Short-process preparation method for high-conductivity and high-wear-resistant titanium diboride / copper boron composite materials

Abstract

The invention discloses a short-process preparation method for a high-conductivity and high-wear-resistant titanium diboride / copper-boron composite material. The method comprises the following steps: according to the mass percentage of titanium diboride in the composite material being 1-5wt.%, the mass percentage of boron being 0.5-1.5wt.%, 70.0-90.2wt.% oxygen-free copper block A, 5.0-15.3wt.% magnesium and 4.8-14.7wt.% boron oxide are weighed and placed in a left inner cavity of a double-cavity crucible, wherein the sum of the mass percentages of the above components is 100%, 93.1-98.6wt.% oxygen-free copper block B and 1.4-6.9wt.% titanium particles are weighed and placed in a right inner cavity of the double-cavity crucible, wherein the sum of the mass percentages of the above components is 100%, the composite material is smelted in a vacuum induction furnace, cast into a water-cooled copper mold, and finally subjected to thermomechanical treatment. The preparation method solves the problems of gravity segregation and insufficient Ti reaction in the titanium diboride / copper composite material prepared by the existing composite casting method.

Description

Technical Field

[0001] The invention belongs to the technical field of metal-based composite material preparation, and relates to a short-process preparation method of a high-conductivity and high-wear-resistant titanium diboride / copper-boron composite material. Background Art

[0002] Ceramic particle-reinforced copper-based composites are widely used in the field of electrical materials due to their excellent mechanical and electrical properties. Among the many methods for preparing copper-based composites, the composite casting method has the advantages of simple process, ability to prepare complex structural workpieces, low manufacturing cost, and suitability for industrial production, making it one of the important technical means for preparing ceramic-reinforced copper-based composites. However, due to the existence of specific gravity segregation and incomplete in-situ reaction, the ceramic phase reacts and forms only in certain areas of the composite matrix, causing it to segregate in the copper matrix, directly affecting the performance of the composite material. This is also the technical obstacle that currently limits the large-scale application of the composite casting method.

[0003] Titanium diboride ceramic particles, a rare conductive ceramic, are widely used in copper-based composites. Currently, the mainstream method for preparing titanium diboride / copper-based composites is an in-situ reaction. However, due to the extremely short in-situ reaction time between the Ti and B elements, the resulting titanium diboride particles adsorb, aggregate, and grow, deteriorating the mechanical properties of the composite. Furthermore, the imprecise control of the B and Ti content in conventional copper-boron and copper-titanium master alloys results in the presence of incompletely reacted Ti, which affects the electrical conductivity of the composite. Summary of the Invention

[0004] The purpose of the present invention is to provide a short-process preparation method for a highly conductive and wear-resistant titanium diboride / copper boron composite material, which solves the problems of gravity segregation and insufficient Ti reaction in the in-situ self-generated titanium diboride / copper composite material prepared by the existing composite casting method.

[0005] The technical solution adopted by the present invention is a short-process preparation method of a high-conductivity and high-wear-resistant titanium diboride / copper boron composite material, comprising the following steps:

[0006] Step 1: Weigh 70.0-90.2 wt.% of oxygen-free copper block A, 5.0-15.3 wt.% of magnesium, and 4.8-14.7 wt.% of boron oxide by mass, and the sum of the mass percentages of the above components is 100%; weigh 93.1-98.6 wt.% of oxygen-free copper block B and 1.4-6.9 wt.% of titanium particles by mass, and the sum of the mass percentages of the above components is 100%;

[0007] Step 2: placing the weighed oxygen-free copper block A, magnesium, and boron oxide into the inner cavity of one side of a double-cavity crucible, and placing the weighed oxygen-free copper block B and titanium particles into the inner cavity of the other side of the double-cavity crucible, based on the mass percentage of titanium diboride in the composite material being 1 to 5 wt.%, and the mass percentage of boron being 0.5 to 1.5 wt.%. The double-cavity crucible is located in a vacuum induction furnace, and a pouring funnel and a water-cooled copper mold are placed below the double-cavity crucible in sequence;

[0008] Step 3, performing induction melting under an argon atmosphere, and after the raw materials are completely melted, casting them into a water-cooled copper mold through a pouring funnel to obtain a cast titanium diboride / copper boron block;

[0009] Step 4: subjecting the as-cast titanium diboride / copper boron block to thermomechanical treatment to achieve a deformation of 60-70%, thereby obtaining a highly conductive and wear-resistant titanium diboride / copper boron composite material.

[0010] In step 2, a 200-325 mesh tungsten mesh is placed on the top of one side of the pouring funnel opposite to the inner cavity of the crucible where the oxygen-free copper block A, magnesium and boron oxide are placed.

[0011] The double-cavity crucible is a cylindrical graphite crucible with a vertical baffle installed in the middle, which divides the crucible cavity into two separate cavities.

[0012] The specific process of step 3 is as follows: use a two-stage vacuum system to exhaust the air in the vacuum induction furnace and fill it with high-purity argon. At the same time, preheat the pouring funnel and perform induction melting in an argon atmosphere. After the raw materials in the double-cavity crucible are completely melted, flip the double-cavity crucible to allow the melt to enter the pouring funnel. When the melt passes through the melt flow channel in the pouring funnel, the two metal liquids are fully mixed and react in situ, and finally flow into a water-cooled copper mold to obtain a cast titanium diboride / copper boron block.

[0013] In step 3, a two-stage vacuum system is used to exhaust the air in the vacuum induction furnace. When the vacuum degree reaches 3.6×10 -2 After reaching 0.05 MPa, the vacuum system was turned off and high-purity argon was filled in to make the total pressure in the furnace chamber -0.05 MPa. The above vacuuming and argon filling processes were repeated 3 times. At the same time, the pouring funnel was preheated to raise the pouring funnel temperature to 1100°C, the induction heating power was turned on, and the induction heating power was increased to 12 kW ~ 14 kW at a rate of 1 kW / min. After the raw materials in the double-cavity crucible were completely melted, the melt temperature was measured. When the melt temperature was 1300 ~ 1500°C, it was kept warm for 3 min ~ 5 min, and then the double-cavity crucible was turned over.

[0014] In step 4, the cast titanium diboride / copper boron block is subjected to deformation heat treatment, including first placing the cast titanium diboride / copper boron block in a muffle furnace, heating it to 800°C and keeping it warm for 30 minutes, and then forging it with an air forging hammer. After each deformation of 10%, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes. When the total deformation exceeds 50%, the single deformation is 5%, and after the single deformation, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes, until the final total deformation reaches 60-70%.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) By introducing 0.5-1.5wt.% excess boron, the Ti element is forced to react completely to form titanium diboride particles. Since copper-based composite materials are mainly used in the field of electrical materials, they have high requirements for electrical conductivity. In the process of preparing titanium diboride copper-based composite materials by in-situ reaction, the reaction is difficult to control, so there will often be residual Ti elements. However, the residual Ti elements in the composite material will directly deteriorate the electrical conductivity of the alloy. Therefore, by excessively adding 0.5-1.5wt.% of B elements, it can be ensured that there is no residual Ti element in the composite material, thereby improving the electrical conductivity of the composite material. In addition, the excessive B element makes the composite material a copper-boron matrix. The addition of B element improves the wear resistance of the material, so that the composite material has both high electrical conductivity and high wear resistance.

[0017] (2) Since Ti and B elements are very likely to react in situ in the copper melt to generate titanium diboride particles, if the titanium-containing melt and the B-containing melt are mixed before pouring, it will directly lead to the adsorption and agglomeration of titanium diboride particles, causing serious segregation of the composite material, thereby affecting the electrical conductivity, wear resistance and strength of the alloy. The present application separates the titanium-containing melt and the B-containing melt through a double-cavity crucible, blocking the generation of TiB2 during the smelting process from the source, effectively avoiding the generation of segregation and agglomeration, and finally obtaining a titanium diboride / copper boron composite material with complete reaction, uniform dispersion distribution and good comprehensive performance;

[0018] (3) Due to the great difference in melting points between Cu (melting point of 1083°C) and B (melting point of 2076°C), the conventional method for preparing copper-boron alloy is to use powder metallurgy to mix copper powder and boron powder, press them into a blank, and then obtain them by hot pressing and sintering. This method is inefficient and cannot accurately grasp the content of element B. The present application uses oxygen-free copper block, magnesium and boron oxide as raw materials, adopts molten salt method to prepare copper-boron intermediate alloy, introduces element B in the form of adding boron oxide, and adopts redox reaction method to reduce Mg from boron oxide and generate magnesium oxide particles. This method avoids secondary heating of copper-boron alloy and reduces component burnout. At the same time, this method does not require pre-preparation of copper-boron alloy, reduces the process, and realizes the short process for preparing titanium diboride / copper-boron composite material.

[0019] (4) By placing a tungsten mesh on the top of the pouring funnel opposite to the inner cavity of the crucible where the oxygen-free copper block A, magnesium and boron oxide are placed, the generated magnesium oxide particles and other infusible impurities can be prevented from entering the melt;

[0020] (5) There are tiny shrinkage holes in the as-cast composite material. By subjecting the composite material to large plastic deformation through thermomechanical treatment, the tiny casting defects inside the material can be removed and the strength of the composite material can be improved.

[0021] (6) The preparation method of the present application has fewer steps, low cost, extremely competitive performance, and is easy to industrialize, so it has great development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the vacuum casting system used in the short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper-boron composite material of the present invention;

[0023] Figure 2 This is a SEM microstructure image of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material prepared in Example 3 of the present invention;

[0024] Figure 3 This is a comparison chart of the electrical conductivity and friction coefficient of the highly conductive and wear-resistant titanium diboride / copper boron composite materials in Examples 1, 2 and 3 of the present invention.

[0025] In the figure, 1. Double-cavity crucible, 2. Pouring funnel, 3. Water-cooled copper mold, 4. Tungsten mesh, 5. Baffle, 6. Induction coil. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] A short-process preparation method for a highly conductive and wear-resistant titanium diboride / copper boron composite material comprises the following steps:

[0029] Step 1: Weigh 90.2 wt.% of oxygen-free copper block A, 5.0 wt.% of magnesium block, and 4.8 wt.% of boron oxide particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%; weigh 98.6 wt.% of oxygen-free copper block B and 1.4 wt.% of titanium particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%;

[0030] Step 2, refer to Figure 1According to the mass percentage of titanium diboride in the composite material being 1wt.%, the mass percentage of boron being 0.5wt.%, the weighed oxygen-free copper block A, magnesium block and boron oxide particles are placed into the left inner cavity of the double-cavity crucible 1, and the weighed oxygen-free copper block B and titanium particles are placed into the right inner cavity of the double-cavity crucible 1. The double-cavity crucible 1 is located in the induction coil 6 in the vacuum induction furnace. A pouring funnel 2 and a water-cooled copper mold 3 are placed under the double-cavity crucible 1 in sequence. The double-cavity crucible 1 is a cylindrical graphite crucible with a vertical baffle 5 installed in the middle. The baffle 5 divides the inner cavity of the crucible into two separate cavities. A 325-mesh tungsten mesh 4 is placed on the top of the pouring funnel 2 facing the left inner cavity of the double-cavity crucible 1.

[0031] Step 3: Use a two-stage vacuum system to exhaust the air in the vacuum induction furnace. When the vacuum degree reaches 3.6×10 -2 Pa, turn off the vacuum system, fill with high-purity argon, and let the total pressure in the furnace chamber be -0.05MPa. Repeat the above vacuuming and argon filling processes 3 times. At the same time, preheat the pouring funnel 2 to raise the temperature of the pouring funnel 2 to 1100℃, turn on the induction heating power supply, and increase the induction heating power to 12kW at a rate of 1kW / min. After the raw materials in the double-cavity crucible 1 are completely melted, measure the melt temperature. When the melt temperature reaches 1300℃, keep it warm for 3 minutes, and then turn over the double-cavity crucible 1 to allow the melt to enter the pouring funnel 2. When the melt passes through the melt flow channel in the pouring funnel 2, the two metal liquids are fully mixed and react in situ, and finally flow into the water-cooled copper mold 3 to obtain a cast titanium diboride / copper boron block.

[0032] Step 4, subjecting the cast titanium diboride / copper boron block to thermomechanical treatment, comprising first placing the cast titanium diboride / copper boron block in a muffle furnace, heating it to 800°C and keeping it warm for 30 minutes, and then forging it with an air forging hammer. After each deformation of 10%, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes. When the total deformation exceeds 50%, the single deformation is 5%, and after the single deformation, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes, until the final total deformation reaches 70%, thereby obtaining a highly conductive and wear-resistant titanium diboride / copper boron composite material.

[0033] The performance of the highly conductive and wear-resistant titanium diboride / copper boron composite material prepared in Example 1 was tested, and the conductivity was measured to be 75.42% IACS and the friction coefficient was 0.57.

[0034] Example 2

[0035] A short-process preparation method for a highly conductive and wear-resistant titanium diboride / copper boron composite material comprises the following steps:

[0036] Step 1: Weigh 79.1 wt.% of oxygen-free copper block A, 10.7 wt.% of magnesium block, and 10.2 wt.% of boron oxide particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%; weigh 95.9 wt.% of oxygen-free copper block B and 4.1 wt.% of titanium particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%;

[0037] Step 2: According to the mass percentage of titanium diboride in the composite material of 3wt.%, the mass percentage of boron is 1wt.%, and the weighed oxygen-free copper block A, magnesium block and boron oxide particles are placed in the left inner cavity of the double-cavity crucible, and the weighed oxygen-free copper block B and titanium particles are placed in the right inner cavity of the double-cavity crucible. The double-cavity crucible is located in the induction coil in the vacuum induction furnace, and a pouring funnel and a water-cooled copper mold are placed below the double-cavity crucible in sequence. The double-cavity crucible is a cylindrical graphite crucible with a vertical baffle installed in the middle. The baffle divides the crucible cavity into two separate cavities. A 270-mesh tungsten mesh is placed on the top of the pouring funnel on the left inner cavity of the double-cavity crucible 1.

[0038] Step 3: Use a two-stage vacuum system to exhaust the air in the vacuum induction furnace. When the vacuum degree reaches 3.6×10 -2 Pa, turn off the vacuum system, fill with high-purity argon, and let the total pressure in the furnace chamber be -0.05MPa. Repeat the above vacuuming and argon filling processes 3 times. At the same time, preheat the pouring funnel to raise the pouring funnel temperature to 1100℃, turn on the induction heating power supply, and increase the induction heating power to 13kW at a rate of 1kW / min. After the raw materials in the double-cavity crucible are completely melted, measure the melt temperature. When the melt temperature reaches 1400℃, keep it warm for 4 minutes, and then turn the double-cavity crucible over to allow the melt to enter the pouring funnel. When the melt passes through the melt flow channel in the pouring funnel, the two metal liquids are fully mixed and react in situ, and finally flow into the water-cooled copper mold to obtain a cast titanium diboride / copper boron block.

[0039] Step 4, performing thermomechanical treatment on the cast titanium diboride / copper boron block, including first placing the cast titanium diboride / copper boron block in a muffle furnace, heating it to 800°C and keeping it warm for 30 minutes, and then forging it with an air forging hammer. After each deformation of 10%, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes. When the total deformation exceeds 50%, the single deformation is 5%, and after the single deformation, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes, until the final total deformation reaches 65%, thereby obtaining a highly conductive and wear-resistant titanium diboride / copper boron composite material.

[0040] The performance of the highly conductive and wear-resistant titanium diboride / copper boron composite material prepared in Example 2 was tested, and the conductivity was measured to be 72.36% IACS and the friction coefficient was 0.54.

[0041] Example 3

[0042] A short-process preparation method for a highly conductive and wear-resistant titanium diboride / copper boron composite material comprises the following steps:

[0043] Step 1: Weigh 70.0 wt.% of oxygen-free copper block A, 15.3 wt.% of magnesium block, and 14.7 wt.% of boron oxide particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%; weigh 93.1 wt.% of oxygen-free copper block B and 6.9 wt.% of titanium particles, respectively, by mass percentage, and the sum of the mass percentages of the above components is 100%;

[0044] Step 2: According to the mass percentage of titanium diboride in the composite material of 5wt.%, the mass percentage of boron is 1.5wt.%, and the weighed oxygen-free copper block A, magnesium block and boron oxide particles are placed in the left inner cavity of the double-cavity crucible, and the weighed oxygen-free copper block B and titanium particles are placed in the right inner cavity of the double-cavity crucible. The double-cavity crucible is located in the induction coil in the vacuum induction furnace, and a pouring funnel and a water-cooled copper mold are placed under the double-cavity crucible in sequence. The double-cavity crucible is a cylindrical graphite crucible with a vertical baffle installed in the middle. The baffle divides the crucible cavity into two separate cavities, and a 200-mesh tungsten mesh is placed on the top of the pouring funnel opposite the left inner cavity of the double-cavity crucible.

[0045] Step 3: Use a two-stage vacuum system to exhaust the air in the vacuum induction furnace. When the vacuum degree reaches 3.6×10 -2 Pa, turn off the vacuum system, fill with high-purity argon, and let the total pressure in the furnace chamber be -0.05MPa. Repeat the above vacuuming and argon filling processes 3 times. At the same time, preheat the pouring funnel to raise the pouring funnel temperature to 1100℃, turn on the induction heating power supply, and increase the induction heating power to 14kW at a rate of 1kW / min. After the raw materials in the double-cavity crucible are completely melted, measure the melt temperature. When the melt temperature reaches 1500℃, keep it warm for 5 minutes, then turn over the double-cavity crucible to allow the melt to enter the pouring funnel. When the melt passes through the melt flow channel in the pouring funnel, the two metal liquids are fully mixed and react in situ, and finally flow into the water-cooled copper mold to obtain a cast titanium diboride / copper boron block.

[0046] Step 4, performing thermomechanical treatment on the cast titanium diboride / copper boron block, including first placing the cast titanium diboride / copper boron block in a muffle furnace, heating it to 800°C and keeping it warm for 30 minutes, and then forging it with an air forging hammer. After each deformation of 10%, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes. When the total deformation exceeds 50%, the single deformation is 5%, and after the single deformation, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes, until the final total deformation reaches 60%, thereby obtaining a highly conductive and wear-resistant titanium diboride / copper boron composite material.

[0047] The microstructure of the titanium diboride / copper boron composite material prepared in Example 3 was observed, and its SEM microstructure was as follows: Figure 2 As shown, from Figure 2 It can be seen from the figure that the titanium diboride / copper boron composite material prepared by the method of the present invention has fine grains and uniform distribution of ceramic particles.

[0048] The performance of the titanium diboride / copper boron composite material prepared in Example 3 was tested, and the electrical conductivity was measured to be 68.59% IACS and the friction coefficient was 0.49.

[0049] Figure 3 The conductivity and friction coefficient of the titanium diboride / copper boron composite material in Example 1, Example 2 and Example 3 of the present invention are compared. Figure 3 It can be seen that with the increase of titanium diboride content in the composite material, the conductivity and friction coefficient of the titanium diboride / copper boron composite material gradually decrease, indicating that when titanium diboride is 1wt.%, the conductivity is the best, and with the increase of titanium diboride content in the composite material, its wear resistance gradually improves.

Claims

1. A short-process preparation method for a highly conductive and wear-resistant titanium diboride / copper boron composite material, characterized in that: The following steps are involved: Step 1: Weigh 70.0-90.2 wt.% of oxygen-free copper block A, 5.0-15.3 wt.% of magnesium, and 4.8-14.7 wt.% of boron oxide by mass, and the sum of the mass percentages of the above components is 100%; weigh 93.1-98.6 wt.% of oxygen-free copper block B and 1.4-6.9 wt.% of titanium particles by mass, and the sum of the mass percentages of the above components is 100%; Step 2: placing weighed oxygen-free copper block A, magnesium, and boron oxide into the left inner cavity of a double-cavity crucible (1), and placing weighed oxygen-free copper block B and titanium particles into the right inner cavity of the double-cavity crucible (1), with the mass percentage of titanium diboride being 1-5 wt.% and the mass percentage of boron being 0.5-1.5 wt.% in the composite material; and placing the weighed oxygen-free copper block B and titanium particles into the right inner cavity of the double-cavity crucible (1); the double-cavity crucible (1) is located in a vacuum induction furnace, and a pouring funnel (2) and a water-cooled copper mold (3) are sequentially placed below the double-cavity crucible (1); Step 3, performing induction melting under an argon atmosphere, after the raw materials are completely melted, casting them into a water-cooled copper mold (3) through a pouring funnel (2), thereby obtaining a cast titanium diboride / copper boron block; Step 4: subjecting the as-cast titanium diboride / copper boron block to thermomechanical treatment to achieve a deformation of 60-70%, thereby obtaining a highly conductive and wear-resistant titanium diboride / copper boron composite material.

2. The short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material according to claim 1, characterized in that: In the step 2, a 200-325 mesh tungsten mesh (4) is placed on the top of the pouring funnel (2) on the left side of the double-cavity crucible (1) facing the inner cavity.

3. The short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material according to claim 1, characterized in that: The double-cavity crucible (1) is a cylindrical graphite crucible, with a vertical baffle (5) installed in the middle of the interior, and the baffle (5) divides the inner cavity of the crucible into two separate cavities.

4. The short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material according to claim 1, characterized in that: The specific process of step 3 is as follows: after the air in the vacuum induction furnace is exhausted using a two-stage vacuum system, high-purity argon gas is filled in, and at the same time, the pouring funnel (2) is preheated, and induction melting is performed in an argon atmosphere. After the raw materials in the double-cavity crucible (1) are completely melted, the double-cavity crucible (1) is turned over to allow the melt to enter the pouring funnel (2). When the melt passes through the melt flow channel in the pouring funnel (2), the two metal liquids are fully mixed and react in situ, and finally flow into a water-cooled copper mold (3) to obtain a cast titanium diboride / copper boron block.

5. The short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material according to claim 4, characterized in that: In step 3, a two-stage vacuum system is used to exhaust the air in the vacuum induction furnace. When the vacuum degree reaches 3.6×10 -2 After reaching 0.05 MPa, the vacuum system is turned off and high-purity argon is filled in to make the total pressure in the furnace chamber -0.05 MPa. The above vacuuming and argon filling process is repeated 3 times. At the same time, the pouring funnel (2) is preheated to raise the temperature of the pouring funnel (2) to 1100°C. The induction heating power is turned on and the induction heating power is increased to 12 kW to 14 kW at a rate of 1 kW / min. After the raw materials in the double-cavity crucible (1) are completely melted, the melt temperature is measured. When the melt temperature is 1300°C to 1500°C, it is kept warm for 3 min to 5 min, and then the double-cavity crucible (1) is turned over.

6. The short-process preparation method of the high-conductivity and high-wear-resistant titanium diboride / copper boron composite material according to claim 4, characterized in that: In step 4, the cast titanium diboride / copper boron block is subjected to thermomechanical treatment, including first placing the cast titanium diboride / copper boron block in a muffle furnace, heating it to 800°C and keeping it warm for 30 minutes, and then forging it with an air forging hammer. After each deformation of 10%, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes. When the total deformation exceeds 50%, the single deformation is 5%, and after the single deformation, it is placed in a muffle furnace and heated to 800°C and kept warm for 5 minutes, until the final total deformation reaches 60-70%.

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