Biomedical titanium and titanium alloy surface multi-performance alloy layer and preparation method

Abstract

This invention discloses a multi-performance alloy layer for biomedical titanium and titanium alloy surfaces, composed of the following components by atomic percentage: 82% ≥ Ti ≤ 88%, 4% ≥ Cu ≤ 6%, 4% ≥ Zn ≤ 6%, and 4% ≥ Sn ≤ 6%, with the sum of the atomic percentages of these components being 100%. This alloy layer possesses excellent mechanical properties, corrosion resistance, biocompatibility, and antibacterial characteristics, significantly improving the overall performance of implanted biomedical titanium and titanium alloys and maintaining the structural and performance stability of the implanted metal during long-term service in complex bodily fluid environments. A method for preparing the FSP (Follicular Unit Extraction) layer for biomedical titanium and titanium alloy surfaces is also provided.

Description

Technical Field

[0001] This invention belongs to the field of metallic materials, specifically relating to a multi-performance alloy layer on the surface of biomedical titanium and titanium alloys, and also to a method for preparing the FSP of the multi-performance alloy layer on the surface of biomedical titanium and titanium alloys. Background Technology

[0002] With the increasing aging of the world's population and the continuous rise in demand for implants and prostheses, biomedical metals, as an advanced multifunctional material, are finding increasingly widespread applications in the medical field. Titanium and titanium alloys possess excellent biocompatibility and corrosion resistance, are non-toxic, have potential osteogenic reactivity, high specific strength, low Young's modulus, and are easy to process. Due to these superior properties, titanium and titanium alloys have been the main raw materials for mid-to-high-end surgical implants since World War II. The surface of titanium and titanium alloy implants is the initial substrate for all biological reactions, and the reaction process between the implant surface and the surrounding living tissue plays a crucial role in practical use. Biomedical titanium and its alloys typically operate in corrosive bodily fluids and complex stress environments, requiring their surfaces to have good biocompatibility, antibacterial properties, as well as a certain degree of wear resistance and excellent corrosion resistance. Surface modification is an important way to improve the surface properties of biomedical titanium and its alloys. Applying surface modification processes to form coatings or modify the surface of materials is beneficial for improving the specific properties of implanted titanium and titanium alloys. However, existing modification processes suffer from problems such as poor bonding between the coating and the substrate, sudden changes in the physicochemical properties between the coating and the substrate leading to implant performance defects, high energy consumption and emissions, and limited performance improvement.

[0003] In summary, there is an urgent need to develop surface modification processes that integrate well with the substrate, consume little energy, and comprehensively improve the mechanical, corrosion, and antibacterial properties of biomedical titanium and alloy surfaces. Summary of the Invention

[0004] The first objective of this invention is to provide a multi-performance alloy layer on the surface of biomedical titanium and titanium alloys. This alloy layer has good mechanical properties, corrosion resistance, and biocompatibility, which can significantly improve the overall performance of implanted biomedical titanium and titanium alloys and maintain the stability of the structure and performance of the implanted metal during long-term service in complex body fluid environments.

[0005] The second objective of this invention is to provide a method for preparing a multi-performance alloy layer (FSP) on the surface of biomedical titanium and titanium alloys.

[0006] The first technical solution adopted in this invention is a multi-performance alloy layer on the surface of biomedical titanium and titanium alloys, which is composed of the following components according to the atomic percentage: 82% ≥ Ti ≤ 88%, 4% ≥ Cu ≤ 6%, 4% ≥ Zn ≤ 6%, 4% ≥ Sn ≤ 6%, and the sum of the atomic percentages of the above components is 100%.

[0007] The second technical solution adopted in this invention is a method for preparing a multi-performance alloy layer (FSP) on the surface of biomedical titanium and titanium alloys, specifically including the following steps:

[0008] Step 1: Make several blind holes on the surface of the titanium and titanium alloy substrate materials and clean them;

[0009] Step 2, Preparation and addition of TiCuZnSn mixed powder: Equimolar amounts of Ti, Cu, Zn and Sn metal powders are placed in a metal powder mixer for mixing. The mixed TiCuZnSn metal powder is added to the pre-made blind holes and compacted.

[0010] Step 3: Obtain the modified TiCuZnSn layer by friction stirring.

[0011] Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained by friction stirring in Step 3;

[0012] Step 5: Perform annealing heat treatment on the workpiece obtained in step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy.

[0013] The invention is further characterized in that,

[0014] Step 1 is as follows:

[0015] Beforehand, machine several blind holes with a diameter of 2mm-3mm and a depth of 2mm-2.5mm on the surface of titanium and titanium alloy, with a spacing of 3mm-4mm between the blind holes; clean the surface of titanium and titanium alloy with a stainless steel wire brush until the surface shows a metallic luster.

[0016] In step 2: the particle size of Ti, Cu, Zn, and Sn metal powders is 6-8 μm.

[0017] Step 3 specifically involves:

[0018] During the friction stir processing, the surface of titanium and titanium alloy is protected with argon gas of 99.99% or higher purity, and the argon gas flow rate is 15L / min to 18L / min. First, the surface of titanium and titanium alloy is processed with a stirring head without stirring pin to achieve pre-drilled hole sealing. Then, a tungsten-rhenium alloy stirring head assembly is used to process the surface of titanium and titanium alloy in two passes along the center line of the pre-drilled hole to obtain the modified TiCuZnSn layer.

[0019] The tungsten-rhenium alloy stirring head assembly includes a stirring pin, a shoulder, a shoulder base, and a connecting rod connected in sequence, with the stirring pin being conical.

[0020] Step 4 is as follows:

[0021] First, the modified TiCuZnSn layer prepared by friction stir processing is ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer is polished with sandpaper of 150 mesh, 240 mesh, 600 mesh, 1000 mesh and 1500 mesh to make the surface roughness of the modified layer between 3.0 μm and 4.0 μm.

[0022] Step 5 specifically involves:

[0023] The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace, and a vacuum level higher than 8.0 × 10⁻⁶ is applied. -3 Pa; then, the furnace temperature is heated to 390℃~420℃ for 35min~40min; subsequently, it is held at this temperature for 80min~90min and then cooled in the furnace. When the furnace temperature is below 100℃, the workpiece can be removed.

[0024] The alloy layer prepared in step 5 consists of the following components in terms of atomic number: 82% ≥ Ti ≤ 88%, 4% ≥ Cu ≤ 6%, 4% ≥ Zn ≤ 6%, 4% ≥ Sn ≤ 6%, and the sum of the atomic number percentages of the above components is 100%.

[0025] The beneficial effects of this invention are:

[0026] (1) The multi-performance alloy layer on the surface of biomedical titanium and titanium alloy of the present invention has good mechanical properties, corrosion resistance, biocompatibility and antibacterial properties, which can significantly improve the comprehensive performance of implanted biomedical titanium and titanium alloy, and maintain the stability of the structure and performance of implanted metal during long-term service in complex body fluid environment.

[0027] (2) The method of the present invention can significantly improve the mechanical properties of the implanted titanium and titanium alloy surface layer, greatly enhance the corrosion resistance of the implanted titanium and titanium alloy, and improve the biocompatibility and antibacterial ability of the implanted titanium and titanium alloy. The multi-performance alloy layer can ensure the stability of the structure and various properties of the implanted titanium and titanium alloy during long-term service in complex body fluid environment. Attached Figure Description

[0028] Figure 1 This is a flowchart of the method for preparing the FSP of the multi-performance alloy layer on the surface of biomedical titanium and titanium alloys according to the present invention;

[0029] Figure 2 This is a schematic diagram showing the distribution of pre-fabricated blind holes on the surface of titanium and titanium alloys, the matrix materials of this invention.

[0030] Figure 3 This is a schematic diagram of the structure of the stirring head assembly of the present invention;

[0031] Figure 4This is an energy spectrum diagram of the alloy element content of the multi-performance alloy layer on the surface of biomedical titanium and titanium alloys of this invention;

[0032] Figure 5 The elemental distribution of the multi-performance alloy layer on the surface of biomedical titanium and titanium alloys of this invention;

[0033] Figure 6 The friction time-friction coefficient curves of the multi-performance alloy layer on the surface of biomedical titanium and titanium alloys of this invention;

[0034] Figure 7 This is a comparison of the electrochemical polarization curves of the titanium substrate and the multi-performance alloy layer on the surface of the biomedical titanium and titanium alloy based on the present invention during electrochemical corrosion testing.

[0035] In the diagram, 1. stirring needle, 2. shaft shoulder, 3. shaft shoulder base, 4. connecting rod. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0037] This invention provides a biomedical titanium and titanium alloy surface multi-performance alloy layer, which is composed of the following components according to atomic percentage: 82% ≥ Ti ≤ 88%, 4% ≥ Cu ≤ 6%, 4% ≥ Zn ≤ 6%, 4% ≥ Sn ≤ 6%, and the sum of the atomic percentages of the above components is 100%.

[0038] This invention also provides a method for preparing a multi-performance alloy layer (FSP) on the surface of biomedical titanium and titanium alloys, such as... Figure 1 As shown, the specific steps include:

[0039] Step 1: Make several blind holes on the surface of the titanium and titanium alloy substrate materials and clean them;

[0040] like Figure 2 As shown, several blind holes with a diameter of 2mm-3mm and a depth of 2mm-2.5mm are pre-machined on the surface of titanium and titanium alloy, with a spacing of 3mm-4mm between the blind holes; the surface of titanium and titanium alloy is cleaned with a stainless steel wire brush until the surface shows a metallic luster; after cleaning, the surface of titanium and titanium alloy is wiped clean with a clean white silk cloth soaked in acetone to thoroughly remove the surface oxide film, grease and water, etc.

[0041] Step 2, Preparation and addition of TiCuZnSn mixed powder:

[0042] Equimolar amounts of Ti, Cu, Zn, and Sn metal powders were placed in a metal powder mixer for mixing. The purity of each metal powder was higher than 99.95%, and the particle size of each metal powder was 6–8 μm. Finally, a TiCuZnSn mixed powder with a mixing rate of 99.9% was obtained. The mixed TiCuZnSn metal powder was added to pre-made blind holes and compacted to ensure the metal powder filling amount. After cleaning the TiCuZnSn mixed powder residue from the surface of the titanium matrix, it was subjected to stirring and friction processing.

[0043] Step 3: Friction stir processing (FSP) to obtain the modified TiCuZnSn layer:

[0044] During the friction stir machining process, the surface of titanium and titanium alloy is protected with argon gas of 99.99% purity or higher, and the argon gas flow rate is 15L / min to 18L / min. First, the surface of titanium and titanium alloy is machined with a stirring head without stirring pin to seal the pre-made holes and prevent the pre-made metal powder from overflowing during the subsequent processing. Then, the surface of titanium and titanium alloy is machined in two passes along the center line of the pre-made holes to obtain the modified TiCuZnSn layer. During the friction stir machining process, the stirring head rotates at 250 r / min, moves at a speed of 45 mm / min along the processing direction, and is tilted back by 2°.

[0045] Among them, such as Figure 3 As shown, the stirring head assembly includes a stirring pin 1, a shoulder 2, a shoulder base 3, and a connecting rod 4 connected in sequence. The stirring pin 1 is conical, the diameter of the stirring head shoulder is 15mm, the stirring pin is conical with upper and lower diameters of 4mm and 6mm respectively, and the length of the stirring pin is 2.7mm. The stirring head 1 is made of tungsten rhenium alloy, and the connecting rod 4 is connected to the friction stir welding spindle.

[0046] Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained in Step 3 by friction stirring.

[0047] First, the modified TiCuZnSn layer prepared by friction stir processing is ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer is polished with sandpaper of 150 mesh, 240 mesh, 600 mesh, 1000 mesh and 1500 mesh to make the surface roughness of the modified layer between 3.0 μm and 4.0 μm.

[0048] Step 5: Perform annealing heat treatment on the workpiece obtained in Step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy:

[0049] The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment to remove friction stir processing stress and achieve homogenization of the internal microstructure. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace and a vacuum level higher than 8.0 × 10⁻⁶.-3 Pa; then, the furnace temperature is heated to 390℃~420℃ for 35min~40min; subsequently, it is held at this temperature for 80min~90min and then cooled in the furnace. When the furnace temperature is below 100℃, the workpiece can be removed.

[0050] Example 1

[0051] Step 1: Make several blind holes on the surface of the titanium and titanium alloy substrate materials and clean them;

[0052] Beforehand, machine several blind holes with a diameter of 2mm and a depth of 2mm on the surface of titanium and titanium alloy, with a spacing of 3mm between the blind holes; clean the surface of titanium and titanium alloy with a stainless steel wire brush until the surface shows a metallic luster; after cleaning, wipe the surface of titanium and titanium alloy with a clean white silk cloth soaked in acetone to thoroughly remove the surface oxide film, grease and water, etc.

[0053] Step 2, Preparation and addition of TiCuZnSn mixed powder:

[0054] Equimolar amounts of Ti, Cu, Zn, and Sn metal powders were mixed in a metal powder mixer. The purity of each metal powder was higher than 99.95%, and the particle size of each metal powder was 7 μm. Finally, a TiCuZnSn mixed powder with a mixing rate of 99.9% was obtained. The mixed TiCuZnSn metal powder was added to pre-made blind holes and compacted to ensure the metal powder filling amount. After cleaning the TiCuZnSn mixed powder residue from the surface of the titanium matrix, it was subjected to stirring and friction processing.

[0055] Step 3: Friction stir processing (FSP) to obtain the modified TiCuZnSn layer:

[0056] During the friction stir machining process, the surface of titanium and titanium alloy is protected with argon gas of 99.99% purity or higher at a flow rate of 15 L / min. First, the surface of titanium and titanium alloy is machined with a stirring head without stirring pins to seal the pre-made holes and prevent the pre-made metal powder from overflowing during subsequent processing. Then, the surface of titanium and titanium alloy is machined in two passes along the center line of the pre-made holes to obtain the modified TiCuZnSn layer. During the friction stir machining process, the stirring head rotates at 250 r / min, moves at a speed of 45 mm / min along the processing direction, and is tilted back by 2°.

[0057] Among them, such as Figure 3 As shown, the stirring head assembly includes a stirring pin 1, a shoulder 2, a shoulder base 3, and a connecting rod 4 connected in sequence. The stirring pin 1 is conical, the diameter of the stirring head shoulder is 15mm, the stirring pin is conical with upper and lower diameters of 4mm and 6mm respectively, and the length of the stirring pin is 2.7mm. The stirring head 1 is made of tungsten rhenium alloy, and the connecting rod 4 is connected to the friction stir welding spindle.

[0058] Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained in Step 3 by friction stirring.

[0059] First, the modified TiCuZnSn layer prepared by friction stir processing was ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer was polished with sandpaper of 150 mesh, 240 mesh, 600 mesh, 1000 mesh and 1500 mesh to make the surface roughness of the modified layer 3.0 μm.

[0060] Step 5: Perform annealing heat treatment on the workpiece obtained in Step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy:

[0061] The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment to remove friction stir processing stress and achieve homogenization of the internal microstructure. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace and a vacuum level higher than 8.0 × 10⁻⁶. -3 Pa; then, the furnace temperature is heated to 400℃ for 40 minutes; subsequently, it is held at that temperature for 90 minutes and then cooled in the furnace. When the furnace temperature is below 100℃, the workpiece can be removed.

[0062] Based on the above preparation process, a TiCuZnSn alloy layer was obtained on the surface of titanium and titanium alloys. The alloying elements in this layer are uniformly distributed. (See...) Figure 4-5 The atomic ratio of Ti:Cu:Zn:Sn in the alloy layer is 85.6:4.9:4.75:4.75.

[0063] 1. This preparation method can effectively solve the problems of poor bonding between the coating and the substrate, sudden changes in the physicochemical properties between the coating and the substrate leading to implant performance defects, and large energy consumption and emissions during the traditional physical and chemical modification of titanium and titanium alloys.

[0064] 2. This preparation method significantly improves the mechanical properties of implanted titanium and titanium alloy surface layers, reducing the wear rate by more than 25% to 30% compared with the substrate material, and by more than 10% to 12% compared with modified layers processed only by FSP (without adding TiCuZnSn). Figure 6 The figures show the friction time-friction coefficient curves for the titanium substrate, the FSP-modified titanium surface, and the titanium surface alloy layer based on this invention during friction and wear tests. The test results show that the wear rate of pure titanium is 1.52 × 10⁻⁶. -3 The wear rate of the modified layer processed using only FSP was 1.16 × 10⁻⁶. -3 The wear rate of the titanium surface alloy layer based on the present invention is 1.01 × 10⁻⁶. -3 .

[0065] 3. This preparation method significantly improves the corrosion resistance of implanted titanium and titanium alloy surface layers, solving the problem that when only FSP is used to modify the titanium surface, the corrosion potential of the modified layer is unstable, and the corrosion performance of the surface modified layer decreases compared with the titanium substrate. The corrosion rate of the surface TiCuZnSn alloy layer obtained based on the preparation process of this invention is approximately 20% to 25% of that of the titanium substrate. Figure 7 The figure shows the electrochemical polarization curves of the titanium substrate and the titanium surface alloy layer based on the present invention during electrochemical corrosion testing. The test results show that the self-corrosion current density of pure titanium is 1.67 × 10⁻⁶. -6 A / cm 2 The self-corrosion current density of the alloy layer based on the present invention is 3.24 × 10⁻⁶. -7 A / cm 2 .

[0066] 4. Extensive literature and practical experience have confirmed that Zn, an alloying element, is an essential trace element for the human body, participating in bone metabolism and immune regulation; surface-modified layers containing a certain amount of Cu exhibit anti-inflammatory and osteogenic effects; Ti-Sn alloys possess higher flexural strength and flexural modulus than industrially pure titanium, exhibiting good ductility. Based on the preparation method of this invention, a uniformly distributed TiCuZnSn alloy layer was prepared on the titanium surface, which exhibits good biocompatibility and antibacterial properties.

[0067] Example 2

[0068] Step 1: Make several blind holes on the surface of the titanium and titanium alloy substrate materials and clean them;

[0069] Beforehand, machine several blind holes with a diameter of 3mm and a depth of 2.5mm on the surface of titanium and titanium alloy, with a spacing of 4mm between the blind holes; clean the surface of titanium and titanium alloy with a stainless steel wire brush until the surface shows a metallic luster; after cleaning, wipe the surface of titanium and titanium alloy with a clean white silk cloth soaked in acetone to thoroughly remove the surface oxide film, grease and water, etc.

[0070] Step 2, Preparation and addition of TiCuZnSn mixed powder:

[0071] Equimolar amounts of Ti, Cu, Zn, and Sn metal powders were placed in a metal powder mixer for mixing. The purity of each metal powder was higher than 99.95%, and the particle size of each metal powder was 8 μm. Finally, a TiCuZnSn mixed powder with a mixing rate of 99.9% was obtained. The mixed TiCuZnSn metal powder was added to pre-made blind holes and compacted to ensure the metal powder filling amount. After cleaning the TiCuZnSn mixed powder residue from the surface of the titanium matrix, it was subjected to stirring and friction processing.

[0072] Step 3: Friction stir processing (FSP) to obtain the modified TiCuZnSn layer:

[0073] During the friction stir machining process, the surface of titanium and titanium alloy is protected with argon gas of 99.99% purity or higher at a flow rate of 18 L / min. First, the surface of titanium and titanium alloy is machined with a stirring head without stirring pins to seal the pre-formed holes and prevent the pre-formed metal powder from overflowing during subsequent processing. Then, the surface of titanium and titanium alloy is machined in two passes along the center line of the pre-formed holes to obtain the modified TiCuZnSn layer. During the friction stir machining process, the stirring head rotates at 250 r / min, moves at a speed of 45 mm / min along the processing direction, and is tilted back by 2°.

[0074] Among them, such as Figure 3 As shown, the stirring head assembly includes a stirring pin 1, a shoulder 2, a shoulder base 3, and a connecting rod 4 connected in sequence. The stirring pin 1 is conical, the diameter of the stirring head shoulder is 15mm, the stirring pin is conical with upper and lower diameters of 4mm and 6mm respectively, and the length of the stirring pin is 2.7mm. The stirring head 1 is made of tungsten rhenium alloy, and the connecting rod 4 is connected to the friction stir welding spindle.

[0075] Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained in Step 3 by friction stirring.

[0076] First, the modified TiCuZnSn layer prepared by friction stir processing was ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer was polished with sandpaper of 150 mesh, 240 mesh, 600 mesh, 1000 mesh and 1500 mesh to make the surface roughness of the modified layer 3.5 μm.

[0077] Step 5: Perform annealing heat treatment on the workpiece obtained in Step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy:

[0078] The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment to remove friction stir processing stress and achieve homogenization of the internal microstructure. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace and a vacuum level higher than 8.0 × 10⁻⁶. -3 Pa; then, the furnace temperature is heated to 420℃ for 35 minutes; subsequently, it is held at this temperature for 80 minutes and then cooled in the furnace. When the furnace temperature is below 100℃, the workpiece can be removed.

[0079] Based on the above preparation process, a TiCuZnSn alloy layer was obtained on the surface of titanium and titanium alloys. The alloy elements in the alloy layer are uniformly distributed, and the atomic ratio of Ti:Cu:Zn:Sn in the alloy layer is 82:6:6:6.

[0080] Example 3

[0081] Step 1: Make several blind holes on the surface of the titanium and titanium alloy substrate materials and clean them;

[0082] Beforehand, machine several blind holes with a diameter of 2.5 mm and a depth of 2.5 mm on the surface of titanium and titanium alloy, with a spacing of 3.5 mm between the blind holes; clean the surface of titanium and titanium alloy with a stainless steel wire brush until the surface shows a metallic luster; after cleaning, wipe the surface of titanium and titanium alloy with a clean white silk cloth soaked in acetone to thoroughly remove the surface oxide film, grease and water, etc.

[0083] Step 2, Preparation and addition of TiCuZnSn mixed powder:

[0084] Equimolar amounts of Ti, Cu, Zn, and Sn metal powders were placed in a metal powder mixer for mixing. The purity of each metal powder was higher than 99.95%, and the particle size of each metal powder was 6–8 μm. Finally, a TiCuZnSn mixed powder with a mixing rate of 99.9% was obtained. The mixed TiCuZnSn metal powder was added to pre-made blind holes and compacted to ensure the metal powder filling amount. After cleaning the TiCuZnSn mixed powder residue from the surface of the titanium matrix, it was subjected to stirring and friction processing.

[0085] Step 3: Friction stir processing (FSP) to obtain the modified TiCuZnSn layer:

[0086] During the friction stir machining process, the surface of titanium and titanium alloy is protected with argon gas of 99.99% purity or higher at a flow rate of 16 L / min. First, the surface of titanium and titanium alloy is machined with a stirring head without stirring pins to seal the pre-made holes and prevent the pre-made metal powder from overflowing during subsequent processing. Then, the surface of titanium and titanium alloy is machined in two passes along the center line of the pre-made holes to obtain the modified TiCuZnSn layer. During the friction stir machining process, the stirring head rotates at 250 r / min, moves at a speed of 45 mm / min along the processing direction, and is tilted back by 2°.

[0087] Among them, such as Figure 3 As shown, the stirring head assembly includes a stirring pin 1, a shoulder 2, a shoulder base 3, and a connecting rod 4 connected in sequence. The stirring pin 1 is conical, the diameter of the stirring head shoulder is 15mm, the stirring pin is conical with upper and lower diameters of 4mm and 6mm respectively, and the length of the stirring pin is 2.7mm. The stirring head 1 is made of tungsten rhenium alloy, and the connecting rod 4 is connected to the friction stir welding spindle.

[0088] Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained in Step 3 by friction stirring.

[0089] First, the modified TiCuZnSn layer prepared by friction stir processing was ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer was polished with sandpaper of 150 mesh, 240 mesh, 600 mesh, 1000 mesh and 1500 mesh to make the surface roughness of the modified layer 4.0 μm.

[0090] Step 5: Perform annealing heat treatment on the workpiece obtained in Step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy:

[0091] The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment to remove friction stir processing stress and achieve homogenization of the internal microstructure. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace and a vacuum level higher than 8.0 × 10⁻⁶. -3 Pa; then, the furnace temperature is heated to 390℃ for 38 minutes; subsequently, it is held at that temperature for 85 minutes and then cooled in the furnace. When the furnace temperature is below 100℃, the workpiece can be removed.

[0092] Based on the above preparation process, a TiCuZnSn alloy layer was obtained on the surface of titanium and titanium alloys. The alloy elements in the alloy layer are uniformly distributed, and the atomic ratio of Ti:Cu:Zn:Sn in the alloy layer is 88:4:4:4.

Claims

1. A multi-performance alloy layer on the surface of biomedical titanium and titanium alloys, characterized in that, The composition is based on the following atomic percentages: 82%≤Ti≤88%, 4%≤Cu≤6%, 4%≤Zn≤6%, 4%≤Sn≤6%, and the sum of the atomic percentages of the above components is 100%.

2. The method for preparing FSP for multi-performance alloy layers on the surface of biomedical titanium and titanium alloys according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Machine several blind holes on the surface of the base material titanium and titanium alloy and clean them; Step 2, Preparation and addition of TiCuZnSn mixed powder: Ti, Cu, Zn and Sn metal powders are placed in a metal powder mixer for mixing. The mixed TiCuZnSn metal powder is added to the pre-made blind holes and compacted. Step 3: Obtain the modified TiCuZnSn layer by friction stirring. Step 3 specifically involves: During the friction stir processing, the surface of titanium and titanium alloy is protected with argon gas of 99.99% or higher purity, and the argon gas flow rate is 15L / min~18L / min. First, the surface of titanium and titanium alloy is processed with a stirring head without stirring pin to achieve pre-drilled hole sealing. Then, a tungsten-rhenium alloy stirring head assembly is used to process the surface of titanium and titanium alloy in two passes along the center line of the pre-drilled hole to obtain the modified TiCuZnSn layer. The tungsten-rhenium alloy stirring head assembly includes a stirring pin (1), a shoulder (2), a shoulder base (3), and a connecting rod (4) connected in sequence. The stirring pin (1) is conical. Step 4: Perform surface treatment on the modified TiCuZnSn layer obtained by friction stirring in Step 3; Step 5: Perform annealing heat treatment on the workpiece obtained in step 4, that is, obtain an alloy layer on the surface of titanium and titanium alloy.

3. The method for preparing FSP for multi-performance alloy layers on the surface of biomedical titanium and titanium alloys according to claim 2, characterized in that, Step 1 is as follows: Beforehand, machine several blind holes with a diameter of 2mm-3mm and a depth of 2mm-2.5mm on the surface of titanium and titanium alloy, with a spacing of 3mm-4mm between the blind holes; clean the surface of titanium and titanium alloy with a stainless steel wire brush until the surface shows a metallic luster.

4. The method for preparing FSP for multi-performance alloy layers on the surface of biomedical titanium and titanium alloys according to claim 3, characterized in that, In step 2: the particle size of Ti, Cu, Zn and Sn metal powders is 6~8μm.

5. The method for preparing FSP for multi-performance alloy layers on the surface of biomedical titanium and titanium alloys according to claim 2, characterized in that, Step 4 is as follows: First, the modified TiCuZnSn layer prepared by friction stir processing is ground with a grinding machine to remove the burrs from the friction stir processing. Then, the modified layer is polished with sandpaper of 150 grit, 240 grit, 600 grit, 1000 grit and 1500 grit to make the surface roughness of the modified layer between 3.0µm and 4.0µm.

6. The method for preparing FSP for biomedical titanium and titanium alloy surface multi-performance alloy layers according to claim 5, characterized in that, Step 5 specifically involves: The surface-polished workpiece is placed in a vacuum heat treatment furnace for vacuum heat treatment. Heat treatment parameters: The workpiece is placed in the vacuum heat treatment furnace, and a vacuum level higher than 8.0 × 10⁻⁶ is applied. -3 Pa; then, the furnace temperature is heated to 390 ℃~ 420 ℃ for 35 min~ 40 min; then, it is held at that temperature for 80 min~ 90 min and then cooled in the furnace. When the furnace temperature is below 100 ℃, the workpiece can be removed.

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