A method for preparing ultrafine-grained titanium ultrafine wire

Abstract

The present invention discloses a method for preparing ultrafine-grained titanium ultrafine wire, which comprises: 1. ultrasonically cleaning the titanium wire; 2. micro-arc oxidation treatment; 3. drawing the titanium ultrafine wire at room temperature; 4. surface pickling; and 5. low-temperature annealing treatment to obtain the ultrafine-grained titanium ultrafine wire. The present invention prepares a wear-resistant coating on the surface of the titanium wire by micro-arc oxidation and lubricates the titanium wire for drawing, thereby enhancing the lubrication effect during the cold drawing process of the titanium wire and ensuring the smooth progress of the titanium wire drawing process. Continuous cold drawing deformation at room temperature accumulates a large amount of deformation, thereby reducing the diameter of the titanium wire to obtain the titanium ultrafine wire, improving the strength of the titanium ultrafine wire, and then combining low-temperature recrystallization annealing to refine the grains and control the structure, thereby improving the plasticity of the titanium ultrafine wire and obtaining a high-strength and tough ultrafine-grained titanium ultrafine wire. The process is simple and suitable for promotion and application.

Description

Technical Field

[0001] The invention belongs to the technical field of high-strength ultrafine metal wire preparation, and particularly relates to a method for preparing ultrafine-grained titanium ultrafine wire. Background Art

[0002] Titanium and titanium alloy wires have high specific strength, excellent corrosion resistance, and biocompatibility, making them widely used in aviation, aerospace, navigation, healthcare, and other fields. Titanium wire, due to its reduced alloying element content and higher biosafety, has gained widespread acceptance in medical implants. However, this reduction in alloying elements results in a lower strength than titanium alloys, limiting its application in certain high-performance medical implants. For example, high-strength and tough titanium wires used in stents, orthopedics, dentistry, and cardiology require not only high strength but also good plasticity. The strength and plasticity of titanium wire are closely related to its grain size. Currently, the main industrial method for producing titanium wire is hot drawing. Due to the high deformation temperature, dynamic recrystallization occurs within the material during deformation, resulting in larger grains and lower strength. Ultrafine-grained structures are recognized as high-strength and plastic structures, and the production of ultrafine-grained wires holds the promise of achieving both strength and plasticity.

[0003] To achieve fine-grain strengthening, researchers have proposed a method for grain refinement through high plastic cold deformation combined with low-temperature annealing. This involves cumulative deformation and wire size reduction through room-temperature drawing, followed by heat treatment to control the microstructure. Patents CN112522650A and CN112593171A have reportedly produced ultrafine-grained pure titanium rods through high plastic swaging combined with recrystallization annealing. While this method effectively refines grains, swaging is only suitable for processing rods or thick wires and is not suitable for producing ultrafine wires.

[0004] In addition, there is a problem of lubrication difficulty during the cold drawing process of titanium wire. That is, due to the physical properties of titanium itself, lubricating substances such as graphite emulsion and lubricating oil are difficult to adhere to the surface of the wire at room temperature. Therefore, it is difficult to perform cold drawing using conventional means. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned prior art and provide a method for preparing ultrafine-grained titanium ultrafine wire. This method uses micro-arc oxidation to prepare a wear-resistant coating on the surface of the titanium wire and lubricates it with lubricating oil for drawing, thereby enhancing the lubrication effect during the cold drawing process of the titanium wire and ensuring the smooth progress of the titanium wire drawing process. As a result, a large amount of deformation is accumulated through continuous cold drawing deformation at room temperature, achieving the reduction of the titanium wire diameter to obtain titanium ultrafine wire. Combined with low-temperature recrystallization annealing to refine the grains and control the structure, the strength and plasticity of the titanium ultrafine wire are improved, solving the problem that cold drawing is difficult to process titanium ultrafine wire due to lubrication difficulties.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing ultrafine-grained titanium ultrafine wire, characterized in that the method comprises the following steps:

[0007] Step 1: Ultrasonic cleaning of titanium wire;

[0008] Step 2: Micro-arc oxidation treatment is performed on the titanium wire after ultrasonic cleaning in step 1 using a micro-arc oxidation device to obtain a titanium wire with a wear-resistant coating on the surface;

[0009] Step 3: Using a wire drawing machine to draw the titanium wire with the wear-resistant coating on the surface obtained in step 2 at room temperature, and lubricating with lubricating oil during the drawing process to obtain titanium ultrafine wire;

[0010] Step 4: pickling the surface of the titanium ultrafine wire obtained in step 3;

[0011] Step 5: subjecting the titanium ultrafine wire after pickling in step 4 to low-temperature annealing to obtain ultrafine-grained titanium ultrafine wire; the ultrafine-grained titanium ultrafine wire has a diameter of 0.05 mm to 0.5 mm and a grain size of 0.02 μm to 2 μm.

[0012] The present invention performs ultrasonic cleaning on a titanium wire to clean its surface, then prepares a wear-resistant coating on its surface through micro-arc oxidation treatment, and then lubricates and draws the titanium wire with the wear-resistant coating on its surface using lubricating oil, and obtains an ultrafine-grained titanium ultrafine wire through pickling and low-temperature annealing treatment. In this preparation process, the present invention uses micro-arc oxidation to prepare a wear-resistant coating on the surface of the titanium wire, and at the same time combines lubricating oil lubrication to improve the adhesion of the lubricating oil to the surface of the titanium wire, enhance the lubrication effect of the titanium wire during the room temperature cold drawing process, improve the online drawing ability of the titanium wire, and ensure the smooth progress of the titanium wire drawing process, thereby accumulating a large amount of deformation through continuous cold drawing deformation at room temperature, achieving the reduction of the titanium wire to obtain the titanium ultrafine wire, improving the strength of the titanium ultrafine wire, and then refining the grains through subsequent low-temperature recrystallization annealing, improving the plasticity of the titanium ultrafine wire, and preparing a high-strength and tough ultrafine-grained titanium ultrafine wire.

[0013] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the titanium wire in step 1 is made of industrial pure titanium.

[0014] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the ultrasonic cleaning process in step 1 is: first cleaning with NaOH solution and then cleaning with deionized water.

[0015] The aforementioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the electrolyte used in the micro-arc oxidation treatment in step 2 comprises water, NaAlO2, Na3PO4·12H2O, and NaOH. Typically, the electrolyte is prepared by mixing and fully dissolving water, NaAlO2, Na3PO4·12H2O, and NaOH in a mass ratio of 500:1-15:1-10:1-5. This composition produces a ceramic coating with enhanced lubricity.

[0016] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the process parameters of the micro-arc oxidation treatment in step 2 are: forward voltage 300V~600V, duty cycle 20%~40%, pulse frequency 400Hz~600Hz, temperature 10℃~30℃, time 2min~5min, and deionized water is used to remove residual electrolyte on the surface after micro-arc oxidation treatment.

[0017] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the micro-arc oxidation treatment in step 2 is performed online, and the time of the micro-arc oxidation treatment is controlled by adjusting the wire pay-off speed.

[0018] The aforementioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the drawing in step three is lubricated with a composite lubricant, the deformation per pass does not exceed 15%, and the cumulative deformation exceeds 85%. After the large plastic cold deformation with a cumulative deformation exceeding 85%, a high density of dislocations and other crystal defects accumulate within the titanium metal, providing a large number of nucleation sites for the subsequent recrystallization annealing process.

[0019] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the components of the composite lubricating oil include mineral oil and pasty graphite.

[0020] The above-mentioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the components of the pickling solution used in the pickling in step 4 include water, HF, and HNO3, and deionized water is used to remove the residual pickling solution on the surface after pickling.

[0021] The aforementioned method for preparing ultrafine-grained titanium ultrafine wire is characterized in that the low-temperature annealing treatment in step 5 is performed at a temperature of 300°C to 650°C and for a time of 1 minute to 120 minutes. By controlling the temperature and time of the low-temperature annealing treatment, the present invention adjusts the grain size within a range of 0.02 μm to 2 μm, thereby regulating the strength and plasticity of the ultrafine-grained titanium ultrafine wire.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The present invention prepares a wear-resistant coating on the surface of the titanium wire through micro-arc oxidation and combines it with lubricating oil lubrication for drawing, thereby enhancing the lubrication effect during the cold drawing process of the titanium wire and ensuring the smooth progress of the titanium wire drawing process. As a result, a large amount of deformation is accumulated through continuous cold drawing deformation at room temperature, thereby reducing the diameter of the titanium wire to obtain titanium ultrafine wire, thereby improving the strength of the titanium ultrafine wire. Combined with low-temperature recrystallization annealing to refine the grains and control the organization, the plasticity of the titanium ultrafine wire is improved, and a high-strength and tough ultrafine-grained titanium ultrafine wire is obtained.

[0024] 2. Compared with the conventional hot drawing method for preparing titanium wire, the present invention adopts large plastic cold deformation at room temperature plus low temperature annealing treatment to obtain titanium ultrafine wire and perform microstructure control, effectively refines the grains, has a simple process, is easy to control, and has high product quality stability and good process stability, which is conducive to industrial production and promotes the import substitution process of high-performance titanium wire.

[0025] 3. The present invention adopts a micro-arc oxidation coating combined with lubricating oil to enhance the lubrication effect of titanium wire during the cold drawing process, solves the problem of lubrication difficulty of titanium wire during the cold drawing process, improves the surface quality of titanium ultrafine wire, reduces damage to the drawing die, and extends the service life of the drawing die.

[0026] 4. The preparation process of the present invention is short, has good effects, and has a wide range of applications. It can be extended and applied to the preparation of other high-strength and high-toughness metal ultrafine wires.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a microstructure diagram of the wear-resistant coating on the surface of the TA2 titanium wire in Example 1 of the present invention.

[0029] Figure 2 This is a microstructure diagram of the ultrafine-grained TA2 titanium ultrafine wire in Example 1 of the present invention.

[0030] Figure 3 This is a physical picture of the ultrafine-grained TA2 titanium ultrafine wire in Example 1 of the present invention.

[0031] Figure 4 This is a microstructure diagram of the wear-resistant coating on the surface of the TA2 titanium wire in Example 2 of the present invention.

[0032] Figure 5 This is the microstructure diagram of the ultrafine-grained TA2 titanium ultrafine wire in Example 2 of the present invention.

[0033] Figure 6 This is a microstructure diagram of the wear-resistant coating on the surface of the TA2 titanium wire in Example 3 of the present invention.

[0034] Figure 7 This is the microstructure diagram of the ultrafine-grained TA2 titanium ultrafine wire in Example 3 of the present invention. DETAILED DESCRIPTION

[0035] Example 1

[0036] This embodiment includes the following steps:

[0037] Step 1: ultrasonically clean the hot-drawn TA2 titanium wire with a diameter of Φ1.0 mm. The ultrasonic cleaning process is as follows: first, clean it with a 60°C NaOH solution for 10 minutes, and then clean it with deionized water for 20 minutes.

[0038] Step 2: Micro-arc oxidation treatment is performed on the TA2 titanium wire after ultrasonic cleaning in step 1 using a micro-arc oxidation device to form a wear-resistant coating. The components of the electrolyte used in the micro-arc oxidation treatment include water, NaAlO2, Na3PO4·12H2O, and NaOH in a mass ratio of 500:10:5:5. The process parameters of the micro-arc oxidation treatment are: forward voltage 600V, duty cycle 20%, pulse frequency 600Hz, temperature 10°C, and time 2min. After the micro-arc oxidation treatment, deionized water is used to remove the residual electrolyte on the surface to obtain a TA2 titanium wire with a wear-resistant coating on the surface. The micro-arc oxidation treatment is carried out online, and the time of the micro-arc oxidation treatment is controlled by adjusting the wire pay-off speed.

[0039] Step 3: Using a wire drawing machine to draw the TA2 titanium wire with a wear-resistant coating on the surface obtained in step 2 at room temperature, the deformation of a single pass is 8% to 10%, the cumulative deformation is 94%, and a composite lubricant is used for lubrication during the drawing process to obtain a TA2 titanium ultrafine wire with a diameter of 0.25 mm; the composite lubricant includes mineral oil and pasty graphite;

[0040] Step 4: pickling the surface of the TA2 titanium ultrafine wire obtained in step 3, wherein the pickling solution used for pickling comprises water, HF, and HNO3 in a volume ratio of 100:1:5, and the pickling time is 5 minutes. After pickling, deionized water is used to remove the residual pickling solution on the surface;

[0041] Step 5: The TA2 titanium ultrafine wire after pickling in step 4 is subjected to low-temperature annealing treatment at a temperature of 450° C. for 5 minutes to obtain an ultrafine-grained TA2 titanium ultrafine wire with a diameter of 0.25 mm.

[0042] According to tests, the ultrafine-grained TA2 titanium ultrafine wire prepared in this embodiment has a strength of 763 MPa and a grain size of 1 μm to 2 μm.

[0043] Figure 1 The microstructure of the wear-resistant coating on the surface of TA2 titanium wire in this embodiment is shown in FIG. Figure 1 It can be seen that a uniform wear-resistant coating has been formed on the surface of the TA2 titanium wire.

[0044] Figure 2 The microstructure of the ultrafine-grained TA2 titanium ultrafine wire in this embodiment is shown in FIG. Figure 2 It can be seen that the grain size of the ultrafine-grained TA2 titanium ultrafine wire is 1 μm to 2 μm.

[0045] Figure 3 This is a physical picture of the ultrafine-grained TA2 titanium ultrafine wire in this embodiment. Figure 3 It can be seen that the ultrafine-grained TA2 titanium ultrafine wire has good plasticity and can be knotted smoothly.

[0046] Example 2

[0047] This embodiment includes the following steps:

[0048] Step 1: ultrasonically clean the hot-drawn TA2 titanium wire with a diameter of Φ0.5 mm; the ultrasonic cleaning process is as follows: first, use a 60°C NaOH solution to clean for 10 minutes, and then use deionized water to clean for 20 minutes;

[0049] Step 2: Using a micro-arc oxidation device to perform micro-arc oxidation treatment on the TA2 titanium wire after ultrasonic cleaning in step 1 to form a wear-resistant coating, the components of the electrolyte used in the micro-arc oxidation treatment include water, NaAlO2, Na3PO4·12H2O, and NaOH in a mass ratio of 500:10:5:5, and the process parameters of the micro-arc oxidation treatment are: forward voltage 300V, duty cycle 30%, pulse frequency 500Hz, temperature 30°C, time 4min, and after the micro-arc oxidation treatment, deionized water is used to remove the residual electrolyte on the surface to obtain a TA2 titanium wire with a wear-resistant coating on the surface; the micro-arc oxidation treatment is carried out in an online manner, and the time of the micro-arc oxidation treatment is controlled by adjusting the wire pay-off speed;

[0050] Step 3: Using a wire drawing machine to draw the TA2 titanium wire with a wear-resistant coating on the surface obtained in step 2 at room temperature, the deformation of a single pass is 8% to 10%, the cumulative deformation is 99%, and a composite lubricant is used for lubrication during the drawing process to obtain a TA2 titanium ultrafine wire with a diameter of 0.05 mm; the composite lubricant includes mineral oil and pasty graphite;

[0051] Step 4: pickling the surface of the TA2 titanium ultrafine wire obtained in step 3, wherein the pickling solution used for pickling comprises water, HF, and HNO3 in a volume ratio of 100:1:5, and the pickling time is 5 minutes. After pickling, deionized water is used to remove the residual pickling solution on the surface;

[0052] Step 5: The TA2 titanium ultrafine wire after pickling in step 4 is subjected to low-temperature annealing treatment at a temperature of 300° C. for 120 min to obtain an ultrafine-grained TA2 titanium ultrafine wire with a diameter of 0.05 mm.

[0053] After testing, the ultrafine-grained TA2 titanium ultrafine wire prepared in this embodiment has a strength of 1045 MPa and a grain size of 0.02 μm to 0.1 μm.

[0054] Figure 4 The microstructure of the wear-resistant coating on the surface of TA2 titanium wire in this embodiment is shown in FIG. Figure 4 It can be seen that a uniform wear-resistant coating has been formed on the surface of the TA2 titanium wire.

[0055] Figure 5 The microstructure of the ultrafine-grained TA2 titanium ultrafine wire in this embodiment is shown in FIG. Figure 5 It can be seen that the grain size of the ultrafine-grained TA2 titanium ultrafine wire is 0.02 μm to 0.1 μm.

[0056] Example 3

[0057] This embodiment includes the following steps:

[0058] Step 1: ultrasonically clean the hot-drawn TA2 titanium wire with a diameter of Φ1.5 mm. The ultrasonic cleaning process is as follows: first, use a 60°C NaOH solution to clean for 10 minutes, and then use deionized water to clean for 20 minutes.

[0059] Step 2: Using a micro-arc oxidation device to perform micro-arc oxidation treatment on the TA2 titanium wire after ultrasonic cleaning in step 1 to form a wear-resistant coating, the components of the electrolyte used in the micro-arc oxidation treatment include water, NaAlO2, Na3PO4·12H2O, and NaOH in a mass ratio of 500:10:5:5, and the process parameters of the micro-arc oxidation treatment are: forward voltage 400V, duty cycle 40%, pulse frequency 400Hz, temperature 20°C, time 5min, and after the micro-arc oxidation treatment, deionized water is used to remove the residual electrolyte on the surface to obtain a TA2 titanium wire with a wear-resistant coating on the surface; the micro-arc oxidation treatment is carried out in an online manner, and the time of the micro-arc oxidation treatment is controlled by adjusting the wire pay-off speed;

[0060] Step 3: Using a wire drawing machine to draw the TA2 titanium wire with a wear-resistant coating on the surface obtained in step 2 at room temperature, the deformation of a single pass is 8% to 10%, the cumulative deformation is 89%, and a composite lubricant is used for lubrication during the drawing process to obtain a TA2 titanium ultrafine wire with a diameter of 0.5 mm; the composite lubricant includes mineral oil and paste graphite;

[0061] Step 4: pickling the surface of the TA2 titanium ultrafine wire obtained in step 3, wherein the pickling solution used for pickling comprises water, HF, and HNO3 in a volume ratio of 100:1:5, and the pickling time is 5 minutes. After pickling, deionized water is used to remove the residual pickling solution on the surface;

[0062] Step 5: The TA2 titanium ultrafine wire after pickling in step 4 is subjected to low-temperature annealing treatment at a temperature of 650° C. for 1 minute to obtain an ultrafine-grained TA2 titanium ultrafine wire with a diameter of 0.5 mm.

[0063] According to tests, the ultrafine-grained TA2 titanium ultrafine wire prepared in this embodiment has a strength of 813 MPa and a grain size of 1 μm to 2 μm.

[0064] Figure 6 The microstructure of the wear-resistant coating on the surface of TA2 titanium wire in this embodiment is shown in FIG. Figure 6 It can be seen that a uniform wear-resistant coating has been formed on the surface of the TA2 titanium wire.

[0065] Figure 7 The microstructure of the ultrafine-grained TA2 titanium ultrafine wire in this embodiment is shown in FIG. Figure 7 It can be seen that the grain size of the ultrafine-grained TA2 titanium ultrafine wire is 1 μm to 2 μm.

[0066] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing ultrafine-grained titanium ultrafine wire, characterized in that: The method comprises the following steps: Step 1: Ultrasonic cleaning of titanium wire; Step 2: Micro-arc oxidation treatment is performed on the titanium wire after ultrasonic cleaning in step 1 using a micro-arc oxidation device to obtain a titanium wire with a wear-resistant coating on the surface; Step 3: Using a wire drawing machine to draw the titanium wire with the wear-resistant coating on the surface obtained in step 2 at room temperature, and lubricating with lubricating oil during the drawing process to obtain titanium ultrafine wire; Step 4: pickling the surface of the titanium ultrafine wire obtained in step 3; Step 5: subjecting the titanium ultrafine wire after pickling in step 4 to low-temperature annealing to obtain ultrafine-grained titanium ultrafine wire; the ultrafine-grained titanium ultrafine wire has a diameter of 0.05 mm to 0.5 mm and a grain size of 0.02 μm to 2 μm.

2. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The titanium wire material in step 1 is made of industrial pure titanium.

3. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The ultrasonic cleaning process in step 1 is: first cleaning with NaOH solution, and then cleaning with deionized water.

4. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The components of the electrolyte used in the micro-arc oxidation treatment in step 2 include water, NaAlO2, Na3PO4·12H2O, and NaOH.

5. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The process parameters of the micro-arc oxidation treatment in step 2 are: forward voltage 300V~600V, duty cycle 20%~40%, pulse frequency 400Hz~600Hz, temperature 10℃~30℃, time 2min~5min, and after the micro-arc oxidation treatment, deionized water is used to remove residual electrolyte on the surface.

6. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The micro-arc oxidation treatment in step 2 is performed online, and the time of the micro-arc oxidation treatment is controlled by adjusting the discharge speed.

7. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The drawing in step 3 is lubricated with composite lubricating oil, and the deformation of a single pass does not exceed 15%, and the cumulative deformation is greater than 85%.

8. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 7, characterized in that: The components of the composite lubricating oil include mineral oil and pasty graphite.

9. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The components of the pickling solution used in the pickling in step 4 include water, HF, and HNO3, and after pickling, deionized water is used to remove the residual pickling solution on the surface.

10. The method for preparing ultrafine-grained titanium ultrafine wire according to claim 1, characterized in that: The low-temperature annealing treatment in step five is performed at a temperature of 300° C. to 650° C. and for a time of 1 minute to 120 minutes.

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