrystalline / ultrafine crystals, and then annealed to obtain a layered recrystallized soft phase structure in the hard phase matrix. The structure is then controlled to obtain the final homogeneous layered heterogeneous metallic material, such as the preparation of layered heterogeneous pure titanium by asynchronous rolling and incomplete annealing, and the preparation of layered heterogeneous brass alloys by equal channel extrusion and incomplete annealing. However, the above-mentioned preparation techniques for homogeneous layered heterogeneous metallic materials all involve large plastic deformation processes, which present problems such as high difficulty in controlling the preparation process, complex equipment, and limited material size. On the other hand, the above techniques are suitable for metallic materials with good plastic deformation capabilities, such as pure titanium, pure copper, and copper alloys. However, the above preparation techniques are not applicable to magnesium alloys with poor plastic deformation capabilities, which also makes the development of layered heterogeneous magnesium alloy materials very difficult. Summary of the Invention

[0004] To address the difficulties in obtaining layered heterogeneous structures in metallic materials with poor plastic deformation capacity, this invention provides a method for preparing homogeneous layered heterogeneous metallic materials. By utilizing the coupling effect of electricity, heat, and force, the original microstructure of the metallic material is changed simultaneously during welding, and further supplemented by appropriate heat treatment, the preparation of homogeneous layered heterogeneous metallic materials is achieved.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a homogeneous layered heterogeneous metallic material, which uses metal plates or rods as raw materials, and prepares the homogeneous layered heterogeneous metallic material by simultaneously applying pulsed current and external force, and supplementing it with appropriate heat treatment. The specific steps are as follows: Step (1): Use a flap wheel to grind the surface of the plate or rod to remove the surface oxide scale, and at the same time grind the end face of the plate or rod flat, and clean the surface oil stains with acetone. Step (2): Place the two plates or two rods on the clamps respectively, align the end faces and make them in close contact, and then apply pressure to fix them on the clamps; Step (3): Turn on the protective gas, adjust the gas flow rate, turn on the pulse power supply, and conduct the pulse current through the fixed clamp to the end face of the metal plate or rod. At the same time, apply a horizontal external force to one of the clamps. When the displacement of the clamp reaches the set value, cut off the pulse power supply to weld the end face of the metal plate or rod to achieve metallurgical bonding. Then remove the pressure and horizontal external force on the clamp and take out the sample. Step (4): Cut a new end face 2-5mm away from the weld. Repeat steps (2) and (3). By adjusting the pulse current parameters, control the weld width and weld spacing to obtain homogeneous layered heterogeneous metal materials with different layer thicknesses. Step (5) involves annealing the prepared homogeneous layered heterogeneous metal material to eliminate internal stress.

[0006] Furthermore, in step (1), the metal sheet or rod has a modified morphological structure, exhibiting a fibrous microstructure, with an end face area of ​​3~30 mm². 2 .

[0007] Furthermore, in step (2), the fixture used is a Cu-Cr-Zr alloy, the applied pressure is 0.2~0.6MPa, and the distance between the two fixtures is 5~15mm.

[0008] Furthermore, in step (3), the protective gas is high-purity argon, the argon flow rate is 5~15L / min, and the argon nozzles are placed between the fixtures and distributed on the upper and lower sides of the metal plate or rod.

[0009] Furthermore, in step (3), the applied pulse current is 0.8~3kA and the pulse frequency is 1000~2000Hz.

[0010] Furthermore, in step (3), the horizontal external force on the fixture increases linearly from 0 to 0.2~0.5MPa, and the horizontal displacement of the fixture is 4~10mm.

[0011] Furthermore, in step (5), the annealing process is carried out in an argon-protected environment at a temperature of 100-200℃ for 20-30 minutes.

[0012] Furthermore, the weld region of the homogeneous layered heterogeneous metal material prepared by the aforementioned method exhibits a fine equiaxed crystal structure. The resulting homogeneous layered heterogeneous metal rods or plates are composed of layered fibrous structures and fine equiaxed crystal structures.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention does not require large plastic deformation and can construct heterogeneous structures in both metal materials with poor and good plastic deformation capabilities. The distribution and proportion of microstructures in heterogeneous materials can be flexibly controlled by changing the pulse current parameters, pressure, weld width, and weld spacing.

[0014] 2. This invention uses pulsed current to achieve localized heating of the end face of sheet or rod, which is fast and avoids localized melting caused by continuous heat input; at the same time, it improves the plastic deformation capacity of metal materials under electroplastic effect, and then obtains reliable metallurgical bonding of the end face of metal sheet or rod under the coupling effect of electricity, heat and force.

[0015] 3. This invention uses pulsed current heating and cylinder to apply external force, which can be used to construct and control heterogeneous structures in metal plates or bars. It has the advantages of simple equipment structure, low cost, fast forming speed and wide applicability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will take magnesium alloy with poor plastic deformation capacity as an example to briefly introduce the drawings used in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the device used for forming homogeneous heterogeneous metal sheets or bars according to the present invention (the double arrows in the figure indicate the movement direction of the cylinder and the clamp). Figure 2 The microstructure of the homogeneous WE43 magnesium alloy bar in Example 1 of this invention is shown. Figure 3 The room temperature tensile stress-strain curve of the homogeneous WE43 magnesium alloy bar in Example 1 of this invention; In the diagram, 1 is a cylinder that controls the clamping and releasing of the fixture; 2 is the fixture; 3 is a cylinder that controls the horizontal movement of one side of the fixture; and 4 is a pulse power supply. Detailed Implementation

[0018] This invention provides a method for preparing homogeneous layered heterogeneous metallic materials, such as... Figure 1 As shown, it includes the following steps: (1) Using deformed metal rods or plates as raw materials, use a flap wheel to grind the surface to remove the surface oxide scale, and at the same time grind the end face flat and clean the surface oil stains with acetone. (2) Adjust the pressure of the cylinder 1 that controls the clamping and loosening of the clamp to 0.2~0.6MPa, and the distance between the two clamps 2 to 5~15mm. Take two cleaned bars or plates and place them on the clamps 2 respectively, and make the end faces aligned and in close contact. Then apply pressure by the cylinder 1 that controls the clamping and loosening of the clamp to fix the bars or plates on the clamps 2. (3) Open the protective gas (high-purity argon gas is used in this invention) pressure reducing valve, adjust the gas flow rate to 5~15L / min, place the argon gas nozzle between the clamps 2 and distribute it on the upper and lower sides of the metal rod or plate; then turn on the pulse power supply 4, set the pulse current to 0.8~3kA and the pulse frequency to 1000~2000Hz, and conduct the pulse current to the end face of the rod or plate through the clamps 2; at the same time, the cylinder 3 that controls the horizontal movement of one side clamps applies a horizontal external force to one of the clamps, the cylinder pressure increases linearly from 0 to 0.2~0.5MPa, and the horizontal displacement of the clamp is 4~10mm; when the clamp displacement reaches the set value, cut off the pulse power supply, so that the end face of the rod or plate is welded to achieve metallurgical bonding, and then remove the pressure and horizontal external force on the clamp, and take out the sample; (4) Cut a new end face 2-5mm from one side of the weld, then grind the end face flat, repeat (2) and (3) to weld the new end face to another bar or plate to obtain a homogeneous layered heterogeneous metal material. (5) Under argon protection, the prepared homogeneous layered heterogeneous metal material is annealed to eliminate internal stress. The annealing temperature is 100~200℃ and the time is 20~30 minutes. Then it is air-cooled to room temperature.

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the preparation method of the layered heterogeneous magnesium alloy in the embodiments and the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0020] A method for preparing a homogeneous layered heterogeneous WE43 magnesium alloy rod includes the following steps: (1) With a diameter of 3mm (end face area of ​​7mm²) 2 Using WE43 magnesium alloy rods as raw materials, the surface of the rods is polished with a flap wheel, and the end faces of the rods are polished flat. Then, acetone is used to clean the oil stains on the surface of the rods.

[0021] (2) Adjust the pressure of the cylinder that controls the clamping and loosening of the clamp to 0.4MPa, and the distance between the two clamps to 10mm. Take two cleaned bars and place them on the clamps respectively, and make the end faces aligned and in close contact. Then apply pressure through the cylinder to fix the bars on the clamps.

[0022] (3) Open the argon gas pressure reducing valve and adjust the gas flow rate to 10 L / min. Place the argon gas nozzles between the clamps and distribute them on the upper and lower sides of the metal rod. Then turn on the pulse power supply, set the pulse current to 1.2 kA and the pulse frequency to 1000 Hz, and conduct the pulse current to the end face of the rod through the clamps. At the same time, the cylinder controlling the horizontal movement of one side of the clamps applies a horizontal external force to one of the clamps. The cylinder pressure increases linearly from 0 to 0.3 MPa, and the horizontal displacement of the clamp is 5 mm. After the clamp displacement reaches the set value, cut off the pulse power supply to achieve metallurgical bonding of the end face of the rod. Then remove the pressure and horizontal external force on the clamp and take out the sample.

[0023] (4) Cut a new end face 5 mm from one side of the weld, and then grind the end face flat. Repeat (2) and (3) to weld the new end face to another bar to obtain a layered heterogeneous WE43 magnesium alloy bar.

[0024] (5) Under argon protection, the prepared layered heterogeneous WE43 magnesium alloy rods were annealed to eliminate internal stress. The annealing temperature was 200℃ and the time was 30 minutes. Then, the rods were air-cooled to room temperature.

[0025] The microstructure of different regions of the layered heterogeneous WE43 magnesium alloy rod prepared in this embodiment is as follows: Figure 2 As shown, weld regions (a) and (b) exhibit fine equiaxed grain structures. Region (a) has an average grain size of approximately 6 μm and an equiaxed grain layer thickness of 1–1.5 mm; region (b) has an average grain size of approximately 10 μm and an equiaxed grain layer thickness of 1–2 mm. The original bar (c) retains its deformed fibrous structure, with a fibrous layer thickness of 2 mm between welds. Therefore, the prepared layered heterogeneous WE43 magnesium alloy bar is composed of layered fibrous structures and fine equiaxed grain structures. Its room temperature tensile strength reaches 300 MPa. Figure 3 As shown, its room temperature tensile strength reaches 300 MPa, and its elongation at break reaches 9%. In summary, this embodiment has achieved the construction of a layered heterogeneous structure in WE43 magnesium alloy bars. Example 2

[0026] A method for preparing a homogeneous layered heterogeneous AZ91 magnesium alloy sheet includes the following steps: (1) Using a modified AZ91 magnesium alloy plate with a thickness of 3mm and a width of 10mm as raw material, the surface of the bar is polished with a flap wheel, and the end face of the bar is polished flat. Then, acetone is used to clean the oil stains on the surface of the bar.

[0027] (2) Adjust the pressure of the cylinder that controls the clamping and loosening of the clamp to 0.6MPa, and the distance between the two clamps to 15mm. Take two cleaned plates and place them on the clamps respectively, and make the end faces aligned and in close contact. Then, apply pressure through the cylinder to fix the bar on the clamp.

[0028] (3) Open the argon gas pressure reducing valve and adjust the gas flow rate to 15L / min. Place the argon gas nozzles between the fixtures and distribute them on the upper and lower sides of the metal plate. Then turn on the pulse power supply, set the pulse current to 3kA and the pulse frequency to 2000Hz, and conduct the pulse current to the end face of the bar through the fixtures. At the same time, the cylinder controlling the horizontal movement of one side of the fixture applies a horizontal external force to one of the fixtures. The cylinder pressure increases linearly from 0 to 0.5MPa, and the horizontal displacement of the fixture is 10mm. After the fixture displacement reaches the set value, cut off the pulse power supply to achieve metallurgical bonding of the end face of the bar. Then remove the pressure and horizontal external force on the fixture and take out the sample.

[0029] (4) Cut a new end face 5 mm from one side of the weld, and then grind the end face flat. Repeat (2) and (3) to weld the new end face to another plate to obtain a layered heterogeneous AZ91 magnesium alloy plate.

[0030] (5) Under argon protection, the prepared layered heterogeneous AZ91 magnesium alloy plate was annealed to eliminate internal stress. The annealing temperature was 100℃ and the time was 30 minutes. Then it was air-cooled to room temperature.

[0031] The prepared layered heterogeneous AZ91 magnesium alloy sheet has a room temperature tensile strength of 240 MPa and a fracture elongation of 12%. Example 3

[0032] A method for preparing homogeneous layered heterogeneous AZ91 magnesium alloy rods includes the following steps: (1) With a diameter of 4mm (end face area of ​​12.6mm²) 2 Using AZ91 magnesium alloy rods in their modified form as raw material, the surface of the rods is polished with a flap wheel, and the end faces of the rods are polished flat. Then, acetone is used to clean the oil stains on the surface of the rods.

[0033] (2) Adjust the pressure of the cylinder that controls the clamping and loosening of the clamp to 0.5MPa, and the distance between the two clamps to 12mm. Take two cleaned bars and place them on the clamps respectively, making sure the end faces are aligned and in close contact. Then apply pressure through the cylinder to fix the bars on the clamps.

[0034] (3) Open the argon gas pressure reducing valve and adjust the gas flow rate to 12L / min. Place the argon gas nozzles between the clamps and distribute them on the upper and lower sides of the metal rod. Then turn on the pulse power supply, set the pulse current to 2kA and the pulse frequency to 1600Hz, and conduct the pulse current to the end face of the rod through the clamps. At the same time, the cylinder controlling the horizontal movement of one side of the clamps applies a horizontal external force to one of the clamps. The cylinder pressure increases linearly from 0 to 0.4MPa, and the horizontal displacement of the clamp is 7mm. After the clamp displacement reaches the set value, cut off the pulse power supply to achieve metallurgical bonding of the end face of the rod. Then remove the pressure and horizontal external force on the clamps and take out the sample.

[0035] (4) Cut a new end face 5 mm from one side of the weld, and then grind the end face flat. Repeat (2) and (3) to weld the new end face to another bar to obtain a layered heterogeneous AZ91 magnesium alloy bar.

[0036] (5) Under argon protection, the prepared layered heterogeneous AZ91 magnesium alloy rods were annealed to eliminate internal stress. The annealing temperature was 100℃ and the time was 30 minutes. Then, the rods were air-cooled to room temperature.

[0037] The prepared layered heterogeneous AZ91 magnesium alloy rods have a room temperature tensile strength of 260 MPa and a fracture elongation of 15%. Example 4

[0038] A method for preparing a homogeneous layered heterogeneous WE43 magnesium alloy sheet includes the following steps: (1) Using a modified WE43 magnesium alloy plate with a thickness of 1.5mm and a width of 2mm as raw material, the surface of the bar is polished with a flap wheel, and the end face of the bar is polished flat. Then, acetone is used to clean the oil stains on the surface of the bar.

[0039] (2) Adjust the pressure of the cylinder that controls the clamping and loosening of the clamp to 0.2MPa, and the distance between the two clamps to 5mm. Take two cleaned plates and place them on the clamps respectively, and make the end faces aligned and in close contact. Then, apply pressure through the cylinder to fix the bar on the clamp.

[0040] (3) Open the argon gas pressure reducing valve and adjust the gas flow rate to 5L / min. Place the argon gas nozzles between the fixtures and distribute them on the upper and lower sides of the metal plate. Then turn on the pulse power supply, set the pulse current to 0.8kA and the pulse frequency to 1000Hz, and conduct the pulse current to the end face of the bar through the fixtures. At the same time, the cylinder controlling the horizontal movement of one side of the fixture applies a horizontal external force to one of the fixtures. The cylinder pressure increases linearly from 0 to 0.2MPa, and the horizontal displacement of the fixture is 4mm. After the fixture displacement reaches the set value, cut off the pulse power supply to achieve metallurgical bonding of the end face of the bar. Then remove the pressure and horizontal external force on the fixture and take out the sample.

[0041] (4) Cut a new end face 4mm from one side of the weld, and then grind the end face flat. Repeat (2) and (3) to weld the new end face to another plate to obtain a layered heterogeneous WE43 magnesium alloy plate.

[0042] (5) Under argon protection, the prepared layered heterogeneous WE43 magnesium alloy plate was annealed to eliminate internal stress. The annealing temperature was 200℃ and the time was 30 minutes. Then it was air-cooled to room temperature.

[0043] The prepared layered heterogeneous WE43 magnesium alloy sheet has a room temperature tensile strength of 320 MPa and a fracture elongation of 8%.

[0044] Although embodiments of the present invention have been described above, any modifications and substitutions made by those skilled in the art without departing from the principles and spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a homogeneous layered heterogeneous metallic material, characterized in that, This preparation method uses metal plates or rods as raw materials, and prepares homogeneous layered heterogeneous metal materials by simultaneously applying pulsed current and external force, supplemented by appropriate heat treatment. The specific steps are as follows: Step (1): Use a flap wheel to grind the surface of the plate or rod to remove the surface oxide scale, and at the same time grind the end face of the plate or rod flat, and clean the surface oil stains with acetone. Step (2): Place the two plates or two rods on the clamps respectively, align the end faces and make them in close contact, and then apply pressure to fix them on the clamps; Step (3): Turn on the protective gas, adjust the gas flow rate, turn on the pulse power supply, and conduct the pulse current through the fixed clamp to the end face of the metal plate or rod. At the same time, apply a horizontal external force to one of the clamps. When the displacement of the clamp reaches the set value, cut off the pulse power supply to weld the end face of the metal plate or rod to achieve metallurgical bonding. Then remove the pressure and horizontal external force on the clamp and take out the sample. Step (4): Cut a new end face 2-5mm away from the weld. Repeat steps (2) and (3) to obtain homogeneous layered heterogeneous metal materials with different layer thicknesses by controlling the weld width and weld spacing. Step (5) involves annealing the prepared homogeneous layered heterogeneous metal material to eliminate internal stress.

2. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (1), the metal sheet or rod has a modified morphological structure with an end face area of ​​3~30mm². 2 .

3. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (2), the fixture used is a Cu-Cr-Zr alloy, the applied pressure is 0.2~0.6MPa, and the distance between the two fixtures is 5~15mm.

4. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (3), the protective gas is high-purity argon, the argon flow rate is 5~15L / min, and the argon nozzles are placed between the fixtures and distributed on the upper and lower sides of the metal plate or rod.

5. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (3), the applied pulse current is 0.8~3kA and the pulse frequency is 1000~2000Hz.

6. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (3), the horizontal external force on the fixture increases linearly from 0 to 0.2~0.5MPa, and the horizontal displacement of the fixture is 4~10mm.

7. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, In step (5), the annealing process is carried out in an argon-protected environment at a temperature of 100-200°C for 20-30 minutes.

8. The method for preparing homogeneous layered heterogeneous metallic materials according to claim 1, characterized in that, The weld region of the homogeneous layered heterogeneous metal material prepared by the method exhibits a fine equiaxed crystal structure.

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