Ultrafine grain titanium wire and post-processing method thereof

Abstract

The invention provides an ultra-fine grain titanium wire and a post-processing method thereof, and relates to the technical field of medical materials, the method is used for reducing the dislocation density of the ultra-fine grain titanium wire, and the method comprises the steps that an original ultra-fine grain titanium wire prepared through a severe plastic deformation method is obtained; the original ultra-fine grain titanium wire is fixed to a stretching device to be subjected to pre-stretching treatment; the ultra-fine grain titanium wire subjected to pre-stretching treatment is placed in an ultrasonic treatment device to be subjected to first-time ultrasonic treatment; and the ultra-fine grain titanium wire obtained after first-time ultrasonic treatment is placed in an ultrasonic treatment device to be subjected to second-time ultrasonic treatment, and the ultra-fine grain titanium wire is obtained. According to the method, the dislocation density of the ultra-fine grain titanium wire material can be remarkably reduced, meanwhile, the tensile strength and the ductility of the material are improved, the material has the low elastic modulus, the stress shielding effect of an implant can be reduced, the implant can be matched with the elastic modulus between bones, and the effectiveness of the implant is improved.

Description

Technical Field

[0001] The present application relates to the technical field of medical materials, and in particular to an ultrafine-grained titanium wire and a post-processing method thereof. Background Art

[0002] As a high-performance material, ultrafine-grained titanium has shown great potential for application in the field of medical devices. This material is known for its high strength and excellent corrosion resistance, which makes it an ideal choice for biomedical devices. The high strength of ultrafine-grained titanium comes from its numerous grain boundaries, which effectively hinder the movement of dislocations, thereby significantly improving the mechanical strength of the material. At the same time, ultrafine-grained titanium has excellent corrosion resistance and can remain stable even in extreme environments, which further enhances its attractiveness as a biomedical device material.

[0003] The preparation of ultrafine-grained titanium usually adopts large plastic deformation methods, but ultrafine-grained titanium contains a large number of dislocations. Too many dislocations may cause the plasticity and fatigue properties of the material to decrease. In addition, during the correction process after large plastic deformation, dislocations may also cause plastic deformation of the material, affecting the accuracy of material preparation. Existing methods generally use heat treatment methods such as stress relief annealing to adjust the dislocation density, but ultrafine-grained materials are easy to deform during the heating process, resulting in a decrease in the dimensional accuracy of the material and an inability to meet subsequent processing requirements. Excessive heat treatment temperatures may also cause the grains of the material to grow and the strength and plasticity to decrease.

[0004] Therefore, there is an urgent need for a treatment method that can effectively reduce the dislocation density of ultrafine-grained titanium wire. Summary of the invention

[0005] The present application provides an ultrafine-grained titanium wire and a post-processing method thereof, so as to solve the problem that the existing method cannot improve the comprehensive performance of the titanium wire while reducing the dislocation density of the titanium wire.

[0006] In a first aspect, the present application provides a post-processing method for ultrafine-grained titanium wire, the post-processing method for ultrafine-grained titanium wire is used to reduce the dislocation density of the ultrafine-grained titanium wire, and the method comprises the following steps:

[0007] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire ranges from 4 mm to 20 mm;

[0008] Step 2: fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire;

[0009] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0010] Step 4: placing the ultrafine-grained titanium wire subjected to the first ultrasonic treatment in an ultrasonic treatment device and subjecting it to a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire.

[0011] Optionally, the direction of the pre-stretching treatment of the original ultrafine-grained titanium wire is perpendicular to or opposite to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method.

[0012] Optionally, the diameter of the original ultrafine-grained titanium wire in step 1 is in the range of 6 mm to 8 mm.

[0013] Optionally, the stretching strain amount of the pre-stretching treatment in step 2 ranges from 1% to 5%.

[0014] Optionally, the tensile strain amount of the pre-stretching treatment in step 2 ranges from 4% to 5%.

[0015] Optionally, in step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, wherein the ultrasonic frequency range is 20kHz to 100kHz, and the power density range is 50W / cm 2 ~500W / cm 2 The processing time ranges from 20min to 60min.

[0016] Optionally, in step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, wherein the ultrasonic frequency range is 60kHz to 90kHz, and the power density range is 350W / cm 2 ~450W / cm 2 The processing time ranges from 40min to 50min.

[0017] Optionally, the pre-stretching treatment in step 2, and the first ultrasonic treatment and the second ultrasonic treatment in step 3 and step 4 are all carried out at room temperature.

[0018] In a second aspect, the present application provides an ultrafine-grained titanium wire, wherein the ultrafine-grained titanium wire is obtained by post-processing the ultrafine-grained titanium wire according to any one of the ultrafine-grained titanium wire post-processing methods described in the first aspect.

[0019] Optionally, the dislocation density of the ultrafine-grained titanium wire is in the range of 2×10 13 / m 2 ~4×10 14 / m 2, the elastic modulus ranges from 101GPa to 109GPa, the tensile strength ranges from 1050MPa to 1140MPa, and the elongation ranges from 19% to 25%.

[0020] The present application proposes an ultrafine-grained titanium wire and a post-processing method thereof, wherein the ultrafine-grained titanium wire post-processing method is used to reduce the dislocation density of the ultrafine-grained titanium wire, and the method comprises the following steps: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method; fixing the original ultrafine-grained titanium wire on a stretching device, performing a pre-stretching treatment, and obtaining a pre-stretched ultrafine-grained titanium wire; placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device, performing a first ultrasonic treatment, and obtaining a first ultrasonic-treated ultrafine-grained titanium wire; placing the first ultrasonic-treated ultrafine-grained titanium wire in an ultrasonic treatment device, performing a second ultrasonic treatment, and obtaining an ultrafine-grained titanium wire. The present application includes the following advantages:

[0021] (1) By pre-stretching and ultrasonic treatment, the dislocation density of ultrafine-grained titanium wire is significantly reduced, and the elongation of the ultrafine-grained titanium wire can be increased from 16% to 19% to 25% without reducing the strength of the ultrafine-grained titanium wire;

[0022] (2) The post-treatment method (pre-stretching treatment and ultrasonic treatment) of the ultrafine-grained titanium wire is carried out at room temperature, the temperature rise of the ultrafine-grained titanium wire does not exceed 50K, the wire temperature does not exceed 100°C, and the recrystallization temperature of the titanium wire (about 300°C) is not reached, and the grain size of the material will not be changed, which is conducive to ensuring the ultrafine grain state of the ultrafine-grained titanium wire;

[0023] (3) The ultrasonic treatment proposed in the present application does not change the shape accuracy of the ultrafine-grained titanium wire, and the pre-stretching treatment can play a certain straightening role on the ultrafine-grained titanium wire, which is beneficial to the precision processing of subsequent products;

[0024] (4) Through the post-processing method of the present application, the elastic modulus of the ultrafine-grained titanium wire is reduced from 115 GPa to about 105 GPa, which is closer to the elastic modulus of bone tissue, which is beneficial to reduce the stress shielding caused by the mismatch of the elastic modulus and is more suitable for the application of implantable medical devices such as dental implants, bone plates, and bone nails. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1This is a SEM image of the grain characterization of an original ultrafine-grained titanium wire before pre-stretching treatment and an ultrafine-grained titanium wire after two ultrasonic treatments provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] Ultrafine-grained titanium has shown great application potential in the field of medical devices due to its comprehensive performance advantages such as high strength and corrosion resistance. One of its most prominent features is high strength. Ultrafine-grained materials have many grain boundaries, which can serve as an effective barrier to dislocation movement, effectively preventing the slip and expansion of dislocations, thereby significantly improving the mechanical strength of the material. In addition, ultrafine-grained titanium has excellent corrosion resistance and can remain stable even under extreme environmental conditions, making it an ideal choice for biomedical devices. At the same time, ultrafine-grained pure titanium also has excellent biocompatibility and fatigue resistance, making it very suitable for medical implants such as artificial joints and tooth repairs. It is worth mentioning that although grain refinement usually leads to an increase in the hardness of the material, ultrafine-grained pure titanium can still maintain good plasticity and machinability through appropriate heat treatment processes, which is convenient for forming and processing, which further broadens its scope of application.

[0029] However, ultrafine-grained titanium contains a large number of dislocations, and too many dislocations will lead to a decrease in the plasticity, fatigue performance and other properties of pure titanium. In addition, during the correction process after large plastic deformation, dislocations will also cause plastic deformation of the material, affecting the accuracy of material preparation.

[0030] Existing methods generally use heat treatment methods such as stress relief annealing to adjust the dislocation density, but ultrafine-grained materials are easily deformed during the heating process, and the material dimensional accuracy decreases and cannot meet the subsequent processing requirements. Excessive heat treatment temperature may also cause the material grain to grow, and the strength and plasticity to decrease. Therefore, a treatment method that effectively reduces the dislocation density of ultrafine-grained titanium wire is urgently needed.

[0031] Based on this, the present application provides an ultrasonic post-treatment method for reducing the dislocation density of titanium alloy wire. Through the action of ultrasonic waves, the dislocation density in the titanium alloy wire is effectively reduced and the comprehensive performance of the titanium alloy wire is improved.

[0032] In a first aspect, an embodiment of the present application provides a post-processing method for ultrafine-grained titanium wire, wherein the post-processing method for ultrafine-grained titanium wire is used to reduce the dislocation density of the ultrafine-grained titanium wire, and the method comprises the following steps:

[0033] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire ranges from 4 mm to 20 mm.

[0034] Ultrafine-grained titanium wire is generally prepared by large plastic deformation method. The large plastic deformation method produces a large number of dislocations and grain boundaries inside the titanium wire through a high-pressure and high-speed plastic deformation process, thereby forming an ultrafine or even nanoscale grain structure. Ultrafine grains not only greatly improve the strength and hardness of titanium wire, but also maintain good ductility and toughness, achieving a good combination of strength and plasticity. In addition, ultrafine-grained titanium wire after large plastic deformation treatment often exhibits better wear resistance and fatigue resistance.

[0035] Based on this, the original ultrafine-grained titanium wire is prepared by large plastic deformation in the embodiment of the present application. The original ultrafine-grained titanium wire prepared by the method with a diameter ranging from 4mm to 20mm is selected for subsequent processing. For example, the diameter of the selected original ultrafine-grained titanium wire can be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, etc.

[0036] In a preferred embodiment, in step 1, the diameter of the original ultrafine-grained titanium wire selected for subsequent processing ranges from 6 mm to 8 mm. For example, the diameter of the original ultrafine-grained titanium wire selected can be 6 mm, 7 mm, 8 mm, etc.

[0037] Step 2: Fix the original ultrafine-grained titanium wire on a stretching device and perform a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire.

[0038] In order to reduce the dislocation density of ultrafine-grained titanium wire, the post-processing method proposed in this application firstly adopts a pre-stretching treatment to reduce the dislocations generated during the large plastic deformation process.

[0039] Specifically, the original ultrafine-grained titanium wire material obtained by large plastic deformation is fixed on a stretching device and subjected to a pre-stretching treatment to obtain the pre-stretched ultrafine-grained titanium wire material.

[0040] It should be noted that, during the pre-stretching process, the direction of the original ultrafine-grained titanium wire in the pre-stretching process is perpendicular to or opposite to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method. The direction of the dislocation generated is compared with the dislocation generated in the large plastic deformation process, and the Burgers vector is opposite, so it is easier to annihilate after meeting.

[0041] In an optional embodiment, the tensile strain amount of the pre-stretching treatment in step 2 ranges from 1% to 5%. Exemplarily, the tensile strain amount of the pre-stretching treatment can be 1%, 2%, 3%, 4%, 5%, etc.

[0042] In a preferred embodiment, the tensile strain amount of the pre-stretching process in step 2 ranges from 4% to 5%. For example, the tensile strain amount of the pre-stretching process may be 4%, 5%, and so on.

[0043] Among them, the stretching device used in step 2 can be a medical device stretching inspection device, a stretching bed body, etc.

[0044] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device, performing a first ultrasonic treatment, and obtaining a first ultrasonically treated ultrafine-grained titanium wire.

[0045] In order to further reduce the dislocation density of the ultrafine-grained titanium wire, the embodiment of the present application uses ultrasonic treatment to reduce the dislocation density in the titanium alloy wire.

[0046] Specifically, the pre-stretched ultrafine-grained titanium wire is placed in an ultrasonic treatment device and subjected to a first ultrasonic treatment to obtain an ultrafine-grained titanium wire subjected to a first ultrasonic treatment. Through the first ultrasonic treatment, high-frequency vibration and shear force are generated inside the ultrafine-grained titanium wire, which promotes the slip and annihilation of dislocations and significantly reduces the dislocation density of the ultrafine-grained titanium wire.

[0047] Step 4: placing the ultrafine-grained titanium wire subjected to the first ultrasonic treatment in an ultrasonic treatment device and subjecting it to a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire.

[0048] In order to further reduce the dislocation density of the ultrafine-grained titanium wire on the basis of the first ultrasonic treatment, a second ultrasonic treatment is performed on it.

[0049] Specifically, the ultrafine-grained titanium wire subjected to the first ultrasonic treatment is placed in an ultrasonic treatment device and subjected to a second ultrasonic treatment. In order to effectively promote dislocation annihilation, the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire. Through the second ultrasonic treatment in the perpendicular direction, the number of dislocation annihilations is further increased and the dislocation density is reduced.

[0050] It should be noted that in step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, and only the ultrasonic direction is changed through the same ultrasonic treatment process to promote the annihilation of dislocation density. The ultrasonic frequency range is 20kHz to 100kHz, and the power density range is 50W / cm 2 ~500W / cm 2 The processing time ranges from 20min to 60min.

[0051] For example, the ultrasonic frequency may be 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, 100 kHz, etc., and the power density may be 50 W / cm 2 , 100W / cm 2 、150W / cm 2 , 200W / cm 2 , 250W / cm 2 、300W / cm 2 、350W / cm 2 , 400W / cm 2 、450W / cm 2 , 500W / cm 2 And so on. The processing time can be 20min, 30min, 40min, 50min, 60min, etc.

[0052] After reducing the dislocations caused by large plastic deformation through pre-stretching treatment, the dislocation density inside the ultrafine-grained titanium wire was further reduced through two ultrasonic treatments.

[0053] In a preferred embodiment, in step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, wherein the ultrasonic frequency range is 60kHz to 90kHz, and the power density range is 350W / cm 2 ~450W / cm 2 , the treatment time range is 40min to 50min. For example, the ultrasonic frequency can be 60kHz, 70kHz, 80kHz, 90kHz, etc., and the power density can be 350W / cm 2 , 400W / cm 2 、450W / cm 2 Etc., the processing time can be 40min, 50min, etc.

[0054] In an optional embodiment, the pre-stretching treatment in step 2, and the first ultrasonic treatment and the second ultrasonic treatment in step 3 and step 4 are all performed at room temperature. Operating at room temperature can ensure that the grains of the ultrafine-grained titanium wire will not grow, which is conducive to ensuring the ultrafine-grained state of the titanium wire. In addition, during the ultrasonic treatment, the temperature rise of the ultrafine-grained titanium wire does not exceed 50K. Since it is carried out at room temperature, the wire temperature does not exceed 100°C, and does not reach the recrystallization temperature of the titanium wire (about 300°C), and the grain size of the material will not be changed.

[0055] The grain characterization results of ultrafine-grained titanium wire can be found in Figure 1 , Figure 1 Part (a) is the SEM image of the grain characterization of the original ultrafine-grained titanium wire before pre-stretching treatment. Figure 1 Part (b) is a SEM image of the grain characterization of the ultrafine-grained titanium wire after the second ultrasonic treatment. It can be seen that the grain size of the ultrafine-grained titanium wire has not changed after the pre-stretching treatment and the two ultrasonic treatments. Therefore, the post-treatment method proposed in this application will not change the grain size of the ultrafine-grained titanium wire, and will not further reduce the strength and plasticity of the material.

[0056] In a second aspect, an embodiment of the present application provides an ultrafine-grained titanium wire, which is obtained by post-processing the ultrafine-grained titanium wire according to the ultrafine-grained titanium wire post-processing method described in the first aspect.

[0057] In an optional embodiment, the dislocation density of the ultrafine-grained titanium wire treated by the above-mentioned post-treatment method is in the range of 2×10 13 / m 2 ~4×10 14 / m 2 , the elastic modulus ranges from 101GPa to 109GPa, the tensile strength ranges from 1050MPa to 1140MPa, and the elongation ranges from 19% to 25%.

[0058] It can be seen that the dislocation density of ultrafine-grained titanium wire can be significantly reduced by pre-stretching and ultrasonic treatment. Under the condition that the tensile strength of ultrafine-grained titanium material does not decrease (1050MPa~1140MPa), the elongation of the material can be increased from 16% to 19%~25%, and the dislocation density can be greatly reduced to 2×10 13 / m 2 ~4×10 14 / m 2 between.

[0059] In order to facilitate the understanding of the present invention, an ultrafine-grained titanium wire and a post-processing method thereof proposed in the present application will be described in detail in combination with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, the present application can also make several variations and improvements, which all belong to the scope of protection of the present application. The experimental methods used in the following embodiments are all conventional methods unless otherwise specified.

[0060] Example 1

[0061] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 4 mm;

[0062] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 5%, and the direction of the pre-stretched original ultrafine-grained titanium wire is opposite to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0063] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0064] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 20 kHz, and the power density range is 50 W / cm 2 , the processing time range is 20min.

[0065] Example 2

[0066] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 20 mm;

[0067] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 1%, and the direction of the pre-stretching of the original ultrafine-grained titanium wire is opposite to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0068] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0069] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 80 kHz, and the power density range is 500 W / cm 2 , the processing time range is 25min.

[0070] Example 3

[0071] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 12 mm;

[0072] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 3%, and the direction of the pre-stretched original ultrafine-grained titanium wire is perpendicular to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0073] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0074] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 20 kHz, and the power density range is 300 W / cm 2 , the processing time range is 60min.

[0075] Example 4

[0076] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 6 mm;

[0077] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 5%, and the direction of the pre-stretched original ultrafine-grained titanium wire is opposite to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0078] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0079] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 60 kHz, and the power density range is 350 W / cm 2 , the processing time range is 40min.

[0080] Example 5

[0081] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 7 mm;

[0082] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 4.5%, and the direction of the pre-stretched original ultrafine-grained titanium wire is perpendicular to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0083] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0084] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 80 kHz, and the power density range is 400 W / cm 2 , the processing time range is 45min.

[0085] Example 6

[0086] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 8 mm;

[0087] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire, wherein the pre-stretching strain is 4%, and the direction of the pre-stretched original ultrafine-grained titanium wire is perpendicular to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0088] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire;

[0089] Step 4: placing the first ultrasonically treated ultrafine-grained titanium wire in an ultrasonic treatment device and performing a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire, and the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same: the ultrasonic frequency is 90 kHz, and the power density range is 450 W / cm 2 , the processing time range is 50min.

[0090] Comparative Example 1

[0091] The operation is performed according to step 1 of Example 6: an original ultrafine-grained titanium wire is obtained as the final ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 8 mm.

[0092] Comparative Example 2

[0093] Follow steps 1 and 2 of Example 6:

[0094] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 8;

[0095] Step 2: Fix the original ultrafine-grained titanium wire on a stretching device and perform a pre-stretching treatment to obtain the pre-stretched ultrafine-grained titanium wire as the final ultrafine-grained titanium wire. The pre-stretching strain is 4%. The direction of the pre-stretched original ultrafine-grained titanium wire is perpendicular to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method.

[0096] Comparative Example 3

[0097] Follow steps 1 to 3 of Example 6:

[0098] Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire is in the range of 8;

[0099] Step 2: Fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire as the final ultrafine-grained titanium wire, the pre-stretching strain is 4%, and the direction of the pre-stretched original ultrafine-grained titanium wire is perpendicular to the deformation direction of the original ultrafine-grained titanium wire in the large plastic deformation method;

[0100] Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device for a first ultrasonic treatment to obtain the first ultrasonic-treated ultrafine-grained titanium wire as the final ultrafine-grained titanium wire. The working parameters of the first ultrasonic treatment are: an ultrasonic frequency of 90 kHz and a power density range of 450 W / cm 2 , the processing time range is 50min.

[0101] Comparative Example 4

[0102] The operation was carried out according to step 1 to step 4 of Example 6, and the ultrafine-grained titanium wire was subjected to a third ultrasonic treatment. The working parameters of the third ultrasonic treatment were the same as those of the first two ultrasonic treatments.

[0103] Example 7: Mechanical Properties Characterization

[0104] The mechanical properties of the ultrafine-grained titanium wires prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were characterized, including dislocation density, elastic modulus, tensile strength, and elongation.

[0105] Among them, the elastic modulus, tensile strength and elongation are measured by the tensile method, the dislocation density is measured by the EBSD (electron backscatter diffraction) method, and the dislocation density is calculated by the KAM diagram. The characterization results are shown in Table 1.

[0106]

[0107] As can be seen from Table 1, Comparative Example 1 is an ultrafine-grained titanium wire without any post-treatment, and Comparative Example 2 is an ultrafine-grained titanium wire after pre-stretching treatment, and their dislocation densities are both relatively high. For the ultrafine-grained titanium wire in Comparative Example 2, although it has been pre-stretched, its dislocation density is higher than that of the ultrafine-grained titanium wire before treatment. The reason is that the plastic deformation caused by the pre-stretching produces a large number of dislocations inside the wire. Although a small amount of dislocations are annihilated with the original dislocations of the ultrafine-grained wire, the degree of plastic deformation of the material is increased overall, and the dislocation density is therefore increased.

[0108] The ultrafine-grained titanium wire in Comparative Example 3 was subjected to pre-stretching and the first ultrasonic treatment, and its dislocation density was significantly reduced to 6×10 13 / m 2 , indicating that ultrasonic treatment has a good effect on reducing the dislocation density of ultrafine-grained titanium wire prepared by large plastic deformation.

[0109] As for the ultrafine-grained titanium wire obtained by pre-stretching and two ultrasonic treatments as proposed in the embodiment of the present application, it can be seen that the dislocation density is significantly reduced compared with the comparative example, and the minimum can be reduced to 2×10 13 / m 2 (Example 6) It is shown that the dislocation density of the original ultrafine-grained titanium wire prepared by the large plastic deformation method can be greatly reduced by pre-stretching treatment and two ultrasonic treatments.

[0110] However, it can be seen from Comparative Example 4 that after the third ultrasonic treatment, the dislocation density did not decrease further, indicating that ultrasonic treatment of the material three times or more cannot further reduce the dislocation density inside the ultrafine-grained titanium wire, and its elongation and tensile strength cannot be further improved, and the elastic modulus cannot be further reduced, indicating that more ultrasonic treatments cannot further improve the mechanical properties of the ultrafine-grained titanium wire.

[0111] Among them, although the original ultrafine-grained titanium wires of Examples 1 to 6 have all been subjected to pre-stretching treatment and two ultrasonic treatments, the dislocation densities of the obtained ultrafine-grained titanium wires are not consistent. For Example 2, after all the treatments, the dislocation density is still 5×10 14 / m 2 , compared with Comparative Example 1, the dislocation density is only reduced by 37.5%.

[0112] It can be seen from Examples 3 and 4 that, compared with Example 2, although the power density is reduced, the dislocation density can still be reduced by increasing the ultrasonic treatment time. It can be seen from Example 5 that, compared with Examples 3 and 4, increasing the power density and ultrasonic time can reduce the dislocation density. It can be seen from Example 6 that the power density of ultrasonic treatment is relatively large (450W / cm 2 ), the ultrasonic time is relatively long (50min) to achieve the effect of significantly reducing the dislocation density.

[0113] Although the first ultrasonic treatment can effectively reduce the dislocation density of ultrafine-grained titanium wire (6×10 13 / m 2 ), after the second ultrasonic treatment, the dislocation density of the ultrafine-grained titanium wire was not reduced as much as the first ultrasonic treatment (2×10 13 / m 2), but after the second ultrasonic treatment, it can be seen that without reducing the tensile strength, its elongation can be further increased from 22% to 25%. Elongation is an important indicator for measuring the plasticity, fatigue performance and formability of ultrafine-grained titanium wire. A higher elongation means that the ultrafine-grained titanium wire has better plasticity and formability, as well as excellent fatigue resistance. Therefore, the improvement of elongation has an important influence on the performance improvement of ultrafine-grained titanium wire.

[0114] In addition, the elastic modulus of the ultrafine-grained titanium wire treated by Examples 1 to 6 can be seen to decrease from 115 GPa to about 105 GPa after pre-stretching and two ultrasonic treatments, which is closer to the elastic modulus of bone tissue, and is beneficial to reducing the stress shielding caused by the mismatch of the elastic modulus, and is suitable for use as an implantable medical device.

[0115] At the same time, since the ultrasonic treatment does not change the shape accuracy of the ultrafine-grained titanium wire, and the pre-stretching treatment can play a certain straightening role on the ultrafine-grained titanium wire, it is beneficial to the subsequent precision processing of medical devices.

[0116] Based on this, the optimal parameters for post-treatment in the embodiment of the present application are: pre-stretching strain of 4%, ultrasonic frequency of the first ultrasonic treatment and the second ultrasonic treatment of 90kHz, power density range of 450W / cm 2 The treatment time range is 50min. The mechanical properties of the ultrafine-grained titanium wire obtained by this treatment are as follows: dislocation density is 2×10 13 / m 2 , elastic modulus is 101GPa, tensile strength is 1070MPa, and elongation is 25%.

[0117] The ultrafine-grained titanium wire obtained by the processing of the embodiment of the present application has a low dislocation density, and also has good tensile strength and elongation, and is not prone to abnormal fracture. It has a low elastic modulus, which is conducive to reducing the stress shielding effect of the implant, so that it can match the elastic modulus between bones and improve the effectiveness of the implant. Therefore, the ultrafine-grained titanium tantalum palladium alloy prepared by the present application has good application prospects in the biomedical field, in dental implants, bone plates, bone nails and other implantable medical devices.

[0118] The above is a detailed introduction to an ultrafine-grained titanium wire and a post-processing method thereof provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A post-processing method for ultrafine-grained titanium wire, characterized in that: The ultrafine-grained titanium wire post-processing method is used to reduce the dislocation density of the ultrafine-grained titanium wire, and the method comprises the following steps: Step 1: obtaining an original ultrafine-grained titanium wire, wherein the original ultrafine-grained titanium wire is prepared by a large plastic deformation method, and the diameter of the original ultrafine-grained titanium wire ranges from 4 mm to 20 mm; Step 2: fixing the original ultrafine-grained titanium wire on a stretching device and performing a pre-stretching treatment to obtain a pre-stretched ultrafine-grained titanium wire; Step 3: placing the pre-stretched ultrafine-grained titanium wire in an ultrasonic treatment device and performing a first ultrasonic treatment to obtain a first ultrasonic-treated ultrafine-grained titanium wire; Step 4: placing the ultrafine-grained titanium wire subjected to the first ultrasonic treatment in an ultrasonic treatment device and subjecting it to a second ultrasonic treatment to obtain an ultrafine-grained titanium wire, wherein the direction of the second ultrasonic treatment of the ultrafine-grained titanium wire is perpendicular to the direction of the first ultrasonic treatment of the ultrafine-grained titanium wire.

2. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: The direction of the pre-stretching treatment of the original ultra-fine-grained titanium wire is perpendicular to or opposite to the deformation direction of the original ultra-fine-grained titanium wire in the large plastic deformation method.

3. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: The diameter of the original ultrafine-grained titanium wire in step 1 ranges from 6 mm to 8 mm.

4. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: The amount of stretching strain in the pre-stretching treatment in step 2 ranges from 1% to 5%.

5. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: The amount of stretching strain in the pre-stretching process in step 2 ranges from 4% to 5%.

6. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: In step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, wherein the ultrasonic frequency range is 20kHz to 100kHz, and the power density range is 50W / cm 2 ~500W / cm 2 The processing time ranges from 20min to 60min.

7. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: In step 3 and step 4, the working parameters of the first ultrasonic treatment and the second ultrasonic treatment are the same, wherein the ultrasonic frequency range is 60kHz to 90kHz, and the power density range is 350W / cm 2 ~450W / cm 2 The processing time ranges from 40min to 50min.

8. The method for post-processing ultrafine-grained titanium wire according to claim 1, characterized in that: The pre-stretching treatment in step 2, and the first ultrasonic treatment and the second ultrasonic treatment in step 3 and step 4 are all performed at room temperature.

9. An ultrafine-grained titanium wire, characterized in that: The ultrafine-grained titanium wire is obtained by post-processing the ultrafine-grained titanium wire according to any one of claims 1 to 8.

10. The ultrafine-grained titanium wire according to claim 9, characterized in that: The dislocation density of the ultrafine-grained titanium wire is in the range of 2×10 13 / m 2 ~4×10 14 / m 2 , the elastic modulus ranges from 101GPa to 109GPa, the tensile strength ranges from 1050MPa to 1140MPa, and the elongation ranges from 19% to 25%.

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