Method for improving performance of additive manufacturing tc4 by using fly ash and tc4 alloy

Abstract

The application discloses a method for improving the performance of additive manufacturing TC4 by using fly ash and a TC4 alloy, and relates to the technical field of additive manufacturing material modification. The method comprises the following steps: fly ash of grade I and Ti6Al4V powder are loaded into a powder mixing device, and zirconium oxide grinding balls are added at the same time to mix the powders uniformly; the mixed powders are screened, and powders with a particle size less than or equal to a preset threshold value are screened out; the screened powders are dried through a vacuum drying box, and are cooled to room temperature after drying; the dried powders are used to manufacture Ti6Al4V alloy by using a laser powder bed fusion additive manufacturing technology, and a fly ash modified LPBF-Ti6Al4V alloy forming piece is obtained; the obtained forming piece is polished, polished and cleaned to obtain a fly ash modified LPBF-Ti6Al4V alloy finished product. The application successfully improves the mechanical properties and corrosion resistance of the LPBF-Ti6Al4V by modifying the TC4 powder with fly ash.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing material modification technology, and particularly relates to a method for improving the performance of TC4 in additive manufacturing and TC4 alloy. Background Technology

[0002] Titanium alloys are widely used in aerospace and biomedical fields due to their excellent comprehensive mechanical properties and good biocompatibility. As a typical α+β type titanium alloy, Ti6Al4V (TC4) has formed a mature commercial system, and its strength, toughness, bioactivity, and antibacterial properties have been further enhanced through alloy design, heat treatment, and surface engineering, attracting widespread attention from the academic community. However, current research on Ti6Al4V mainly focuses on the construction of surface-modified coatings to compensate for its inherent functional limitations; in contrast, research on the compositional design and performance control of the Ti6Al4V matrix itself is relatively limited, leaving room for improvement.

[0003] In the early stages of Ti6Al4V alloy development, researchers attempted to improve its properties by incorporating micro / nano reinforcing phases, a method that attracted widespread research interest around 2018. In the search for low-cost reinforcing materials, magnesium-based alloys, due to their inherent limitations, are often partially replaced by natural renewable biomass waste (such as bamboo fiber, bagasse, and straw) to reduce raw material costs. However, systematic research on these low-cost reinforcing agents in Ti6Al4V remains relatively lacking. After comprehensively examining various potential reinforcing resources, we found that fly ash, an inorganic solid byproduct generated during coal combustion in thermal power plants, is rich in C, SiO2, CaCO3, and other components that can serve as effective reinforcing phases, possessing the potential to be used as a reinforcing agent for Ti6Al4V alloys.

[0004] In the high-energy laser molten pool of LPBF, carbon (C) reacts with titanium to form an ultra-hard TiC ceramic phase in situ. These fine TiC particles are uniformly dispersed in the matrix, effectively pinning grain boundaries and dislocations, producing a significant second-phase strengthening effect, thereby improving the alloy's strength, hardness, and wear resistance. SiO2 is a thermodynamically unstable oxide in titanium melt. It undergoes a substitution reaction with highly reactive Ti to generate more stable titanium oxides (such as TiO2) and titanium silicides (such as Ti5Si3). Ti5Si3 is a silicide with a high melting point and hardness, providing excellent high-temperature strengthening. The introduced calcium (Ca) is a key element in the formation of human bone. Introducing calcium-containing phases such as CaTiO3 into the Ti6Al4V alloy significantly enhances the alloy's surface bioactivity, making it easier to form a strong chemical bond (osseointegration) with bone tissue after implantation, thus greatly improving the osteogenic properties of Ti6Al4V as a medical implant.

[0005] Most importantly, the unit cost of fly ash is far lower than that of a single reinforcing material, priced at approximately $50 per ton. Considering that the amount of reinforcing material added is typically less than 5% of the matrix mass, the raw material cost of modifying Ti6Al4V using fly ash can be reduced to an extremely low level, approximately three orders of magnitude lower than when using C, SiO2, or CaCO3 alone as reinforcing materials. Currently, the application of fly ash is mainly concentrated in the field of building materials, especially in improving the performance of concrete. However, research in high-performance metal structural materials, particularly titanium-based composites, is still lacking and urgently needs further exploration. Summary of the Invention

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method and TC4 alloy for improving the performance of additive manufacturing of TC4 by using fly ash. The mechanical properties and corrosion resistance of laser powder bed molten TC4 titanium alloy (i.e., LPBF-Ti6Al4V) molded samples are improved by modifying TC4 powder with inexpensive fly ash.

[0007] According to one aspect of the present invention, a method for improving the performance of additive manufacturing TC4 using fly ash is provided, comprising: S1, loading Class I fly ash and Ti6Al4V powder into a mixing device, and simultaneously adding zirconia grinding balls to mix evenly; S2, screening the mixed powder to screen out powder with a particle size less than or equal to a preset threshold; S3, drying the screened powder in a vacuum drying oven, and cooling it to room temperature after drying; S4, using the dried powder to manufacture Ti6Al4V alloy using laser powder bed fusion additive manufacturing technology to obtain fly ash modified LPBF-Ti6Al4V alloy molded parts; S5, grinding, polishing and cleaning the obtained molded parts to obtain fly ash modified LPBF-Ti6Al4V alloy finished products.

[0008] Optionally, in S1, the content of Grade I fly ash is 0.05 wt% of the total amount of Ti6Al4V fly ash.

[0009] Optionally, in S1, the added zirconia grinding balls include different sizes and are prepared in a ratio of φ5 mm:φ8 mm:φ10 mm=5:3:2, where φ represents the diameter of the grinding ball.

[0010] Optionally, in S1, the powder mixing equipment is a horizontal planetary powder mixer, and the powder mixing parameters are set as follows: the rotation speed is set to 500 rpm, the working time is 300 minutes, and the machine stops for 1 minute after rotating clockwise every 5 minutes, followed by 5 minutes of counterclockwise rotation.

[0011] Optionally, in S2, a 250-mesh sieve is used to screen the mixed powder.

[0012] Optionally, in S3, the temperature of the vacuum drying oven is set to 100°C, and the drying time is 3 to 6 hours.

[0013] Optionally, in S4, the additive manufacturing equipment is a laser powder bed-selective laser printer. During the printing process, a protective gas, argon, is introduced into the forming chamber to control the oxygen content to be less than 1000 mmpm, the fan speed to be controlled above 30%, and the air humidity to be less than 30%.

[0014] Optionally, in S4, the processing conditions for laser powder bed fusion additive manufacturing technology are set as follows: laser power is 180W, laser strip width is 10mm, scanning speed is 1200mm / s, and scanning line spacing is 80μm.

[0015] Optionally, in S5, sanding and polishing are performed using sandpaper ranging from 80# to 2000#, followed by ultrasonic cleaning in anhydrous ethanol and deionized water for 20 minutes each.

[0016] According to another aspect of the present invention, a TC4 alloy is provided, which is prepared by the method described above for improving the performance of additive manufacturing TC4 using fly ash.

[0017] The beneficial effects of this invention are:

[0018] (1) This invention successfully strengthens Ti6Al4V alloy (i.e., TC4 alloy) using extremely inexpensive fly ash. The addition of fly ash refines the grain size and promotes the formation of more β phases in the sample. Appropriate fly ash doping can synergistically enhance the strength (increase by 9.9%) and toughness (increase by 38.4%) of Ti6Al4V.

[0019] (2) The addition of fly ash improves the corrosion resistance and corrosion current density of Ti6Al4V (Icorr = 2.4 ± 1.5 × 10⁻⁷ A / cm²). 2 ).

[0020] (3) The cost of fly ash is only one-tenth of that of SiO2, one-one-hundred-and-one-thirty-third of that of rare earth element-enhanced tools, and one-one-two-hundred-and-thirty-fifth of that of graphene.

[0021] These findings demonstrate the feasibility of using fly ash as a reinforcing agent in the additive manufacturing process of titanium alloys, providing a new approach to economically improve the mechanical properties of Ti6Al4V. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 The images are electron micrographs of powder, where (a), (b), (c), and (d) are electron micrographs of the powders prepared before molding in Examples 1, 2, 3, and 4, respectively.

[0024] Figure 2 The images are electron microscope (EM) images of the samples before and after etching. (a), (b), (c), and (d) are EM images of Examples 1, 2, 3, and 4 after etching, respectively.

[0025] Figure 3 The figures show the mechanical property test results, where (a) is the stress-strain curve of the four specimens, and (b), (c), (d), and (e) are the tensile fracture morphologies of Examples 1, 2, 3, and 4, respectively.

[0026] Figure 4 The figures are electrochemical analysis diagrams, where (a), (b), (c), and (d) are polarization curves, impedance diagrams, Bode |Z| value diagrams, and Bode phase angle diagrams for Examples 1, 2, 3, and 4, respectively. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present application can be combined with each other.

[0028] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0029] Example 1: This embodiment of the invention provides a method for improving the performance of TC4 additive manufacturing using fly ash. Fly ash is added to Ti6Al4V powder, and the mixed powder of fly ash and Ti6Al4V powder is used as a raw material for laser powder bed fusion additive manufacturing to prepare a fly ash-modified TC4 alloy. The method includes the following steps:

[0030] S1, Mixing powder and grinding ball ratio: Grade I fly ash and Ti6Al4V powder are loaded into a horizontal planetary mixer, and zirconium oxide grinding balls are added at the same time.

[0031] The ratio of zirconia grinding balls is φ5 mm:φ8 mm:φ10 mm = 5:3:2, where φ represents the diameter of the grinding balls (adding zirconia grinding balls can make the mixed powder of fly ash and Ti6Al4V more fully dispersed and refined).

[0032] In this step, the content of Grade I fly ash is 0.05 wt% of the total Ti6Al4V.

[0033] The powder mixer is made of corundum, and the matching agate ball weighs 0.165 kg.

[0034] Grade I fly ash is a major solid waste discharged from thermal power plants in my country. Its main components are SiO2, Al2O3, FeO, Fe2O3, CaO, and TiO2, and it costs approximately 15 RMB per kilogram. Generally, Grade I fly ash refers to fly ash with an SiO2 content exceeding 50%, a fineness (residue on a 45μm square-hole sieve) not exceeding 12%, a water requirement ratio not exceeding 95%, a loss on ignition not exceeding 5%, and a sulfur trioxide content not exceeding 3.0%.

[0035] The Ti6Al4V powder has a particle size of 15-53 micrometers and was purchased from AVIC MITEK for approximately 300 RMB per kilogram.

[0036] S2, Powder mixing equipment parameter settings: The horizontal planetary powder mixer rotates at 500 rpm and operates for 300 minutes; it rotates clockwise for 5 minutes, then stops for 1 minute, followed by 5 minutes of counterclockwise rotation.

[0037] S3, Modified Powder Screening: After the powder mixing equipment completes its work, the mixed grinding balls and powder are passed through a 250-mesh sieve to separate the powder and grinding balls (the particle size to be screened is approximately 63.5μm or less; in actual use, the size can be adjusted according to the situation and requirements).

[0038] S4. After screening, the powder is dehumidified in a vacuum drying oven: the temperature is set to 100°C and the drying time is 300 minutes. After the equipment completes the drying, the powder is taken out and put into use after cooling to room temperature.

[0039] The vacuum degree of the vacuum drying oven should be below -1.0 pamm, the drying temperature should be 100℃, and the drying time should be 3 to 6 hours.

[0040] S5. The modified powder is used to manufacture Ti6Al4V alloy using laser powder bed fusion (LPBF) additive manufacturing technology to obtain LPBF-Ti6Al4V alloy molded parts modified with fly ash.

[0041] The additive manufacturing equipment is a laser powder bed selective laser printer. During the forming process, the forming chamber is filled with a protective gas—argon—ensuring an oxygen content of less than 1000 mmpm, and the fan speed is above 30%. The processing conditions are: laser power 180W, laser strip width 10mm, scanning speed 1200mm / s, and scanning line spacing 80μm. The preparation process is carried out under dry indoor conditions with an air humidity of less than 30%.

[0042] S6. The fly ash modified molded parts of LPBF-Ti6Al4V alloy are processed by grinding and polishing with 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500# and 2000# sandpaper, and ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively. After being taken out and dried, the fly ash modified LPBF-Ti6Al4V alloy finished products are obtained.

[0043] It should be further noted that those skilled in the art should understand that the specific operations and parameters listed in Embodiment 1 above may be adjusted in actual implementation due to differences in scale or conditions, and are not exhaustive of all implementation methods. Those skilled in the art can make appropriate and flexible adjustments to the process conditions according to the actual situation without departing from the technical principles of this invention, as long as the same or similar technical effects as the embodiments of this invention can be achieved. For example, regarding the drying of the screened powder, although this invention provides a vacuum drying oven method, other drying methods such as oven drying and natural air drying are also conceivable to those skilled in the art. Furthermore, in practical applications, the drying time can be shortened or extended according to the material's humidity or scale. Other operations are similar and will not be elaborated upon.

[0044] Furthermore, the effectiveness of the method for improving the performance of TC4 additive manufacturing using fly ash is verified through specific examples below.

[0045] Example 1: No fly ash added:

[0046] S1, Mixing powder and grinding ball ratio: Ti6Al4V powder is loaded into a horizontal planetary powder mixer, and zirconia grinding balls prepared according to the ratio (φ5mm:φ8mm:φ10mm=5:3:2) are added.

[0047] S2, Powder mixing equipment parameter settings: The horizontal planetary powder mixer rotates at 500 rpm and operates for 300 minutes; it rotates clockwise for 5 minutes, then stops for 1 minute, followed by 5 minutes of counterclockwise rotation.

[0048] S3, Modified Powder Screening: After the powder mixing equipment completes its work, the mixed grinding balls and powder are passed through a 250-mesh sieve to screen out the powder.

[0049] S4. After screening, the powder is dehumidified in a vacuum drying oven at 100°C for 300 minutes. After drying, the powder is allowed to cool to room temperature before being removed for use.

[0050] S5. Ti6Al4V alloy was manufactured using laser powder bed melting additive manufacturing technology to obtain LPBF-Ti6Al4V alloy dog ​​bone tensile strips and blocks.

[0051] S6. The LPBF-Ti6Al4V alloy matrix obtained in S5 was pretreated by grinding and polishing with sandpaper of 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500# and 2000#. Then it was ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and dried to obtain the finished LPBF-Ti6Al4V alloy, which is the sample of Example 1.

[0052] like Figure 1 (a) shows the surface morphology of the powder before molding of the sample in Example 1 (i.e., the powder after drying in step S4). It can be observed that although the Ti6Al4V powder was ground by grinding balls, the overall roundness of the powder was good and did not change.

[0053] like Figure 2 (a) shows a scanning electron microscope image of the sample from Example 1 after etching with Keller's reagent (1 mL HF + 1.5 mL HCl + 2.5 mL HNO3 + 95 mL H2O) for 1 min.

[0054] Example 2: 0.1wt% fly ash:

[0055] S1, Mixing powder and grinding ball ratio: Ti6Al4V powder and 0.1wt% fly ash (FA) are loaded into a horizontal planetary mixer, and zirconia grinding balls prepared according to the ratio (φ5 mm: φ8 mm: φ10 mm=5:3:2) are added.

[0056] S2, Powder mixing equipment parameter settings: The horizontal planetary powder mixer rotates at 500 rpm and operates for 300 minutes; it rotates clockwise for 5 minutes, then stops for 1 minute, followed by 5 minutes of counterclockwise rotation.

[0057] S3, Modified Powder Screening: After the powder mixing equipment completes its work, the mixed grinding balls and powder are passed through a 250-mesh sieve to screen out the powder.

[0058] S4. After screening, the powder is dehumidified in a vacuum drying oven at 100°C for 300 minutes. After drying, the powder is allowed to cool to room temperature before being removed for use.

[0059] S5. Modified Ti6Al4V alloy is manufactured by laser powder bed melting additive manufacturing technology using modified powder, resulting in modified LPBF-Ti6Al4V alloy dog ​​bone tensile strips and blocks.

[0060] S6. The LPBF-Ti6Al4V alloy matrix obtained in S5 was pretreated by grinding and polishing with 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper. Then, it was ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and dried to obtain 0.1wt%FA-Ti6Al4V alloy, which is the sample of Example 2.

[0061] like Figure 1 (b) shows the surface morphology of the powder before molding of the sample in Example 2. It can be observed that the powder roundness is poor after mixing due to the high fly ash content. At the same time, the main components of fly ash can be observed.

[0062] like Figure 2 (b) shows a scanning electron microscope image of the sample from Example 2 after etching with Keller's reagent (1 mL HF + 1.5 mL HCl + 2.5 mL HNO3 + 95 mL H2O) for 1 min.

[0063] Example 3: 0.5wt% fly ash:

[0064] S1, Mixing powder and grinding ball ratio: Ti6Al4V powder and 0.5wt% fly ash are loaded into a horizontal planetary mixer, and zirconia grinding balls prepared according to the ratio (φ5 mm: φ8 mm: φ10 mm=5:3:2) are added.

[0065] S2, Powder mixing equipment parameter settings: The horizontal planetary powder mixer rotates at 500 rpm and operates for 300 minutes; it rotates clockwise for 5 minutes, then stops for 1 minute, followed by 5 minutes of counterclockwise rotation.

[0066] S3, Modified Powder Screening: After the powder mixing equipment completes its work, the mixed grinding balls and powder are passed through a 250-mesh sieve to screen out the powder.

[0067] S4. After screening, the powder is dehumidified in a vacuum drying oven at 100°C for 300 minutes. After drying, the powder is allowed to cool to room temperature before being removed for use.

[0068] S5. Modified Ti6Al4V alloy is manufactured by laser powder bed melting additive manufacturing technology using modified powder, resulting in modified LPBF-Ti6Al4V alloy dog ​​bone tensile strips and blocks.

[0069] S6. The LPBF-Ti6Al4V alloy matrix obtained in S5 was pretreated by grinding and polishing with 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper. Then, it was ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and dried to obtain 0.5wt%FA-Ti6Al4V alloy, which is the sample of Example 3.

[0070] like Figure 1 (c) shows the surface morphology of the powder before molding of the sample in Example 3. It can be observed that the powder roundness is poor after mixing due to the high fly ash content. The main constituent elements of fly ash are also observed.

[0071] like Figure 2 (c) shows a scanning electron microscope image of the sample from Example 3 after etching with Keller's reagent (1 mL HF + 1.5 mL HCl + 2.5 mL HNO3 + 95 mL H2O) for 1 min.

[0072] Example 4: 0.05wt% fly ash:

[0073] S1, Mixing powder and grinding ball ratio: Ti6Al4V powder and 0.05wt% fly ash are loaded into a horizontal planetary mixer, and zirconia grinding balls prepared according to the ratio (φ5 mm: φ8 mm: φ10 mm=5:3:2) are added.

[0074] S2, Powder mixing equipment parameter settings: The horizontal planetary powder mixer rotates at 500 rpm and operates for 300 minutes; it rotates clockwise for 5 minutes, then stops for 1 minute, followed by 5 minutes of counterclockwise rotation.

[0075] S3, Modified Powder Screening: After the powder mixing equipment completes its work, the mixed grinding balls and powder are passed through a 250-mesh sieve to screen out the powder.

[0076] S4. After screening, the powder is dehumidified in a vacuum drying oven at 100°C for 300 minutes. After drying, the powder is allowed to cool to room temperature before being removed for use.

[0077] S5. Modified Ti6Al4V alloy is manufactured by laser powder bed melting additive manufacturing technology using modified powder, resulting in modified LPBF-Ti6Al4V alloy dog ​​bone tensile strips and blocks.

[0078] S6. The LPBF-Ti6Al4V alloy matrix obtained in S5 was pretreated by grinding and polishing with 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500#, and 2000# sandpaper. Then, it was ultrasonically treated in anhydrous ethanol and deionized water for 20 min respectively, and then taken out and dried to obtain 0.05wt%FA-Ti6Al4V alloy, which is the sample of Example 4.

[0079] like Figure 1 (d) shows the surface morphology of the powder before the sample of Example 4 was formed. It can be observed that the sphericity of the powder after mixing with fly ash remains basically unchanged. At the same time, the main constituent elements of fly ash can also be observed.

[0080] like Figure 2 (d) shows a scanning electron microscope image of the sample from Example 4 after etching with Keller's reagent (1 mL HF + 1.5 mL HCl + 2.5 mL HNO3 + 95 mL H2O) for 1 min.

[0081] Figure 1 SEM images and elemental distributions of Ti6Al4V (Example 1), 0.1wt%FA-Ti6Al4V (Example 2), 0.5wt%FA-Ti6Al4V (Example 3), and 0.05wt%FA-Ti6Al4V (Example 4) powders. From... Figure 1 It can be seen that the Ti6Al4V powder exhibits good spherical shape, with Ti, Al, and V elements evenly distributed within the powder, demonstrating the high quality of the gas atomized powder. With increasing fly ash (FA) content, the sphericity of the FA-Ti6Al4V powder gradually deteriorates, with the mixed powder in Example 4 exhibiting the best sphericity. Figure 1 (d) showed no significant difference in sphericity compared to Ti6Al4V powder. Figure 1 (a) Furthermore, with the increase of FA content, the aggregation of Si, Fe, and Ca elements in the powders of Examples 3 and 2 may lead to significant elemental segregation in certain areas during additive manufacturing, affecting the final performance of the samples. In contrast, Example 4 exhibits a uniform elemental distribution, indicating that FA is uniformly distributed within the Ti6Al4V powder. Considering the sphericity and elemental distribution of the mixed powder, the powder of Example 4 is in the optimal state and exhibits the best performance.

[0082] like Figure 2As shown, optical electron microscope (OEM) images of four samples before and after corrosion are presented to investigate the reasons for the changes in the mechanical properties of the samples. The Ti6Al4V surface exhibits a certain degree of porosity, which is a result of rapid cooling during sample formation using the LPBF technique. The sample is mainly composed of acicular α′ martensite, and no β phase was observed under an OEM. In contrast, coarse columnar grains appeared on the surface of samples 2 and 3, which is likely the main factor leading to the decrease in elongation. Compared to Ti6Al4V, Examples 2, and 3, the surface of Example 4 showed no columnar particles and fewer pores. This indicates that sample 4 should have the best mechanical properties.

[0083] like Figure 3 The stress-strain curves of the four specimens are shown, and Table 1 shows the ultimate tensile strength and elongation. Specimen 4 exhibits the best elongation and ultimate tensile strength. However, when the fly ash content increases to 0.1 wt% and 0.5 wt%, the elongation of the specimen decreases sharply (5.87 for Example 3 and 5.02 for Example 2). Despite the decrease in elongation, the ultimate tensile strength of the specimens significantly increases with increasing fly ash content (reaching 1205.8 MPa for Example 3 and 1250.7 MPa for Example 2). The tensile fracture morphology of the four specimens is shown in the figure. Figure 3 As shown in (be).

[0084] Table 1: Ultimate Tensile Strength and Elongation

[0085]

[0086] like Figure 4 To compare the electrochemical behavior of FA-doped Ti6Al4V with that of substrate Ti6Al4V, electrochemical experiments were performed on Ti6Al4V and three FA-Ti6Al4V samples. The polarization curves of the FA-Ti6Al4V and Ti6Al4V samples are shown below. Figure 4 As shown in (a), the specific electrochemical parameters are shown in Table 2. corr The smaller the value, the stronger the corrosion resistance of the material and the slower the corrosion rate. For example 4, I corr The corrosion current in Example 2 decreased to 2.4 ± 1.5 × 10⁻⁷ A / cm², exhibiting the best corrosion resistance compared to Example 1. When the amount of FA added was too high, the corrosion current in Example 2 exceeded Ti₆Al₄V, reaching 8.1 ± 1.4 × 10⁻⁷ A / cm², resulting in poorer corrosion resistance. Figure 4 (b) shows the Nyquist plots for Examples 1, 2, 3, and 4. The size of the capacitance loop radius generally indicates the corrosion resistance of the sample; the larger the radius, the stronger the corrosion resistance. Clearly, the capacitance loop radius of Example 4 is larger than that of Examples 1, 2, and 3. In the low-frequency Bode |Z| value plot ( Figure 4In (c)), the |Z| value of Example 4 is higher than that of the other three examples. This also indicates that Example 4 has excellent corrosion resistance. The Bode phase diagram of Example 4 ( Figure 4 (d) shows that there is a time constant in the mid-frequency region. Furthermore, in the mid-frequency region, the phase angle value of Example 4 is higher and wider than the other three examples. This also demonstrates that Example 4 has the best corrosion resistance.

[0087] Table 2: Corrosion Current Density, Corrosion Voltage

[0088]

[0089] In summary, this invention utilizes extremely inexpensive fly ash to strengthen Ti6Al4V alloy. The addition of fly ash refines the grain size and promotes the formation of more β-phase in the sample. Appropriate fly ash doping synergistically enhances the strength (by 9.9%) and toughness (by 38.4%) of Ti6Al4V. The addition of fly ash also improves the corrosion resistance and corrosion current density (I0.05) of Ti6Al4V. corr = 2.4±1.5×10-7 A / cm²). The cost of fly ash is only one-tenth that of SiO2, one-one-two-thirds that of rare earth element-reinforced tools, and one-one-two-hundred-and-thirty-fifth that of graphene. These results demonstrate the feasibility of using fly ash as a reinforcing agent in the additive manufacturing process of titanium alloys, providing a new way to economically improve the mechanical properties of Ti6Al4V.

[0090] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0091] The steps in the method of this invention can be adjusted, combined, or deleted according to actual needs. The technical features can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the embodiments are described. However, as long as the combinations of these technical features do not contradict each other, they should all be considered within the scope of this invention.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the performance of additive manufacturing TC4 by using fly ash, characterized in that, The method comprises the following steps: S1, the first-class fly ash and Ti6Al4V powder are loaded into a powder mixing device, and zirconia grinding balls are added and uniformly mixed; S2, the mixed powder is screened to screen out powder with a particle size less than or equal to a preset threshold value; S3, the screened powder is dried by a vacuum drying box, and then cooled to room temperature after drying; S4, the dried powder is used to manufacture a Ti6Al4V alloy by using a laser powder bed fusion additive manufacturing technology to obtain a fly ash modified LPBF-Ti6Al4V alloy formed piece; S5, the obtained formed piece is polished, polished and cleaned to obtain a fly ash modified LPBF-Ti6Al4V alloy finished product.

2. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S1, the content of the first-class fly ash added is 0.05wt% of the total amount of Ti6Al4V powder.

3. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S1, the zirconia grinding balls added include different sizes and are prepared according to a ratio of φ5 mm:φ8 mm:φ10 mm=5:3:2, wherein φ represents the diameter of the grinding ball.

4. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S1, the powder mixing device is a horizontal planetary powder mixer, and the powder mixing parameters are set as follows: the rotation speed is set to 500 revolutions / minute, the working time is 300 minutes, every 5 minutes clockwise rotation is stopped for 1 minute, and then 5 minutes counterclockwise rotation is performed.

5. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S2, a 250 mesh screen is used to screen the mixed powder.

6. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S3, the temperature of the vacuum drying box is set to 100℃, and the drying time is 3-6 hours.

7. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S4, the additive manufacturing equipment is a laser powder bed-selective laser printer, and during the printing forming process, protective gas-argon is filled into the forming chamber to control the oxygen content to be less than 1000ppm, the fan speed is controlled to be more than 30%, and the air humidity is less than 30%.

8. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S4, the processing conditions of the laser powder bed fusion additive manufacturing technology are set as follows: the laser power is 180W, the laser strip width is 10mm, the scanning speed is 1200mm / s, and the scanning line spacing is 80μm.

9. The method for improving the performance of additive manufacturing TC4 by using fly ash according to claim 1, wherein, In S5, 80#, 180#, 240#, 400#, 600#, 800#, 1000#, 1200#, 1500# and 2000# sandpaper are used for polishing and polishing, and then ultrasonic treatment and cleaning in anhydrous ethanol and deionized water for 20 minutes, respectively.

10. A TC4 alloy, characterized in that, The method for improving the performance of additive manufacturing TC4 by using fly ash according to any one of claims 1-9 is prepared. The method for improving the performance of additive manufacturing TC4 by using fly ash according to any one of claims 1-9 is prepared.

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