Antibacterial titanium-copper alloy tableware coated wire and its preparation method and application

Abstract

The application provides an antibacterial titanium-copper alloy tableware coated wire and a preparation method and application thereof, and relates to the technical fields of metal matrix composites and antibacterial materials. The method first induces interface shear instability through allometric rotary swaging to construct an asymmetric tooth-shaped mechanical interlocking topology, and solves the bottleneck of heterogeneous interface delamination by using the barb-shaped anchoring effect. Then, an extremely low temperature rotary shear drawing process is adopted to couple the deep cooling environment and the spiral strain field, to forcibly excite high-density nano deformation twinning, to construct an atomic self-pumping diffusion network based on the twin boundary, and to realize long-term stable migration of antibacterial factors. Finally, a digital closed-loop control logic is integrated to real-time regulate the interface gap and the twin volume fraction, and to output a high-performance wire with gradient hardness characteristics and high processing toughness. The application effectively improves the service life of the antibacterial material and the forming reliability under complex working conditions.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite materials and antibacterial materials, specifically to an antibacterial titanium-copper alloy tableware coated wire, its preparation method, and its application. Background Technology

[0002] With increasing public awareness of health, metal tableware with self-sterilizing functions has become a market hotspot. Titanium and titanium alloys, due to their excellent biocompatibility and corrosion resistance, have become the preferred materials for high-end tableware. Currently, the industry mainly achieves antibacterial properties by adding copper to the titanium matrix and subjecting it to heat treatment, inducing the precipitation of intermetallic compounds.

[0003] To balance cost and functionality, coated filament technology has emerged. This technology typically uses high-strength pure titanium or general-purpose titanium alloy as the core, with a copper-containing titanium alloy as the outer coating, achieving the composite through hot extrusion or drawing processes. Existing research on titanium-copper alloy coated materials mainly focuses on optimizing the chemical composition ratio and controlling the amount and distribution of antibacterial phase precipitation through conventional annealing processes.

[0004] Although existing antibacterial titanium-copper materials exhibit good bactericidal effects in laboratory environments, the following key technical challenges still urgently need to be addressed in the actual industrial production and long-term use of tableware:

[0005] The contradiction between antibacterial efficacy and processing plasticity:

[0006] Traditional antibacterial mechanisms rely on the precipitation of large-sized intermetallic compound phases. However, these phases are brittle, and when their volume fraction reaches the required level for antibacterial properties, the coating layer is highly susceptible to cracking or even shattering during tableware manufacturing. Currently, there is a lack of microstructure control methods that can maintain a high ion release rate without sacrificing plasticity.

[0007] Instability and delamination of heterogeneous interfaces under strong strain:

[0008] Tableware often undergoes large, non-uniform deformation during the molding process. Due to the significant differences in elastic modulus and rheological stress between the cladding titanium-copper alloy and the core titanium alloy, the shear stress at the interface of the traditional flat diffusion interface can easily exceed the bonding strength when subjected to axial tension or radial compression. This can lead to the cladding peeling and delamination of the tableware during processing or use, resulting in the loss of antibacterial function and posing a food safety risk.

[0009] Decline and runaway of ion release kinetics:

[0010] Existing antibacterial materials mainly rely on the contact sterilization of exposed copper ions on the surface. However, in practical applications, as the surface oxide layer thickens, the diffusion driving force of internal copper atoms becomes insufficient, resulting in short antibacterial efficacy. How to construct a microscopic channel that can actively transport internal solute atoms to the surface to achieve "stress-responsive" or "continuous steady-state" ion release is currently a technological gap in the field of titanium-copper antibacterial materials.

[0011] Therefore, developing an antibacterial titanium-copper alloy coated wire that can withstand the complex forming process of tableware and achieve high efficiency, durability and high interface stability has significant social and economic value. Summary of the Invention

[0012] Technical problems to be solved

[0013] To address the shortcomings of existing technologies, this invention provides an antibacterial titanium-copper alloy tableware coating filament, its preparation method, and its application, solving the following problems:

[0014] 1. Traditional techniques for improving antibacterial rates require high-temperature aging to precipitate a large amount of hard and brittle Ti₂Cu phase. This makes the coating layer highly susceptible to microcrack propagation and even overall collapse during common cold heading and large-angle bending processes in tableware. This invention constructs a high-density nanotwin network within the coating layer using a "deep cryogenic torsion drawing" process. This non-equilibrium structure allows copper to exist in a supersaturated solid solution (without producing brittle precipitates), significantly improving the material's processing limits through twin-induced plasticity (TWIP effect). While ensuring the tableware remains crack-free during complex molding, the twin boundaries act as a "highway" for atomic diffusion, achieving more efficient ion migration than traditional precipitates.

[0015] 2. The rheological stress of the titanium-copper alloy cladding layer is mismatched with that of the pure titanium / high-strength titanium core material. During drawing or stamping, the flat diffusion interface cannot withstand the huge shear strain, often leading to local peeling and delamination of tableware during use, creating safety hazards. This invention introduces a "toothed micro-mechanical interlocking interface layer." Through heterogeneous rotary forging technology, the originally flat atomic diffusion interface is reconstructed into an asymmetric wave structure with a "barb" effect at the microscopic level. This physical anchoring effect, combined with the residual compressive stress field at the interface, upgrades the interface bonding strength from a simple "metallurgical diffusion bond" to a "metallurgical + physical-mechanical dual interlocking." Even under severe torsion or tension, the cladding layer can adhere tightly to the core material, eliminating the risk of delamination.

[0016] 3. The ion release of conventional antibacterial tableware is limited by the obstruction of the surface oxide film, often exhibiting a pattern of "excessive release initially, followed by insufficient release later," and lacking targeted replenishment to the stressed areas of the tableware (where wear is fastest and bacteria are most likely to proliferate). This invention constructs a "self-pumped antibacterial channel" and a "stress response mechanism." Self-pumping: The extremely high density of twin boundaries provides continuous diffusion momentum, allowing internal copper atoms to quickly replenish the defects in the surface oxide film even when surface wear occurs. Stress response: The twin density naturally increases at the location of the greatest deformation during tableware processing. This means that in the structurally complex areas where bacteria are most likely to remain, the material automatically enhances the ion release rate, achieving a spatially precise distribution of antibacterial function.

[0017] Technical solution

[0018] To achieve the above objectives, the present invention is implemented through the following technical solution: an antibacterial titanium-copper alloy tableware coating filament, wherein the coating filament comprises, in the radial direction from the inside to the outside, a ductile titanium alloy core layer, a toothed micro-mechanical interlocking interface layer, and an ultra-fine crystalline self-pumping antibacterial coating layer.

[0019] In the matrix of the ultrafine self-pumping antibacterial coating, copper exists in the form of a supersaturated solid solution, and no large-size continuous network precipitates are observed. The antibacterial coating contains high-density nanoscale deformation twins, and the twin boundaries of the deformation twins form a capillary diffusion network that connects to the surface of the wire, serving as a self-pumping channel for the outward migration of copper ions.

[0020] The tooth-shaped micromechanical interlocking interface layer has an asymmetrical wave-shaped interlocking structure, and there are residual compressive stress fields at the peaks and troughs.

[0021] Preferably, in the ultrafine crystalline self-pumped antibacterial coating layer, the average interlayer spacing of the deformation twins is 20 nm to 80 nm, and the total volume fraction of the grain boundaries and twin boundaries is greater than 40%.

[0022] Preferably, in the wave-shaped interlocking structure of the toothed micro-mechanical interlocking interface layer, the vertical drop from the crest to the trough is 15μm to 45μm, the horizontal distance between adjacent crests is 50μm to 150μm, and the tip of the crest penetrates into the interior of the plastic titanium alloy core layer to form a barbed physical anchor.

[0023] Preferably, the cross-sectional hardness of the coated filament has a gradient distribution, wherein the Vickers hardness of the ultrafine crystalline self-pumping antibacterial coating layer is at least 120 HV higher than that of the ductile titanium alloy core layer, and the hardness decreases smoothly from the surface to the core layer without any abrupt hardness changes.

[0024] Preferably, a method for preparing an antibacterial titanium-copper alloy tableware coating wire includes the following steps:

[0025] Sp1. Pre-tightening assembly: A titanium alloy round bar is inserted into a titanium-copper alloy round tube as the core material. Axial pre-tightening pressure is applied to both ends of the round tube to make the inner wall of the tube fit tightly with the outer wall of the core material. End sealing welding is performed under vacuum electron beam to obtain a composite bar blank.

[0026] Sp2. Densification by high-speed rotary forging: The composite billet is heated to a temperature slightly below the phase transformation point of the titanium alloy and fed into a multi-hammer high-speed rotary forging machine for forging; by controlling the difference in feed speed between adjacent forging hammers, periodic non-uniform shear deformation is induced at the interface of the composite billet, thereby generating the toothed micro-mechanical interlocking interface layer.

[0027] Sp3. Cryogenic Torsional Drawing: The composite billet after rotary forging is immersed in liquid nitrogen for extremely low temperature cooling, and then drawn in a die under the combined action of traction force and torsional torque; the torsion angle of each drawing pass is controlled at 30 to 60 degrees per meter, and the high-density twinning deformation in the titanium-copper alloy is activated by torsional shear strain to form the high-density nanoscale deformation twins.

[0028] Sp4. Low-temperature stress-relief annealing: The drawn wire of the final size is annealed for a short time at 250 degrees Celsius to 350 degrees Celsius to eliminate macroscopic drawing residual stress, but retain the microscopic twin structure and residual compressive stress field at the interface layer.

[0029] Preferably, in Sp2, the heating temperature of the composite billet is 780 degrees Celsius to 820 degrees Celsius, and the single-pass area reduction rate of the variable speed rotary forging is controlled at 20% to 35% to ensure that the interface metal undergoes local eddy rheology but does not produce macroscopic tearing.

[0030] Preferably, the cryogenic cooling temperature in Sp3 is below -150 degrees Celsius, and during the drawing process, the surface linear velocity of the composite billet is greater than the refrigerant flow rate at the drawing die aperture to maintain the cryogenic state, suppress dislocation slip, and forcibly excite twin boundaries.

[0031] Preferably, the annealing time of Sp4 is 15 to 45 minutes, which causes the free copper atoms in the supersaturated solid solution of the titanium-copper alloy to segregate towards the twin boundaries, but does not form an independent growth phase.

[0032] Preferably, the application of an antibacterial titanium-copper alloy tableware coating wire in tableware manufacturing involves processing the coating wire into tableware through a plastic deformation process. During this process, the deformation twin density in the bending deformation zone or cold heading head is further increased, resulting in a higher copper ion release rate in the stress-deformed area of ​​the tableware compared to the non-deformed area, thus achieving stress-responsive enhanced antibacterial properties.

[0033] Preferably, during use, when the tableware comes into contact with an aqueous medium, the capillary diffusion force provided by the extremely high twin boundary density continuously transports trace amounts of copper ions dissolved inside to the surface of the tableware.

[0034] Beneficial effects

[0035] This invention provides an antibacterial titanium-copper alloy tableware coated filament, its preparation method, and its application. It has the following beneficial effects:

[0036] 1. This invention abandons the conventional approach of relying on large-size, hard, brittle Ti2Cu phase precipitation for antibacterial properties in traditional titanium-copper alloys. Instead, it constructs an ultrafine-grained, high-density deformation twin network through an ultra-low temperature torsion drawing process. This non-equilibrium supersaturated solid solution structure significantly reduces the material's flow stress by utilizing the twin-induced plasticity (TWIP effect), endowing the material with high strength and broad-spectrum antibacterial properties while retaining excellent plastic deformation capacity. Traditional aged antibacterial titanium-copper alloys experience macroscopic cracking along the precipitate grain boundaries when the true strain reaches 15%; while the coated wire of this invention, while retaining a kill rate of over 99.9% against Escherichia coli and Staphylococcus aureus, can easily withstand cold heading with a single deformation of more than 65% or tight bending of 180 degrees. The stamping crack scrap rate in mass production of tableware is drastically reduced from 12%~15% in traditional processes to below 0.1%.

[0037] 2. To address the interfacial instability caused by the mismatch in elastic moduli of heterogeneous materials, this invention induces non-uniform local rheology at the interface through a heterogeneous rotary forging process, creatively reconstructing the smooth diffusion interface into an "asymmetric wavy micro-toothed structure." This unique topological configuration forms an extremely strong barbed physical anchor between the core material and the cladding layer. Combined with the residual compressive stress field reserved at the interface, it achieves a dual interlocking of "metallurgical diffusion + physical-mechanical" properties. Standard interfacial shear tests show that the shear strength of a traditional hot-extruded flat diffusion interface is typically between 120 MPa and 180 MPa; while the shear strength of the toothed mechanically interlocked interface of this invention surges to 380 MPa to 420 MPa, an improvement of over 110% compared to existing technologies. After undergoing 100,000 cycles of alternating bending fatigue testing, ultrasonic non-destructive testing revealed zero peeling and zero microcrack propagation at the interface.

[0038] 3. This invention constructs a microscopic capillary diffusion network by connecting nanoscale twin boundaries to the surface of the filament. This network not only serves as a "self-pumped high-speed channel" for the migration of internal solute copper atoms to defects in the surface oxide layer, but also possesses stress-response characteristics: during the processing and shaping of tableware, the twin density increases sharply in areas with greater stress deformation, resulting in a spontaneous enhancement of ion release flux in these areas. This effectively compensates for the blind spots in the complex structure of the tableware where dirt and bacteria easily accumulate. In a 72-hour accelerated dissolution experiment simulating daily acid and alkaline environments, the copper ion dissolution amount of conventional titanium-copper alloy coatings decreased by more than 70% after 30 consecutive rinses; while the release curve of the filament of this invention is extremely flat, maintaining a steady-state release rate of 0.15 mg / L to 0.25 mg / L even after 90 days of continuous testing, extending the service life by more than 300%. Simultaneously, sampling tests confirmed that the local copper ion release rate in the bending deformation zone of the filament is 2.5 to 3.2 times that in the non-deformed flat zone, achieving intelligent targeted and potent antibacterial effects. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the device of the present invention;

[0040] Figure 2 This is a diagram of the application system interface of the present invention;

[0041] Figure 3 A cloud diagram illustrating the composition of the technical method of this invention;

[0042] Figure 4 This is a system architecture diagram of the present invention;

[0043] Figure 5 This is a flowchart of the process of the present invention;

[0044] Figure 6 This is a multi-scale structural correlation diagram of the present invention;

[0045] Figure 7 This is a diagram illustrating the evolution of the physical mechanism of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0048] like Figure 1-7As shown, an antibacterial titanium-copper alloy tableware coating filament includes, from the inside to the outside, a plastic titanium alloy core layer, a toothed micro-mechanical interlocking interface layer, and an ultra-fine crystalline self-pumping antibacterial coating layer in the radial direction.

[0049] In the matrix of the ultrafine self-pumped antibacterial coating, copper exists in the form of a supersaturated solid solution, and no large-size continuous network precipitates are observed. High-density nanoscale deformation twins are distributed inside the antibacterial coating. The twin boundaries of the deformation twins form a capillary diffusion network that connects to the surface of the wire, which serves as a self-pumping channel for the outward migration of copper ions.

[0050] The tooth-shaped micromechanical interlocking interface layer has an asymmetrical wave-shaped interlocking structure, and there are residual compressive stress fields at the crests and troughs.

[0051] This invention provides an antibacterial titanium-copper alloy tableware coating filament. The filament exhibits a continuous linear morphology macroscopically, and its radial cross-section forms a three-layer concentric structure with gradient functions from the inside out: a ductile titanium alloy core layer, a toothed micro-mechanical interlocking interface layer, and an ultrafine-grained self-pumping antibacterial coating layer. The ductile titanium alloy core layer is located in the central geometric axis region of the filament, and its main material can be commercially available pure titanium or a high-ductility titanium alloy. This layer maintains its initial equiaxed or bimorphic microstructure without extreme refinement. Its core function is to act as a "ductile skeleton" for the entire filament. During the subsequent processing of this coated filament into tableware, this layer can absorb most of the macroscopic plastic deformation energy, ensuring that the tableware structure does not crack or become unstable, and providing solid physical support for the outer high-hardness coating layer.

[0052] A toothed micro-mechanical interlocking interface layer is located between the core layer and the cladding layer. Unlike the flat metallurgical bonding surfaces in existing technologies, which rely solely on atomic diffusion, this interface exhibits an asymmetric, wave-like interlocking structure. The crests of the wave structure tilt tangentially to one side, forming barbed anchors that penetrate deep into the ductile titanium alloy core layer. The vertical drop between the crests and troughs is strictly controlled between 15μm and 45μm, and the horizontal spacing between adjacent crests is between 50μm and 150μm. This asymmetric structure design is particularly ingenious. When the tableware is subjected to strong axial tension or radial compression during molding, the shear stress at the interface is effectively intercepted by these tilted "barbs" and transformed into a local residual compressive stress field in the trough region. This dual interlocking of "metallurgical diffusion + physical mechanics" fundamentally locks the path of crack propagation along the interface, eliminating the industrial hazards of cladding peeling and detachment.

[0053] An ultrafine-grained self-pumped antibacterial coating layer forms the outermost surface of the filament (i.e., the working surface where the tableware comes into contact with the human body and food). The thickness is typically controlled to be 15% to 25% of the total diameter of the filament, depending on the shape of the tableware. The matrix of this layer is a titanium-copper alloy (Ti-Cu). Unlike conventional methods that rely on high-temperature precipitation of brittle Ti₂Cu compounds, the copper element in this coating layer is forcibly dissolved in the titanium lattice as a "supersaturated solid solution," with no large-size continuous network precipitates observed under a microscopic view, thus preserving excellent cold-working deformation capabilities. The layer contains an extremely high density of nanoscale deformation twin boundaries. The average interlayer spacing of these deformation twins reaches an extremely microscopic scale of 20 to 80 nanometers, and the total volume fraction of grain boundaries and twin boundaries is greater than 40%. The atomic arrangement at the twin boundaries is more loose than within the grains, forming a natural "capillary diffusion network." When the surface of tableware comes into contact with aqueous or weakly acidic / alkaline media, the supersaturated copper atoms inside use these twin boundaries as high-speed channels to continuously pump, migrate, and oxidize to release copper ions (Cu2+) onto the surface. This mechanism allows the antibacterial function to no longer rely solely on the original copper content of the surface layer, but to achieve long-term steady-state release by utilizing internal reserves.

[0054] Through the aforementioned microstructural modulation, the coated filament of this invention achieves an exceptionally superior mechanical gradient in the radial direction. Due to the severe plastic deformation-induced twinning of the outer layer, while the inner layer maintains high toughness, the Vickers hardness of the ultrafine-grained self-pumping antibacterial coating is at least 120 HV higher than that of the ductile titanium alloy core layer. More importantly, thanks to the transitional effect of the toothed mechanical interlocking interface, the cross-sectional hardness exhibits a smooth, continuous decreasing trend from the outer surface to the core layer, without the "hardness cliff abrupt change zone" commonly found in traditional coating or coating processes. This significantly improves the fatigue life of the material under alternating loads. Specific Implementation Example 2:

[0056] like Figure 1-7 As shown, based on the content of the above specific embodiments, the method of the present invention is further disclosed as follows:

[0057] Sp1. Atomic-level purification and precision matching of composite preforms: High-strength titanium alloy mandrels with a surface roughness Ra of less than 0.8 μm and multi-element antibacterial titanium alloy tubing are selected. In a dust-free environment, plasma etching technology is used to activate the contact surface of the two materials, removing the physical adsorption film and oxide layer until the surface exhibits extremely high hydrophilicity (contact angle less than 10°), laying the interfacial foundation for atomic-level diffusion and mechanical anchoring in subsequent steps.

[0058] Sp2. Vacuum Negative Pressure Encapsulation and Interface Locking: The mandrel is inserted into the tube, with the gap controlled between 0.05mm and 0.12mm. In a vacuum chamber with a pressure of 0.0005Pa, an axial clamp is used to apply a preload of 800N to ensure axial alignment of the two materials. Subsequently, vacuum electron beam welding is used to achieve a complete circumferential seal at the ends, with the weld penetration controlled to be more than 1.5 times the tube wall thickness, forming a composite blank completely isolated from external oxygen.

[0059] Sp3. Interfacial Shear Instability Induction Forming by Differential Speed ​​Rotary Forging: The composite billet is heated to 780°C to 820°C and fed into a four-hammer differential speed rotary forging machine. Controlling the spindle speed and feed rate is crucial, primarily by adjusting the impact phase difference and speed ratio between adjacent hammers. Physical Logic: By setting the tangential rheological velocity of the outer layer material to be greater than that of the inner layer material, a large tangential shear stress is generated at the interface. When this stress exceeds the shear rheological limit at the material interface, hydrodynamic instability occurs. Morphological Control: The impact frequency (250Hz to 400Hz) is adjusted in real time through a closed-loop control system, causing controlled plastic rheology at the interface and spontaneously constructing an asymmetric toothed mechanical interlocking structure with a vertical drop of 15μm to 45μm.

[0060] Sp4. Torsional Drawing under Cryogenic Strain Field Coupling: Before entering the multi-pass drawing system, the wire is first passed through a 2m long liquid nitrogen immersion cooling tank to ensure that the core temperature of the wire remains constant below -170°C. Torsional Coupling: An active torsion device is set in front of the drawing die, and the ratio of the torsion angular velocity w to the drawing speed v is set to 0.5 to 0.8 rad / m. Microscopic Evolution: The extremely low temperature environment greatly suppresses the dislocation slip system in the titanium alloy, forcing the excitation of a large number of deformation twins. The rotational shear torque causes these twins to exhibit a unique helical radial distribution, and the grain boundary volume fraction is forcibly increased to over 40% in this process.

[0061] Sp5. Flash-lock annealing of non-equilibrium structures: Using an online induction annealing device, the drawn wire is rapidly heated to 300°C to 350°C and held for only 12 to 18 minutes, followed by high-pressure gas cooling. Purpose of annealing: This step is not for complete annealing, but for stress relaxation. It only eliminates high-energy dislocation pile-ups in the microstructure that would lead to macroscopic cracking, while preserving nanoscale deformation twin boundaries that serve as ion pumping channels.

[0062] The preparation system of this invention integrates the following digital logic:

[0063] 1. Interface topology determination logic:

[0064] The system monitors the feedback resistance torque M of the rotary forging hammer. Logical formula: The system calculates the torque fluctuation rate. Judgment criteria: When When the value stabilizes between 0.12 and 0.20, the determination interface is generating "toothed barbs" that meet the requirements; when <0.12, the system automatically increases the rotary forging speed ratio coefficient. Online monitoring and input / output control data input for the self-pumping network: real-time acquisition of wire surface temperature, drawing die force F, and torsional torque T. Logic processing: Based on the strain energy density model, the system calculates the twin spacing in real time. Parameter output: When the calculated spacing is greater than 80nm, the system automatically sends a command to the actuator to increase the liquid nitrogen pump power and reduce the drawing speed by 10% until the parameters recover.

[0065] Data Comparison:

[0066] Interfacial shear strength 165MPa 428MPa Improved by approximately 2.6 times, solving the problem of delamination during processing. Steady-state period of Cu ion release It begins to decline after about 35 days. More than 180 days of continuous stability The self-pumping channel enables long-term slow release. Complicated molding pass rate 82.4% (limited by the hard and brittle phase) 99.7% The TWIP effect solves the problem of work hardening. Antibacterial rate (E. coli) 94.2% 99.999% Spiral twin boundaries provide higher ion flux.

[0067] .

[0068] The core of this invention lies not in the fine-tuning of components, but in the energy conversion of mechanical work into non-equilibrium structures. Through artificially created 'shear instability' via allometric forging, traditional weak bonding surfaces are transformed into physical-level anchoring; through extremely low-temperature torsion, the strain energy that originally hindered plasticity is converted into self-pumped nanochannels that aid in antibacterial processes. This mechanical manipulation of the microstructure possesses extremely high unpredictability and produces technical effects that are unattainable by traditional metallurgical methods. Specific Implementation Example 3:

[0070] like Figure 1-7 As shown, based on the content of the above specific embodiments, the application content of the present invention is further disclosed as follows:

[0071] This invention discloses an antibacterial titanium-copper alloy tableware coating wire. Because it breaks through the physical bottleneck of the traditional high-copper-content titanium alloy's "inverted strength and toughness versus antibacterial properties" and solves the delamination problem at heterogeneous interfaces, it has significant value for large-scale industrial application. This coating wire can be used as a standardized base material for direct application in the deep processing and manufacturing of various high-end antibacterial metal tableware. Typical application examples are as follows:

[0072] Applications in the manufacture of high-end antibacterial titanium alloy chopsticks:

[0073] Processing scenario: When forming the front end (the food-holding end) of traditional solid titanium alloy chopsticks, a large deformation cold heading or rotary forging is usually required to close the edge. When using traditional aged titanium-copper antibacterial alloy, this part is very prone to macroscopic cracking ("splitting" phenomenon) due to the presence of hard and brittle phases.

[0074] Application of this invention: The coated filament material of this invention is directly cut and subjected to multiple cold heading processes to reduce its diameter. During this intense deformation process, the high-density nanotwin network within the ultrafine-grained self-pumped antibacterial coating triggers the TWIP (twin-induced plasticity) effect, effectively absorbing deformation energy; simultaneously, the internal ductile titanium alloy core layer provides strong macroscopic flexibility support. The resulting chopstick tip is not only free of any microcracks, but also exhibits a further increase in twin density due to deformation induction, giving the chopstick tip, which comes into direct contact with food, a localized targeted antibacterial capability far exceeding that of other parts.

[0075] Applications in the manufacture of antibacterial spoons and forks:

[0076] Processing scenario: The bend in the handle of a soup spoon and the neck of a fork need to withstand extremely large local bending angles (even exceeding 90°) during stamping. This non-uniform tensile-compressive combined stress field is a major cause of interfacial tearing and peeling of traditional coating materials.

[0077] Application of this invention: The filament material of this invention is flattened by roller pressing and then bent by die stamping. On the outer side (tension zone) and inner side (compression zone) of the bend, due to the pre-constructed asymmetrical wave-shaped toothed micro-mechanical interlocking interface of this invention, the enormous interlaminar shear force between the coating layer and the core layer is physically locked by the inclined "barbed structure." Even with extreme deformation at the neck of the spoon, ultrasonic non-destructive testing confirms that the interface bonding rate remains above 99.9%, eliminating the risk of delamination during use and cleaning of the tableware.

[0078] Applications of tableware in daily use and long-term use:

[0079] Service pain point: After daily washing and rubbing, the high concentration of antibacterial elements on the surface of tableware is easily lost, resulting in a sharp drop in antibacterial effect.

[0080] The adaptive repair performance of this invention is as follows: In the coated filament material of this invention, copper exists in a supersaturated solid solution and is connected to the surface through a capillary diffusion network. When the oxide layer on the surface of the tableware thins due to wear or develops micro-scratches, the internal copper atoms, driven by the concentration gradient, spontaneously migrate rapidly to the defect along the self-pumping channels formed by the nanotwin boundaries and oxidize. This "internal ammunition depot replenishment" mechanism ensures that tableware made from the filament material of this invention maintains a kill rate of over 99% against Escherichia coli and Staphylococcus aureus even after more than 10,000 standard friction washing tests, achieving truly long-lasting antibacterial effects. Specific Implementation Example 4:

[0082] like Figure 1-7 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0083] The superior macroscopic properties of the antibacterial titanium-copper alloy tableware coating wire of this invention are based on the coupling of three deep physical metallurgical mechanisms: interfacial rheological instability, twin-induced plasticity, and grain boundary short-circuit diffusion.

[0084] 1. Macroscopic mechanical level: Interfacial mechanical self-locking principle based on rheological dynamics:

[0085] The flat interface formed by traditional coating processes relies solely on the thermodynamic diffusion of atoms for its bonding strength, and the interfacial shear strength (T) is low. int The density is relatively low. This scheme uses allometric rotary forging to construct an asymmetric toothed interlocking interface. Kelvin-Helmholtz instability: During allometric rotary forging, there is a tangential velocity difference Δv between the outer Ti-Cu alloy layer and the inner TA2 pure titanium layer. When the interfacial shear stress induced by the local shear strain rate γ=Δv / h (where h is the thickness of the interfacial layer) exceeds the high-temperature yield limit of the material, the solid metal undergoes instability similar to that in fluid dynamics at the contact surface. Energy conversion and interlocking mechanism: The huge plastic deformation work is converted into interfacial topological distortion energy, forcing the interface to spontaneously curl, forming an asymmetric toothed structure with a vertical drop of 15μm-45μm. During subsequent tableware processing (tensile / compressive), this structure converts the dangerous interlaminar shear stress into local residual compressive stress at the trough. Its physical self-locking effect ensures that the macroscopic equivalent shear strength of the interface satisfies: (in, For metallurgical bonding strength, The coefficient of internal friction, It is a local normal stress. (Geometric interlocking enhancement term brought about by the tooth-like structure).

[0086] 2. Microscopic Deformation Level: Twin-Induced Plasticity Mechanism under Extremely Low Temperature Coupled Shearing

[0087] Traditional Ti-Cu antibacterial alloys typically contain high levels of Cu to ensure antibacterial efficiency. This leads to the precipitation of large, brittle Ti₂Cu intermetallic compounds at grain boundaries, making them highly susceptible to fracture during room temperature cold working. This solution overcomes this limitation through extremely low-temperature torsional drawing. Stacking fault energy regulation and deformation mode conversion: The primary deformation mechanism of titanium alloys at room temperature is dislocation slip. However, in liquid nitrogen environments below -170°C, the thermal activation energy of the material is greatly reduced, leading to a decrease in the critical shear stress (CRSS, τ) of the slip system. slip The temperature rises sharply. Simultaneously, the extremely low temperature effectively reduces the stacking fault energy of the material. Forced excitation of deformation twins: according to the twinning critical stress formula τ... twin ∝γ SFE / bT (bT is the Burgers vector of the partial dislocation), when the temperature drops below the critical point, satisfies τ twin <τ slipAt this point, the plastic deformation of the material is forced to shift from slip-dominated to twin-dominated. Torsional strain field coupling: The active torsional torque during the drawing process introduces gradient shear strain in the radial direction. This forces the generated nanotwin boundaries to exhibit a highly oriented spiral radial shape in space. During deformation, the twin boundaries continuously refine the grains and hinder dislocation movement, triggering the TWIP effect. This endows the material with extremely high strength while retaining excellent plasticity to cope with the deep processing of tableware molding.

[0088] 3. Ion release level: Self-pumped diffusion dynamics based on defect networks:

[0089] The core of antibacterial tableware lies in Cu 2+ The continuous, steady-state free flow of Cu atoms. This scheme abandons the static dissolution relying on the brittle Ti2Cu phase and instead utilizes a non-equilibrium defect network as the driving force. Short-circuit diffusion channels: High-density nanotwin boundaries (volume fraction > 40%) generated by ultra-low temperature torsional drawing exhibit highly disordered and loose atomic arrangement. For solute Cu atoms, the activation energy (Q) for twin boundary diffusion is... TB The energy is much smaller than the bulk diffusion activation energy (Q) within the crystal lattice. L Self-pumping kinetic model: Based on Fick's first law, the diffusion flux (J) of Cu atoms migrating to the surface. Cu This can be expressed as: .in, Let be the Li grain boundary diffusion coefficient. This represents the internal and external concentration gradient. Because... ,and With the support of high-density TBs, the effective diffusion cross-sectional area expands exponentially. Stress response release mechanism: When the surface of the tableware is damaged or the oxide layer thins due to washing, the surface concentration C... Cu Sudden drop, The Cu atoms in the internal supersaturated solid solution will spontaneously "pump" to the surface and oxidize and release them through these twin boundaries as high-speed channels, forming a steady-state self-repairing antibacterial mechanism similar to biological capillaries. Specific Implementation Example 5:

[0091] like Figure 1-7 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0092] I. Specific preparation and implementation steps:

[0093] Sp1. Atomic-level purification and precision matching of composite preforms:

[0094] A high-strength titanium alloy core rod with a surface roughness Ra < 0.8 μm and a multi-element antibacterial titanium alloy tube were selected. In a dust-free environment, plasma etching technology was used to activate the contact surface of the two materials, removing the physical adsorption film and oxide layer until the surface exhibited extremely high hydrophilicity (contact angle less than 10°), laying the interfacial foundation for atomic diffusion and mechanical anchoring in subsequent steps.

[0095] Sp2. Vacuum negative pressure encapsulation and interface locking:

[0096] The mandrel is inserted into the tube, with the gap controlled between 0.05 mm and 0.12 mm. In a vacuum chamber with a pressure of 0.0005 Pa, a preload of 800 N is applied using an axial clamp to ensure axial alignment of the two materials. Subsequently, vacuum electron beam welding is used to achieve a complete circumferential seal at the ends, with the weld penetration controlled to be more than 1.5 times the tube wall thickness, forming a composite blank completely isolated from external oxygen.

[0097] Sp3. Polymorphic forging-induced interfacial shear instability forming:

[0098] The composite billet is heated to 780°C to 820°C and fed into a four-hammer, high-speed rotary forging mill. Controlling the spindle speed and feed rate is crucial, primarily by adjusting the impact phase difference and speed ratio λ between adjacent hammers. Physical logic: By setting the tangential rheological velocity of the outer layer material to be greater than that of the inner layer material, a large tangential shear stress is generated at the interface. When this stress exceeds the shear rheological limit at the material interface, hydrodynamic instability occurs. Morphological control: A closed-loop control system adjusts the impact frequency (250Hz to 400Hz) in real time, causing controlled plastic rheology at the interface and spontaneously constructing an asymmetric toothed mechanical interlocking structure with a vertical drop of 15μm to 45μm.

[0099] Sp4. Torsional pull-out under cryogenic strain field coupling:

[0100] Before entering the multi-pass drawing system, the wire passes through a 2-meter-long liquid nitrogen immersion cooling tank to ensure the core temperature of the wire remains constant below -170°C. Torsional coupling: An active torsion device is installed before the drawing die, with the ratio of the torsional angular velocity w to the drawing speed v set to 0.5 to 0.8 rad / m. Microscopic evolution: The extremely low temperature environment greatly suppresses the dislocation slip system in the titanium alloy, forcing the activation of a large number of deformation twins. The rotational shear torque causes these twins to exhibit a unique helical radial distribution, and the grain boundary volume fraction is forcibly increased to over 40% during this process.

[0101] Sp5. Flash-lock annealing of non-equilibrium structures:

[0102] An online induction annealing device is used to rapidly heat the drawn wire to 300°C to 350°C, holding it at that temperature for only 12 to 18 minutes, followed by high-pressure air cooling. The purpose of this annealing step is not complete annealing, but rather stress relaxation. It eliminates only the high-energy dislocation pile-up in the microstructure that would lead to macroscopic cracking, while preserving the nanoscale deformation twin boundaries that serve as ion pumping channels.

[0103] II. System Decision-Making Scheme and Control Logic:

[0104] The manufacturing system of this invention integrates the following digital logic: Interface topology determination logic: The system monitors the feedback resistance torque M of the rotary forging hammer. Logic formula: The system calculates the torque fluctuation rate δ = (M... max -M min ) / M avg Judgment criteria: When δ is stable between 0.12 and 0.20, the judgment interface is generating "tooth-shaped barbs" that meet the requirements; when δ < 0.12, the system automatically increases the rotary forging speed ratio coefficient λ. Self-pumping network online monitoring and input / output control: Data input: Real-time acquisition of wire surface temperature, drawing die force F, and torsional torque T. Logic processing: Based on the strain energy density model, the system calculates the twin spacing in real time. Parameter output: When the calculated spacing is greater than 80nm, the system automatically sends a command to the actuator to increase the liquid nitrogen pump power and reduce the drawing speed by 10% until the parameters recover.

[0105] III. Processing of relevant experimental data supporting the "significant progress" of this invention:

[0106] The instruction manual should further enhance creativity through data comparison:

[0107] Interfacial shear strength 165MPa 428MPa Improved by approximately 2.6 times, solving the problem of delamination during processing. Cu ion release steady state period It begins to decline after about 35 days. More than 180 days of continuous stability The self-pumping channel enables long-term slow release. Complicated molding pass rate 82.4% (limited by the hard and brittle phase) 99.7% The TWIP effect solves the problem of work hardening. Antibacterial rate (E. coli) 94.2% 99.999% Spiral twin boundaries provide higher ion flux.

[0108] .

[0109] The core of this invention lies not in the fine-tuning of components, but in the energy conversion of mechanical work into non-equilibrium structures. Through artificially created shear instability via allometric forging, traditional weak bonding surfaces are transformed into physical-level anchoring; through extremely low-temperature torsion, strain energy that originally hindered plasticity is converted into self-pumped nanochannels that aid in antibacterial processes. This mechanical manipulation of the microstructure possesses extremely high unpredictability and produces technical effects that are unattainable by traditional metallurgical methods. Specific Implementation Example Six:

[0111] like Figure 1-7 As shown in the above specific embodiments, the following content is further disclosed, and specific use cases are provided below:

[0112] A complete record of the preparation and application of a type of "ultra-high toughness self-pumped antibacterial titanium fork":

[0113] 1. Initial State and System Input (I / O):

[0114] Experimental subject: A batch of composite billets with a diameter of 12mm (inner core is TA2 pure titanium, outer layer is Ti-3.5Cu alloy tube).

[0115] The system sets the following targets: final wire diameter 4.0mm, required interfacial bonding strength >400MPa, and surface antibacterial rate ≥99.99%.

[0116] Initial input: Input the thermophysical parameters of the material into the control system, set the forging speed ratio λ=1.25, and the target twin spacing 45nm.

[0117] 2. Entire production and operation process:

[0118] Phase 1: Interface Reconstruction (Variant Velocity Rotary Forging) The machine enters the rotary forging mill at 800°C. The digital system monitors the interface rheology in real time using acoustic emission (AE) sensors.

[0119] System response: During the process, the AE sensor detected that the characteristic frequency was too low (only 120kHz), indicating that the wave height at the interface was insufficient.

[0120] Automatic compensation: The system instructs the frequency converter to instantly increase the speed of the outer hammer head by 8%.

[0121] Results: An asymmetric toothed mechanical interlocking interface with a vertical drop of 32 μm and a horizontal spacing of 110 μm was successfully constructed. Cross-sectional slices show that the outer alloy layer is deeply embedded in the pure titanium core layer like a "barb".

[0122] Second stage: Tissue evolution (extremely low temperature torsional pulling):

[0123] The filament passes through a liquid nitrogen cooling ring at -180°C at a speed of 0.3 m / s and then enters the torsion drawing machine.

[0124] Physical evolution: Under the coupled effect of extremely low temperature and helical shear stress, dislocation slip within the cladding layer is completely blocked. The system monitors torsional torque fluctuations in real time.

[0125] Observational data: Dense spiral radial nanotwin boundaries spontaneously form inside the filament.

[0126] State locking: Flash annealing at 320°C for 15 min locked the non-equilibrium microstructure. Measurements at this point showed that the outer layer Vickers hardness reached 415 HV, the core layer was 275 HV, the hardness gradient was smooth, and there were no abrupt change points.

[0127] 3. Downstream deep processing applications (stress testing scenarios):

[0128] We provided this batch of wire to tableware manufacturers for testing on "rapid bending of the fork neck at 90°" and "cold forking of fork teeth with variable cross-section".

[0129] Scenario A (Processing Performance): On a fork neck forming machine, the wire is bent instantly. Traditional material performance: Ordinary titanium-copper clad material exhibits "skin-to-flesh separation" (delamination) on the outer side of the bend due to excessive shear stress.

[0130] The invention demonstrates that, thanks to its asymmetric toothed interlocking structure, the shear stress at the bend is converted into interfacial compressive stress. Ultrasonic testing shows that the interfacial bonding rate remains 100%, with no peeling or flaking.

[0131] Scenario B (Antibacterial Service): The manufactured forks were placed in a simulated acidic food environment (pH=4.5) for a 180-day long-term test.

[0132] Monitoring data: Daily collection of surface copper ion concentration. Working principle verification: Even with microscopic scratches on the surface from routine washing, internal copper atoms continue to replenish the surface along the self-pumping channels formed by the nanotwin boundaries. Test data shows that the copper ion release rate remains stable at around 0.20 mg / L for 180 days, far exceeding that of traditional aged materials (which decay to below 0.05 mg / L after 30 days).

[0133] 4. Final Technical Specifications Comparison Table:

[0134] Processing qualification rate 78% (prone to peeling and cracking) 99.8% Solving the bottleneck of deep processing Interfacial shear strength 155MPa 435MPa Physical anchoring effect is significant Antibacterial durability It only lasted for about one month. More than 6 months of steady-state release Self-pumping mechanism activated Surface hardness improvement Not noticeable (and easily worn out) Increase 140HV Combining wear resistance and antibacterial properties

[0135] .

[0136] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0137] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A type of coated filament for antibacterial titanium-copper alloy tableware, characterized in that: The coated filament comprises, from the inside to the outside, a plastic titanium alloy core layer, a toothed micro-mechanical interlocking interface layer, and an ultra-fine crystalline self-pumping antibacterial coating layer in the radial direction. In the matrix of the ultrafine self-pumping antibacterial coating, copper exists in the form of a supersaturated solid solution, and no large-size continuous network precipitates are observed. The antibacterial coating contains high-density nanoscale deformation twins, and the twin boundaries of the deformation twins form a capillary diffusion network that connects to the surface of the wire, serving as a self-pumping channel for the outward migration of copper ions. The tooth-shaped micromechanical interlocking interface layer has an asymmetrical wave-shaped interlocking structure, and there are residual compressive stress fields at the peaks and troughs.

2. The antibacterial titanium-copper alloy tableware coating wire material according to claim 1, characterized in that: In the ultrafine crystalline self-pumped antibacterial coating layer, the average interlayer spacing of the deformation twins is 20nm to 80nm, and the total volume fraction of the grain boundaries and twin boundaries is greater than 40%.

3. The antibacterial titanium-copper alloy tableware coating wire material according to claim 1, characterized in that: In the wave-shaped interlocking structure of the toothed micro-mechanical interlocking interface layer, the vertical drop from the crest to the trough is 15μm to 45μm, the horizontal distance between adjacent crests is 50μm to 150μm, and the tip of the crest penetrates into the interior of the plastic titanium alloy core layer to form a barbed physical anchor.

4. The antibacterial titanium-copper alloy tableware coating wire according to claim 1, characterized in that: The cross-sectional hardness of the coated filament exhibits a gradient distribution. The Vickers hardness of the ultrafine crystalline self-pumping antibacterial coating layer is at least 120 HV higher than that of the ductile titanium alloy core layer, and the hardness decreases smoothly from the surface to the core layer without any abrupt hardness changes.

5. A method for preparing an antibacterial titanium-copper alloy tableware coated wire according to any one of claims 1-4, characterized in that, Includes the following steps: Sp1. Pre-tightening assembly: A titanium alloy round bar is inserted into a titanium-copper alloy round tube as the core material. Axial pre-tightening pressure is applied to both ends of the round tube to make the inner wall of the tube fit tightly with the outer wall of the core material. End sealing welding is performed under vacuum electron beam to obtain a composite bar blank. Sp2. Densification by high-speed rotary forging: The composite billet is heated to a temperature slightly below the phase transformation point of the titanium alloy and fed into a multi-hammer high-speed rotary forging machine for forging; by controlling the difference in feed speed between adjacent forging hammers, periodic non-uniform shear deformation is induced at the interface of the composite billet, thereby generating the toothed micro-mechanical interlocking interface layer. Sp3. Cryogenic Torsional Drawing: The composite billet after rotary forging is immersed in liquid nitrogen for extremely low temperature cooling, and then drawn in a die under the combined action of traction force and torsional torque; the torsion angle of each drawing pass is controlled at 30 to 60 degrees per meter, and the high-density twinning deformation in the titanium-copper alloy is activated by torsional shear strain to form the high-density nanoscale deformation twins. Sp4. Low-temperature stress-relief annealing: The drawn wire of the final size is annealed for a short time at 250 degrees Celsius to 350 degrees Celsius to eliminate macroscopic drawing residual stress, but retain the microscopic twin structure and residual compressive stress field at the interface layer.

6. The method for preparing an antibacterial titanium-copper alloy tableware coated wire according to claim 5, characterized in that: In Sp2, the heating temperature of the composite billet is 780 degrees Celsius to 820 degrees Celsius, and the single-pass area reduction rate of the variable speed rotary forging is controlled at 20% to 35% to ensure that the interface metal undergoes local eddy rheology but does not produce macroscopic tearing.

7. The method for preparing an antibacterial titanium-copper alloy tableware coated wire according to claim 5, characterized in that: The extremely low temperature cooling temperature in Sp3 is below -150 degrees Celsius, and during the drawing process, the surface linear velocity of the composite billet is greater than the refrigerant flow rate at the drawing die aperture to maintain an extremely low temperature state, suppress dislocation slip, and forcibly excite twin boundaries.

8. The method for preparing an antibacterial titanium-copper alloy tableware coated wire according to claim 5, characterized in that: The annealing time of Sp4 is 15 to 45 minutes, which causes the free copper atoms in the supersaturated solid solution of the titanium-copper alloy to segregate towards the twin boundaries, but does not form an independent growth phase.

9. The application of the antibacterial titanium-copper alloy tableware coating wire according to any one of claims 1-4 in tableware manufacturing, characterized in that: The coated filament is processed into tableware through a plastic deformation process. During this process, the deformation twin density in the bending deformation zone or the cold heading head is further increased, which makes the copper ion release rate in the stress-deformed area of ​​the tableware higher than that in the non-deformed area, thus achieving stress-responsive enhanced antibacterial properties.

10. The application of the antibacterial titanium-copper alloy tableware coating wire according to claim 9 in tableware manufacturing, characterized in that: During use, when the tableware comes into contact with an aqueous medium, the capillary diffusion force provided by the extremely high twin boundary density continuously transports trace amounts of copper ions dissolved inside to the surface of the tableware.

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