A high-toughness high-damage-tolerance titanium alloy component and a laser additive manufacturing method

Abstract

A high-strength, high-toughness, and high-damage-tolerance titanium alloy component and a laser additive manufacturing method are disclosed, relating to the field of metal material additive manufacturing. The method includes: S1: fixing a substrate in a forming chamber; S2: loading titanium alloy powder into a powder feeding device; S3: after the oxygen content in the forming chamber drops below 50 ppm, laser forming begins, melting and depositing the synchronously fed titanium alloy powder layer by layer onto the substrate; after one layer is deposited, the next layer is formed after a set time interval; S4: after deposition, the deposited sample is removed from the forming chamber, cut to prepare a titanium alloy specimen, and the phase transition point T of the titanium alloy specimen is measured. β S5: Based on T β Based on the measurement results, the samples were placed in a heat treatment furnace for special heat treatment to obtain titanium alloy components. The prepared titanium alloy exhibits simultaneous improvements in strength, toughness, damage tolerance, fatigue crack propagation resistance, and fracture toughness, which can significantly enhance the service safety of titanium alloy components.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing of metallic materials, and specifically relates to a laser additive manufacturing method for obtaining high-strength, high-toughness, and high-damage-tolerance titanium alloys. Background Technology

[0002] As aircraft design concepts have evolved from simple static strength to safety-life, failure-safety, and durability / damage tolerance design principles, titanium alloy materials have also evolved from focusing solely on strength and high fatigue performance to prioritizing high toughness and high damage tolerance. Damage tolerance refers to the maximum degree or magnitude of damage that a structural material can withstand under normal load conditions to ensure the safe operation of the component. Currently, the most widely used damage-tolerant titanium alloys domestically and internationally are the medium-strength, high-toughness, damage-tolerant TC4-DT (or TC4ELI) titanium alloy and the high-strength, high-toughness, high-damage-tolerance TC21 (or Ti-622S). Medium-strength, high-toughness, damage-tolerant titanium alloys refer to those with a tensile strength (R... m In the range of 825–900 MPa, the fatigue crack propagation rate (R = 0.1, ΔK = 11 MPa·m) 1 / 2 )da / dN is 1×10 -5 mm / cycle, fracture toughness (K) IC Greater than 90 MPa·m 1 / 2 The above are titanium alloy materials. High-strength and high-toughness titanium alloys refer to R... m Above 1000 MPa, the fatigue crack propagation rate (R = 0.1, ΔK = 11 MPa·m) 1 / 2 )da / dN is 1~1.5×10 -5 mm / cycle, K IC At 60 MPa·m 1 / 2 The above are titanium alloy materials. TC4-DT titanium alloy mainly improves damage tolerance by reducing the amount of C, N, and O elements in the alloy, thereby lowering its tensile properties. TC21 alloy improves high-temperature strength and creep resistance by adding Si, and simultaneously improves its strength and damage tolerance through triple heat treatment and plastic processing.

[0003] Titanium alloys primarily improve their strength by increasing the number of alloying elements, but this can reduce their damage tolerance. Therefore, the approach of improving damage tolerance by controlling alloying elements has limitations. Patent CN113355559B, by controlling alloying elements such as Al, Mo, Zr, Si, and Fe, improves the uniformity of alloy composition and solidification cooling rate through micro-area metallurgy, achieving low segregation and high solution treatment, resulting in an Rm exceeding 1200 MPa and K... IC Reaching 100 MPa·m 1 / 2The above are titanium alloy materials. However, changing the alloy composition will affect the application range of titanium alloy materials to some extent. Patent CN113249667B, without changing the composition of TC11 titanium alloy, obtains a material composed of long strips of primary α phase (α...) by controlling the high-temperature heat treatment process. P ) and secondary α phase (α S The biphasic structure composed of ) yields an Rm between 985 and 1070 MPa, K IC At 90.5–115 MPa·m 1 / 2 Titanium alloy materials. Without altering the existing titanium alloy composition, and addressing the development needs for lightweight and high-load-bearing titanium alloy structures, high-strength, high-toughness, and high-damage-tolerance titanium alloy components have significant application value, can significantly improve the safety of in-service components, and have important potential in the aerospace field. In recent years, laser additive manufacturing of titanium alloy components has been gradually applied to the manufacture of load-bearing structures in the aerospace field, and the demand for high strength, high toughness, and high damage tolerance is becoming increasingly apparent. However, the lack of relevant preparation technologies seriously affects its widespread application in the aerospace field. How to prepare high-strength, high-toughness, and high-damage-tolerance titanium alloy components through laser additive manufacturing without altering the titanium alloy composition has become one of the important challenges facing its engineering applications. Summary of the Invention

[0004] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components. Without changing the existing alloy element composition, the method uses laser additive manufacturing to form titanium alloy components, precisely matching high-temperature heat treatment to obtain a long, strip-shaped primary α-type titanium alloy component. P Phase and α S The phase composition forms a two-phase structure, thereby simultaneously improving the strength, toughness, and damage tolerance of titanium alloys. Its fatigue crack propagation resistance and fracture toughness are also simultaneously improved, which can significantly enhance the service safety of titanium alloy components.

[0005] The technical solution provided in this application is as follows:

[0006] A laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components includes:

[0007] S1: Fix the substrate in a forming chamber filled with argon gas;

[0008] S2: Load titanium alloy powder into the powder feeding device;

[0009] S3: When the oxygen content inside the forming process is below 50ppm, laser forming begins, and the synchronously fed titanium alloy powder is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed after a set time interval.

[0010] S4: After deposition is complete, the deposited sample is removed from the forming chamber, cut to prepare titanium alloy specimens of specific dimensions, and the phase transformation point T of the titanium alloy specimens is determined. β ;

[0011] S5: Based on T β Based on the phase transformation point measurement results, the sample is placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component.

[0012] In step S3, the laser additive manufacturing process parameters during deposition are as follows: laser scanning power is 1.0–2.5 kW, scanning rate is 500–800 mm / min, spot diameter is 1–3 mm, powder feeding rate is 10–15 g / min, overlap spacing is 41–59%, and layer thickness is 0.4–1.0 mm.

[0013] In step S3, the energy density of the titanium alloy deposition zone is controlled to be 45–67 J / mm² by controlling the process parameters of laser additive manufacturing. 2 The overlap ratio is 45%–60%, resulting in a cooling rate of 10 at the leading edge of the solid-liquid molten pool interface. 3.5 ~10 5.5 K / s, to prepare layers with a height of 0.4–1.0 mm and a dislocation density greater than 10. -19 m -2 The titanium alloy sample contained 100% lamellar structure with a width of 0.85–1.16 μm, which is conducive to the subsequent formation of elongated primary α-structures. P Phase and α S The phase provides the driving force.

[0014] The special heat treatment includes a first heat treatment and a second heat treatment; the first heat treatment includes: heating the sample at a rate of 10-15°C / min to (T... β -30)℃~(T β -10℃, hold at that temperature for 2-4 hours, and cool to room temperature at a rate not less than 60℃ / s; after the first heat treatment is completed, perform the second heat treatment, which includes: heating the sample to (T)℃ at a rate of 25-35℃ / min. β -400)℃~(T β Keep at -300℃ for 4 to 6 hours, and control the cooling rate to cool to room temperature at a rate of not less than 40℃ / s.

[0015] Through the above-mentioned special heat treatment, the formation of elongated α-rays is avoided. P The phase is too coarsened and α S Phase coarsening (reducing the tensile properties of titanium alloys) yields a microstructure consisting of α phases with a volume fraction of 35%–45% and a width not exceeding 4.52 μm. P A phase with a volume fraction of 55%–65% and a width not exceeding 8.65 μm.S Biphasic structure.

[0016] In step S3, the time is set to 25-35 minutes.

[0017] In step S2, the titanium alloy powder has a particle size of 55–275 μm and an oxygen content of not less than 0.13 wt.%.

[0018] In step S2, the [Al] equivalent in the titanium alloy powder is in the range of 1.9 to 7.5.

[0019] In step S1, the purity of argon gas in the forming chamber is not less than 99.99%.

[0020] In step S4, the phase transition point T β Measurement accuracy within (T) β Within ±5)℃.

[0021] A high-strength, high-toughness, and high-damage-tolerance titanium alloy component is prepared by any of the laser additive manufacturing methods described above.

[0022] This invention proposes a laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components. The main idea is to obtain a density greater than 10 through laser additive forming. -19 m -2 A fine micron-sized sheet structure with a volume fraction of 100% and a width of 0.85–1.16 μm was obtained. Based on this, a special heat treatment was precisely matched to obtain α-lamellae with a volume fraction of 35%–45% and a width of no more than 4.52 μm. P A phase with a volume fraction of 55%–65% and a width not exceeding 8.65 μm. S The two-phase structure synergistically regulates the static and dynamic deformation behavior of titanium alloys, enabling convenient and low-cost manufacturing of high-strength, high-toughness, and high-damage-tolerance titanium alloy components.

[0023] In summary, this application includes at least the following beneficial technical effects:

[0024] First, through the "precise control of laser additive manufacturing process and special heat treatment" provided by this invention, an α-structure with a volume fraction of no more than 35% and a width of no more than 4.52 μm is obtained. P α phase with a volume fraction not exceeding 65% and a width not exceeding 8.65 μm S A biphasic structure, in which long strips of primary α P Phase orientation inconsistency, α P The good matching of the α / s phase interface can significantly improve the room temperature mechanical properties of titanium alloy components. Figure 1 and Figure 2 );

[0025] Second, the lamellar tissue width within this biphasic tissue is moderate, and α... P The clusters formed at the αs / α phase interface can significantly deflect crack propagation, increase the tortuosity of crack propagation, and give the specimen higher crack propagation resistance, thereby reducing the crack propagation rate and improving fracture toughness, significantly improving the strength, toughness and damage tolerance of the component. Figure 1 and Figure 2 );

[0026] Third, without altering the titanium alloy composition, this method enables the fabrication of high-strength, high-toughness, and high-damage-tolerance titanium alloy components. It is also applicable to the design and use of other duplex titanium alloy components requiring high strength, high toughness, and high damage tolerance. Figure 1 and Figure 2 ). Attached Figure Description

[0027] Figure 1 The deposited sample of the TC11 titanium alloy component for laser additive manufacturing exhibits a fine micron-scale flake structure.

[0028] Figure 2 The laser additive manufacturing of TC11 titanium alloy components after special heat treatment exhibits a biphase microstructure. Detailed Implementation

[0029] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0030] A laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components specifically includes the following steps:

[0031] First, the titanium alloy substrate is fixed in a forming chamber filled with argon gas, the purity of which is not less than 99.99%.

[0032] Second, titanium alloy powder with a particle size of 55-275 μm is loaded into the powder feeding device, and the oxygen content of the titanium alloy powder is not less than 0.13 wt.%.

[0033] Third, when the oxygen content in the forming chamber is below 50 ppm, laser forming begins, and the titanium alloy powder fed in simultaneously is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed, with a forming time interval of 25 to 35 minutes.

[0034] The laser additive manufacturing forming parameters are as follows: laser scanning power is 1-2.5kW, scanning rate is 500-800mm / min, spot diameter is 1-3mm, powder feeding rate is 10-15g / min, overlap spacing is 41-59%, and layer thickness is 0.4-1.0mm.

[0035] During laser additive manufacturing, the energy density of the titanium alloy deposition zone is controlled to be 45–67 J / mm². 2 The overlap ratio is 45%–60%, resulting in a cooling rate of 10 at the leading edge of the solid-liquid molten pool interface. 3.5 ~10 5.5 K / s, to prepare layers with a height of 0.4–1.0 mm and a dislocation density greater than 10. -19 m -2 The titanium alloy sample contained 100% lamellar structure with a width of 0.85–1.16 μm, which is conducive to the subsequent formation of elongated primary α-structures. P Phase and α S The phase provides the driving force.

[0036] Fourth, after the forming process is complete, the sample is removed from the forming chamber and a 5mm×5mm×5mm sample is prepared using a wire cutting device. The phase transformation point T of the titanium alloy sample is then determined using a DSC device. β ;

[0037] Fifth, according to T β Based on the phase transformation point measurement results, the sample was placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component.

[0038] Special heat treatment is divided into a first heat treatment and a second heat treatment; the titanium alloy deposited sample is placed in a heat treatment furnace for the first heat treatment, specifically: the sample is heated at a rate of 10-15℃ / min to (T β -30)℃~(T β The sample is kept at a temperature between -10℃ and 2-4 hours. Afterward, the sample is removed and cooled to room temperature at a rate not less than 60℃ / s. After the first heat treatment, a second heat treatment is performed, specifically by heating the sample at a rate of 25-35℃ / min to (T...). β -400)℃~(T β Keep the sample at a temperature between -300℃ and 4 to 6 hours, then remove it and cool it to room temperature at a rate of no less than 40℃ / s.

[0039] The titanium alloys used in the following examples are all TC11 titanium alloys with an [Al] equivalent of 3.5.

[0040] Example 1

[0041] like Figure 1 and Figure 2As shown, a laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components specifically includes the following steps:

[0042] First, the titanium alloy substrate is fixed in a forming chamber filled with argon gas, the purity of which is not less than 99.99%.

[0043] Second, titanium alloy powder with a particle size of 165μm is loaded into the powder feeding device, and the oxygen content of the titanium alloy powder is not less than 0.13wt.%.

[0044] Third, when the oxygen content in the forming chamber is below 50ppm, laser forming begins, and the titanium alloy powder fed in simultaneously is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed, with a forming time interval of 30 minutes.

[0045] The laser additive manufacturing parameters are as follows: laser scanning power of 2.5kW, scanning rate of 800mm / min, spot diameter of 3mm, powder feeding rate of 15g / min, and overlap spacing of 50%. The laser additive manufacturing process produces a layer with a height of 1mm and a dislocation density of 102. -18 m -2 The titanium alloy sample contained a 100% volume fraction of sheet-like structures with a width of 0.95 μm.

[0046] Fourth, after forming is completed, the sample is removed from the forming chamber and a 10mm×10mm×5mm sample is prepared using a wire cutting device. The phase transformation point T of the titanium alloy sample is determined using a DSC device. β It is 970℃;

[0047] Fifth, based on the phase transformation point measurement results, the sample is placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component. The special heat treatment is divided into a first heat treatment and a second heat treatment. The first heat treatment is as follows: the sample is heated to 940℃ at 10℃ / min and held for 2 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 65℃ / s. After the first heat treatment is completed, the second heat treatment is performed. Specifically, the sample is heated to 570℃ at 30℃ / min and held for 4 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 50℃ / s.

[0048] Example 2

[0049] A laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components specifically includes the following steps:

[0050] First, the titanium alloy substrate is fixed in a forming chamber filled with argon gas, the purity of which is not less than 99.99%.

[0051] Second, titanium alloy powder with a particle size of 275μm is loaded into the powder feeding device, and the oxygen content of the titanium alloy powder is not less than 0.13wt.%.

[0052] Third, when the oxygen content in the forming chamber is below 50 ppm, laser forming begins, and the titanium alloy powder fed in simultaneously is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed, with a forming time interval of 35 minutes.

[0053] The laser additive manufacturing parameters were as follows: laser scanning power of 2.0 kW, scanning rate of 700 mm / min, spot diameter of 3 mm, powder feeding rate of 13 g / min, and overlap distance of 59%. The laser additive manufacturing produced a layer with a thickness of 0.8 mm and a dislocation density of 102. -18.4 m -2 The titanium alloy sample contained a 100% volume fraction of sheet-like microstructure with a width of 1.12 μm.

[0054] Fourth, after forming is completed, the sample is removed from the forming chamber and a 10mm×10mm×5mm sample is prepared using a wire cutting device. The phase transformation point T of the titanium alloy sample is determined using a DSC device. β It is 985℃;

[0055] Fifth, based on the phase transformation point measurement results, the sample is placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component. The special heat treatment is divided into a first heat treatment and a second heat treatment. The first heat treatment is as follows: the sample is heated to 975°C at 15°C / min and held for 4 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 70°C / s. After the first heat treatment is completed, the second heat treatment is performed. Specifically, the sample is heated to 685°C at 35°C / min and held for 6 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 50°C / s.

[0056] Example 3

[0057] A laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components specifically includes the following steps:

[0058] First, the titanium alloy substrate is fixed in a forming chamber filled with argon gas, the purity of which is not less than 99.99%.

[0059] Second, titanium alloy powder with a particle size of 55μm is loaded into the powder feeding device, and the oxygen content of the titanium alloy powder is not less than 0.13wt.%.

[0060] Third, when the oxygen content in the forming chamber is below 50 ppm, laser forming begins, and the titanium alloy powder fed in simultaneously is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed, with a forming time interval of 25 minutes.

[0061] The laser additive manufacturing parameters were as follows: laser scanning power of 1kW, scanning rate of 500mm / min, spot diameter of 0.5mm, powder feeding rate of 10g / min, and overlap spacing of 41%. The laser additive manufacturing produced a layer with a thickness of 0.4mm and a dislocation density of 102. -18.5 m -2 The titanium alloy sample contained a 100% volume fraction of sheet-like structures with a width of 0.85 μm.

[0062] Fourth, after forming is completed, the sample is removed from the forming chamber and a 10mm×10mm×5mm sample is prepared using a wire cutting device. The phase transformation point T of the titanium alloy sample is determined using a DSC device. β It is 990℃;

[0063] Fifth, based on the phase transformation point measurement results, the sample is placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component. The special heat treatment is divided into a first heat treatment and a second heat treatment. The first heat treatment is as follows: the sample is heated to 965℃ at 12℃ / min and held for 3 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 62℃ / s. After the first heat treatment is completed, the second heat treatment is performed. Specifically, the sample is heated to 650℃ at 25℃ / min and held for 5 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 45℃ / s.

[0064] Example 4

[0065] The difference from Example 1 is that in the third step, the forming time interval is 25 minutes.

[0066] The phase transformation point T of the obtained titanium alloy sample β It is 975℃;

[0067] The corresponding special heat treatment process conditions are as follows: The first heat treatment is as follows: the sample is heated to 955℃ at 14℃ / min and held for 4 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 65℃ / s. After the first heat treatment is completed, the second heat treatment is performed as follows: the sample is heated to 665℃ at 28℃ / min and held for 5.5 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 52℃ / s.

[0068] Example 5

[0069] The difference from Example 1 is that in the third step, the forming time interval is 35 minutes.

[0070] The phase transformation point T of the obtained titanium alloy sample β It is 965℃;

[0071] The corresponding special heat treatment process conditions are as follows: The first heat treatment is as follows: the sample is heated to 945℃ at 20℃ / min and held at that temperature for 3.2h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 66℃ / s. After the first heat treatment is completed, the second heat treatment is performed as follows: the sample is heated to 645℃ at 27℃ / min and held at that temperature for 5.8h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 55℃ / s.

[0072] Example 6

[0073] The difference from Example 1 lies in the following: In the third step, the process parameters for laser additive manufacturing are different; the laser additive manufacturing forming parameters are: laser scanning power of 1.5kW, scanning rate of 650mm / min, spot diameter of 1mm, powder feeding rate of 12g / min, and overlap spacing of 49%; the laser additive manufacturing produces a layer height of 0.7mm and a dislocation density of 10. -18.8 m -2 The titanium alloy sample contained a 100% volume fraction of sheet-like structures with a width of 0.92 μm.

[0074] The phase transformation point T of the obtained titanium alloy sample β To determine the phase transformation point T of the obtained titanium alloy sample β It is 995℃;

[0075] The corresponding special heat treatment process conditions are as follows: The first heat treatment is as follows: the sample is heated to 975℃ at 30℃ / min and held for 2.8h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 70℃ / s. After the first heat treatment is completed, the second heat treatment is performed as follows: the sample is heated to 685℃ at 30℃ / min and held for 5.5h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 57℃ / s.

[0076] Example 7

[0077] The difference from Example 1 lies in the following: In the third step, the process parameters for laser additive manufacturing are different; the laser additive manufacturing forming parameters are: laser scanning power of 1.2kW, scanning rate of 550mm / min, spot diameter of 3mm, powder feeding rate of 14g / min, and overlap spacing of 45%; the laser additive manufacturing produces a layer height of 0.6mm and a dislocation density of 10. -18.2 m -2 The titanium alloy sample contained a 100% volume fraction of sheet-like structures with a width of 1.08 μm.

[0078] The phase transformation point T of the obtained titanium alloy sample β To determine the phase transformation point T of the obtained titanium alloy sample β. It is 985℃;

[0079] The corresponding special heat treatment process conditions are as follows: The first heat treatment is as follows: the sample is heated to 960℃ at 32℃ / min and held for 3.6h. The sample is then taken out and cooled to room temperature at a controlled cooling rate of 62℃ / s. After the first heat treatment is completed, the second heat treatment is carried out, which is as follows: the sample is heated to 625℃ at 28℃ / min and held for 5h. The sample is then taken out and cooled to room temperature at a controlled cooling rate of 52℃ / s.

[0080] Example 8

[0081] The difference from Example 1 is that the conditions for the special heat treatment are different.

[0082] Special heat treatment is divided into a first heat treatment and a second heat treatment. The first heat treatment is as follows: the sample is heated to 950℃ at 12℃ / min and held for 3 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of not less than 62℃ / s. After the first heat treatment is completed, the second heat treatment is performed. Specifically, the sample is heated to 630℃ at 28℃ / min and held for 5.7 hours. The sample is then removed and cooled to room temperature at a controlled cooling rate of 45℃ / s.

[0083] Example 9

[0084] The difference from Example 1 is that the conditions for the special heat treatment are different.

[0085] The special heat treatment is divided into a first heat treatment and a second heat treatment. The first heat treatment is as follows: the sample is heated to 950℃ at 14℃ / min and held at that temperature for 3.8h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 60℃ / s. After the first heat treatment is completed, the second heat treatment is performed, which is as follows: the sample is heated to 640℃ at 31℃ / min and held at that temperature for 5.9h. The sample is then removed and cooled to room temperature at a controlled cooling rate of 48℃ / s.

[0086] Comparative Example 1

[0087] The difference between Comparative Example 1 and Example 1 is that the heat treatment method in the fifth step is different. The specific heat treatment method used is as follows:

[0088] Based on the phase transformation point measurement results, the sample was placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component. The special heat treatment was divided into a first heat treatment and a second heat treatment. The first heat treatment was as follows: the sample was heated to 850°C at a rate of 10°C / min and held for 2 hours. The sample was then removed and cooled to room temperature at a controlled cooling rate of 65°C / s. After the first heat treatment was completed, the second heat treatment was performed. Specifically, the sample was heated to 550°C at a rate of 30°C / min and held for 4 hours. The sample was then removed and cooled to room temperature at a controlled cooling rate of 50°C / s.

[0089] The microstructure of the sedimentary sample obtained in Example 1 was observed, and the following results were obtained. Figure 1 The microstructure of the titanium alloy obtained in Example 1 was observed, and the following results were obtained. Figure 2 The tensile strength R of the titanium alloys obtained in the above embodiments and comparative examples was measured. m Yield strength R p0.2 Elongation A (%), fatigue crack propagation rate (da / dN), fracture toughness (K) IC The test results are shown in Table 1.

[0090] As shown in Table 1, Figure 1 and Figure 2 As shown, the specimen of Comparative Example 1 exhibits a fine lamellar structure. Its tensile strength and yield strength are higher than the standard, but it also shows plastic anisotropy in two directions, with da / dN and K... IC It is also below the standard requirement. After adopting this invention, the tensile strength of the specimen is higher than the standard, and the specimen shows no plastic anisotropy in both directions, da / dN and K... IC It also exceeds the standard requirements. Using the method of this invention, high-strength, high-toughness, and high-damage-tolerance laser additive manufacturing titanium alloy components can be directly prepared without changing the existing titanium alloy composition.

[0091] Table 1 Comparison of strength, toughness, and damage tolerance properties of TC11 titanium alloy components manufactured using laser additive manufacturing and those manufactured using laser additive manufacturing after special heat treatment.

[0092]

[0093]

[0094] In step S3, when the laser power, scanning rate, and powder feed rate are too low (less than 1kW), the heat generated during laser additive manufacturing is too high, and the cooling rate is too high, which easily leads to the formation of martensitic structures and cracking of large titanium alloy components. Excessive heat input can also cause severe thermal stress accumulation during component forming, resulting in cracking and rendering the process unsuitable for industrial production. Conversely, when the laser power, scanning rate, and powder feed rate are too high (greater than 2.5kW), scanning rate, and powder feed rate, the heat generated during laser additive manufacturing is too low, resulting in coarse, thin lamellar structures and achieving a dislocation density below 10. -19 m -2 The titanium alloy samples could not provide sufficient driving force for subsequent heat treatment to regulate the microstructure and properties, and could not obtain the biphase microstructure required for high strength, high toughness and high damage tolerance.

[0095] In step S5, when the first heat treatment temperature is below (T) βWhen the temperature is -30℃ and the holding time is less than 2 hours, the fine lamellar structure of the sample coarsens and transforms into a coarse lamellar structure, resulting in tensile properties lower than the standard requirements. When the first heat treatment temperature is higher than (T... β When the second heat treatment temperature is below -10℃ and the holding time is higher than 4 hours, the fine lamellar structure of the sample transforms into a coarse lamellar structure, and the tensile properties of the sample are lower than the standard requirements; when the second heat treatment temperature is lower than (T... β When the temperature is below -400℃ and the holding temperature is below 4h, the sample cannot form a fine αs phase, and the tensile properties of the sample are lower than the standard requirements; when the second heat treatment temperature is higher than (T β At -300℃, if the holding time exceeds 6 hours, the fine αs phase in the sample transforms into coarse αs phase, and the tensile properties of the sample are lower than the standard requirements. The 10 obtained in this application... -19 m -2 Titanium alloy samples, after being subjected to special coupled heat treatment, can yield titanium alloy components with high strength, high toughness, and high damage tolerance.

[0096] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

[0097] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

Claims

1. A laser additive manufacturing method for high-strength, high-toughness, and high-damage-tolerance titanium alloy components, characterized in that, include: S1: Fix the substrate in a forming chamber filled with argon gas; S2: Load titanium alloy powder into the powder feeding device; S3: When the oxygen content in the forming chamber is below 50ppm, laser forming begins, and the synchronously fed titanium alloy powder is melted and deposited layer by layer on the substrate; after one layer is deposited, the next layer is formed after a set time interval. The laser additive manufacturing process parameters during deposition are as follows: laser scanning power of 1.0–2.5 kW, scanning rate of 500–800 mm / min, spot diameter of 1–3 mm, powder feeding rate of 10–15 g / min, and overlap spacing of 41–59%. Laser additive manufacturing during deposition yields dislocation densities greater than 102. -19 m -2 The titanium alloy sample contained a sheet structure with a volume fraction of 100% and a width of 0.85~1.16µm. S4: After deposition is complete, the deposited sample is removed from the forming chamber, cut to prepare a titanium alloy sample, and the phase transformation point T of the titanium alloy sample is determined. β ; S5: Based on T β Based on the phase transformation point measurement results, the sample was placed in a heat treatment furnace for special heat treatment to obtain the final titanium alloy component. Special heat treatment includes a first heat treatment and a second heat treatment; the first heat treatment includes: heating the sample at a rate of 10-15℃ / min to (T β -30)℃~(T β -10℃, hold at that temperature for 2-4 hours, and cool to room temperature at a rate not less than 60℃ / s; after the first heat treatment is completed, perform the second heat treatment, which includes: heating the sample to (T) ℃ at a rate of 25-35℃ / min. β -400)℃~(T β -300)℃, keep warm for 4 to 6 hours, and control the cooling rate to cool to room temperature at a rate of not less than 40℃ / s; This yields an α-structure with a volume fraction of 35%–45% and a width not exceeding 4.52 µm. P A phase with a volume fraction of 55%–65% and a width not exceeding 8.65 µm. S A biphase structure composed of phases.

2. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S3, the laser additive manufacturing process during deposition ensures that the energy density of the titanium alloy deposition zone is 45~67 J / mm². 2 The cooling rate at the leading edge of the solid-liquid molten pool interface is 10. 3.5 ~10 5.5 K / s.

3. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S3, the height of the single-layer deposition layer obtained by laser additive manufacturing during deposition is 0.4~1.0 mm.

4. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S3, the time is set to 25-35 minutes.

5. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S2, the titanium alloy powder has a particle size of 55–275 µm and an oxygen content of not less than 0.13 wt.%.

6. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S2, the Al equivalent in the titanium alloy powder is in the range of 1.9 to 7.

5.

7. The laser additive manufacturing method for a high-strength, high-toughness, and high-damage-tolerance titanium alloy component according to claim 1, characterized in that: In step S1, the purity of argon gas in the forming chamber is not less than 99.99%.

8. A high-strength, high-toughness, high-damage-tolerance titanium alloy component, characterized in that: The high-strength, high-toughness, and high-damage-tolerance titanium alloy component was prepared using the laser additive manufacturing method described in any one of claims 1-7.

Images