A high-strength titanium alloy powder core wire special for additive manufacturing and a preparation method of a component thereof

Abstract

The application discloses a kind of high-strength titanium alloy powder core wire special for additive manufacturing and the preparation method of its component, the method is: one, select TA1 titanium band as outer skin, select Al powder, Cu powder, Fe powder, C powder and LaB6 powder as internal filler;Two, ball milling is uniformly obtained mixed powder;Three, after being rolled into U-shaped groove, TA1 titanium band is sent into mixed powder, and initial wire is obtained by roller compaction;Four, after spinning the initial wire, it is annealed and rolled in multiple passes online to obtain titanium alloy powder core wire;Five, additive manufacturing obtains titanium alloy component.The application introduces C powder in the internal filler to improve its fluidity, combined with spinning and multiple-pass low-temperature short-time online annealing, to compact the gap and gradually weaken the stress, promote nucleation by Cu powder and Fe powder in the internal filler, improve the mechanical property anisotropy of the component, improve the strength of the component by solid solution strengthening of Al element and synergistic reinforcement of strengthening phase, suitable for additive manufacturing field.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing technology, specifically relating to a method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing. Background Technology

[0002] With the rapid development of industries such as aerospace, marine, and weaponry, the requirements for the structure and service performance of key components have become increasingly stringent. Wire additive manufacturing, with its advantages of high forming efficiency and low cost, is widely used in the fabrication of titanium alloy components. Currently, the titanium alloy wires used in additive manufacturing are all existing grades of forged titanium alloys. However, because the alloy composition of existing wires cannot match the rapid cooling and heating and multiple reheating cycles of additive manufacturing processes, the printed parts typically exhibit coarse β-columnar crystals, significant anisotropy in mechanical properties, and low strength.

[0003] Researchers primarily promote equiaxed β-grains and enhanced strength by controlling the process and improving alloy composition. Process control mainly involves forming process parameters and post-heat treatment, but the process window is relatively narrow. Alloy composition is generally achieved through a wire-powder co-feeding mechanism, which is complex and prone to compositional segregation. Some researchers have also attempted to prepare novel titanium alloy wires using traditional methods of melting, forging, and rolling. However, the addition of multiple alloying strengthening elements leads to severe segregation during melting, and cracking during forging and rolling, resulting in low wire yield. Powder-core wire is the preferred method for preparing multi-component titanium alloy wires, but it suffers from problems such as easy delamination during multi-component powder transport, powder leakage during rolling, and cracking. Therefore, there is an urgent need to develop a new preparation method to obtain high-strength titanium alloy powder-core wires and their components specifically for additive manufacturing. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a method for preparing high-strength titanium alloy powder core wire and its components for additive manufacturing. This method improves the fluidity of the titanium alloy powder core wire by introducing carbon powder into the internal filler, reducing delamination during transport. Combined with rotary forging and multi-pass low-temperature short-time online annealing processes, the gaps are tightened and stress is gradually reduced, avoiding powder leakage during rolling and wire cracking. During additive manufacturing, the segregation of Cu and Fe powder in the internal filler promotes nucleation through compositional supercooling, improving the anisotropy of the component's mechanical properties. The strength of the component is further enhanced by solid solution strengthening of Al and strengthening with reinforcing phases of Ti2Cu, Ti2Fe, TiC, La2O3, and TiB. This method solves the problems of powder delamination during transport, powder leakage during rolling, and cracking in the preparation of multi-component titanium alloy powder core wires, as well as the issues of coarse β-columnar crystals, significant anisotropy of mechanical properties, and low strength in the printed wire.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for preparing high-strength titanium alloy powder core wire and its components for additive manufacturing, characterized in that the method includes the following steps:

[0006] Step 1, Material Selection: TA1 titanium strip is selected as the outer skin, and Al powder, Cu powder, Fe powder, C powder and LaB6 powder are selected as the internal fillers;

[0007] Step 2: Preparation of filler: The Al powder, Cu powder, Fe powder, C powder and LaB6 powder selected in Step 1 are ball-milled and mixed according to the ratio to obtain a mixed powder;

[0008] Step 3, Initial filament forming: The TA1 titanium strip from Step 1 is rolled into a U-shaped groove by rollers. The mixed powder from Step 2 is fed into the U-shaped groove by a conveyor belt and then rolled and closed by rollers to obtain the initial filament.

[0009] Step 4: Wire compaction and diameter reduction: The initial wire obtained in Step 3 is forged by rotary forging to obtain intermediate transition wire. Then, the intermediate transition wire is subjected to multiple online annealing and rolling processes to gradually reduce its diameter, thereby obtaining high-strength titanium alloy powder core wire of the required size.

[0010] Step 5, Additive Manufacturing: Using the high-strength titanium alloy powder core wire prepared in Step 4, additive manufacturing is carried out to obtain an arc-additively manufactured titanium alloy component; the tensile strength of the arc-additively manufactured titanium alloy component is not less than 1200MPa, and the tensile strength anisotropy is less than 2%.

[0011] The above-mentioned method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing is characterized in that the thickness of the TA1 titanium strip in step one is 0.2mm~0.4mm, the hardness is 130HV~180HV, the particle size of the metal powder in the internal filler is 15μm~53μm, and the particle size of the non-metallic powder is 3μm.

[0012] The above-mentioned method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing is characterized in that the mass of Al powder, Cu powder, Fe powder, C powder and LaB6 powder in step two accounts for 3%~5%, 1%~3%, 1%~3%, 0.05%~0.15% and 0.3%~0.6% of the total mass of the mixed powder and TAI titanium strip, respectively.

[0013] The above-mentioned method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing is characterized in that, in step three, the filling rate of the mixed powder fed into the U-shaped groove is 25%~40% by mass, and the diameter of the initial wire is 3mm~4.5mm. Typically, the filling rate is the proportion of the mass of the mixed powder to the total mass of the TA1 titanium strip and the TA1 titanium strip.

[0014] The above-mentioned method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing is characterized in that the diameter of the intermediate transition wire in step four is 2.6 mm to 3.6 mm, the temperature of the multi-pass online annealing is 350°C to 550°C and the time is 8 min to 20 min, and the rolling passes are no less than 6.

[0015] The above-mentioned method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing is characterized in that the wire feeding speed of the high-strength titanium alloy powder core wire in the additive manufacturing process in step five is 1500mm / min to 2500mm / min.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The titanium alloy powder core wire of the present invention improves the surface state of the mixed powder in the internal filler by introducing C powder into the internal filler, improves the flowability of the mixed powder on the conveyor belt, effectively reduces the problem of easy stratification of multi-component powder during conveying, and increases the selection range of particle size and morphology of the mixed powder.

[0018] 2. The titanium alloy powder core wire preparation method of the present invention adopts rotary forging process, which not only achieves appropriate diameter reduction, but also tightens the gap of the wire and solves the problem of easy powder leakage during rolling.

[0019] 3. In the method for preparing titanium alloy powder core wire of the present invention, the stress of the wire is gradually reduced by multiple low-temperature short-time online annealing, so as to avoid cracking of the wire during rolling and ensure the smooth preparation of titanium alloy powder core wire.

[0020] 4. By introducing Cu powder and Fe powder into the internal filler of the titanium alloy powder core wire of the present invention, the compositional supercooling formed by segregation at the solid-liquid interface front of the titanium alloy molten pool in additive manufacturing promotes the nucleation of equiaxed crystals and improves the anisotropy of mechanical properties of titanium alloy components manufactured by arc additive manufacturing.

[0021] 5. In the titanium alloy powder core wire of the present invention, Al powder is introduced into the internal filler, and the solid solution strengthening of Al element is utilized. Combined with the strengthening phases formed by other elements, including Ti2Cu, Ti2Fe, TiC, La2O3 and TiB, the strength of the titanium alloy components manufactured by arc additive manufacturing is improved.

[0022] 6. The oxygen absorption properties of LaB6 in the internal filler of the titanium alloy powder core wire of the present invention reduce the interstitial oxygen content of the titanium alloy components manufactured by arc additive manufacturing, thereby improving the forming ability and plasticity of the components.

[0023] 7. The preparation process of this invention is easy to implement, low in cost, and has a wide range of applications. The entire preparation process is short and suitable for industrial mass production. It also provides a new idea for the design of wire additive manufacturing of titanium alloys.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a physical image of the TA1 titanium strip used in Embodiment 1 of the present invention.

[0026] Figure 2 This is a diagram showing the transport of the mixed powder in Embodiment 1 of the present invention.

[0027] Figure 3 This is a morphology diagram of the high-strength titanium alloy powder core wire prepared in Example 1 of the present invention.

[0028] Figure 4 This is a physical image of the arc additive manufacturing titanium alloy component prepared in Example 1 of the present invention.

[0029] Figure 5 This is a grain morphology diagram of the arc additive manufacturing titanium alloy component prepared in Example 1 of the present invention. Detailed Implementation

[0030] Example 1

[0031] This embodiment includes the following steps:

[0032] Step 1: Select as follows Figure 1 The outer skin is made of TA1 titanium strip with a thickness of 0.2 mm and a hardness of 130 HV. The inner filler is non-spherical Al powder, spherical Cu powder and Fe powder with a particle size of 15 μm to 53 μm, as well as irregular C powder and LaB6 powder with a particle size of 3 μm.

[0033] Step 2: Preparation of filler: The Al powder, Cu powder, Fe powder, C powder, and LaB6 powder selected in Step 1 are ball-milled and mixed according to the specified ratio to obtain a mixed powder; the mass percentages of the Al powder, Cu powder, Fe powder, C powder, and LaB6 powder are 4%, 3%, 1%, 0.1%, and 0.4% of the total mass of the mixed powder and the TA1 titanium strip, respectively.

[0034] Step 3, Initial Wire Forming: The TA1 titanium strip from Step 1 is rolled into a U-shaped groove using rollers. The mixed powder from Step 2 is fed into the U-shaped groove via a conveyor belt at a 40% filling rate. Figure 2 As shown, the titanium strip is then rolled and closed by rollers to obtain a primary wire with a diameter of 4.5 mm.

[0035] Step 4: Wire compaction and diameter reduction: The initial wire obtained in Step 3 is forged to obtain an intermediate transition wire with a diameter of 3.6 mm. Then, the intermediate transition wire undergoes 12 passes of online annealing and rolling to gradually reduce its diameter. The online annealing temperature is 550℃ and the time is 8 minutes, resulting in the desired wire diameter. Figure 3 The high-strength titanium alloy powder core wire shown has a diameter of φ2mm;

[0036] Step 5, Additive Manufacturing: Using the high-strength titanium alloy powder-core wire prepared in Step 4, additive manufacturing is performed with the following parameters: voltage 14V, current 120A, wire feed speed 2500mm / min. This yields an arc-additively manufactured titanium alloy component with equiaxed β grains of approximately 226μm in size. Figure 4 and Figure 5 As shown.

[0037] Testing revealed that the tensile strengths of the transverse and longitudinal tensile specimens of the arc additive manufacturing titanium alloy component prepared in this embodiment were 1252 MPa and 1237 MPa, respectively, with an anisotropy index of 1.2%.

[0038] Example 2

[0039] This embodiment includes the following steps:

[0040] Step 1: Select TA1 titanium strip with a thickness of 0.4 mm and a hardness of 180 HV as the outer skin, and select non-spherical Al powder, spherical Cu powder and Fe powder with a particle size of 15 μm to 53 μm, as well as irregular C powder and LaB6 powder with a particle size of 3 μm as the internal filler.

[0041] Step 2: Preparation of filler: The Al powder, Cu powder, Fe powder, C powder, and LaB6 powder selected in Step 1 are ball-milled and mixed according to the specified ratio to obtain a mixed powder; the mass percentages of the Al powder, Cu powder, Fe powder, C powder, and LaB6 powder are 5%, 1%, 3%, 0.05%, and 0.3% of the total mass of the mixed powder and the TA1 titanium strip, respectively.

[0042] Step 3, Initial filament forming: The TA1 titanium strip from Step 1 is rolled into a U-shaped groove by rollers. The mixed powder from Step 2 is fed into the U-shaped groove by a conveyor belt with a filling rate of 25%. The titanium strip is then rolled and closed by rollers to obtain an initial filament with a diameter of 3mm.

[0043] Step 4: Wire compaction and diameter reduction: The initial wire obtained in Step 3 is forged to obtain an intermediate transition wire with a diameter of 2.6 mm. Then, the intermediate transition wire is subjected to 8 passes of online annealing and rolling to gradually reduce the diameter. The online annealing temperature is 350℃ and the time is 20 min to obtain a high-strength titanium alloy powder core wire with a diameter of φ2 mm.

[0044] Step 5, Additive Manufacturing: Using the high-strength titanium alloy powder core wire prepared in Step 4, additive manufacturing is carried out. The process parameters are: voltage 12V, current 150A, wire feeding speed 1500mm / min, to obtain an arc additively manufactured titanium alloy component with equiaxed β grains of approximately 320μm in size.

[0045] Testing revealed that the tensile strengths of the transverse and longitudinal tensile specimens of the arc additive manufacturing titanium alloy component prepared in this embodiment were 1276 MPa and 1258 MPa, respectively, with an anisotropy index of 1.4%.

[0046] Example 3

[0047] This embodiment includes the following steps:

[0048] Step 1: Select TA1 titanium strip with a thickness of 0.3mm and a hardness of 150HV as the outer skin, and select non-spherical Al powder, spherical Cu powder and Fe powder with a particle size of 15μm~53μm, as well as irregular C powder and LaB6 powder with a particle size of 3μm as the internal filler.

[0049] Step 2: Preparation of filler: The Al powder, Cu powder, Fe powder, C powder, and LaB6 powder selected in Step 1 are ball-milled and mixed according to the specified ratio to obtain a mixed powder; the mass percentages of the Al powder, Cu powder, Fe powder, C powder, and LaB6 powder are 3%, 2%, 2.5%, 0.15%, and 0.6% of the total mass of the mixed powder and the TA1 titanium strip, respectively.

[0050] Step 3, Initial filament forming: The TA1 titanium strip from Step 1 is rolled into a U-shaped groove by rollers. The mixed powder from Step 2 is fed into the U-shaped groove by a conveyor belt with a filling rate of 35%. The titanium strip is then rolled and closed by rollers to obtain an initial filament with a diameter of 4mm.

[0051] Step 4: Wire compaction and diameter reduction: The initial wire obtained in Step 3 is forged to obtain an intermediate transition wire with a diameter of 3mm. Then, the intermediate transition wire is subjected to 10 passes of online annealing and rolling to gradually reduce its diameter. The online annealing temperature is 400℃ and the time is 15min to obtain a high-strength titanium alloy powder core wire with a diameter of φ2mm.

[0052] Step 5, Additive Manufacturing: Using the high-strength titanium alloy powder core wire prepared in Step 4, additive manufacturing is carried out. The process parameters are: voltage 13V, current 140A, wire feeding speed 2000mm / min, to obtain an arc additively manufactured titanium alloy component with equiaxed β grains of approximately 266μm in size.

[0053] Testing revealed that the tensile strengths of the transverse and longitudinal tensile specimens of the arc additive manufacturing titanium alloy component prepared in this embodiment were 1226 MPa and 1215 MPa, respectively, with an anisotropy index of 0.9%.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing, characterized in that, The method includes the following steps: Step 1, Material Selection: TA1 titanium strip is selected as the outer skin, and Al powder, Cu powder, Fe powder, C powder and LaB6 powder are selected as the internal fillers; Step 2: Preparation of filler: The Al powder, Cu powder, Fe powder, C powder and LaB6 powder selected in Step 1 are ball-milled and mixed according to the ratio to obtain a mixed powder; Step 3, Initial filament forming: The TA1 titanium strip from Step 1 is rolled into a U-shaped groove by rollers. The mixed powder from Step 2 is fed into the U-shaped groove by a conveyor belt and then rolled and closed by rollers to obtain the initial filament. Step 4: Wire compaction and diameter reduction: The initial wire obtained in Step 3 is forged by rotary forging to obtain intermediate transition wire. Then, the intermediate transition wire is subjected to multiple online annealing and rolling processes to gradually reduce its diameter, thereby obtaining high-strength titanium alloy powder core wire of the required size. Step 5, Additive Manufacturing: Using the high-strength titanium alloy powder core wire prepared in Step 4, additive manufacturing is carried out to obtain an arc-additively manufactured titanium alloy component; the tensile strength of the arc-additively manufactured titanium alloy component is not less than 1200MPa, and the tensile strength anisotropy is less than 2%.

2. The method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing according to claim 1, characterized in that, The TA1 titanium strip mentioned in step one has a thickness of 0.2mm~0.4mm and a hardness of 130HV~180HV. The particle size of the metal powder in the internal filler is 15μm~53μm, and the particle size of the non-metallic powder is 3μm.

3. The method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing according to claim 1, characterized in that, In step two, the Al powder, Cu powder, Fe powder, C powder, and LaB6 powder account for 3%~5%, 1%~3%, 1%~3%, 0.05%~0.15%, and 0.3%~0.6% of the total mass of the mixed powder and the TA1 titanium strip, respectively.

4. The method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing according to claim 1, characterized in that, In step three, the filling rate of the mixed powder fed into the U-shaped groove is 25% to 40% by mass, and the diameter of the initial filament is 3mm to 4.5mm.

5. The method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing according to claim 1, characterized in that, In step four, the diameter of the intermediate transition wire is 2.6mm to 3.6mm, the temperature of the multi-pass online annealing is 350℃ to 550℃, the time is 8min to 20min, and the rolling passes are no less than 6.

6. The method for preparing a high-strength titanium alloy powder core wire and its components for additive manufacturing according to claim 1, characterized in that, In step five, the feeding speed of the high-strength titanium alloy powder core wire in the additive manufacturing process is 1500 mm / min to 2500 mm / min.

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