A method for electron beam fusion additive manufacturing of beta titanium alloy components

Abstract

The application discloses a method for electron beam fuse additive manufacturing of beta titanium alloy components, and belongs to the technical field of additive manufacturing. The application aims to solve the problems of long preparation period, low efficiency, low utilization rate, serious oxidation, significant beta spot and poor strength and toughness of the prior art. The method comprises the following steps: pretreating the printing wire and the substrate; establishing a three-dimensional entity model based on the target beta titanium alloy component, performing slice processing on the three-dimensional entity model to generate multi-layer two-dimensional slice data, and then importing the slice data into an electron beam fuse additive manufacturing equipment, and setting a scanning path, preheating parameters and printing process parameters; starting the equipment and performing vacuumization, printing the beta titanium alloy according to the set printing parameters and procedures, completing all layers, and obtaining the beta titanium alloy component. The beta titanium alloy component prepared by the application has high density, and provides a reliable technical approach for the preparation of high-performance beta titanium alloy components in the fields of aviation and aerospace.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and more specifically, relates to a method for electron beam filament additive manufacturing of β-titanium alloy components. Background Technology

[0002] Titanium alloys, due to their low density, high specific strength, and excellent corrosion resistance, have become ideal materials in aerospace, chemical equipment, and biomedical fields. As modern aerospace equipment continuously pursues longer service life and lighter structural weight, increasingly stringent requirements are being placed on the strength and toughness of lightweight structural materials such as titanium alloys. Against this backdrop, developing large high-strength titanium alloy components suitable for aircraft and capable of replacing ultra-high-strength steel has become one of the important directions in current materials research. Currently, the room temperature tensile strength of commonly used high-strength β-type titanium alloys in China after solution aging treatment is generally in the range of 1050–1300 MPa. Traditional preparation methods for these alloys mostly rely on forging processes; however, this method has significant limitations: long production cycles, high processing costs, and when the content of β-stabilizing elements in the alloy is high, compositional segregation defects such as β spots are prone to occur, affecting the material's uniformity and performance stability. Summary of the Invention

[0003] This invention aims to address the problems of long production cycles, low efficiency, low utilization rate, severe oxidation, significant β spots, and poor strength and toughness in the preparation of β titanium alloys using existing technologies, and provides a method for electron beam fused wire additive manufacturing of β titanium alloy components.

[0004] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a method for electron beam filament additive manufacturing of β-titanium alloy components, comprising the following steps: Step 1: Pre-treat the printing filament and substrate; Step 2: Establish a three-dimensional solid model based on the target β titanium alloy component, slice the three-dimensional solid model to generate multi-layer two-dimensional slice data, and then import the slice data into the electron beam fused wire additive manufacturing equipment, and set the scanning path, preheating parameters and printing process parameters. Step 3: Turn on the equipment and evacuate the vacuum. Print β titanium alloy according to the set printing parameters and program. Complete all layers to obtain β titanium alloy components with good forming, dense structure and excellent performance. The filament composition is Al 2.6wt.%-3.4wt.%, Fe 1.6wt.%-2.2wt.%, V 9wt.%-11wt.%, O≤0.09wt.%, N≤0.01wt.%, C≤0.01wt.%, H≤0.01wt.%, with the remainder being Ti and unavoidable impurity elements.

[0005] Further specified, the diameter of the filament is 0.6 mm to 4.2 mm.

[0006] Further specified, the substrate is a TA1 pure titanium substrate, the additive substrate size is 150mm×10mm×10mm, and the TA1 substrate composition contains 99.9wt.% Ti element and other avoidable impurity elements.

[0007] Further specifying, the substrate pretreatment steps are as follows: polish the surface of the TA1 substrate until it is smooth and clean, then wipe it with acetone, and dry it at a constant temperature of 40℃-60℃.

[0008] Further specifying the pretreatment steps for the printing filament, the printing filament is as follows: first, it is acid-washed to remove the surface oxide film, then soaked and cleaned with acetone, and dried at a constant temperature of 40℃-60℃.

[0009] Further specified, vacuum was applied to 9.9 × 10⁻⁶. -3 Pa.

[0010] Furthermore, the angle between the filament feed nozzle and the TA1 substrate is 40°-50°.

[0011] Furthermore, the length of the printing filament feed nozzle to the electron beam center axis is specified as 5mm-15mm.

[0012] Further specified preheating parameters: acceleration voltage 60kV, focusing current 1030mA, electron beam current 20mA-40mA, preheating printing speed 300mm / min-600mm / min, and scanning path is a cyclic reciprocating linear motion path.

[0013] Further specify the printing process parameters: acceleration voltage is 60kV, focusing current is 1030mA, electron beam current is 35mA-60mA, printing speed is 300mm / min-600mm / min, filament feed speed is 1m / min-3m / min, knob control speed coefficient is 100%, interlayer cooling time is 5s-30s, and the scanning path is a cyclic reciprocating linear motion path.

[0014] Another object of the present invention is to provide β-titanium alloy components manufactured by any of the methods described above.

[0015] Compared with the prior art, the present invention has the following beneficial effects: By utilizing the high vacuum environment and rapid near-net-shape forming characteristics, it is possible to effectively avoid contamination and inclusions in highly reactive titanium alloys, significantly improve the internal quality of components, and greatly reduce subsequent machining requirements and material waste.

[0016] The high temperature gradient and rapid cooling conditions created by the method of this invention can effectively refine the grain structure, improve the solid solubility of elements, and suppress macroscopic segregation. At the same time, the strong penetrability of the high-energy electron beam promotes interlayer remelting, realizes conformal in-situ heat treatment, and is conducive to promoting the precipitation of uniformly distributed ultrafine α phase in β titanium alloy, thereby significantly improving the strength, toughness, and fatigue performance of the component.

[0017] Compared with additive manufacturing technology using powder as raw material, the filament raw material used in this invention has a more uniform composition, lower cost, and higher deposition efficiency. Furthermore, the residual stress level during the forming process is significantly reduced, which helps to achieve high-precision, high-performance, and low-cost manufacturing of large and complex components. This provides a reliable technical approach for the preparation of high-performance β-titanium alloy components in aerospace and other fields.

[0018] This invention uses filament as raw material, which has the significant advantages of low cost and high deposition efficiency, and is suitable for rapid and direct forming of complex β-titanium alloy components. By precisely controlling the process parameters, it is possible to stably obtain well-formed, densely structured, and mechanically excellent parts.

[0019] This invention uses a high-power, high-energy-efficiency electron beam as a heat source and is adapted to a high-vacuum processing environment. This technical solution can not only achieve conformal in-situ heat treatment through multi-layer remelting effect, effectively eliminating structural defects such as β spots, but also fundamentally avoid the oxidation of materials during the printing process. Ultimately, it can achieve near-net-shape forming and shape-property integrated preparation of large and complex metal components, and overcome the technical bottleneck of large-size β titanium alloy component preparation.

[0020] The β-titanium alloy components prepared by this invention have high density, exceeding 99.7% as tested, and are free from obvious defects such as voids and cracks. The deposited material exhibits excellent comprehensive mechanical properties, with a tensile strength of up to 1034 MPa and an elongation of up to 10.3%. In particular, the interface between the deposited β-titanium alloy and the substrate can achieve a smooth transition without cracks or warping, overcoming the problems of high cost and difficulty in large-scale production caused by relying on substrates of the same composition.

[0021] The technical solution provided by this invention has good universality and practicality. Its process principle is also applicable to the rapid preparation of other high-melting-point and high-activity alloys and the near-net-shape forming of complex structures with integrated structure and performance, and has broad application prospects.

[0022] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0023] Figure 1 The TB6 titanium alloy component prepared by electron beam fused wire additive manufacturing in Example 1; Figure 2 The microstructure of the upper, middle and lower regions of TB6 titanium alloy prepared by electron beam fused wire additive manufacturing in Example 1; Figure 3 The TB6 titanium alloy component prepared by electron beam fused wire additive manufacturing in Example 2; Figure 4 The microstructure of the upper, middle, and lower regions of TB6 titanium alloy prepared by electron beam fused wire additive manufacturing in Example 2. Figure 5 The TB6 titanium alloy component prepared by electron beam fused wire additive manufacturing in Example 3; Figure 6 The microstructure of the upper, middle, and lower regions of TB6 titanium alloy prepared by electron beam fused wire additive manufacturing in Example 3. Figure 7 XRD patterns of TB6 titanium alloys prepared by electron beam fused wire additive manufacturing in Examples 1-3; Figure 8 IPF diagrams and corresponding phase diagrams of TB6 titanium alloys prepared by electron beam fused wire additive manufacturing in Examples 1-3; Figure 9 Tensile stress-elongation curves of TB6 titanium alloys prepared in Examples 1-3. Detailed Implementation

[0024] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0025] Example 1: The method for electron beam fused wire additive manufacturing of TB6 titanium alloy components in this example is achieved through the following steps: (1) Pretreatment of TB6 wire and TA1 additive substrate: pickling of TB6 wire with a diameter of 1.6 mm to remove surface oxide film, and then soaking and cleaning with acetone to ensure that there is no oil or impurities on the surface of TB6 wire. Grinding of the surface of TA1 pure titanium substrate with a size of 150 mm × 100 mm × 10 mm with an angle grinder until the surface is smooth and clean, and then wiping the surface with acetone to remove oil and impurities on the substrate surface. Placing TB6 alloy wire and TA1 substrate in a drying oven and drying at a constant temperature of 50°C for 5 hours to remove moisture in TB6 alloy wire and TA1 pure titanium substrate and reduce residual deformation in raw materials. Installing the treated TB6 alloy wire on the wire feeding mechanism of the electron beam fused wire deposition equipment, and clamping the treated TA1 pure titanium substrate on the motion system in the vacuum chamber of the equipment. (2) Establish a three-dimensional solid model based on the target TB6 titanium alloy component. Slice the three-dimensional solid model to generate multi-layer two-dimensional slice data. Then import the slice data into the electron beam filament additive manufacturing equipment, set the scanning path, preheating parameters and printing process parameters; turn on the equipment and evacuate to 9.9×10 -3 Pa; (3) Set the following preheating parameters: acceleration voltage is 60kV, focusing current is 1030mA, electron beam current is 25mA, preheating printing speed is 500mm / min, and the scanning path is a cyclic linear motion path according to the reciprocating scanning mode. Edit the printing program under the preheating parameters in the automatic operation window of the electron beam fused wire deposition equipment and start preheating.

[0026] (4) After preheating, the printing of TB6 titanium alloy components began. The following printing parameters were set: accelerating voltage of 60kV, focusing current of 1030mA, electron beam current of 55mA, printing speed of 500mm / min, wire feed speed of 1.2m / min, knob control speed coefficient of 100%, interlayer cooling time of 10s, and scanning path of cyclic linear motion. The TB6 titanium alloy produced by electron beam filament additive manufacturing was obtained, with a length of 85mm, a height of 58mm, and a width of 9.8mm. A physical image of the TB6 titanium alloy is shown below. Figure 1 As shown, in Figure 1 In (b), it can be observed that along the deposition height direction, the original β grains gradually change from a near-equiaxed morphology at the bottom to a columnar morphology, and the columnar original β grains at the top become even coarser.

[0027] Figure 7 The phase composition of the material in Example 1 is shown, revealing that the microstructure consists of an α phase with an HCP structure and a small amount of a β phase with a BCC structure. Figure 8 (c, f) shows the volume fractions of the α and β phases in Example 1, revealing that the β phase accounted for only 6.8%.

[0028] Figure 2 The microstructure of the upper, middle, and lower regions in Example 1 is shown. The α-lamellae at the top are finer, while those in the middle and bottom regions are coarser, forming a gradient structure from bottom to top. This is likely because the higher heat input causes the middle and bottom regions to experience more thermal history, inducing α-lamellae growth.

[0029] Figure 9 The tensile properties of the TB6 titanium alloy specimen deposited in Example 1 are shown under loading parallel to the deposition height direction. From Figure 8 It can be seen that the deposited TB6 titanium alloy exhibits excellent tensile strength, with a tensile strength of 1034 MPa and an elongation of up to 10.3%.

[0030] Example 2 The difference between this embodiment and embodiment 1 is as follows: (3) The preheating parameters are: acceleration voltage of 60kV, focusing current of 1030mA, electron beam current of 20mA, and preheating printing speed of 400mm / min; (4) The parameters for electron beam filament additive manufacturing are: acceleration voltage of 60kV, focusing current of 1030mA, electron beam current of 50mA, printing speed of 400mm / min, wire feeding speed of 1.8m / min, knob control speed coefficient of 100%, and interlayer cooling time of 20s. TB6 titanium alloy manufactured by electron beam filament additive manufacturing is obtained, with a length of 85mm, a height of 60mm, and a width of 8.6mm. The actual picture of the TB6 titanium alloy is shown below. Figure 3 As shown, in Figure 3 In (b), it can be seen that the original β grains gradually change from a near-equiaxed morphology at the bottom to a columnar morphology, and the columnar original β grains at the top become further coarsened. Meanwhile, in... Figure 3 (b) The observed original β-columnar crystal size appears to be larger than Figure 1 (b) Smaller, due to the reduction in heat input, which weakens heat accumulation in the deposit, thereby inducing refinement of the original β crystals.

[0031] Figure 7 The phase composition of the material in Example 2 is shown, revealing that the microstructure consists of an α phase with an HCP structure and a small amount of a β phase with a BCC structure. Figure 8 (b, e) shows the volume fractions of α and β phases in Example 2. It is found that the β phase is about 12.7%. Obviously, the volume fraction of β phase in this example is increased compared to Example 1. This is because the reduction in heat input increases the heat dissipation rate of TB6, and the faster cooling rate allows more β phase to remain at room temperature.

[0032] Figure 4The microstructure of the upper, middle, and lower regions in Example 2 is shown. The α lamellae at the top and bottom are finer, while those in the middle are slightly coarser. This is because the reduced heat input leads to faster heat dissipation at the bottom, making it difficult to maintain the high temperature that promotes α grain growth in the bottom region for a long time. In the top region, the lack of a complete thermal history makes it difficult for α grains to grow. The higher heat accumulation and multiple thermal cycles in the middle region induce α grain coarsening.

[0033] Figure 9 The tensile properties of the TB6 titanium alloy specimen deposited in Example 2 are shown under loading parallel to the deposition height direction. From Figure 9 It can be seen that the deposited TB6 titanium alloy exhibits excellent tensile strength, with a tensile strength of 1099 MPa and an elongation of up to 9.0%.

[0034] Example 3: The difference between this embodiment and embodiment 1 is as follows: (3) The preheating parameters are: accelerating voltage of 60kV, focusing current of 1030mA, electron beam current of 30mA, and preheating printing speed of 450mm / min; (4) The parameters for electron beam filament additive manufacturing are: accelerating voltage of 60kV, focusing current of 1030mA, electron beam current of 45mA, printing speed of 600mm / min, wire feeding speed of 1.5m / min, knob control speed coefficient of 100%, and interlayer cooling time of 30s. TB6 titanium alloy manufactured by electron beam filament additive manufacturing is obtained. The actual picture of the TB6 titanium alloy is shown below. Figure 5 As shown, it is 83mm long, 64mm high, and 8.1mm wide. A picture of the actual TB6 titanium alloy is shown below. Figure 5 As shown, in Figure 5 In (b), it can be seen that the original β grains gradually change from a near-equiaxed morphology at the bottom to a columnar morphology, and the columnar original β grains at the top become further coarsened. Meanwhile, in... Figure 5 (b) The observed size of the original β columnar crystals appears to have decreased further due to the reduced heat input, which weakens heat accumulation in the deposit and thus induces refinement of the original β crystals.

[0035] Figure 7 The phase composition of the material in Example 3 is shown, revealing that the microstructure consists of an α phase with an HCP structure and a small amount of a β phase with a BCC structure. Figure 8 (a, d) shows the volume fractions of the α and β phases in Example 3. It is found that the β phase is about 14.8%. Obviously, the volume fraction of the β phase is further increased in this example. This is because the further reduction of heat input increases the heat dissipation rate of TB6, and the faster cooling rate allows more β phase to be retained to room temperature.

[0036] Figure 6The microstructure of the upper, middle, and lower regions in Example 3 is shown. The α lamellae at the top and bottom are finer, while those in the middle are slightly coarser. This is because the reduced heat input leads to faster heat dissipation at the bottom, making it difficult to maintain the high temperature that promotes α grain growth in the bottom region for a long time. In the top region, the lack of a complete thermal history makes it difficult for α grains to grow. The higher heat accumulation and multiple thermal cycles in the middle region induce α grain coarsening.

[0037] Figure 9 The tensile properties of the TB6 titanium alloy specimen deposited in Example 3 are shown under loading parallel to the deposition height direction. From Figure 9 It can be seen that the deposited TB6 titanium alloy exhibits excellent tensile strength, with a tensile strength of 1178 MPa and an elongation of up to 8.9%.

[0038] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A method for electron beam fused wire additive manufacturing of β-titanium alloy components, comprising the following steps: Step 1: Pre-treat the printing filament and substrate; Step 2: Establish a three-dimensional solid model based on the target β titanium alloy component, slice the three-dimensional solid model to generate multi-layer two-dimensional slice data, and then import the slice data into the electron beam fused wire additive manufacturing equipment, and set the scanning path, preheating parameters and printing process parameters. Step 3: Turn on the equipment and evacuate the vacuum. Print β titanium alloy according to the set printing parameters and program. Complete all layers to obtain β titanium alloy components. The wire material composition is as follows: Al 1.5wt.%-6.5wt.%, Mo 0wt.%-5.0wt.%, Cr 0wt.%-4.0wt.%, Fe 0.3wt.%-3.5wt.%, Zr 0wt.%-1.2wt.%, V 5wt.%-15wt.%, O≤0.09wt.%, N≤0.01wt.%, C≤0.01wt.%, H≤0.01wt.%, with the remainder being Ti and unavoidable impurity elements. The substrate is a TA1 substrate; The substrate pretreatment steps are as follows: polish the surface of the TA1 substrate until it is smooth and clean, then soak and wipe it with acetone, and dry it at a constant temperature of 40℃-60℃. The angle between the filament feed nozzle and the TA1 substrate is 40°-50°; The length of the printing filament feed nozzle to the electron beam center axis is 5mm. 15mm; Preheating parameters: accelerating voltage is 60kV, focusing current is 1030mA, electron beam current is 20mA-40mA, preheating printing speed is 300mm / min-600mm / min, and scanning path is a cyclic reciprocating linear motion path; Printing process parameters: accelerating voltage 60kV, focusing current 1030mA, electron beam current 35mA 60mA, printing speed 300mm / min The speed is 600 mm / min, the wire feeding speed is 1 m / min-3 m / min, the speed coefficient controlled by the knob is 100%, the interlayer cooling time is 5 s-30 s, and the scanning path is a cyclic reciprocating linear motion path.

2. The method according to claim 1, characterized in that, The diameter of the wire is 0.6 mm to 4.2 mm.

3. The method according to claim 1, characterized in that, The pretreatment steps for printing filament are as follows: First, the printing filament is acid-washed to remove the surface oxide film, then soaked and cleaned with acetone, and dried at a constant temperature of 40℃-60℃.

4. A β-titanium alloy component manufactured by the method of any one of claims 1-3.

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