High-strength and high-plasticity TA15 titanium alloy laser melting deposition component and preparation method thereof

Abstract

The invention discloses a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component and a preparation method thereof, and an air heat treatment furnace is adopted to carry out double annealing heat treatment on a TA15 titanium alloy laser additive component. The TA15 titanium alloy laser additive component is loaded into an air heat treatment furnace, the temperature is raised to 860-1020 DEG C, the temperature raising rate is 200-300 DEG C / h, the TA15 titanium alloy laser additive component is subjected to air cooling to the room temperature after heat preservation is conducted for 2 h, and the cooling rate is 15-25 DEG C / min; and secondary annealing is conducted, specifically, the TA15 titanium alloy laser additive component is loaded into the air heat treatment furnace and heated to 600 DEG C, heat preservation is conducted for 4 h, then furnace cooling is conducted to the room temperature, and the cooling rate is 6-8 DEG C / min. The TA15 titanium alloy is subjected to two-stage annealing heat treatment, the primary alpha phase content of the TA15 titanium alloy laser melting deposition component is controlled, the microscopic structure is homogenized, and the strong plasticity of the TA15 titanium alloy laser melting deposition component is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and specifically relates to a high-strength and plastic TA15 titanium alloy laser melting deposition component and a preparation method thereof. Background Art

[0002] Laser melting deposition is an advanced additive manufacturing technology that uses a high-energy laser beam to rapidly melt metal powder layer by layer and track by track to achieve near-net-shape forming of complex-shaped parts. It has the advantages of short processing cycle, free design of complex parts, high material utilization, and less subsequent processing. It solves the technical problem of rapid manufacturing of complex-shaped and high-performance metal components.

[0003] TA15 titanium alloy is a medium-strength titanium alloy with excellent comprehensive mechanical and processing properties. It boasts higher strength and weldability than TC4 titanium alloy and can operate at 500°C for 3000 hours. It is widely used in aerospace applications, including engine blades and casings, aircraft sheet metal components, beams, joints, wall panels, and welded load-bearing frames. However, the traditional "melting-blank-forging-machining" process for manufacturing complex TA15 titanium alloy parts presents a series of challenges, including high thermal processing difficulty, long processing cycles, and low material utilization.

[0004] Laser melting deposition, as a highly efficient laser additive manufacturing technology, provides technical support for TA15 titanium alloy in the fields of aviation and aerospace. However, the plasticity and toughness of components made from large-scale and thick TA15 titanium alloys formed by laser melting deposition are significantly reduced, and the elongation and fracture toughness cannot meet application requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength and plastic TA15 titanium alloy laser melting deposition component and a preparation method thereof, aiming to solve the problems of low elongation and poor toughness in forming large-size and large-thickness TA15 titanium alloy laser additive components.

[0006] The present invention is mainly achieved through the following technical solutions: A method for preparing a high-strength and plastic TA15 titanium alloy laser melting and deposition component comprises the following steps: Step S1: preparing a TA15 titanium alloy laser additive component based on a laser melting deposition method; Step S2: using an air heat treatment furnace to perform a double annealing heat treatment on the TA15 titanium alloy laser additive component; Step S21: Perform the first - stage annealing: Load the TA15 titanium alloy laser - additive manufacturing component into an air heat - treatment furnace. Then, raise the temperature of the air heat - treatment furnace to 860 - 1020 °C at a heating rate of 200 - 300 °C / h, hold for 2 h, and then air - cool to room temperature with a cooling rate of 15 - 25 °C / min; Step S22: Perform the second - stage annealing: Load the TA15 titanium alloy laser - additive manufacturing component into an air heat - treatment furnace, raise the temperature to 600 °C, hold for 4 h, and then furnace - cool to room temperature with a cooling rate of 6 - 8 °C / min.

[0007] To better implement the present invention, further, in the step S1, the particle size of the TA15 powder used in the laser melting deposition method is 75 - 178 μm.

[0008] To better implement the present invention, further, in the step S1, in the laser melting deposition method, the laser power is 2.8 - 3.3 KW, the scanning speed is 800 - 1000 mm / min, and the powder feeding rate is 20 - 25 g / min.

[0009] To better implement the present invention, further, the laser power is 3.3 KW, the scanning speed is 1000 mm / min, and the powder feeding rate is 20 g / min.

[0010] To better implement the present invention, further, in the step S21, raise the temperature of the air heat - treatment furnace to 860 °C or 900 °C or 940 °C or 980 °C, and the average value of the cooling rate is 20 °C / min; in the step S22, the average value of the cooling rate is 7 °C / min.

[0011] A high - strength and high - plasticity TA15 titanium alloy laser - melting deposition component is prepared by the above - mentioned preparation method.

[0012] The beneficial effects of the present invention are as follows: (1) The present invention performs two - stage annealing heat - treatment on the TA15 titanium alloy formed by laser melting deposition, which can control the content of primary α - phase in the TA15 titanium alloy laser - melting deposition component, homogenize the microstructure, and significantly improve the strength and plasticity of the TA15 titanium alloy laser - melting deposition component. Therefore, by using double - stage annealing heat - treatment on the TA15 titanium alloy laser - additive manufacturing component, a performance with good combination of strength and plasticity can be obtained.

[0013] (2) Under the condition of air-cooled annealing, the acicular martensite α′ in the TA15 titanium alloy laser additive manufacturing component gradually decomposes, and the average width of the α phase gradually increases. After double annealing heat treatment, the macroscopic grain morphology is mainly columnar crystals, and the banding phenomenon gradually disappears with the increase of the first-stage annealing temperature, and the grain size becomes more uniform. Compared with the non-heat-treated sample, the tensile strength of the TA15 titanium alloy laser melting deposition component treated by the present invention is smaller, but the fracture toughness and elongation are significantly improved. The heat treatment obtains a more stable microstructure, eliminates the residual stress, and enhances the plasticity of the component.

[0014] The present invention significantly improves the strength and plasticity of the TA15 titanium alloy laser melting deposition component, which is beneficial to the application of the laser melting deposition technology in the preparation of large-size and large-thickness titanium alloy components.

[0015] (3) The present invention can regulate the strength, plasticity and toughness of the large-size and large-thickness laser melting deposition formed TA15 titanium alloy. By controlling the content and width of the primary α phase of the laser melting deposition TA15 titanium alloy, a tissue type beneficial to the matching of the strength and toughness indexes of the TA15 titanium alloy is obtained. And through the innovation of the heat treatment system and the optimization of the parameters, on the basis of the excellent tissue type, the strength and toughness levels of the TA15 titanium alloy are further improved at the same time, and a TA15 titanium alloy with high strength and high toughness is obtained, which can be widely used in key load-bearing structural parts such as the fuselage load-bearing frame and beam of the aircraft, and significantly improves the service performance and service life of the aircraft. Description of the Drawings

[0016] Figure 1 SEM images of the TA15 titanium alloy in Examples 2-6; Figure 2 Analysis curves of the yield and tensile strengths in the X direction of Examples 2-6; Figure 3 Analysis curves of the yield and tensile strengths in the Z direction of Examples 2-6; Figure 4 Analysis curves of the elongation in the X direction of Examples 2-6; Figure 5 Analysis curves of the elongation in the Z direction of Examples 2-6; Figure 6 Flow chart of the preparation method of the high-strength and high-plasticity TA15 titanium alloy laser melting deposition component of the present invention. Detailed Embodiments

[0017] Example 1: A preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, as Figure 6 shown, includes the following steps: Step S1: Prepare a laser additive component on a TA15 titanium alloy substrate by using a laser melting deposition forming method with coaxial synchronous powder feeding; Step S2: Use an air heat treatment furnace to perform double annealing heat treatment on the TA15 titanium alloy laser additive component.

[0018] Step S21: The first-stage annealing is as follows: Heat the laser additive component in the furnace to 860 - 1020 °C at a heating rate of 200 - 300 °C / h, hold for 2 h, and then air-cool to room temperature at a cooling rate of 15 - 25 °C / min to ensure that large-size and large-thickness components can be completely heat-penetrated.

[0019] Step S22: The second-stage annealing is as follows: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h, and then furnace-cool to room temperature at a cooling rate of 6 - 8 °C / min to control the microstructure and improve the plasticity and toughness of the component.

[0020] Preferably, in step S1, the particle size of the TA15 powder used in the laser melting deposition forming is 75 - 178 μm.

[0021] Preferably, in step S1, in the laser melting deposition forming, the laser power is 2.8 - 3.3 KW, the scanning speed is 800 - 1000 mm / min, and the powder feeding rate is 20 - 25 g / min. Specifically, in the laser melting deposition forming, the laser power is 3.3 KW, the scanning speed is 1000 mm / min, and the powder feeding rate is 20 g / min.

[0022] Example 2: A preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: Prepare a laser additive component on a TA15 titanium alloy substrate by using a laser melting deposition forming method with coaxial synchronous powder feeding; Step S2: Use an air heat treatment furnace to perform heat treatment on the TA15 titanium alloy laser melting deposition forming component.

[0023] Step S21: Heat the laser additive component in the furnace to 860 °C, hold for 2 h, and then air-cool to room temperature, and the average value of the cooling rate is 20 °C / min.

[0024] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h, and then furnace-cool to room temperature, and the average value of the cooling rate is 7 °C / min.

[0025] Example 3: A preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: Prepare a laser additive component on a TA15 titanium alloy substrate by using the laser melting deposition forming method with coaxial synchronous powder feeding; Step S2: Heat-treat the TA15 titanium alloy laser melting deposition formed component by using an air heat treatment furnace.

[0026] Step S21: Heat the laser additive component in the furnace to 900 °C, hold for 2 h, and then air-cool to room temperature. The average cooling rate is 20 °C / min.

[0027] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h, and then furnace-cool to room temperature. The average cooling rate is 7 °C / min.

[0028] Example 4: A preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: Prepare a laser additive component on a TA15 titanium alloy substrate by using the laser melting deposition forming method with coaxial synchronous powder feeding; Step S2: Heat-treat the TA15 titanium alloy laser melting deposition formed component by using an air heat treatment furnace.

[0029] Step S21: Heat the laser additive component in the furnace to 940 °C, hold for 2 h, and then air-cool to room temperature. The average cooling rate is 20 °C / min.

[0030] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h, and then furnace-cool to room temperature. The average cooling rate is 7 °C / min.

[0031] Example 5: A preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: Prepare a laser additive component on a TA15 titanium alloy substrate by using the laser melting deposition forming method with coaxial synchronous powder feeding; Step S2: Heat-treat the TA15 titanium alloy laser melting deposition formed component by using an air heat treatment furnace.

[0032] Step S21: Heat the laser additive component in the furnace to 980 °C, hold for 2 h, and then air-cool to room temperature. The average cooling rate is 20 °C / min.

[0033] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h, and then furnace-cool to room temperature. The average cooling rate is 7 °C / min.

[0034] Example 6: A preparation method for a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: On a TA15 titanium alloy substrate, a laser additive component is prepared by a laser melting deposition forming method with coaxial and synchronous powder feeding; Step S2: Use an air heat treatment furnace to perform heat treatment on the TA15 titanium alloy laser melting deposition formed component.

[0035] Step S21: Heat the laser additive component in the furnace to 1020 °C, hold for 2 h and then air-cool to room temperature, and the average value of the cooling rate is 20 °C / min.

[0036] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h and then furnace-cool to room temperature, and the average value of the cooling rate is 7 °C / min.

[0037] Comparative example 1: A preparation method for a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, comprising the following steps: Step S1: On a TA15 titanium alloy substrate, a laser additive component is prepared by a laser melting deposition forming method with coaxial and synchronous powder feeding; Step S2: No heat treatment is performed.

[0038] Comparative example 2: A high-strength and high-plasticity TA15 titanium alloy laser melting deposition component, the heat treatment comprising the following steps: Step S1: On a TA15 titanium alloy substrate, a laser additive component is prepared by a laser melting deposition forming method with coaxial and synchronous powder feeding; Step S2: Use an air heat treatment furnace to perform heat treatment on the TA15 titanium alloy laser melting deposition formed component.

[0039] Step S21: Load the laser additive component into the furnace at a temperature of 940 °C, hold for 2 h and then air-cool to room temperature, and the average value of the cooling rate is 20 °C / min.

[0040] Step S22: Heat the laser additive component cooled to room temperature in the furnace to 600 °C, hold for 4 h and then air-cool to room temperature, and the average value of the cooling rate is 20 °C / min.

[0041] Such as Figure 1As shown, (a1) and (a2) therein are respectively the SEM images of the TA15 titanium alloy laser melting deposition components prepared in Example 2 at 500 μm and 50 μm; (b1) and (b2) therein are respectively the SEM images of the TA15 titanium alloy laser melting deposition components prepared in Example 3 at 500 μm and 50 μm; (c1) and (c2) therein are respectively the SEM images of the TA15 titanium alloy laser melting deposition components prepared in Example 4 at 500 μm and 50 μm; (d1) and (d2) therein are respectively the SEM images of the TA15 titanium alloy laser melting deposition components prepared in Example 5 at 500 μm and 50 μm; (e1) and (e2) therein are respectively the SEM images of the TA15 titanium alloy laser melting deposition components prepared in Example 6 at 500 μm and 50 μm.

[0042] Based on the attached Figure 1 It can be analyzed that: after heat treatment, the macroscopic grain morphology is mainly columnar crystals, and the banding phenomenon gradually disappears with the increase of the first-stage annealing temperature, and is almost invisible at 980 °C. With the increase of the first-stage annealing temperature, both the acicular α-phase and the grain boundary α-phase gradually coarsen, the grain size becomes more uniform, and the microstructure tends to be stable. When the first-stage annealing temperature reaches 980 °C, fine secondary α-phases precipitate between the acicular α-phases.

[0043] As Figures 2 - 5 As well as shown in Table 1, compared with Comparative Example 1 without heat treatment, the elongation of Examples 2 - 6 increased by up to 46.6%, and the fracture toughness increased by up to 51.8%. Therefore, the plasticity of the TA15 laser melting deposition components is effectively improved by heat treatment in the present invention. By comparing Comparative Example 2 and Example 4, it is found that: under high-temperature conditions, when the laser additive manufacturing component was loaded into the furnace, the large-thickness TA15 titanium alloy laser additive manufacturing component did not completely heat through, resulting in a mismatch between strength and plastic toughness. Compared with Comparative Example 1 without heat treatment, its elongation and fracture toughness increased less.

[0044] Table 1 Mechanical property test data table The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification and equivalent change made to the above embodiments according to the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A preparation method for a laser melting deposition component of a high-strength and high-plasticity TA15 titanium alloy, characterized in that, It includes the following steps: Step S1: Prepare a TA15 titanium alloy laser additive manufacturing component based on the laser melting deposition method; Step S2: Use an air heat treatment furnace to perform double annealing heat treatment on the TA15 titanium alloy laser additive manufacturing component; Step S21: Perform the first-stage annealing: Load the TA15 titanium alloy laser additive manufacturing component into the air heat treatment furnace, then raise the temperature of the air heat treatment furnace to 860 - 1020 °C at a heating rate of 200 - 300 °C / h, hold for 2 h and then air cool to room temperature, and the cooling rate is 15 - 25 °C / min; Step S22: Perform the second-stage annealing: Load the TA15 titanium alloy laser additive manufacturing component into the air heat treatment furnace and raise the temperature to 600 °C, hold for 4 h and then furnace cool to room temperature, and the cooling rate is 6 - 8 °C / min.

2. The preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component according to claim 1, characterized in that In the said Step S1, the particle size of the TA15 powder used in the laser melting deposition method is 75 - 178 μm.

3. The preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component according to claim 1, characterized in that, In the said Step S1, in the laser melting deposition method, the laser power is 2.8 - 3.3 KW, the scanning speed is 800 - 1000 mm / min, and the powder feeding rate is 20 - 25 g / min.

4. The preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component according to claim 3, wherein The laser power is 3.3 KW, the scanning speed is 1000 mm / min, and the powder feeding rate is 20 g / min.

5. The preparation method of a high-strength and high-plasticity TA15 titanium alloy laser melting deposition component according to claim 1, characterized in that In the said Step S21, raise the temperature of the air heat treatment furnace to 860 °C or 900 °C or 940 °C or 980 °C, and the average value of the cooling rate is 20 °C / min; in the said Step S22, the average value of the cooling rate is 7 °C / min.

6. A high-strength and high-plasticity TA15 titanium alloy component by laser melting deposition, characterized in that, Prepared by the preparation method according to any one of claims 1 - 5.

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