Titanium alloy material surface crystal flower preparation method, titanium alloy material and equipment shell

Abstract

The application discloses a titanium alloy material surface crystal flower preparation method, a titanium alloy material and an equipment shell. The preparation method comprises the following steps: hot forging and pressing a titanium alloy raw material to form a titanium alloy material with a set structure, wherein the titanium alloy material has an alpha phase and a beta phase; performing homogenization heat treatment on the titanium alloy material, wherein the holding temperature of the homogenization heat treatment is 950 DEG C-1020 DEG C, the holding time is 30min-90min, and then cooling; performing crystal growth heat treatment on the titanium alloy material, wherein the holding temperature of the crystal growth heat treatment is 1020 DEG C-1100 DEG C, and the holding time is 1.5h-5h; wherein the holding temperature of the crystal growth heat treatment is higher than that of the homogenization heat treatment, and the homogenization heat treatment and the crystal growth heat treatment are performed under vacuum conditions.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy surface treatment technology, and more specifically, to a method for preparing surface flowers of titanium alloy materials, titanium alloy materials, and equipment housings. Background Technology

[0002] In related technologies, titanium alloys, due to their low density, high strength, good corrosion resistance, and excellent biocompatibility, are used in structural components of high-end smartwatches and wearable devices. Common surface treatments for titanium alloys include sandblasting, wire drawing, polishing, and PVD. However, these methods result in a lack of unique visual appeal and a limited range of surface finishes. Applying coatings to titanium alloy surfaces is prone to wear and peeling, leading to insufficient aesthetic stability after long-term wear. Summary of the Invention

[0003] One objective of this invention is to provide a new technical solution for preparing surface crystal flowers on titanium alloy materials.

[0004] According to a first aspect of the present invention, a method for preparing surface grains on a titanium alloy material is provided. The method includes: Titanium alloy raw materials are hot forged to form a titanium alloy material with a set structure, wherein the titanium alloy material has an α phase and a β phase; The titanium alloy material is subjected to a homogenization heat treatment, wherein the holding temperature of the homogenization heat treatment is 950℃-1020℃ and the holding time is 30min-90min, and then it is cooled. The titanium alloy material is subjected to a crystal growth heat treatment, wherein the holding temperature of the crystal growth heat treatment is 1020℃-1100℃ and the holding time is 1.5h-5h; wherein the holding temperature of the crystal growth heat treatment is higher than the holding temperature of the homogenization heat treatment, and the homogenization heat treatment and the crystal growth heat treatment are carried out under vacuum conditions.

[0005] Optionally, the homogenization heat treatment and / or the heating process of the homogenization heat treatment includes multiple heat holding stages.

[0006] Optionally, the heating process of the homogenization heat treatment includes multiple heat preservation stages, wherein the heat preservation temperature of the first heat preservation stage is 400℃-500℃, the heat preservation temperature of the second heat preservation stage is 600℃-700℃, and the heat preservation temperature of the third heat preservation stage is 800℃-900℃.

[0007] Optionally, the heat preservation time of the first heat preservation stage is 20-30 minutes, the heat preservation time of the second heat preservation stage is 20-30 minutes, and the heat preservation time of the third heat preservation stage is 15-25 minutes.

[0008] Optionally, the heating process of the crystal growth heat treatment includes multiple holding stages, wherein the holding temperature of the first holding stage is 400℃-500℃, the holding temperature of the second holding stage is 550℃-650℃, the holding temperature of the third holding stage is 800℃-900℃, and the holding temperature of the fourth holding stage is the microstructure transformation temperature of the titanium alloy material.

[0009] Optionally, the heat preservation time of the first heat preservation stage is 20-30 minutes, the heat preservation time of the second heat preservation stage is 10-20 minutes, the heat preservation time of the third heat preservation stage is 5-15 minutes, and the heat preservation time of the fourth heat preservation stage is 5-15 minutes.

[0010] Optionally, the vacuum degree of the vacuum condition is less than or equal to 6. 10 -3 Pa.

[0011] Optionally, a surface treatment may be included prior to the homogenization heat treatment.

[0012] Optionally, the surface treatment includes polishing and / or sandblasting.

[0013] Optionally, the titanium alloy raw material is a TC series titanium alloy.

[0014] Optionally, the elongation of the titanium alloy raw material is 13%-15%.

[0015] According to another aspect of this disclosure, a titanium alloy material is provided. This titanium alloy material is prepared by the surface marbling preparation method for titanium alloy materials described in this disclosure.

[0016] Optionally, the crystal flower size on the surface of the titanium alloy material is 2mm-5mm.

[0017] According to another aspect of this disclosure, a device housing is provided, which is manufactured using the surface grain preparation method of the titanium alloy material described in any one of the above claims.

[0018] This embodiment of the invention first hot-forges a titanium alloy raw material with a dual-phase structure of α and β phases into a titanium alloy material with a predetermined structure. Then, the titanium alloy material undergoes a homogenization heat treatment to homogenize the grains and store kinetic energy for subsequent crystal growth heat treatment. Next, the titanium alloy material undergoes a crystal growth heat treatment to allow the grains to grow sufficiently at a predetermined temperature. Cooling is then performed to promote the regular precipitation and layered stacking of the lamellar α phase. Because the holding temperature of the crystal growth heat treatment is higher than that of the homogenization heat treatment, the grains of the titanium alloy material can grow rapidly. This preparation method can directly form a texture with a unique visual ice crystal effect on the surface of the titanium alloy product without the need for surface coatings or other external treatment processes. The holding temperature of the crystal growth heat treatment is higher than that of the homogenization heat treatment, allowing the grains of the titanium alloy material to grow rapidly.

[0019] In addition, since both the homogenization heat treatment and the grain growth heat treatment are carried out under vacuum conditions, it can prevent the titanium alloy material from reacting chemically with other elements such as oxygen and nitrogen, which would cause the surface of the titanium alloy material to turn gray.

[0020] This preparation method overcomes the problems of limited surface finish and insufficient appearance stability caused by easy wear and peeling of external coatings in related technologies. Titanium alloy materials combine excellent appearance with long-term stability, making them suitable for applications requiring high-quality appearance, such as high-end smartwatches and wearable device structural components.

[0021] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0023] Figure 1 This is a flowchart of a method for preparing surface crystal flowers of titanium alloy materials according to an embodiment of this disclosure.

[0024] Figure 2 This is a photograph of the titanium alloy material of Embodiment 1 of this disclosure after homogenization heat treatment.

[0025] Figure 3 This is a photograph of the titanium alloy material of Embodiment 1 of this disclosure after grain growth heat treatment.

[0026] Figure 4 This is a photograph of the titanium alloy raw material with an elongation of 12% in Example 2 after homogenization heat treatment and crystal growth heat treatment.

[0027] Figure 5This is a photograph of the titanium alloy raw material with an elongation of 13% in Example 2 after homogenization heat treatment and crystal growth heat treatment.

[0028] Figure 6 This is a photograph of the titanium alloy raw material with an elongation of 15% in Example 2 after homogenization heat treatment and crystal growth heat treatment.

[0029] Figure 7 This is a photograph of the titanium alloy raw material with an elongation of 16% in Example 2 after homogenization heat treatment and crystal growth heat treatment.

[0030] Figure 8 This is a photograph of the titanium alloy raw material with an elongation of 19% in Example 2 after homogenization heat treatment and crystal growth heat treatment.

[0031] Figure 9 This is a process flow diagram of the homogenization heat treatment according to Embodiment 1 of this disclosure.

[0032] Figure 10 This is a process flow diagram of the crystal growth heat treatment according to Embodiment 1 of this disclosure. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0034] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0035] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0036] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0038] In related technologies, titanium alloys, due to their low density, high strength, good corrosion resistance, and excellent biocompatibility, are used in structural components of high-end smartwatches and wearable devices. Common surface treatments for titanium alloys include sandblasting, wire drawing, polishing, and physical vapor deposition (PVD). However, these methods suffer from limitations in achieving a uniform surface finish and a lack of unique visual appeal. Applying coatings to titanium alloy surfaces is prone to wear and peeling, resulting in insufficient aesthetic stability over long-term wear and failing to meet the long-term aesthetic consistency requirements of high-end wearable devices.

[0039] To address the aforementioned technical problems, this disclosure provides a method for preparing surface crystalline patterns on titanium alloy materials and the titanium alloy material itself. First, a titanium alloy raw material with an α-phase and β-phase dual-phase structure is hot-forged into a titanium alloy material with a predetermined structure. Then, the titanium alloy material undergoes a homogenization heat treatment to homogenize the grains and store kinetic energy for subsequent grain growth heat treatment. Next, the titanium alloy material undergoes a grain growth heat treatment to allow the grains to grow sufficiently at a predetermined temperature. Cooling then promotes the regular precipitation and layered stacking of the lamellar α-phase. Because the holding temperature of the grain growth heat treatment is higher than that of the homogenization heat treatment, the grains of the titanium alloy material can grow rapidly, and crystalline patterns form on the surface of the titanium alloy material. This preparation method can directly form a texture with a unique visual ice crystal effect on the surface of titanium alloy products without the need for surface coatings or other external treatment processes.

[0040] In addition, since both the homogenization heat treatment and the grain growth heat treatment are carried out under vacuum conditions, it can prevent the titanium alloy material from reacting chemically with other elements such as oxygen and nitrogen, which would cause the surface of the titanium alloy material to turn gray.

[0041] The technical solutions provided by the embodiments of this disclosure will be described below with reference to the accompanying drawings.

[0042] In some embodiments of this disclosure, a method for preparing surface flowers on titanium alloy materials is provided. For example... Figure 1 As shown, the preparation method includes the following steps: S1. Hot forging is performed on titanium alloy raw materials to form a titanium alloy material with a set structure, wherein the titanium alloy material has an α phase and a β phase.

[0043] S2. The titanium alloy material is subjected to homogenization heat treatment. The holding temperature of the homogenization heat treatment is 950℃-1020℃, and the holding time is 30min-90min, followed by cooling.

[0044] S3. Perform a crystal growth heat treatment on the titanium alloy material. The holding temperature of the crystal growth heat treatment is 1020℃-1100℃, and the holding time is 1.5h-5h. The holding temperature of the crystal growth heat treatment is higher than that of the homogenization heat treatment. The homogenization heat treatment and the crystal growth heat treatment are performed under vacuum conditions.

[0045] Specifically, in step S1, titanium alloy raw material refers to titanium alloy raw material with an initial shape of a predetermined shape, such as titanium alloy bars, titanium alloy ingots, and titanium alloy plates. For ease of understanding, titanium alloy plates will be used as an example. Titanium alloy plates refer to plate-shaped titanium alloy raw materials formed after processes such as smelting, billeting, and hot rolling. Titanium alloy plates are the starting material for hot forging processing in this embodiment of the disclosure.

[0046] Hot forging is a processing method that utilizes high-temperature plastic deformation to form titanium alloy materials while simultaneously controlling the microstructure of these materials. For example, hot forging is used to process watch cases and frame components. Hot forging can shape titanium alloy raw materials into a desired form and compact the internal pores, introducing deformation energy storage and providing numerous recrystallization nuclei for subsequent grain growth heat treatment.

[0047] Alpha and β phases are two basic phase structures in titanium alloys. The α phase has a close-packed hexagonal structure, exhibiting high strength and corrosion resistance; the β phase has a body-centered cubic structure, possessing good plasticity and machinability. In this embodiment, the titanium alloy sheet possesses both α and β phases. Therefore, the room-temperature microstructure of the hot-forged titanium alloy material retains both α and β phases, thus forming a dual-phase titanium alloy. This dual-phase titanium alloy provides the microstructure basis for the precipitation and regular arrangement of lamellar α phases during subsequent grain growth heat treatment.

[0048] The titanium alloy material with the defined structure is placed in a heat treatment furnace and gradually heated from room temperature to undergo homogenization heat treatment. Homogenization heat treatment refers to holding the titanium alloy material at a set temperature to achieve a more uniform grain distribution within the alloy. It can be understood that homogenization heat treatment can homogenize the titanium alloy grains and accumulate dislocations and defects at grain boundaries and within the crystal lattice, providing a thermodynamic driving force for sufficient grain growth in the subsequent S3 step. In other words, the purpose of homogenization heat treatment is to homogenize the titanium alloy grains and store kinetic energy. During this stage, due to the relatively short holding time, the grains do not continue to grow abnormally; only kinetic energy is stored, thus laying the foundation for uniform grain growth in the grain growth heat treatment stage.

[0049] In step S2, the holding temperature for homogenization heat treatment is 950℃-1020℃, and the holding time is 30min-90min, followed by cooling. It should be noted that if the holding temperature is too low and / or the holding time is too short, the atomic diffusion motive force of the titanium alloy is insufficient, the internal grain distribution of the titanium alloy material cannot be sufficiently homogenized, retaining more uneven microstructural defects. Furthermore, the dislocation density and thermodynamic driving force accumulated within the titanium alloy material are insufficient, resulting in insufficient driving force for grain growth in the subsequent grain growth heat treatment stage, leading to slow grain growth or even failure to grow to the target size. Conversely, if the holding temperature is too high and / or the holding temperature is too long, the grains are prone to abnormal growth during the homogenization stage, which may lead to abnormal grain coarsening and weakened grain boundaries in the titanium alloy material, affecting the surface texture aesthetics and mechanical properties of the titanium alloy product. The homogenization heat treatment in this embodiment uses a holding temperature of 950℃-1020℃ and a holding time of 30min-90min. The holding temperature can be, for example, 950℃, 960℃, 980℃, 1000℃, 1020℃, etc.; the holding time can be, for example, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc. Within this range, it ensures the homogenization of the titanium alloy grains, reserves sufficient kinetic energy, and prevents abnormal grain growth. Furthermore, after reaching the holding time, the heat treatment furnace can be rapidly cooled to prevent abnormal grain growth.

[0050] In step S3, after cooling, the heat treatment furnace is reheated to perform grain growth heat treatment on the titanium alloy material. Grain growth heat treatment refers to a high-temperature heat treatment process performed on titanium alloy materials after homogenization heat treatment. Its purpose is to promote the full growth of grains by holding them at a set temperature (e.g., a temperature above the β phase transformation point), and then transforming the β phase into the α phase during the subsequent controlled cooling process. The lamellar α phase precipitates regularly and stacks in layers, ultimately forming a texture with a visual ice crystal effect on the surface of the titanium alloy product.

[0051] It should be noted that if the set temperature of the grain growth heat treatment is too high, the grain growth rate will be accelerated drastically. Excessively coarse β-phase grains will not only weaken the strength, toughness and fatigue performance of titanium alloy materials, but may also lead to local coarse grains, resulting in excessively large stacking size and sparse and uneven distribution of the subsequent lamellar α-phase, which will destroy the regularity and fineness of the texture. Conversely, if the set temperature is too low, the titanium alloy material will still be in the α-phase + β-phase two-phase region, and the grains cannot grow sufficiently. The subsequent cooling process will also fail to form regular lamellar α-phase precipitation from the β-phase.

[0052] In this embodiment of the disclosure, the set temperature for the grain growth heat treatment is 1020℃-1100℃, for example, it can be 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1100℃, etc.; the holding time is 1.5h-5h, for example, it can be 1.5h, 2h, 2.5h, 3h, 4h, 5h, etc. By holding the temperature within this range for a sufficient time, the grains inside the titanium alloy material can grow fully and uniformly.

[0053] After the heat treatment is completed, the temperature inside the furnace is reduced to below the β-phase transformation point at a cooling rate of 1℃ / min to 6℃ / min. For example, the cooling rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, or 6℃ / min. It should be noted that if the cooling rate is too fast, the lamellar α-phase will not precipitate completely, and a regular lamellar α-phase stack cannot be formed; conversely, if the cooling rate is too slow, the heat treatment time will be too long. A cooling rate within the range of 1℃ / min to 6℃ / min ensures that the lamellar α-phase precipitates fully and orderly, and is arranged in a regular lamellar stack, forming a regularly arranged lamellar α-phase texture, while also achieving high production efficiency.

[0054] This embodiment of the invention first hot-forges a titanium alloy raw material with a dual-phase microstructure of α and β phases into a titanium alloy material with a predetermined structure. Then, the titanium alloy material undergoes a homogenization heat treatment to homogenize the grains and store kinetic energy for subsequent crystal growth heat treatment. Next, the titanium alloy material undergoes a crystal growth heat treatment to allow the grains to grow sufficiently at a predetermined temperature. Cooling is then performed to promote the regular precipitation and layered stacking of the lamellar α phase. Because the holding temperature of the crystal growth heat treatment is higher than that of the homogenization heat treatment, the grains of the titanium alloy material can grow rapidly, and crystallization forms on the surface of the titanium alloy material. This preparation method can directly form a texture with a unique visual ice crystal effect on the surface of titanium alloy products without the need for surface coatings or other external treatment processes. The rapid grain growth of the titanium alloy material is due to the higher holding temperature of the crystal growth heat treatment compared to the homogenization heat treatment.

[0055] In addition, since both the homogenization heat treatment and the grain growth heat treatment are carried out under vacuum conditions, it can prevent the titanium alloy material from reacting chemically with other elements such as oxygen and nitrogen, which would cause the surface of the titanium alloy material to turn gray.

[0056] This preparation method overcomes the problems of limited surface finish and insufficient appearance stability caused by easy wear and peeling of external coatings in related technologies. Titanium alloy materials combine excellent appearance with long-term stability, making them suitable for applications requiring high-quality appearance, such as high-end smartwatches and wearable device structural components.

[0057] In some embodiments of this disclosure, the homogenization heat treatment and / or the heating process of the homogenization heat treatment includes multiple heat holding stages.

[0058] Multiple holding stages refer to holding the material at multiple intermediate temperatures during the heating process, ensuring that the temperature reaches these intermediate temperatures throughout the heat treatment furnace before proceeding to the next stage. This multiple holding stages ensure uniform temperature distribution throughout the furnace, preventing uneven heating of the titanium alloy material due to temperature inconsistencies, and thus guaranteeing the consistency of homogenization and / or grain growth heat treatment effects across different batches of material.

[0059] The preparation method of this embodiment adopts a multi-stage stepped heating method, which can effectively balance the temperature field distribution in the heat treatment furnace and provide a uniform heat treatment environment for the homogenization and growth of titanium alloy materials.

[0060] In some embodiments of this disclosure, the heating process of the homogenization heat treatment includes multiple heat preservation stages, wherein the heat preservation temperature of the first heat preservation stage is 400℃-500℃, the heat preservation temperature of the second heat preservation stage is 600℃-700℃, and the heat preservation temperature of the third heat preservation stage is 800℃-900℃.

[0061] In this embodiment, the homogenization heat treatment is performed in a heat treatment furnace. The heating process of the homogenization heat treatment includes at least four stages: a first heating, a second heating, a third heating, and a fourth heating. A holding period is performed at the end of the first three heating stages, namely, a first holding period, a second holding period, and a third holding period. After the fourth heating, the holding temperature of the homogenization heat treatment is reached. The first heating stage heats from room temperature to the holding temperature of the first holding stage. The holding temperature of the first holding stage is 400℃-500℃, for example, 400℃, 430℃, 450℃, 470℃, 500℃, etc. The second heating stage heats from the holding temperature of the first holding stage to the holding temperature of the second holding stage. The holding temperature of the second holding stage is 600℃-700℃, for example, 600℃, 620℃, 650℃, 680℃, 700℃, etc. The third heating stage heats from the holding temperature of the second holding stage to the holding temperature of the third holding stage. The third heat preservation stage has a heat preservation temperature of 800℃-900℃, such as 800℃, 820℃, 850℃, 880℃, 900℃, etc. The fourth heating stage heats the temperature from the third heat preservation stage to the heat preservation temperature of the homogenization heat treatment, which is 950℃-1020℃, such as 950℃, 960℃, 980℃, 1000℃, 1020℃, etc.

[0062] In this embodiment, the homogenization heat treatment involves a stepped holding process across multiple heating stages. Once the temperature within the furnace is uniform across each stage, the heating continues to the next stage, ultimately reaching the holding temperature for homogenization. These three heating stages cover the low-temperature, medium-temperature, and high-temperature zones between room temperature and the holding temperature for homogenization. This segmented temperature equalization effectively ensures uniform temperature throughout the furnace during the homogenization process, providing a favorable heating environment for the subsequent holding stage and thus guaranteeing the uniformity of the homogenization heat treatment effect.

[0063] In some embodiments of this disclosure, the heating rate in the homogenization heat treatment is 1°C / min to 5°C / min.

[0064] Specifically, the heating rate refers to the magnitude of temperature increase per unit time during the process of raising the temperature in the furnace from room temperature or the temperature of the previous process to the holding temperature of the homogenization heat treatment. In the embodiments of this disclosure, the heating rate of the homogenization heat treatment is controlled to be 1℃ / min-5℃ / min, for example, it can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, etc.

[0065] In this embodiment of the disclosure, by controlling the heating rate of the homogenization heat treatment within the above-mentioned range, the temperature inside the heat treatment furnace and the internal temperature of the titanium alloy material can be raised uniformly, avoiding the phenomenon of uneven temperature inside the heat treatment furnace and the internal temperature of the titanium alloy material due to excessively rapid heating.

[0066] Of course, the heating rate is not limited to the above embodiments, and those skilled in the art can select one according to actual needs.

[0067] In some embodiments of this disclosure, the heat preservation time of the first heat preservation stage is 20-30 minutes, the heat preservation time of the second heat preservation stage is 20-30 minutes, and the heat preservation time of the third heat preservation stage is 15-25 minutes.

[0068] In this embodiment, the holding time for each holding stage depends on the duration required for the temperature field inside the furnace to homogenize during that stage. Specifically, the first and second holding stages are each set with a holding time of 20-30 minutes, and the third holding stage is set with a holding time of 15-25 minutes. It is understood that the above-mentioned holding time settings can adequately ensure temperature uniformity throughout the heat treatment furnace at each stage, avoiding uneven temperature distribution due to insufficient holding time, which would affect the heat treatment effect. Simultaneously, it ensures overall processing efficiency, avoiding unnecessary extension of the processing cycle due to excessively long holding times, thus balancing heat treatment uniformity and production efficiency.

[0069] After the homogenization heat treatment holding is completed, the temperature inside the heat treatment furnace is reduced to below the β phase transformation point at a cooling rate of 1℃ / min to 5℃ / min. For example, the cooling rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, or 5℃ / min. It should be noted that if the cooling rate is too fast, the microstructure of the titanium alloy material will not be properly adjusted, easily leading to defects; conversely, if the cooling rate is too slow, the heat treatment time will be too long. A cooling rate within the range of 1℃ / min to 5℃ / min allows for proper microstructure adjustment of the titanium alloy material and results in high production efficiency. In this embodiment, the titanium alloy material can be cooled to room temperature or other temperatures, such as 50℃ to 200℃.

[0070] In some embodiments of this disclosure, the heating process of the crystal growth heat treatment includes multiple holding stages, wherein the holding temperature of the first holding stage is 400℃-500℃, the holding temperature of the second holding stage is 550℃-650℃, the holding temperature of the third holding stage is 800℃-900℃, and the holding temperature of the fourth holding stage is the microstructure transformation temperature of the titanium alloy material.

[0071] In this embodiment, the crystal growth heat treatment is performed in a heat treatment furnace. The heating process of the crystal growth heat treatment includes at least five stages: a first heating, a second heating, a third heating, a fourth heating, and a fifth heating. A holding period is performed at the end of the first four heating stages: a first holding period, a second holding period, a third holding period, and a microstructure transformation holding period. After the fifth heating, the holding temperature for the crystal growth heat treatment is reached. The first heating stage heats the crystal from room temperature to the holding temperature of the first holding stage. The holding temperature of the first holding stage is 400℃-500℃, for example, 400℃, 430℃, 450℃, 470℃, 500℃, etc. The second heating stage heats the crystal from the holding temperature of the first holding stage to the holding temperature of the second holding stage. The holding temperature of the second holding stage is 550℃-650℃, for example, 550℃, 580℃, 600℃, 620℃, 650℃, etc. The third heating stage involves heating from the holding temperature of the second holding stage to the holding temperature of the third holding stage. The holding temperature of the third holding stage is 800℃-900℃, for example, 800℃, 820℃, 850℃, 880℃, 900℃, etc. The fourth heating stage involves heating from the holding temperature of the third holding stage to the microstructure transformation temperature, i.e., 950℃-1000℃. The microstructure transformation temperature varies depending on the type of titanium alloy material, for example, 950℃, 980℃, 1000℃, etc. The microstructure transformation temperature refers to the critical temperature at which the α+β dual-phase microstructure transforms into a single β-phase microstructure in the titanium alloy, i.e., the β transformation temperature. In this embodiment, the holding temperature is maintained at the microstructure transformation temperature. The fifth heating stage involves heating from the microstructure transformation temperature to the holding temperature of the grain growth heat treatment, for example, 1020℃-1080℃.

[0072] The process involves sequentially holding the material at multiple heating stages to ensure uniform temperature throughout the furnace before proceeding to the next stage, ultimately reaching the holding temperature for crystal growth. This sequential holding at four temperature stages effectively ensures temperature uniformity throughout the furnace during the crystal growth heat treatment process. The fourth holding stage, at the β-transformation temperature, guarantees that the titanium alloy material undergoes a preliminary α+β phase to β phase transformation before reaching the holding temperature for crystal growth, thus providing a microstructural guarantee for uniform grain growth during the crystal growth heat treatment stage.

[0073] In some embodiments of this disclosure, the heating rate in the crystal growth heat treatment is 1°C / min to 5°C / min.

[0074] In this embodiment, by controlling the heating rate of the homogenization heat treatment within the aforementioned range, the internal temperature of the titanium alloy material can rise uniformly, avoiding uneven internal temperature caused by excessively rapid heating, which would affect the consistency of crystal growth. Furthermore, the crystal growth heat treatment ensures a smooth transition of grains during the heating process, providing stable temperature conditions for the subsequent full growth of grains and facilitating the regular precipitation of lamellar α-phase.

[0075] Of course, the heating rate is not limited to the above embodiments, and those skilled in the art can select one according to actual needs.

[0076] In some embodiments of this disclosure, the heat preservation time of the first heat preservation stage is 20-30 minutes, the heat preservation time of the second heat preservation stage is 10-20 minutes, the heat preservation time of the third heat preservation stage is 5-15 minutes, and the heat preservation time of the fourth heat preservation stage is 5-15 minutes.

[0077] In this embodiment, the holding time at each stage of the crystal growth heat treatment process gradually decreases as the temperature increases. Specifically, the holding time for the first stage is 20-30 minutes, the second stage is 10-20 minutes, the third stage is 5-15 minutes, and the fourth stage is 5-15 minutes. It can be understood that the above holding time settings balance the need for temperature uniformity within the heat treatment furnace with processing efficiency. In higher temperature ranges, the heat transfer efficiency within the furnace is higher, requiring a correspondingly shorter homogenization time. Therefore, the holding time at each stage decreases as the temperature increases, effectively improving processing efficiency while ensuring heat treatment uniformity.

[0078] After the heat treatment for crystal growth is completed, the temperature inside the furnace is reduced to below the β-phase transformation point at a cooling rate of 1℃ / min to 5℃ / min. For example, the cooling rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, or 5℃ / min. It should be noted that if the cooling rate is too fast, the lamellar α-phase will not precipitate completely, and a regular lamellar α-phase stack cannot be formed; conversely, if the cooling rate is too slow, the heat treatment time will be too long. A cooling rate in the range of 1℃ / min to 5℃ / min allows the lamellar α-phase to precipitate fully and orderly, and to be arranged in a regular lamellar stack, thus forming a regularly arranged lamellar α-phase texture, and resulting in high production efficiency.

[0079] In some embodiments of this disclosure, the vacuum degree of the vacuum condition is less than or equal to 6 × 10⁻⁶. -3 Pa.

[0080] In this embodiment, vacuum degree refers to the degree to which the gas pressure inside the heat treatment furnace is lower than the standard atmospheric pressure; the smaller the vacuum degree value, the higher the vacuum degree. In this embodiment of the disclosure, the vacuum degree inside the furnace during crystal growth heat treatment is less than or equal to 6 × 10⁻⁶. -3 Pa, for example, can be 10. -4 Pa, 10 -3 Pa, 2 10 -3 Pa, 4 10 -3 Pa, 6 10 -3 Pa, etc. By controlling the vacuum level in the furnace during the crystal growth heat treatment within the above range, it is possible to effectively reduce the reaction between residual gas in the furnace and titanium alloy materials, avoid the generation of impurities such as oxidation, nitriding, and carburization on the surface and inside of titanium alloy materials, ensure the purity of titanium alloy materials, and provide a stable and clean sintering environment for the precipitation and regular arrangement of lamellar α phase.

[0081] Of course, the vacuum level inside the heat treatment furnace is not limited to the above embodiments, and those skilled in the art can choose according to actual needs.

[0082] In some embodiments of this disclosure, a surface treatment is included prior to the homogenization heat treatment.

[0083] In this embodiment of the disclosure, surface treatment refers to post-processing operations performed on the surface of the titanium alloy material after hot forging, including but not limited to polishing, sandblasting, and other processes. It is understood that pre-treating the surface of the titanium alloy material before homogenization heat treatment can improve the surface condition, making the boundaries between fine grains clearer. This effectively enhances the visual appearance of the ice crystal texture after grain growth heat treatment.

[0084] In some embodiments of this disclosure, the surface treatment includes polishing and / or sandblasting.

[0085] Polishing refers to grinding the surface of titanium alloy materials through mechanical means, which reduces the surface roughness and improves the smoothness, thereby creating a high-gloss visual effect.

[0086] Sandblasting refers to the process of using high-pressure airflow to propel abrasive particles at high speed onto the surface of titanium alloy materials, creating a uniform and fine textured surface that gives the material a uniform matte finish.

[0087] Optionally, depending on the design requirements, the entire surface of the titanium alloy material can be polished; or sandblasted; or polished and sandblasted separately in different areas to create a composite visual effect of contrasting high-gloss and matte areas. For example, the bezel area of ​​the watch case can be polished, while the side areas can be sandblasted to achieve a multi-layered design. Alternatively, the entire surface of the titanium alloy material can be polished first, followed by sandblasting. In this method, polishing effectively reduces the surface roughness of the titanium alloy material, while sandblasting effectively eliminates the defects caused by uneven stress and direction resulting from polishing, leading to significant differences in the morphology of the ice crystal texture. The ice crystal texture has clear boundaries, obvious contrast between light and dark, and an aesthetically pleasing pattern.

[0088] The preparation method of this disclosure involves polishing and / or sandblasting the titanium alloy material before homogenization heat treatment, which can complement and superimpose the ice crystal texture effect formed by subsequent crystal growth heat treatment to create a more layered and unique visual appearance.

[0089] In some embodiments of this disclosure, the titanium alloy raw material is a TC series titanium alloy.

[0090] In the embodiments of this disclosure, the TC series titanium alloys are α+β type dual-phase titanium alloys, such as TC4 (i.e., Ti-6Al-4V) and TC11. The microstructure of TC series titanium alloys contains both α and β phases, exhibiting excellent grain growth characteristics. Within the parameter range of the preparation method in the embodiments of this disclosure, a visual ice crystal texture effect can be effectively formed.

[0091] In addition, the TC series titanium alloys have low density, high specific strength, excellent corrosion resistance and biocompatibility, which can fully meet the requirements of smartwatches and wearable devices in terms of mechanical performance, lightweighting and biosafety.

[0092] In some embodiments of this disclosure, the elongation of the titanium alloy raw material is 13%-15%.

[0093] It should be noted that elongation is an important mechanical indicator for measuring the plasticity of metallic materials, reflecting the material's ability to undergo plastic deformation before fracture. A higher elongation indicates better material plasticity. In this embodiment, the elongation of the titanium alloy raw material is in the range of 13%-15%, ensuring that the titanium alloy raw material possesses good mechanical properties. On the one hand, it maintains good formability during the hot forging process in step S1, reducing the risk of cracking during processing; on the other hand, after homogenization heat treatment and grain growth heat treatment, the prepared titanium alloy material still maintains sufficient strength and toughness, meeting the reliability requirements of wearable device structural components during long-term use.

[0094] In some embodiments of this disclosure, the homogenization heat treatment and the crystal growth heat treatment are performed in a heat treatment furnace or a sintering furnace.

[0095] Specifically, both heat treatment furnaces and sintering furnaces can achieve furnace temperature control, vacuum control, heat preservation, and controllable cooling. In this embodiment, by utilizing the technological advantages of heat treatment furnaces or sintering furnaces in precise temperature control, vacuum adjustment, heat preservation, and slow cooling, the precise control requirements of temperature curves for homogenization heat treatment and crystal growth heat treatment are ensured, which is more conducive to the regular precipitation and layered stacking of lamellar α phase.

[0096] In some embodiments of this disclosure, at least one of punching, annealing, and CNC machining of the titanium alloy sheet is also included.

[0097] In practice, this titanium alloy sheet is used to manufacture the casing of a smartwatch. During preparation, the titanium alloy sheet is first divided into multiple smaller pieces according to a set size, and these smaller pieces are punched to form blanks. Then, the blanks are hot-forged, for example, at a temperature of 900℃-950℃. It should be noted that the hot-forging temperature is less than or equal to 950℃. If the forging temperature is higher than 950℃, the subsequent homogenization heat treatment and crystal growth heat treatment will be less effective. After hot forging, the blanks are annealed, optionally at a temperature of 500℃-550℃. Annealing effectively removes stress from the blanks. Next, the blanks are CNC machined, polished, and sandblasted. Finally, the blanks undergo homogenization heat treatment and crystal growth heat treatment.

[0098] According to another embodiment of this disclosure, a titanium alloy material is provided, which is prepared according to the titanium alloy material surface flower preparation method described in any one of the above embodiments.

[0099] In some embodiments of this disclosure, the crystal flower size on the surface of the titanium alloy material is 2mm-5mm.

[0100] Crystal flower size refers to the average equivalent diameter of a single crystal flower formed on the surface of a titanium alloy material after heat treatment. Specifically, coarse grains with crystal flower sizes ranging from 2mm to 5mm create a visual ice crystal texture effect on the surface of the titanium alloy. Under natural and artificial light, due to the anisotropy of crystallography, grains with different orientations exhibit different reflective properties and luster effects, giving the surface of the titanium alloy material a unique visual sense of layering and metallic beauty.

[0101] The preparation method of this disclosure can stably and repeatedly produce ice crystal texture effects with crystal flower size in the range of 2mm-5mm by precisely controlling the process parameters of homogenization heat treatment and crystal growth heat treatment.

[0102] According to another embodiment of this disclosure, a device housing is provided, which is made by the above-described method for preparing surface crystal flowers of titanium alloy material. That is, the device housing is made of the above-described titanium alloy material, and the surface of the device housing has a visual effect of ice crystal flowers.

[0103] The process involves first hot forging a titanium alloy raw material with a dual-phase microstructure of α and β phases into a titanium alloy material with a predetermined structure. This material is then subjected to a homogenization heat treatment to homogenize the grains and store energy for subsequent grain growth heat treatment. Next, a grain growth heat treatment is performed to allow the grains to grow sufficiently at a predetermined temperature. Cooling then promotes the regular precipitation and layered stacking of the lamellar α phase. Because the holding temperature for the grain growth heat treatment is higher than that for the homogenization heat treatment, the grains of the titanium alloy material can grow rapidly.

[0104] This preparation method can directly form a texture with a unique visual ice crystal effect on the surface of titanium alloy products without the need for surface coatings or other external treatment processes. Furthermore, this texture is formed by precipitation from the titanium alloy's own structure, eliminating issues of coating wear and peeling. It exhibits excellent appearance stability after long-term wear or use, and combines the inherent characteristics of titanium alloys, such as low density, high strength, good corrosion resistance, and excellent biocompatibility. This method is suitable for high-end smartwatches and wearable device structural components, where both appearance quality and long-term stability are critical.

[0105] Example 1 A method for preparing aluminum alloy materials is used to manufacture the casing of a smartwatch. The method includes: (1) Hot forging and surface treatment The titanium alloy sheet is made of TC4 titanium alloy. The elongation of the titanium alloy sheet is 14%. The titanium alloy sheet is divided into multiple smaller pieces according to a set size, and these smaller pieces are punched to form blanks. Then, the blanks are hot-forged, for example, at a temperature of 920℃. After hot forging, the blanks are annealed at a temperature of 540℃. Next, the blanks are CNC machined, polished, and sandblasted.

[0106] (2) Homogenization heat treatment The billet is placed in a heat treatment furnace. For example... Figure 9 As shown, the first heating stage involves heating from room temperature to the first holding stage. The holding temperature for the first holding stage is 450℃, and the holding time is 25 minutes. The second heating stage involves heating from 450℃ to the holding temperature for the second holding stage. The holding temperature for the second holding stage is 650℃, and the holding time is 25 minutes. The third heating stage involves heating from 650℃ to the holding temperature for the third holding stage. The holding temperature for the third holding stage is 850℃, and the holding time is 20 minutes. The fourth heating stage involves heating from 850℃ to the holding temperature for homogenization heat treatment, i.e., 980℃, and the holding time is 60 minutes. After homogenization heat treatment, the billet is cooled to room temperature.

[0107] (3) Heat treatment for crystal growth The crystal growth heat treatment is carried out in a heat treatment furnace. For example... Figure 10 As shown, the first heating stage involves heating from room temperature to the first holding stage. The holding temperature for the first holding stage is 450℃, and the holding time is 20 minutes. The second heating stage involves heating from 450℃ to the second holding stage temperature. The holding temperature for the second holding stage is 600℃, and the holding time is 15 minutes. The third heating stage involves heating from 600℃ to the third holding stage temperature. The holding temperature for the third holding stage is 850℃, and the holding time is 12 minutes. The fourth heating stage involves heating from 850℃ to the microstructure transformation temperature, i.e., 980℃, and the holding time is 10 minutes. The fifth heating stage involves heating from 980℃ to the grain growth heat treatment temperature, i.e., 1050℃, and the holding time is 3 hours. Then, the mixture is cooled to room temperature to obtain the titanium alloy product.

[0108] (4) Post-processing Titanium alloy products are CNC machined to form a specific structure.

[0109] Figure 2 This is a photograph of the titanium alloy material according to an embodiment of this disclosure after homogenization heat treatment. Figure 2 It can be seen that after homogenization heat treatment, the surface of the titanium alloy material forms fine and uniformly distributed grains, with crystal flower size of 0.5mm-1mm. Figure 3 This is a photograph of the titanium alloy material according to an embodiment of this disclosure after grain growth heat treatment. Figure 3 As can be seen, the surface of the titanium alloy product exhibits a visual ice crystal texture. The grain size has increased significantly, with the crystal flower size being approximately 3.5 mm.

[0110] It should be noted that, given a constant holding temperature for crystal growth heat treatment, the grain size can be controlled by adjusting the holding time. A longer holding time results in larger crystal flowers, and vice versa.

[0111] Example 2 The purpose of this embodiment is to select titanium alloy raw materials with suitable elongation. The elongation rates of the titanium alloy raw materials are 12%, 13%, 15%, 16%, and 19%, respectively. The titanium alloy raw materials are titanium alloy plates. The titanium alloy raw materials have not undergone hot forging. The surface treatment, homogenization heat treatment, and grain growth heat treatment process conditions of the titanium alloy raw materials are the same as in Embodiment 1.

[0112] Figures 4-8 These are photographs of titanium alloy raw materials with different elongations after homogenization heat treatment and grain growth heat treatment. Figure 4 The elongation of the titanium alloy raw material used is 12%. Figure 5 The elongation of the titanium alloy raw material used is 13%. Figure 6 The elongation of the titanium alloy raw material used is 15%. Figure 7 The elongation of the titanium alloy raw material used is 16%. Figure 8 The elongation of the titanium alloy raw material used is 19%.

[0113] Figure 4 The titanium alloy raw materials, after homogenization heat treatment and crystal growth heat treatment, form crystal flowers that are too small to present a visual ice crystal texture. Figure 5 and Figure 6 The titanium alloy raw materials, after homogenization heat treatment and crystal growth heat treatment, form complete crystal flower morphology with clear boundaries, and the shape of the crystal flowers is mainly elliptical. Figure 7 , 8 The titanium alloy raw materials, after homogenization heat treatment and grain growth heat treatment, exhibit unclear grain boundaries and irregular shapes. Therefore, titanium alloy raw materials with an elongation of 13%-15% are suitable as the titanium alloy raw materials for the embodiments of this disclosure.

[0114] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0115] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for preparing surface flowers on titanium alloy materials, characterized in that, include: Titanium alloy raw materials are hot forged to form a titanium alloy material with a set structure, wherein the titanium alloy material has an α phase and a β phase; The titanium alloy material is subjected to a homogenization heat treatment, wherein the holding temperature of the homogenization heat treatment is 950℃-1020℃ and the holding time is 30min-90min, and then it is cooled. The titanium alloy material is subjected to a crystal growth heat treatment, wherein the holding temperature of the crystal growth heat treatment is 1020℃-1100℃ and the holding time is 1.5h-5h; wherein the holding temperature of the crystal growth heat treatment is higher than the holding temperature of the homogenization heat treatment, and the homogenization heat treatment and the crystal growth heat treatment are carried out under vacuum conditions.

2. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The heating process of the homogenization heat treatment and / or crystal growth heat treatment includes multiple holding stages.

3. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The heating process of the homogenization heat treatment includes multiple heat preservation stages, wherein the heat preservation temperature of the first heat preservation stage is 400℃-500℃, the heat preservation temperature of the second heat preservation stage is 600℃-700℃, and the heat preservation temperature of the third heat preservation stage is 800℃-900℃.

4. The method for preparing surface flowers of titanium alloy materials according to claim 3, characterized in that, The heat preservation time for the first heat preservation stage is 20-30 minutes, the heat preservation time for the second heat preservation stage is 20-30 minutes, and the heat preservation time for the third heat preservation stage is 15-25 minutes.

5. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The temperature rise process of the crystal growth heat treatment includes multiple holding stages, wherein the holding temperature of the first holding stage is 400℃-500℃, the holding temperature of the second holding stage is 550℃-650℃, the holding temperature of the third holding stage is 800℃-900℃, and the holding temperature of the fourth holding stage is the microstructure transformation temperature of the titanium alloy material.

6. The method for preparing surface flowers of titanium alloy materials according to claim 5, characterized in that, The heat preservation time for the first heat preservation stage is 20-30 minutes, the heat preservation time for the second heat preservation stage is 10-20 minutes, the heat preservation time for the third heat preservation stage is 5-15 minutes, and the heat preservation time for the fourth heat preservation stage is 5-15 minutes.

7. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The vacuum level of the vacuum condition is less than or equal to 6. 10 -3 Pa.

8. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, Surface treatment is included prior to the homogenization heat treatment.

9. The method for preparing surface flowers of titanium alloy materials according to claim 8, characterized in that, The surface treatment includes polishing and / or sandblasting.

10. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The titanium alloy raw material is a TC series titanium alloy.

11. The method for preparing surface flowers of titanium alloy materials according to claim 1, characterized in that, The elongation of the titanium alloy raw material is 13%-15%.

12. A titanium alloy material, characterized in that, It is prepared by the method for preparing surface flowers of titanium alloy materials according to any one of claims 1-11.

13. The titanium alloy material according to claim 12, characterized in that, The crystal flower size on the surface of the titanium alloy material is 2mm-5mm.

14. A device housing, characterized in that, It is prepared using the method for preparing surface flowers of titanium alloy materials as described in any one of claims 1-11.

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