High-strength titanium alloy powder core wire material special for additive manufacturing and preparation method of component of high-strength titanium alloy powder core wire material

Abstract

The invention discloses a special high-strength titanium alloy powder core wire for additive manufacturing and a preparation method of a component of the special high-strength titanium alloy powder core wire. The method comprises the following steps: 1, selecting a TA1 titanium belt as a sheath, and selecting Al powder, Cu powder, Fe powder, C powder and LaB6 powder as internal fillers; 2, ball-milling and uniformly mixing to obtain mixed powder; thirdly, a TA1 titanium strip is rolled into a U-shaped groove, then the mixed powder is fed into the U-shaped groove, and primary wires are obtained through rolling of a roller; fourthly, after the primary wire is subjected to rotary swaging, multi-pass online annealing and rolling reducing are conducted, and the titanium alloy powder core wire is obtained; and fifthly, the titanium alloy component is obtained through additive manufacturing. C powder is introduced into the internal filler to improve the fluidity of the internal filler, rotary swaging and multi-pass low-temperature short-time on-line annealing are combined to compact gaps and gradually weaken stress, nucleation is promoted through Cu powder and Fe powder in the internal filler, the mechanical property anisotropy of a component is improved, and the mechanical property of the component is improved. And the strength of the component is improved through solid solution strengthening of the Al element and strengthening of a strengthening phase, and the method is suitable for the field of additive manufacturing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal additive manufacturing, and particularly relates to a high-strength titanium alloy powder core wire for additive manufacturing and a preparation method of a component thereof. BACKGROUND

[0002] With the rapid development of aerospace, shipping and weapon industries, the requirements for the structure and service performance of key parts are more stringent. Additive manufacturing of wire materials is widely used in the preparation of titanium alloy components due to its high forming efficiency and low cost. The titanium alloy wires used in additive manufacturing are currently existing grades of forged titanium alloys. However, due to the alloy composition of the existing wires, which cannot match the process characteristics of additive manufacturing such as fast cooling and fast heating and multiple reciprocating reheating cycles, the printed parts usually exhibit coarse beta columnar crystals, significant mechanical property anisotropy and low strength.

[0003] Researchers mainly promote the equiaxialization of beta grains and the improvement of strength by adjusting the process and improving the alloy composition: process adjustment mainly includes forming process parameters and post-heat treatment, but the process window is narrow; the alloy composition is generally realized by a wire powder feeding mechanism, which is complex and prone to composition segregation. Some researchers also attempt to prepare new titanium alloy wires through traditional methods such as melting, forging and rolling, but the addition of multiple alloy strengthening elements leads to serious melting segregation, cracking during forging and rolling, and low yield of wire products. Powder core wire is the preferred method for preparing multi-component titanium alloy wires, but there are problems such as easy layering of powder delivery, easy powder leakage and cracking during rolling. Therefore, it is urgent to develop a new preparation method to obtain high-strength titanium alloy powder core wires for additive manufacturing and their components. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a preparation method of high-strength titanium alloy powder core wire for additive manufacturing and its component to solve the problems of the prior art. The method introduces C powder into the internal filler of the titanium alloy powder core wire to improve its flowability and reduce the layering phenomenon of powder delivery. Combined with spin forging and multi-pass low-temperature short-time online annealing process, the method tightens the gaps and gradually reduces the stress, avoids powder leakage and cracking of the wire during rolling, promotes nucleation by the segregation of Cu powder and Fe powder in the internal filler during additive manufacturing, improves the mechanical property anisotropy of the component, improves the strength of the component by solid solution strengthening of Al element and reinforcement of Ti2Cu, Ti2Fe, TiC, La2O3 and TiB, and solves the problems of easy layering of powder delivery, easy powder leakage and cracking during rolling of the powder core wire for preparing multi-component titanium alloy wires, and the problems of coarse beta columnar crystals, significant mechanical property anisotropy and low strength of the wire printed parts.

[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: 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%.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] Compared with the prior art, the present invention has the following advantages: 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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

[0019] Figure 1 This is a physical image of the TA1 titanium strip used in Embodiment 1 of the present invention.

[0020] Figure 2 This is a diagram showing the transport of the mixed powder in Embodiment 1 of the present invention.

[0021] Figure 3 This is a morphology diagram of the high-strength titanium alloy powder core wire prepared in Example 1 of the present invention.

[0022] Figure 4 This is a physical image of the arc additive manufacturing titanium alloy component prepared in Example 1 of the present invention.

[0023] 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

[0024] Example 1 This embodiment includes the following steps: 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. 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. 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. 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; 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.

[0025] 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%.

[0026] Example 2 This embodiment includes the following steps: 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. 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. 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. 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. 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.

[0027] 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%.

[0028] Example 3 This embodiment includes the following steps: 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. 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. 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. 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. 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.

[0029] 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%.

[0030] 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 producing a high-strength titanium alloy powder core wire and a member thereof for additive manufacturing, characterized by, The method comprises the following steps: Step one, material selection: selecting TA1 titanium strip as the outer skin, and selecting Al powder, Cu powder, Fe powder, C powder and LaB6 powder as the internal filler; Step two, preparation of the filler: ball-milling the Al powder, Cu powder, Fe powder, C powder and LaB6 powder selected in step one according to the proportion to obtain a mixed powder; Step three, initial wire forming: rolling the TA1 titanium strip in step one into a U-shaped groove, feeding the mixed powder in step two into the U-shaped groove through a conveyor belt, and then closing the titanium strip through roller rolling to obtain an initial wire; Step four, wire compaction and reduction: performing rotary swaging on the initial wire obtained in step three to obtain an intermediate transition wire, and then reducing the intermediate transition wire in size through multi-pass online annealing and rolling to obtain a high-strength titanium alloy powder core wire with a desired size; Step five, additive manufacturing: using the high-strength titanium alloy powder core wire prepared in step four to perform additive manufacturing to obtain an electric arc additive manufacturing titanium alloy component; the tensile strength of the electric arc additive manufacturing titanium alloy component is not less than 1200 MPa, and the tensile strength anisotropy is less than 2%.

2. The method of claim 1, wherein the high-strength titanium alloy powder core wire for additive manufacturing and the method of manufacturing a member thereof are characterized by comprising: In step one, the thickness of the TA1 titanium strip is 0.2mm~0.4mm, and 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.

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 mass of the Al powder, Cu powder, Fe powder, C powder and LaB6 powder 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 TA1 titanium strip, respectively.

4. The method of claim 1, wherein the high-strength titanium alloy powder core wire for additive manufacturing and the method of manufacturing a member thereof are characterized by comprising: In step three, the filling rate of the mixed powder fed into the U-shaped groove is 25%~40% by mass percentage, and the diameter of the initial wire is 3mm~4.5mm.

5. The method of claim 1, wherein the high-strength titanium alloy powder core wire for additive manufacturing and the method of manufacturing a member thereof are characterized by comprising: In step four, the diameter of the intermediate transition wire is 2.6mm~3.6mm, the temperature of the multi-pass online annealing is 350℃~550℃, and the time is 8min~20min, and the rolling passes are not less than 6 times.

6. The method of claim 1, wherein the high-strength titanium alloy powder core wire for additive manufacturing and the method of manufacturing a member thereof are characterized by, In step five, the wire feeding speed of the high-strength titanium alloy powder core wire during the additive manufacturing process is 1500mm / min~2500mm / min.

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