3D printed titanium alloy workpiece with composite modified layer on surface and preparation method thereof

Abstract

The application discloses a 3D printing titanium alloy workpiece with a composite modified layer on the surface and a preparation method. The 3D printing titanium alloy workpiece has a composite modified layer on the surface, the composite modified layer comprises a first texture, a solid lubricating layer and a second texture, the texture is prepared by extrusion molding, the solid lubricating layer is prepared by powder laying and extrusion, the solid lubricating layer is located between the first texture and the second texture, and the second texture is located at the center position of the solid lubricating layer. According to the preparation method, the solid lubricant is filled and extruded quantitatively in the mode of "filling first and extruding later", and the texture is extruded at the same time, the preparation efficiency of the composite modified layer is improved, the synergistic effect of the texture and the solid lubricating layer is exerted, the friction and wear performance of the workpiece is improved, the wear in the process of contact between the workpiece and other workpieces is reduced, and the service life of the workpiece is prolonged.

Description

3D-printed titanium alloy workpieces with composite modified surfaces and their preparation methods Technical Field

[0001] This invention belongs to the field of additive manufacturing, specifically relating to a 3D printed titanium alloy workpiece with a composite modified layer on its surface and its preparation method. Background Technology

[0002] Since its inception, titanium alloys have received widespread attention and rapid development worldwide, with over 100 types currently available. Due to their high specific strength, good thermal stability, and corrosion resistance, they are widely used in aircraft structure manufacturing, seawater desalination equipment, artificial joints, prostheses, and many other fields. However, with the deepening of research and application of titanium alloys, their shortcomings have gradually become apparent. These include relatively low hardness, making them susceptible to wear during friction and exhibiting poor wear resistance; demanding machining conditions; and the potential for material waste during traditional subtractive processing. Nevertheless, as humanity continues to explore applications in the air, on land, and underwater, titanium alloys will inevitably face increasingly complex application scenarios. Therefore, optimizing the surface properties of titanium alloys, improving their wear resistance and friction reduction capabilities, and refining their processing techniques are urgently needed.

[0003] In terms of processing technology, 3D printing is a type of rapid prototyping manufacturing technology. This technology, based on the concept of "additive manufacturing," uses lasers and electron beams to print powder material layer by layer according to a three-dimensional model to obtain a complete workpiece. Using 3D printing to prepare titanium alloy workpieces allows for the direct printing of the entire structure without secondary machining, thus avoiding the poor machinability of titanium alloys. Simultaneously, the integral molding method simplifies the process and saves processing time. Furthermore, 3D-printed titanium alloy workpieces have high surface precision, less material waste during additive manufacturing, and less environmental pollution from lasers or electron beams, making them more in line with green engineering principles.

[0004] In terms of surface properties, the common friction mode on the surface of titanium alloy workpieces is dry sliding friction. Since there is no lubricant during the friction process, and the material itself has low hardness, wear is a serious problem. The main types of wear on the surface of titanium alloy materials include abrasive wear, adhesive wear, corrosive wear, and fatigue wear. Surface engineering, through surface modification and coating techniques, can achieve the desired properties of the material and is an effective way to improve the friction and wear performance of titanium alloy materials. For additively manufactured titanium alloy workpieces, existing surface modification technologies such as thermal diffusion, laser cladding, and thermal spraying suffer from high-temperature thermal deformation and are not suitable for surface treatment of titanium alloys. Research has found that solid lubricants can still play a lubricating role in complex environments such as high speed, low temperature, and vacuum. Surface texturing can effectively reduce the friction coefficient of the material surface, and the combination of the two can give the workpiece better friction reduction and anti-wear capabilities. However, current solid lubricant filling methods mostly use cloth polishing, which is relatively simple and has problems such as poor uniformity of lubricant powder distribution and difficulty in controlling the amount of lubricant filled.

[0005] Therefore, developing a 3D printed titanium alloy workpiece and its preparation method with synergistic texture and lubrication will help 3D printed titanium alloy workpieces be applied in more fields and under more complex working conditions. Summary of the Invention

[0006] The purpose of this invention is to address the above-mentioned problems by providing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface and a preparation method thereof. The method involves quantitatively filling and extruding a solid lubricant in a "fill-then-press" manner, while simultaneously extruding a texture, thereby improving the preparation efficiency of the composite modified layer, leveraging the synergistic effect of the texture and the solid lubricant layer, improving the friction and wear performance of the workpiece, reducing wear during contact with other workpieces, and extending its service life.

[0007] The present invention relates to a 3D-printed titanium alloy workpiece with a composite modified layer on its surface and its preparation method. The main technical solutions are as follows:

[0008] The workpiece surface has a composite modified layer, which includes a first texture, a solid lubricant layer and a second texture. The texture is prepared by extrusion molding, and the solid lubricant layer is prepared by powder extrusion. The solid lubricant layer is located between the first texture and the second texture, and the second texture is located at the center of the solid lubricant layer.

[0009] The first texture and the second texture may have the same or different shapes. The shape of the first texture is a circular pit, a square pit, or a rhomboid pit. The density of the first texture is 20-50%, and the diameter or side length of the first texture ranges from 50 to 300 micrometers.

[0010] The depth of the second texture does not exceed the depth of the first texture, and the diameter or side length of the second texture does not exceed 2 / 3 of the diameter or side length of the first texture.

[0011] The solid lubricating layer includes at least one of a hard lubricating layer, a soft lubricating layer, or a hybrid soft-hard lubricating layer.

[0012] Preferably, the first textured surface is embedded with a layer of hard solid lubricant with a thickness of no more than 1 micrometer.

[0013] A 3D-printed titanium alloy workpiece with a composite modified layer on its surface and its preparation method, comprising the following steps:

[0014] (1) Preparation of 3D printed titanium alloy workpieces: 3D printed titanium alloy workpieces were prepared using a metal 3D printer;

[0015] (2) Preparation of surface composite modified layer: The first texture is obtained by extruding the first hard alloy indenter on the surface of the 3D printed titanium alloy workpiece; the solid lubricant powder and anhydrous ethanol are mixed in proportion and dripped into the pit of the first texture on the surface of the 3D printed titanium alloy workpiece through a dropper. After the anhydrous ethanol evaporates and the solid lubricant dries, the second hard alloy indenter is used for extrusion to obtain the second texture at the same time as obtaining the solid lubricant layer.

[0016] The surface of the second cemented carbide indenter is provided with micropores, which allow anhydrous ethanol inside the second cemented carbide indenter to pass through.

[0017] The preparation process of the solid lubricant layer includes the following specific steps: S1, the solid lubricant powder and anhydrous ethanol are mixed in proportion and stirred evenly with a magnetic stirrer. Then, the mixture is dripped into the pits of the first texture using a dropper. After the anhydrous ethanol evaporates, the solid lubricant remains in the first texture, completing one layer of powder spreading. This process is repeated multiple times until the first texture is filled. S2, the first texture filled with solid lubricant powder in the previous step is loaded and extruded using a second carbide indenter, and pressure is maintained as needed to complete one layer of solid lubricant preparation. S3, anhydrous ethanol is infiltrated into the contact surface between the second carbide indenter and the solid lubricant layer through the micropores on the surface of the second carbide indenter. Then, the indenter is unloaded and removed to obtain the second texture.

[0018] The second cemented carbide indenter is surrounded by adjustable outer steps. These outer steps remain in contact with the surface of the 3D printed titanium alloy workpiece during the extrusion of solid lubricating powder by the second cemented carbide indenter.

[0019] The preparation of the solid lubricating layer is performed by repeating steps S1-S3 multiple times as needed until the desired solid lubricating layer and second texture are obtained.

[0020] Compared with existing technologies, the 3D printed titanium alloy workpiece with a composite modified layer on its surface and the preparation method of the present invention have the following advantages:

[0021] First, this invention proposes an interlocking dual-texture structure, where both textures are prepared by extrusion molding. A solid lubricant is sandwiched between the first and second textures. In this structure, the second texture and the solid lubricant layer are integrally formed, which effectively improves the forming efficiency of the texture compared to the stepwise preparation of the texture and lubricant layer. In particular, this dual-texture design combines the functions of collecting wear debris and effectively providing solid lubricant to reduce friction, thus improving the tribological properties of the 3D printed titanium alloy workpiece surface. The second texture is a pit located in the center of the solid lubricant layer. During the contact between titanium alloy workpieces and other workpieces, wear debris is inevitably generated. The pit can temporarily store the waste wear debris, reducing dry friction on the workpiece surface. At the same time, the solid lubricant layer is located on the surface of the first texture and is formed by extrusion of hard or soft lubricant powder. During friction, the lubricant returns to a powder state and adheres to the contact surface, forming a solid lubricant film that separates the contact surfaces, reduces frictional wear on the workpiece surface, and protects the worn surface. Compared to a single texture or a single lubrication process, the two work synergistically to improve the surface properties of 3D printed titanium alloys and extend the service life of the workpiece.

[0022] Secondly, this invention proposes a novel method for preparing a composite modified layer. This involves first uniformly mixing solid lubricant powder with anhydrous ethanol and dripping it into the interior of a first texture. After drying, the mixture is then extruded using a second hard alloy indenter to obtain the solid lubricant layer. Compared to conventional powder spreading methods such as manual mechanical spreading or scraper spreading, this process results in a more uniform distribution of solid lubricant powder. The method of first positioning the first texture and then dripping the lubricant into its interior avoids lubricant flowing into non-textured areas and causing contamination. The layer-by-layer powder spreading and extrusion method facilitates adjustment of the thickness of a single solid lubricant layer and makes the lubricant layer structure more compact, less prone to excessive consumption during friction, and can extend the service life of the solid lubricant layer. Furthermore, this process allows the composition and thickness of the solid lubricant layer to be designed as needed, enabling single or multiple hard, soft, or mixed solid lubricant layers to simultaneously perform both friction reduction and wear resistance functions, exhibiting excellent tribological properties.

[0023] Third, the first and second cemented carbide indenters in this invention may have the same or different shapes, i.e., the first and second textures may have the same or different shapes. This ingenious structural design allows the first texture to be prepared on the surface of the 3D-printed titanium alloy workpiece, while the second texture is prepared within the solid lubricant layer, achieving effective coexistence of the texture and the solid lubricant layer. Conventional composite solid lubricant textures are mostly single-pitted structures, while the second texture in this invention has a more flexible shape, meeting the needs of complex texture shapes in actual production. Simultaneously, it provides a direction for studying the influence and synergistic effect of different texture shapes under composite modified layer conditions on 3D-printed titanium alloy workpieces. Furthermore, the microporous structure on the surface of the second cemented carbide indenter, designed for the on-demand seepage of anhydrous ethanol, prevents lubricant adhesion during extrusion, ensuring the integrity of the composite modified layer. The steps around the indenter can block solid lubricant powder overflowing during extrusion, avoiding material waste and practicing the concept of green engineering.

[0024] Fourth, the connection between the solid lubricant layer and the first texture is tighter in this invention. As a preferred embodiment, the first texture is first pretreated—a layer of hard solid lubricant is embedded in the surface of the first texture. Due to its high hardness and rigidity, the hard particles can be embedded into the texture under extrusion pressure, i.e., embedded into the 3D printed titanium alloy workpiece, making the connection stronger and facilitating subsequent extrusion processes. This technical solution is drastically different from the simple direct powder spreading process in existing technologies, and the modification effect on the 3D printed titanium alloy workpiece obtained will also be significantly different. Attached Figure Description

[0025] Figure 1 is a schematic diagram of the overall surface texture of the 3D printed titanium alloy workpiece of the present invention;

[0026] Figure 2 is a cross-sectional view of a single textured single-layer solid lubricant of the present invention;

[0027] Figure 3 is a side view of the second cemented carbide rhomboid indenter of the present invention;

[0028] Figure 4 is a schematic diagram of the first texture extrusion process of the present invention;

[0029] Figure 5 is a cross-sectional view of a single rhomboid textured multilayer solid lubricant of the present invention;

[0030] Figure 6 is a cross-sectional view of a single square textured multilayer solid lubricant of the present invention;

[0031] Figure 7 is a schematic diagram of the irregular texture on the surface of the 3D printed titanium alloy workpiece of the present invention. Detailed Implementation

[0032] As shown in Figures 1-4, the present invention provides a 3D-printed titanium alloy workpiece with a composite modified layer on its surface. The workpiece 1 has a composite modified layer 2 on its surface. The composite modified layer 2 includes a first texture 21, a solid lubricant layer 22, and a second texture 23. The textures 21 and 23 are prepared by extrusion molding, and the solid lubricant layer 22 is prepared by powder extrusion. The solid lubricant layer 22 is located between the first texture 21 and the second texture 23, and the upper surfaces of the first texture 21, the solid lubricant layer 22, and the second texture 23 are all flush with the upper surface of the 3D-printed titanium alloy workpiece 1. The second texture 23 is located at the center of the solid lubricant layer 22.

[0033] The first texture 21 and the second texture 23 may have the same or different shapes. The first texture 21 is a circular, square, or rhomboid pit. The density of the first texture 21 is 20-50%. The diameter or side length of the first texture 21 is 50-300 micrometers.

[0034] The depth of the second texture 23 does not exceed the depth of the first texture 21, and the diameter or side length of the second texture 23 does not exceed 2 / 3 of the diameter or side length of the first texture 21. Preferably, the diameter or side length of the second texture 23 is 1 / 3, 1 / 2, or 3 / 5 of the diameter or side length of the first texture 21.

[0035] The solid lubricating layer 22 includes at least one of a hard lubricating layer, a soft lubricating layer, or a mixed soft and hard lubricating layer.

[0036] The surface of the first texture 21 is embedded with a layer of hard solid lubricant with a thickness of no more than 1 micrometer.

[0037] The present invention provides a method for preparing a 3D printed titanium alloy workpiece 1 with a composite modified layer 2 on its surface, characterized by comprising the following steps: (1) Preparation of 3D printed titanium alloy workpiece 1: 3D printed titanium alloy workpiece 1 is prepared using a metal 3D printer; (2) Preparation of surface composite modified layer 2: A first texture 21 is obtained by extruding the surface of the 3D printed titanium alloy workpiece 1 using a first hard alloy indenter; a solid lubricant powder is mixed with anhydrous ethanol in a certain proportion and dripped into the pits of the first texture 21 on the surface of the 3D printed titanium alloy workpiece 1 through a dropper. After the anhydrous ethanol evaporates and the solid lubricant dries, a second hard alloy indenter 3 is used for extrusion to obtain a second texture 23 while obtaining a solid lubricant layer 22.

[0038] The surface of the second cemented carbide indenter 3 is provided with micropores 4, which allow anhydrous ethanol inside the second cemented carbide indenter 3 to permeate through.

[0039] Furthermore, the preparation process of the solid lubricant layer 22 includes the following specific steps: S1, the solid lubricant powder and anhydrous ethanol are mixed in proportion and stirred evenly with a magnetic stirrer. Then, the mixture is dripped into the pits of the first texture 21 using a dropper. After the anhydrous ethanol evaporates, the solid lubricant remains in the first texture 21, completing one layer of powder spreading. After multiple layers of powder spreading, the first texture 21 is filled. S2, the first texture 21 filled with solid lubricant powder in the previous step is loaded and extruded using a second carbide indenter 3, and pressure is maintained as needed to complete one preparation of the solid lubricant layer 22. S3, anhydrous ethanol is infiltrated into the contact surface between the second carbide indenter 3 and the solid lubricant layer 22 through the micropores 4 on the surface of the second carbide indenter 3. Then, the indenter 3 is unloaded and removed to obtain the second texture 23.

[0040] The second cemented carbide indenter 3 is surrounded by vertically adjustable outer steps 5. These outer steps 5 maintain contact with the surface of the 3D-printed titanium alloy workpiece 1 throughout the process of the second cemented carbide indenter 3 extruding solid lubricating powder. Furthermore, the first cemented carbide indenter also has vertically movable outer steps, which similarly ensures that no matrix material protrudes from the edge of the first texture and attacks the outer surface during the extrusion process, thereby obtaining a surface with low roughness.

[0041] The preparation of the solid lubricant layer 22 is performed by repeating steps S1-S3 multiple times as needed until the desired solid lubricant layer 22 and second texture 23 are obtained. Example 1

[0042] As shown in Figure 5, a 3D-printed titanium alloy workpiece 1 with a composite modified layer 2 on its surface is illustrated. The composite modified layer 2 comprises a first texture 21, a solid lubricant layer 22, and a second texture 23. The textures 21 and 23 are prepared by extrusion molding. The solid lubricant layer 22 is multi-layered and prepared by multiple powder-spreading extrusion processes. The solid lubricant layer 22 is located between the first texture 21 and the second texture 23, with the second texture 23 located at the center of the solid lubricant layer 22. Both the first texture 21 and the second texture 23 are rhomboid in shape. The density of the first texture 21 is 50%, and its side length is 200 micrometers. The depth of the second texture 23 does not exceed the depth of the first texture 21, and its side length is 120 micrometers. The solid lubricant layer 22 is a soft-hard hybrid lubricant layer. The surface of the first texture 21 is embedded with a layer of hard solid lubricant with a thickness of no more than 1 micrometer. Preferably, the particle size of the hard solid lubricant is 300 nanometers or 500 nanometers. The hard solid lubricant with a thickness of no more than 1 micrometer can be prepared by single-layer laying and extrusion.

[0043] The method for preparing a 3D printed titanium alloy workpiece 1 with a composite modified layer 2 on the surface is characterized by the following steps: (1) Preparation of 3D printed titanium alloy workpiece 1: First, the three-dimensional graphic of the 3D printed titanium alloy substrate is drawn using SolidWorks2022 software and imported into the computer. The substrate is obtained by printing TC4 titanium alloy powder layer by layer using Renishaw AM 400 3D printing equipment through selective laser melting (SLM) technology. The SLM process parameters are set as follows: laser diameter 70 micrometers, power 200 watts, exposure time 80 microseconds, dot pitch 50 micrometers, line pitch 75 micrometers, layer thickness 50 micrometers, laser scanning deflection angle of 70 degrees for each layer. Then, the substrate is cut into a rhomboid 3D printed titanium alloy workpiece 1 with a side length of 200 mm and a thickness of 5 mm by wire cutting. The surface of the workpiece is polished with sandpaper. The titanium alloy workpiece 1 prepared by additive manufacturing technology has a simple processing flow and high processing efficiency; it can realize personalized customization processing, saving production time; the titanium alloy powder utilization rate is high during the processing, saving production costs, and the surface quality of the workpiece is good, which can meet the high surface precision requirements. (2) Preparation of surface composite modified layer 2: The first hard alloy indenter and the second hard alloy indenter 3 are both rhomboid. The first hard alloy indenter is used to extrude and form the first texture 21 with a depth of 300 micrometers on the surface of the 3D printed titanium alloy workpiece 1; the solid lubricant powder and anhydrous ethanol are mixed in proportion and dripped into the pit of the first texture 21 on the surface of the 3D printed titanium alloy workpiece 1 through a dropper. After the anhydrous ethanol evaporates and the solid lubricant dries, the second hard alloy indenter 3 is used to extrude and obtain the second texture 23 at the same time as obtaining the solid lubricant layer 22.

[0044] The surface of the second cemented carbide indenter 3 is provided with micropores 4, as shown in Figure 3. The micropores 4 allow anhydrous ethanol inside the second cemented carbide indenter 3 to seep out under internal pressure. When the indenter is squeezed, the anhydrous ethanol flows out from the micropores, which prevents the lubricant from sticking to the indenter and being carried away, thus ensuring the integrity of the lubrication layer.

[0045] The preparation process of the solid lubricant layer 22 includes the following specific steps: The solid lubricant layer 22 is a soft and hard mixed lubricant layer. S1, the hard solid lubricant powder and anhydrous ethanol are mixed in a 1:3 ratio and stirred evenly with a magnetic stirrer for 60 minutes. Then, the hard lubricant mixture is dripped into the pits of the first texture 21 using a dropper. After the anhydrous ethanol evaporates, the solid lubricant remains in the first texture 21, completing one layer of powder spreading. After multiple layers of powder spreading, the first texture 21 is filled. 2. Using a second carbide indenter 3, the first texture 21 filled with hard lubricant in the previous step is loaded and extruded. The extrusion pressure is 100N and the holding time is 30 seconds to complete the preparation of the first solid lubricant layer 22. The thickness of the first solid lubricant layer 22 is 60 micrometers. S3. Anhydrous ethanol is infiltrated into the contact surface between the second carbide indenter 3 and the solid lubricant layer 22 through the micropores 4 on the surface of the second carbide indenter 3. Then, the indenter 3 is unloaded and removed to obtain the second texture 23.

[0046] For the case of the single-layer solid lubricant of the present invention shown in Figure 2, the soft solid lubricant powder and anhydrous ethanol are mixed in a 1:3 ratio and stirred evenly using a magnetic stirrer for 60 minutes. The soft lubricant mixture is then dripped into the pits of the first texture 21 using a dropper. The above steps are repeated until the solid lubricant layer 22 and the second texture 23 shown in Figure 5 are obtained. The above method for preparing the solid lubricant layer 22 is beneficial for precisely controlling the thickness of each lubricant layer, effectively improving the uniformity of powder spreading, and avoiding direct contact with the solid lubricant during the powder spreading process, thus avoiding material contamination. At the same time, the presence of the mixed lubricant layer allows the friction-reducing and anti-wear effects of both hard and soft lubricants to be continuously exerted, which is beneficial for improving the surface properties of the workpiece 1.

[0047] The second cemented carbide indenter 3 is surrounded by adjustable outer steps 5, as shown in Figure 3. During the extrusion of solid lubricant powder by the second cemented carbide indenter 3, the outer steps 5 maintain constant contact with the surface of the 3D-printed titanium alloy workpiece 1. These outer steps prevent solid lubricant from overflowing during extrusion, reducing lubricant waste and preventing contamination of non-textured areas. They also ensure a low surface roughness on the outer surface of the 3D-printed workpiece.

[0048] Furthermore, for the case of multilayer solid lubricant in Figure 5, multiple extrusions of the solid lubricant by the second carbide indenter are required to achieve the preparation of the first solid lubricant layer 221, the second solid lubricant layer 222 and the third solid lubricant layer 223, as well as the preparation of the second texture 23.

[0049] Example 2

[0050] As shown in Figure 6, the difference between Example 2 and Example 1 lies in the different shapes of the first and second textures 21 and 23 in the composite modified layer 2. In Example 2, both the first and second textures 21 and 23 are square recessed textures, and the solid lubricating layer 22 is a soft-hard hybrid lubricating layer. Similarly, both the first and second cemented carbide indenters are square indenters. The side length of the first texture 21 is 300 micrometers, and the side length of the second texture 23 is 180 micrometers, which is 0.6 times the side length of the first texture 21. Likewise, the first and second textures 21 and 23 can also be circular recessed textures, and the first and second cemented carbide indenters can be cylindrical or spherical. Similarly, a first solid lubricating layer 221, a second solid lubricating layer 222, and a third solid lubricating layer 223 can be prepared.

[0051] Example 3

[0052] The difference between Example 3 and Examples 1 and 2 is that the solid lubricant in the solid lubricating layer 22 in this example is of a single type, but the particle size is different, thus forming a single-component multilayer solid lubricating layer. The multilayer hard lubricant is preferably nano-diamond particles with a particle size of 5-20 micrometers, and the multilayer soft lubricant is preferably tungsten disulfide particles with a particle size of 1-10 micrometers.

[0053] Example 4

[0054] As shown in Figure 7, the difference between Embodiment 4 and the above embodiments lies in the shape of the composite modified layer 2. The first and second textures 21 and 23 in the composite modified layer 2 are irregular textures. In Embodiment 4, the first texture 21 is a rhomboid recess, and the second texture 23 is a circular recess; correspondingly, the first cemented carbide indenter is a rhomboid indenter, and the second cemented carbide indenter 3 is a cylindrical indenter. The circumscribed circle diameter of the first texture 21 is 300 micrometers, and the diameter of the second texture 23 is 160 micrometers, which is 0.53 times the diameter of the first texture 21. The irregular textures in this embodiment enrich the combination methods of textures and provide a reference direction for subsequent research on the mutual influence of the shapes of workpiece surface textures.

Claims

1. A method for preparing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface, characterized in that, Includes the following steps: (1) Preparation of 3D printed titanium alloy workpiece: 3D printed titanium alloy workpiece is prepared using a metal 3D printer; (2) Preparation of surface composite modification layer: The first texture is obtained by extruding the surface of the 3D printed titanium alloy workpiece using a first cemented carbide indenter; Solid lubricant powder and anhydrous ethanol are mixed in proportion and dripped into the pits of the first texture on the surface of the 3D printed titanium alloy workpiece through a dropper. After the anhydrous ethanol evaporates and the solid lubricant dries, the second cemented carbide indenter is used for extrusion, and the second texture is obtained at the same time as the solid lubricant layer.

2. The method for preparing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface according to claim 1, characterized in that, The surface of the second cemented carbide indenter is provided with micropores, which allow anhydrous ethanol inside the second cemented carbide indenter to pass through.

3. The method for preparing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface according to claim 1, characterized in that, The preparation process of the solid lubricant layer includes the following specific steps: S1, the solid lubricant powder and anhydrous ethanol are mixed in proportion and stirred evenly with a magnetic stirrer. Then, the mixture is dripped into the pits of the first texture using a dropper. After the anhydrous ethanol evaporates, the solid lubricant remains in the first texture, completing one layer of powder spreading. This process is repeated multiple times until the first texture is filled. S2, the first texture filled with solid lubricant powder in the previous step is loaded and extruded using a second carbide indenter, and pressure is maintained as needed to complete one layer of solid lubricant preparation. S3, anhydrous ethanol is infiltrated into the contact surface between the second carbide indenter and the solid lubricant layer through the micropores on the surface of the second carbide indenter. Then, the indenter is unloaded and removed to obtain the second texture.

4. The method for preparing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface according to claim 3, characterized in that, The second cemented carbide indenter is surrounded by adjustable outer steps. These outer steps remain in contact with the surface of the 3D printed titanium alloy workpiece during the extrusion of solid lubricating powder by the second cemented carbide indenter.

5. The method for preparing a 3D-printed titanium alloy workpiece with a composite modified layer on its surface according to claim 3, characterized in that, The preparation of the solid lubricating layer is performed by repeating steps S1-S3 multiple times as needed until the desired solid lubricating layer and second texture are obtained.

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