Titanium alloy wire, method of making and use thereof

Abstract

The application provides a titanium alloy wire and a preparation method and application thereof, and comprises the following steps: preparing a titanium diboride suspension and placing the suspension in a coating groove; immersing the titanium alloy wire into the titanium diboride suspension through a guide wheel, then drying, coiling and packaging. In the preparation method, the titanium diboride is coated on the surface of the titanium alloy wire, and in the subsequent melting deposition process, the titanium diboride is melted and enters the molten pool, so that the deposited grain of the titanium alloy can be significantly refined, and the grain size can be reduced by one order of magnitude; in the melting process, the ceramic phase TiB with high strength and high rigidity can be generated, so that the strength, hardness and wear resistance of the titanium alloy are improved, and the tensile strength is increased by more than 5%; in the preparation method, after the part is prepared through direct energy deposition, the titanium alloy grain can be prevented from becoming coarse in the heat treatment process, and the mechanical properties of the titanium alloy part can be effectively maintained.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a titanium alloy wire, its preparation method, and its application. Background Technology

[0002] Additive manufacturing, commonly known as 3D printing, is a manufacturing technology that integrates computer-aided design, material processing and forming technologies. Based on digital model files, it uses software and CNC systems to deposit specialized metallic, non-metallic, and medical / biomaterials layer by layer through methods such as extrusion, sintering, melting, photopolymerization, and spraying to create physical objects. Direct energy deposition (DED) technology, as an important metal additive manufacturing method, features high processing efficiency, large processing size, and flexible manufacturing. It can be applied to the additive manufacturing of large parts, rapid prototyping of new products, and mobile maintenance of weaponry, achieving product manufacturing, processing, and remanufacturing, and has broad application prospects. The corresponding manufacturing processes for DED technology are wire arc additive manufacture (WAAM), electron beam freeform fabrication (EBF3), and laser engineered net shaping (LENS).

[0003] Titanium alloys, due to their numerous advantages such as low density, high specific strength, high temperature resistance, oxidation resistance, and corrosion resistance, have become key structural materials for advanced aircraft and aero-engines. Currently, the preparation of large, complex integral titanium alloy key structural components mainly employs the traditional "forging + machining" method, which faces technical challenges such as low material utilization, long processing cycles, and difficulty in controlling the uniformity of microstructure and properties. Furthermore, forging and machining have very strict requirements on site, equipment, and tooling, resulting in high production costs and low rapid response capabilities. Titanium alloy direct energy deposition additive manufacturing technology uses titanium alloy wire as raw material, rapidly manufacturing complex structural parts by molten wire layer-by-layer deposition. It features fast deposition speed, high material utilization, excellent component mechanical properties, and is insensitive to the dimensions of the formed parts, providing an efficient, fast, and low-cost manufacturing approach for the development of large, complex integral titanium alloy components.

[0004] Currently, the titanium alloy wires used in DED (Depth-Edge Additive Manufacturing) technology are mostly standard welding-grade titanium alloy wires. However, DED differs from welding; to achieve stable melt forming, the energy input during the process is increased, and compared to welding, the energy input in DED technology can last for several hours. This energy accumulation process leads to coarse titanium alloy grains, directly affecting the mechanical properties of the parts. Furthermore, due to the complex structure of most parts, forging deformation to break up the grains after forming is not possible, resulting in performance weaker than traditional forgings. Regardless of whether the heat source in DED technology uses an electric arc, plasma arc, or electron beam, this problem cannot be solved. With the rapid development of titanium alloy DED additive manufacturing technology, it is necessary to conduct in-depth research to address the issues of grain coarsening and decreased mechanical properties during the deposition process from the raw materials stage. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a titanium alloy wire based on direct energy deposition (DED) technology, its preparation method, and its applications. Specifically, titanium diboride is coated onto the surface of a titanium alloy wire using a suspension. During the molten deposition process, the titanium diboride melts along with the wire and enters the molten pool, forming crystal nuclei. This significantly refines the grains of the deposited titanium alloy and generates a ceramic phase, TiB, which possesses high strength and stiffness. Furthermore, it inhibits grain coarsening during subsequent heat treatment, thereby improving the strength, hardness, and wear resistance of the titanium alloy.

[0006] To achieve the above objectives, the solution of the present invention is:

[0007] On one hand, the present invention provides a method for preparing titanium alloy wire, which includes the following steps:

[0008] (1) Prepare a titanium diboride suspension and place it in a coating tank;

[0009] (2) Pull out one end of the titanium alloy wire and immerse it in the coating tank containing titanium diboride suspension through the first guide wheel on one side of the upper end of the coating tank. The second, third and fourth guide wheels are arranged vertically in an inverted triangle in the coating tank. The second and third guide wheels are located on the same horizontal plane and parallel to the bottom of the coating tank. The titanium alloy wire passes through the lower end of the second and third guide wheels to ensure that the titanium alloy wire passes parallel in the titanium diboride suspension. The residence time of the titanium alloy wire in the coating tank is ensured by adjusting the distance between the second, third and fourth guide wheels.

[0010] (3) The coated titanium alloy wire enters the drying oven through the fifth guide wheel on the other side of the coating tank, then is coiled and packaged.

[0011] Preferably, in step (1), the titanium diboride used in the titanium diboride suspension has an oxygen content ≤0.8%, a carbon content ≤0.5%, a purity ≥98.5%, and an average particle size of 5-10 μm.

[0012] Preferably, in step (2), the diameter of the titanium alloy wire is 0.1-5 mm.

[0013] Preferably, in step (3), the drying temperature is 200-300℃.

[0014] On the other hand, the present invention provides a titanium alloy wire obtained by the above-described preparation method.

[0015] In another aspect, the present invention provides an application of the above-mentioned titanium alloy wire, specifically its application in additive manufacturing.

[0016] Due to the adoption of the above solution, the beneficial effects of the present invention are:

[0017] First, in the preparation method of the present invention, titanium diboride is coated on the surface of titanium alloy wire. During the subsequent melt deposition process, the titanium diboride melts and enters the molten pool, which can significantly refine the grains of the deposited titanium alloy, and the grain size can be reduced by an order of magnitude. It can also generate a ceramic phase TiB with high strength and high stiffness during the melting process, thereby improving the strength, hardness and wear resistance of the titanium alloy, and increasing the tensile strength by more than 5%.

[0018] Secondly, the preparation method of the present invention, after being deposited into parts by direct energy deposition, can prevent the coarsening of titanium alloy grains during heat treatment, thus effectively maintaining the mechanical properties of titanium alloy parts.

[0019] Third, the preparation method of the present invention is simple to operate, low in cost, and does not have a significant impact on the cost of titanium alloy wire.

[0020] Fourth, the preparation method of the present invention can be applied to a variety of direct energy deposition techniques, including but not limited to electric arc, plasma arc, laser, electron beam, or deposition techniques of two or more combinations of the above methods. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the preparation process of the titanium alloy wire of the present invention.

[0022] Figure description: 1-Raw material roll, 2-Titanium alloy wire, 3-First guide wheel, 4-Coating tank, 5-Second guide wheel, 6-Third guide wheel, 7-Fourth guide wheel, 8-Titanium diboride suspension, 9-Agitator, 10-Fifth guide wheel, 11-Oven, 12-Finished product roll. Detailed Implementation

[0023] This invention provides a titanium alloy wire, its preparation method, and its application.

[0024] like Figure 1 As shown, the method for preparing titanium alloy wire based on direct energy deposition technology of the present invention includes the following steps:

[0025] (1) According to the standard for welding wire, the titanium alloy raw materials are smelted, billeted, forged, rolled, annealed and drawn to obtain the titanium alloy wire with the required diameter, up to the pre-coiling process. Alternatively, titanium alloy wire conforming to GB / T3623-2007 can be used directly as raw material, and the process does not change the diameter of the titanium alloy wire;

[0026] (2) Prepare titanium diboride suspension 8 in coating tank 4 according to the total mass of the drawn wire. After preparation, stir thoroughly. During use, a stirrer 9 is installed in coating tank 4 to prevent titanium diboride suspension 8 from depositing at the bottom of coating tank 4.

[0027] (3) Pull one end of the titanium alloy wire 2 out from the raw material roll 1, pass through the first guide wheel 3 on one side of the upper end of the coating tank 4 and immerse it in the coating tank 4 containing titanium diboride suspension 8. The second guide wheel 5, the third guide wheel 6 and the fourth guide wheel 7 are arranged vertically in an inverted triangle in the coating tank 4. The second guide wheel 5 and the third guide wheel 6 are located on the same horizontal plane and parallel to the bottom of the coating tank 4. The titanium alloy wire 2 passes through the lower end of the second guide wheel 5 and the third guide wheel 6 to ensure that the titanium alloy wire 2 passes parallel in the titanium diboride suspension 8. By adjusting the distance between the second guide wheel 5, the third guide wheel 6 and the fourth guide wheel 7, it can be ensured that the titanium alloy wire 2 passes parallel in the coating tank 4.

[0028] (4) After coating, the titanium alloy wire 2 enters the oven 11 for dehydration through the fifth guide wheel 10 on the other side of the upper end of the coating tank 4. The oven temperature is 200-300℃, which can quickly dry the moisture on the surface of the titanium alloy wire 2, so that titanium diboride can be evenly attached to the surface of the titanium alloy wire 2.

[0029] (5) The dried titanium alloy wire 2 is coiled and packaged through the finished roll 12 to obtain titanium alloy wire based on direct energy deposition technology, which can be used for DED technology deposited parts.

[0030] In step (1), this invention does not require special customization of the composition and specifications of the titanium alloy wire. It can flexibly and directly use wire that meets national standards or manufacture titanium alloy wire according to the technical requirements of the parts, and is applicable to all grades of titanium alloy wire. The composition of the titanium alloy can be determined by referring to relevant welding wire standards or international standards according to the corresponding grade.

[0031] In step (2), the titanium diboride suspension is prepared as follows: the ratio of titanium diboride to water is 1 kg of titanium diboride to 10-30 liters of purified water. This invention does not require specially customized titanium diboride raw materials; conventional high-purity titanium diboride can be used, and separate preparation is unnecessary. The titanium diboride suspension has a purity ≥98.5%, oxygen content ≤0.8%, carbon content ≤0.5%, and water content ≤0.2%. After synthesis and crushing, it is prepared in powder form with an average particle size (D50) of 5-10 μm.

[0032] Compared to conventional core preparation methods, this invention utilizes a specially formulated titanium diboride suspension, which allows for easy coating of titanium diboride onto the surface of titanium alloy wire. The concentration of the titanium diboride suspension is directly proportional to the coating ratio; that is, the higher the concentration, the higher the proportion coated onto the titanium alloy wire. Conversely, the winding speed of the titanium alloy wire is inversely proportional to the coating ratio; that is, the higher the winding speed, the shorter the residence time of the titanium alloy wire in the coating tank, resulting in a lower coating ratio. Furthermore, this invention boasts low preparation costs and simple operation.

[0033] The titanium diboride coated on the surface of titanium alloy wire in this invention enters the molten pool as the titanium alloy wire melts during the DED deposition process, and eventually solidifies into the internal structure of the part, thus hindering grain growth and coarsening during the multi-layer cladding process.

[0034] The titanium alloy wire deposited in this invention can effectively inhibit grain growth during subsequent heat treatment due to the presence of borides, ensuring that the mechanical properties of the parts do not decrease.

[0035] The technical content of the present invention will be further described below with reference to the embodiments. The following embodiments are illustrative and not limiting, and should not be used to limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0036] Example 1:

[0037] The method for preparing titanium alloy wire based on direct energy deposition technology in this embodiment includes the following steps:

[0038] (1) Use one roll (50 kg) of TC4 titanium alloy wire with a diameter of 2 mm conforming to GB / T 3623-2007 standard. Use 1 kg of titanium diboride with a purity of 99%.

[0039] (2) Prepare titanium diboride suspension in coating tank according to the total mass of drawn wire. The ratio of titanium diboride to water is 1 kg of titanium diboride to 30 liters of pure water. After preparation, stir thoroughly. During use, a stirrer is set in coating tank and works continuously at a speed of 20 rpm to prevent titanium diboride suspension from settling to the bottom of coating tank.

[0040] (3) Pull one end of the titanium alloy wire out of the raw material roll and immerse it in the coating tank containing titanium diboride suspension through the first guide wheel on the upper side of the coating tank. The second, third and fourth guide wheels are arranged vertically in an inverted triangle in the coating tank. The second and third guide wheels are located on the same horizontal plane and parallel to the bottom of the coating tank. The titanium alloy wire passes through the lower end of the second and third guide wheels to ensure that the titanium alloy wire passes parallel in the titanium diboride suspension. The residence time of the titanium alloy wire in the coating tank is fixed by adjusting the distance between the second, third and fourth guide wheels to 500mm.

[0041] (4) After coating, the titanium alloy wire enters the drying oven through the fifth guide wheel on the other side of the coating tank to dehydrate. The temperature of the drying oven is 200℃, which quickly dries the moisture on the surface of the titanium alloy wire, so that titanium diboride can be evenly attached to the surface of the titanium alloy wire.

[0042] (5) The dried titanium alloy wire is coiled and packaged using a finished roll.

[0043] The prepared titanium alloy wire was loaded into an electron beam wire feeder for printing. Main printing process parameters: vacuum degree 5×10⁻⁶. -2 The experimental setup was as follows: Pa, accelerating voltage Ua = 60 kV, electron beam current Ib = 50 mA, wire feed speed Vs = 900 mm / min, and molten wire deposition speed V = 150 mm / min. A titanium alloy experimental piece with a length, width, and height of 100 mm was obtained. This piece was then solution-treated below the (α+β) / β phase transformation point for 5 h, air-cooled, and then aged at 650℃ for 8 h, followed by air cooling. Standard samples were prepared by wire cutting and precision machining. Metallographic observation revealed a predominantly equiaxed grain structure with a grain size of 0.5-1 mm. The tensile properties of the experimental piece were also tested.

[0044] Comparative Example 1:

[0045] A 50 kg roll of TC4 titanium alloy wire with a diameter of 2 mm, conforming to GB / T 3623-2007 standard, was directly loaded into the electron beam wire feed printer without any treatment. Main printing process parameters: Vacuum degree 5×10⁻⁶. -2The parameters were: Pa, accelerating voltage Ua = 60 kV, electron beam current Ib = 50 mA, wire feed speed Vs = 900 mm / min, and molten wire deposition speed V = 150 mm / min. A titanium alloy experimental piece with a length, width, and height of 100 mm was obtained. The piece was then solution-treated below the (α+β) / β phase transformation point for 5 h, air-cooled, and then aged at 650℃ for 8 h, followed by air cooling. Standard samples were prepared by wire cutting and precision machining. Metallographic observation revealed equiaxed and columnar crystals, with columnar crystal sizes exceeding 2 mm. The tensile properties of the experimental piece were then tested.

[0046] The test results of the test specimens of Example 1 and Comparative Example 1 of the present invention are shown in Table 1.

[0047] Table 1 Comparison of Mechanical Properties of Titanium Alloy Specimens Fabricated by Electron Beam Fused Wire

[0048]

[0049] The comparison results of Example 1 and Comparative Example 1 show that the TC4 titanium alloy test piece manufactured by electron beam fusion wire according to Example 1 of the present invention has better performance than the test piece prepared by conventional titanium alloy wire using the same process.

[0050] Compared with the comparative example, the grain size of the embodiment was increased from 2 mm to 0.5-1 mm, and the average tensile strength was increased by 7.8%. Therefore, the titanium alloy wire prepared by the present invention has the advantages of low cost, high efficiency and obvious effect. It can meet the needs of all DED technology for preparing titanium alloy parts and has broad application prospects. With the rapid development of DED additive manufacturing technology, it can create good economic benefits for social development.

[0051] The above description of the embodiments is intended to enable those skilled in the art to understand and use the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the principles of the present invention, without departing from the scope of the invention, should be within the protection scope of the present invention.

Claims

1. A method for preparing titanium alloy wire, characterized in that: It includes the following steps: (1) Prepare titanium diboride suspension (8) and place it in coating tank (4); (2) Pull out one end of the titanium alloy wire (2) and immerse it in the coating tank (4) containing titanium diboride suspension (8) through the first guide wheel (3) on the upper side of the coating tank (4). The second guide wheel (5), the third guide wheel (6), and the fourth guide wheel (7) are arranged vertically in an inverted triangle in the coating tank (4). The second guide wheel (5) and the third guide wheel (6) are located on the same horizontal plane and parallel to the bottom of the coating tank (4). The titanium alloy wire (2) passes through the lower end of the second guide wheel (5) and the third guide wheel (6) to ensure that the titanium alloy wire (2) passes parallel in the titanium diboride suspension (8). By adjusting the distance between the second guide wheel (5), the third guide wheel (6), and the fourth guide wheel (7), the residence time of the titanium alloy wire (2) in the coating tank (4) is ensured. (3) The coated titanium alloy wire (2) enters the oven (11) through the fifth guide wheel (10) on the other side of the upper end of the coating tank (4) for drying, and then is coiled and packaged. In step (1), the titanium diboride used in the titanium diboride suspension has an oxygen content ≤0.8%, a carbon content ≤0.5%, a purity ≥98.5%, and an average particle size of 5-10 μm; In step (3), the drying temperature is 200-300℃.

2. The method for preparing titanium alloy wire according to claim 1, characterized in that: In step (2), the diameter of the titanium alloy wire is 0.1-5 mm.

3. A titanium alloy wire, characterized in that: It is obtained by the preparation method described in any one of claims 1-2.

4. An application of the titanium alloy wire as described in claim 3, wherein the titanium alloy wire is used in additive manufacturing.

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