A multi-strand wire based in-situ grown titanium matrix composite material additive manufacturing method

Abstract

This invention discloses an in-situ self-generated titanium-based composite additive manufacturing method based on multi-strand filaments, comprising the following steps: using aluminum-based composite filaments as core filaments; using pure titanium or titanium alloy filaments as outer filaments; mixing and twisting the core and outer filaments together; and preparing in-situ self-generated reinforced titanium-based composites using a fused wire additive manufacturing method. This method refines the matrix grains and reinforcement size through the in-situ self-generated reaction during the melting and solidification process of the multi-strand titanium-based composite filaments, enabling precise control of the reinforcement size distribution. This significantly improves the strength and toughness of the additively manufactured titanium-based composites. This method and technology can help guide the direct preparation of high-strength and high-toughness titanium-based composites and their components using fused wire additive manufacturing, and has significant application value in aerospace and other critical equipment fields.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composites technology, and more specifically to an additive manufacturing method for in-situ self-generated titanium matrix composites based on multi-strand filaments. Background Technology

[0002] Titanium-based composites, with their advantages of high specific strength, good corrosion resistance, and high temperature resistance, are gradually becoming one of the most promising candidate structural materials in high-tech fields such as aerospace and defense weaponry. Introducing high-strength, high-modulus ceramic particles such as TiB and TiC into the titanium alloy matrix and optimizing their size and distribution can significantly improve the modulus and high-temperature oxidation resistance of titanium-based composites. This is currently one of the effective ways to improve the comprehensive mechanical properties and service temperature of titanium-based composites.

[0003] Additive manufacturing technology is a method of forming complex geometrically structured parts by layering and slicing them according to a three-dimensional geometric model and using a layer-by-layer deposition process. It offers advantages such as high design freedom, high material utilization, and high forming accuracy. Additive manufacturing methods for metallic materials can be divided into three categories based on the heat source: laser additive manufacturing, electron beam additive manufacturing, and arc additive manufacturing. These methods are widely used in the fabrication of various large or structurally complex components. Based on the free-form and near-net-shape characteristics of additive manufacturing technology, a significant historical opportunity has been provided for the integrated forming of lightweight, high-strength, and difficult-to-deform titanium-based composite materials, encompassing material, structure, and performance.

[0004] Currently, the main raw material for additive manufacturing of titanium-based composite materials is powder material, primarily used in laser and electron beam additive manufacturing processes. It has the following characteristics and shortcomings: In terms of process preparation, powder materials offer high forming precision, but also suffer from low deposition efficiency (0.1-0.2 kg / h), low material utilization, and high cost. Regarding powder pretreatment, commonly used methods both domestically and internationally include mechanical ball milling, electrochemical deposition, and chemical vapor deposition. These methods involve embedding or adsorbing reinforcing reactants onto the surface of titanium alloy powder using physical or chemical methods, forming various reinforcements through in-situ self-reaction during the additive manufacturing melting process. However, mechanical ball milling easily introduces impurities such as hydrogen and oxygen, and in electrochemical and chemical vapor deposition processes, it is difficult to ensure the uniformity of the reinforcing reactant on the surface of the titanium alloy powder. These shortcomings in process preparation and powder pretreatment limit the development of titanium-based composite additive manufacturing based on powder materials. In contrast, fused wire additive manufacturing offers advantages such as high deposition efficiency (5 kg / h) and dense microstructure, making it particularly suitable for the high-efficiency and high-quality manufacturing of large-size structural components. However, high-strength titanium matrix composites suffer from low slip numbers (α phase has an hcp structure), easy instability at the reinforcement interface, and low plasticity, making them almost impossible to draw into filaments. Therefore, research on the design and fabrication technology of titanium matrix composite filaments is currently scarce. Consequently, how to prepare high-quality titanium matrix composite filaments and achieve stable fused wire additive manufacturing of lightweight, high-strength, and difficult-to-deform titanium matrix composite components through the control of matrix microstructure and reinforcement size distribution has become a key focus for researchers.

[0005] Some progress has been made in the research of fused wire additive manufacturing of metal matrix composites and alloys. For example, patent CN115156551A discloses a method and system for arc additive manufacturing of particle-reinforced aluminum matrix composites. This patent uses in-situ self-generated TiC particle-reinforced Al-6.3Cu alloy wire and ER2319 Al-6.3Cu alloy wire as raw materials for additive manufacturing to prepare particle-reinforced aluminum matrix composites. This method involves preparing particle-reinforced aluminum matrix composite ingots and then directly drawing them into wire raw materials for fused wire additive manufacturing. However, for titanium matrix composites, the α phase in the titanium alloy matrix has a close-packed hexagonal structure, which has few slip systems and is difficult to deform. Cracking and brittle fracture are prone to occur during the drawing process, making it difficult to directly use the "melting-casting-drawing wire" method for additive manufacturing. Patent CN114351004A discloses a method for manufacturing low-cost titanium alloy wire and its structural components for arc additive manufacturing. This method involves forming pre-fabricated titanium alloy wire (without expensive elements such as V, Ta, Nb, and Cr) into wires with a diameter of 1.0 mm to 3.0 mm, and then forming Ti-6Al-4V scrap (residue from the machining process processed through a "cast-drawn wire" method) into wires with a diameter of 1.0 mm to 3.0 mm. These are then combined into a hybrid wire through parallel bundling or winding. However, this method focuses on reducing the amount of expensive elements added to the titanium alloy to lower costs, and it cannot achieve the addition of particulate reinforcement in the titanium alloy to prepare titanium-based composite materials. Furthermore, this patent does not disclose the specific methods of parallel bundling and winding, making it impossible to control the stranding form and stranding parameters. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing an in-situ self-generated titanium-based composite material additive manufacturing method based on multi-strand filaments. This method helps guide the direct preparation of high-strength and high-toughness titanium-based composite materials and their large-size components using fused wire additive manufacturing, and has significant application value in aerospace and other critical equipment fields.

[0007] This invention is achieved through the following technical solution:

[0008] This invention provides an in-situ self-generated titanium-based composite material additive manufacturing method based on multi-strand filaments, comprising the following steps:

[0009] A. Aluminum-based composite material wire is used as the core wire;

[0010] B. Use pure titanium or titanium alloy wire as the outer wire;

[0011] C. Mix and twist the core wire and the outer wire together into one piece;

[0012] D. In-situ self-reinforced titanium-based composite materials were prepared using the fused wire additive manufacturing method.

[0013] Preferably, the diameter of the core wire in step A is 0.08 to 2.4 mm, and the aluminum-based composite material wire includes a matrix and a reinforcing phase.

[0014] Preferably, the matrix comprises pure aluminum or an aluminum alloy.

[0015] Preferably, the reinforcing phase includes at least one of TiB2, TiC, and SiC.

[0016] Preferably, the reinforcing phase is uniformly distributed within the aluminum-based composite filament.

[0017] Preferably, the mass fraction of the reinforcing phase in the aluminum matrix composite filament is 0.1–5 wt.%.

[0018] Preferably, the diameter of the outer wire in step B is 0.01 to 1.2 mm.

[0019] Preferably, the twisting method in step C includes: the core wire is located in the middle, and the outer wires are spirally twisted.

[0020] Preferably, the spiral twisted structure includes one of 1×3, 1×7, and 3+3.

[0021] Preferably, in step C, the twist pitch T of the outer filament is T = m × (douter + dcore) / 2, where m is the twist pitch multiple, douter is the diameter of the outer filament, and dcore is the diameter of the core filament. 3.2 <m<20。

[0022] Preferably, the helix angle of the outer yarn in step C is α, where α = arctan(m / 2π), and m is the twist pitch multiple. 3.2 <m<20,26.99°<α<72.56°。

[0023] Preferably, the fused wire additive manufacturing method described in step D includes one of arc fused wire additive manufacturing, laser fused wire additive manufacturing, and electron beam fused wire additive manufacturing.

[0024] The present invention also provides an in-situ self-reinforced titanium-based composite material prepared by the above method.

[0025] The method of this invention screens aluminum-based composite wires with different reinforcements and matrices, as well as pure titanium or titanium alloy wires with different compositions, and designs the matrix composition system and additive body type of in-situ self-generated titanium-based composite wires. Using aluminum-based composite wires as the core wires and pure titanium or titanium alloy wires as the outer wires, they are spirally twisted into multi-strand welding wires according to a certain stranding structure and twisting parameters. By controlling the stranding parameters of the multi-strand wires (twist pitch T, twist pitch multiple m, and helix angle α, etc.), the wire feeding speed is adjusted to regulate the wire feeding stability, and the melting and solidification characteristics are regulated by changing the energy and distribution of different heat sources. This solves the problems of expensive powder raw materials, low density of prepared materials, and anisotropy in the production of continuous fiber-reinforced titanium-based composites based on wire additive manufacturing methods.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) This invention, by screening aluminum-based composite wires with different reinforcements and matrices, as well as pure titanium or titanium alloy wires with different compositions, can design the matrix composition system and additive types of in-situ self-generated titanium-based composite wires. Taking advantage of the relatively easy preparation of aluminum-based composite wires, using them as the core wire, multiple strands of wire are spirally twisted together using pure titanium or titanium alloy welding wires, thus solving the problem of preparing titanium-based composite wires that are difficult to deform and brittle.

[0028] (2) Compared with powder-based additive manufacturing processes, filament-based additive manufacturing has the advantages of high efficiency, high density and low cost, and is also suitable for the integrated forming of large structural parts.

[0029] (3) This invention is applicable to various types of single-unit reinforced titanium-based composite materials, as well as titanium-based composite materials containing different reinforcing agents, such as TiB, TiB+TiC and other TiB+Ti5Si3 hybrid reinforced series;

[0030] (4) This invention is applicable to pure titanium or titanium alloy matrix, including Ti, Ti-6Al-4V and Ti60, etc., and has a wide range of applications;

[0031] (5) This invention is applicable to various additive manufacturing processes carried out under high-energy heat sources, such as electric arc additive manufacturing, laser additive manufacturing, and electron beam additive manufacturing, and realizes the integrated design and preparation of titanium-based composite materials based on wire materials;

[0032] (6) Based on the titanium-based composite material multi-strand wire of the present invention, the additive manufacturing method is used to carry out the melting, solidification and deposition process layer by layer, and the in-situ chemical reaction is used to generate different types and sizes of reinforcements in the titanium alloy in situ, avoiding poor interface wettability and interface contaminants, improving the high bonding strength between the reinforcement and the matrix interface, and obtaining a high-strength and tough titanium-based composite material with in-situ self-generated reinforcement and integrated shape control.

[0033] (7) During the additive manufacturing process, the matrix grains and reinforcement size are refined by the in-situ self-generation reaction of the multi-strand filaments of titanium-based composite materials, thereby achieving precise control of the reinforcement size distribution and significantly improving the strength and toughness of additively manufactured titanium-based composite materials.

[0034] (8) In order to achieve the goal of preparing particle-reinforced titanium-based composite materials by direct additive manufacturing based on wire, the present invention uses aluminum-based composite wire in the middle and titanium alloy welding wire is spirally twisted according to a certain structure to form a specific twisted structure, so as to realize the direct preparation of titanium-based composite materials by additive manufacturing with controllable wire twisting form and adjustable reinforcement and alloy composition. Attached Figure Description

[0035] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0036] Figure 1 This is a schematic diagram of how multi-strand titanium-based composite wires are spirally twisted together according to a certain twisting structure based on the selected aluminum-based composite wires and titanium alloy wires.

[0037] Figure 2 Twisting methods for multi-strand filaments of titanium-based composite materials with different structural parameters;

[0038] Figure 3 This is a schematic diagram of the in-situ self-reinforced titanium-based composite material melt-filament additive manufacturing process using multi-strand titanium-based composite material wires, where 1-laser, 2-multi-strand titanium-based composite material wires, 3-wire feeding nozzle, 4-in-situ self-reinforced titanium-based composite material, and 5-substrate. Detailed Implementation

[0039] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0040] Example 1

[0041] This embodiment provides an additive manufacturing method for in-situ self-reinforced titanium-based composite materials based on multi-strand filaments, including the following steps:

[0042] A. A 1 wt.% TiB2 / Al composite ingot was prepared using a mixed salt method. The raw materials used were industrial pure aluminum, 99% pure potassium fluoroborate (KBF4), and 98% pure potassium fluorotitanate (K2TiF6). The mixed salt was injected into the aluminum melt in several batches using a bell jar at a Ti:B molar ratio of 1:2. The mass ratio of the mixed salt to the aluminum melt was KBF4:K2TiF6:Al = 126:101:3500. The ingot was prepared using a casting process with a melt temperature of 800℃ and a reaction time of 60 min. First, a homogenization heat treatment was performed: the temperature was raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, followed by furnace cooling. Then, a wire blank was obtained by drawing, and multiple drawing operations were performed to finally obtain an aluminum-based composite wire with a diameter of 0.8 mm as the core wire. The mass fraction of TiB2 in the aluminum-based composite wire was 1 wt.%.

[0043] B. Commercially available Ti6Al4V titanium alloy wire was selected as the outer wire, with a wire diameter of Ф0.8mm. Figure 1 As shown, where Figure 1 (a) is an aluminum-based composite material filament. Figure 1 (b) is a titanium alloy wire.

[0044] C. Based on the selected 1wt.% TiB2 / Al composite wire and Ti6Al4V wire, the aluminum-based composite and titanium alloy wires were first pickled (for the aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) was used to pickle the 1wt.% TiB2 / Al wire; for the titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) was used to pickle the Ti6Al4V wire; finally, they were washed with water to remove the pickling solution and dried for later use). This process removed surface oil and oxide film. Then, a multi-strand stranded welding wire was prepared using a stranding machine (twisting machine). The twist pitch T during the preparation process was 4.8 mm, the twist pitch multiple m was 6, and the corresponding helix angle was 60°, resulting in a 1×7 structure titanium-based composite multi-strand wire. Figure 2 As shown in (a).

[0045] D. Based on the titanium-based composite multi-strand filaments obtained above, additive manufacturing is carried out using laser filament additive manufacturing. The process parameters are a laser power of 1200W and a scanning speed of 300mm / min. Using an RC-LDM8060 powder-feed laser additive manufacturing equipment, a reciprocating deposition strategy is employed, meaning the deposition direction of each subsequent layer is opposite to that of the previous layer. The additive manufacturing process is as follows: Figure 3 As shown, in-situ self-reinforced titanium matrix composite thin-walled parts are prepared.

[0046] Example 2

[0047] This embodiment provides an additive manufacturing method for in-situ self-reinforced titanium-based composite materials based on multi-strand filaments, including the following steps:

[0048] A. An ingot of (1wt.% TiB2 + 1wt.% TiC) / Al composite material was prepared by a mixed salt method. The raw materials used were industrial pure aluminum, potassium fluoroborate (KBF4) with a purity of 99%, potassium fluorotitanate (K2TiF6) with a purity of 98%, and graphite (100 mesh). The mixed salt was pressed into the aluminum melt in several batches using a bell jar according to a Ti:B:C molar ratio of 2:2:1. The mass ratio of the mixed salt to the aluminum melt was KBF4:K2TiF6:C:Al = 256:404:12:6939. The ingots obtained by the casting process with a melt temperature of 800℃ and a reaction time of 60min are first subjected to homogenization heat treatment: the temperature is raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, and then cooled in the furnace. Then, the ingots are drawn to obtain wire blanks, and then drawn multiple times to finally obtain aluminum-based composite wires with a diameter of 0.6mm as the core wire. The mass fraction of the reinforcing phase in the aluminum-based composite wires is 2wt.%.

[0049] B. Commercially available pure Ti wire is selected as the outer wire, with a wire diameter of 0.6mm. Figure 1 As shown, where Figure 1 (a) is an aluminum-based composite material filament. Figure 1 (b) is a titanium alloy wire.

[0050] C. Based on the selected (1wt.% TiB2 + 1wt.% TiC) / Al composite wire and pure Ti wire, they are first subjected to pickling treatment (for aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) is used to pickle the 1wt.% TiB2 / Al wire; for titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) is used to pickle the Ti6Al4V wire; finally, they are uniformly washed with water to remove the pickling solution and dried for later use) to remove surface oil and oxide film. Then, a multi-strand stranded welding wire is prepared using the stranding process of a stranding machine (twisting machine). The twist pitch T during the preparation process is 4.8 mm, the twist pitch multiple m is 8, and the corresponding helix angle is 44.68°, thus obtaining a 1×7 structure titanium-based composite multi-strand wire, such as Figure 2 As shown in (a).

[0051] D. Based on the titanium-based composite multi-strand filaments obtained above, additive manufacturing is carried out using laser filament additive manufacturing. The process parameters are a laser power of 1200W and a scanning speed of 300mm / min. Using an RC-LDM8060 powder-feed laser additive manufacturing equipment, a reciprocating deposition strategy is employed, meaning the deposition direction of each subsequent layer is opposite to that of the previous layer. The processing procedure is as follows: Figure 3 As shown, in-situ self-reinforced titanium matrix composite thin-walled parts are prepared.

[0052] Example 3

[0053] This embodiment provides an additive manufacturing method for in-situ self-reinforced titanium-based composite materials based on multi-strand filaments, including the following steps:

[0054] A. A 5wt.% TiC / Al composite ingot was prepared using a mixed salt method. The raw materials used were industrial pure aluminum, 98% pure potassium fluorotitanate (K2TiF6), and graphite (100 mesh). The mixed salt was injected into the aluminum melt in several batches using a bell jar at a Ti:C molar ratio of 1:1. The mass ratio of the mixed salt to the aluminum melt was K2TiF6:C:Al = 101:60:570. The ingot obtained by casting at a melt temperature of 800℃ and a reaction time of 60 min was first subjected to homogenization heat treatment: the temperature was raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, followed by furnace cooling. Then, a wire blank was obtained by drawing, and multiple drawing processes were performed to finally obtain a Φ0.6mm aluminum-based composite wire as the core wire. The mass fraction of the reinforcing phase in the aluminum-based composite wire was 5wt.%.

[0055] B. Commercially available Ti6Al4V titanium alloy wire was selected as the outer wire, with a wire diameter of 0.8mm; Commercially available Ti6Al4V titanium alloy wire was selected as the outer wire, with a wire diameter of 0.8mm, such as... Figure 1 As shown, where Figure 1 (a) is an aluminum-based composite material filament. Figure 1 (b) is a titanium alloy wire.

[0056] C. Based on the selected 1wt.% TiC / Al composite wire and Ti6Al4V wire, they were first subjected to pickling treatment (for aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) was used to pickle the 1wt.% TiB2 / Al wire; for titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) was used to pickle the Ti6Al4V wire; finally, they were washed with water to remove the pickling solution and dried for later use) to remove surface oil and oxide film. Then, a multi-strand stranded welding wire was prepared using a stranding machine (twisting machine). The twist pitch T during the preparation process was 16mm, the twist pitch multiple m was 20, and the corresponding helix angle was 72.56°, resulting in a 1×3 structure titanium-based composite multi-strand wire. Figure 2 As shown in (a).

[0057] D. Based on the titanium-based composite multi-strand wire obtained above, additive manufacturing was carried out using arc welding. A REHM Tiger 180DC arc welding power source was used, with a welding current of 120A, a welding speed of 3mm / s, and a wire feed speed of 12mm / s. A reciprocating deposition strategy was employed, meaning the deposition direction of each subsequent layer was opposite to that of the previous layer. The processing procedure is as follows: Figure 3 As shown, in-situ self-reinforced titanium matrix composite thin-walled parts are prepared.

[0058] Example 4

[0059] This embodiment provides an additive manufacturing method for in-situ self-reinforced titanium-based composite materials based on multi-strand filaments, including the following steps:

[0060] A. A 0.1 wt.% TiB2 / Al composite ingot was prepared using a mixed salt method. The raw materials used were industrial pure aluminum, potassium fluoroborate (KBF4) with a purity of 99%, and potassium fluorotitanate (K2TiF6) with a purity of 98%. The mixed salt was injected into the aluminum melt in several batches using a bell jar at a Ti:B molar ratio of 1:2. The mass ratio of the mixed salt to the aluminum melt was KBF4:K2TiF6:Al = 252:202:70011. The ingot obtained by casting at a melt temperature of 800℃ and a reaction time of 60 min was first subjected to homogenization heat treatment: the temperature was raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, followed by furnace cooling. Then, a wire blank was obtained by drawing, and multiple drawing processes were performed to finally obtain an aluminum-based composite wire with a diameter of 0.8 mm as the core wire. The mass fraction of the reinforcing phase in the aluminum-based composite wire was 0.1 wt.%.

[0061] B. Commercially available Ti6Al4V titanium alloy wire was selected as the outer wire, with a wire diameter of 0.8mm. Figure 1As shown, where Figure 1 (a) is an aluminum-based composite material filament. Figure 1 (b) is a titanium alloy wire.

[0062] C. Based on the selected 1wt.% TiB2 / Al composite wire and Ti6Al4V wire, they were first subjected to pickling treatment (for aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) was used to pickle the 1wt.% TiB2 / Al wire; for titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) was used to pickle the Ti6Al4V wire; finally, they were washed with water to remove the pickling solution and dried for later use) to remove surface oil and oxide film. Then, a multi-strand stranded welding wire was prepared using a stranding machine (twisting machine). The twist pitch T during the preparation process was 2.56 mm, the twist pitch multiple m was 3.2, and the corresponding helix angle was 26.99°, resulting in a 1×7 structure titanium-based composite multi-strand wire. Figure 2 As shown in (a).

[0063] D. Based on the multi-strand titanium-based composite material obtained above, additive manufacturing was carried out using laser filament additive manufacturing. The process parameters were 1500W laser power and 500mm / min scanning speed. Using an RC-LDM8060 powder-feeding laser additive manufacturing equipment, the continuous laser was changed to a pulsed laser mode with a pulse frequency of 5Hz. The melting process was controlled by periodic solidification of the molten pool. Simultaneously, a 67° interlayer rotation deposition strategy was adopted, meaning the deposition direction of the next layer differed from the direction of the previous layer by 67°. The processing procedure is as follows: Figure 3 As shown, in-situ self-reinforced titanium matrix composite thin-walled parts are prepared.

[0064] Example 5

[0065] This embodiment provides an additive manufacturing method for in-situ self-reinforced titanium-based composite materials based on multi-strand filaments, including the following steps:

[0066] A. An ingot of (1wt.% TiB2 + 1wt.% TiC) / Al composite material is prepared by a mixed salt method. The raw materials used are industrial pure aluminum, potassium fluoroborate (KBF4) with a purity of 99%, potassium fluorotitanate (K2TiF6) with a purity of 98%, and graphite (100 mesh). The mixed salt is pressed into the aluminum melt in several batches using a bell jar according to a Ti:B:C molar ratio of 2:2:1. The mass ratio of the mixed salt to the aluminum melt is KBF4:K2TiF6:C:Al = 256:404:12:6939. The ingots obtained by the casting process with a melt temperature of 800℃ and a reaction time of 60min are first subjected to homogenization heat treatment: the temperature is raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2h, and then cooled in the furnace. Then, the ingots are drawn to obtain wire blanks, and then drawn multiple times to finally obtain aluminum-based composite wires with a diameter of 0.8mm as the core wire. The volume fraction of the reinforcing phase in the aluminum-based composite wires is 2wt.%.

[0067] B. Commercially available pure Ti wire is selected as the outer wire, with a wire diameter of 0.8mm. Figure 1 As shown, where Figure 1 (a) is an aluminum-based composite material filament. Figure 1 (b) is a titanium alloy wire.

[0068] C. Based on the selected (1wt.% TiB2 + 1wt.% TiC) / Al composite wire and pure Ti wire, they are first subjected to pickling treatment (for aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) is used to pickle the 1wt.% TiB2 / Al wire; for titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) is used to pickle the Ti6Al4V wire; finally, they are uniformly washed with water to remove the pickling solution and dried for later use) to remove surface oil and oxide film. Then, multi-strand stranded welding wire is prepared using the stranding process of a stranding machine (twisting machine). The twist pitch T during the preparation process is 6.4 mm, the twist pitch multiple m is 8, and the corresponding helix angle is 44.68°, thus obtaining a 1×7 structure titanium-based composite multi-strand wire, such as Figure 2 As shown in (a).

[0069] D. Based on the titanium-based composite multi-strand filaments obtained above, additive manufacturing was carried out using electron beam fusion additive manufacturing. The KL-106M electron beam fusion additive manufacturing equipment was used, and the additive manufacturing process parameters were: accelerating voltage 60kV, beam current 40-60mA, melt pool movement speed 800-1400mm / min, wire feed speed approximately 3kg / h, overlap ratio 30%, layer thickness 2mm, and vacuum pressure 5×10⁻⁶. -2Pa. A reciprocating deposition strategy is employed, meaning the deposition direction of the next layer is opposite to that of the previous layer. The processing is as follows: Figure 3 As shown, in-situ self-reinforced titanium matrix composite thin-walled parts are prepared.

[0070] Comparative Example 1

[0071] This comparative example uses a single 1wt.% TiB2-reinforced pure Al composite wire for additive manufacturing. The 1wt.% TiB2 / Al composite ingot is prepared by a mixed salt method. The raw materials used are industrial pure aluminum, potassium fluoroborate (KBF4) with a purity of 99%, and potassium fluorotitanate (K2TiF6) with a purity of 98%. The mixed salt is pressed into the aluminum melt in several batches using a bell jar at a Ti:B molar ratio of 1:2. The mass ratio of the mixed salt to the aluminum melt is KBF4:K2TiF6:Al = 126:101:3500. The ingots obtained through a casting process with a melt temperature of 800℃ and a reaction time of 60 min were first subjected to homogenization heat treatment: the temperature was raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, followed by furnace cooling. Then, wire blanks were obtained through drawing, and subsequent drawing was performed multiple times to finally obtain aluminum-based composite wires with a diameter of 0.8 mm. The volume fraction of TiB2 in the aluminum-based composite wires was 1 wt.%. Based on these wires, additive manufacturing deposition was performed using a laser power of 1200W and a scanning speed of 300 mm / min, employing an RC-LDM8060 powder-feed laser additive manufacturing equipment and a reciprocating deposition strategy, where the deposition direction of each subsequent layer is opposite to that of the previous layer. Using this method, additive manufacturing can only obtain in-situ TiB2-reinforced aluminum-based composites; titanium cannot be added to the additive body from the material source or during the preparation process, thus preventing the production of in-situ reinforced titanium-based composites. The high-temperature mechanical properties of the prepared aluminum-based composite additives are insufficient to meet the high-temperature service environment of future aerospace vehicles.

[0072] Comparative Example 2

[0073] The difference between this comparative example and Example 1 is that the twist ratio of the spiral stranding is 2; the ingot of 1 wt.% TiB2 / Al composite material is prepared by the mixed salt method, and the raw materials used are industrial pure aluminum, potassium fluoroborate (KBF4) with a purity of 99% and potassium fluorotitanate (K2TiF6) with a purity of 98%. The mixed salt is pressed into the aluminum melt in several batches using a bell jar according to the Ti:B molar ratio of 1:2. The mass ratio of the mixed salt to the aluminum melt is KBF4:K2TiF6:Al = 126:101:3500. The ingots obtained by the casting process with a melt temperature of 800℃ and a reaction time of 60min are first subjected to homogenization heat treatment: the temperature is raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, and then cooled in the furnace. The ingots are then drawn to obtain wire blanks, and then drawn multiple times to finally obtain aluminum-based composite wires with a diameter of 0.8mm. The volume fraction of TiB2 in the aluminum-based composite wires is 1wt.%. Based on the selected 1wt.% TiB2 / Al composite wire and Ti6Al4V wire, they were first pickled (for aluminum-based composite wire, a 2% HF + 3% HF + 5% HNO3 aqueous solution (volume fraction) was used to pickle the 1wt.% TiB2 / Al wire; for titanium alloy wire, a 5% HF + 30% HNO3 aqueous solution (volume fraction) was used to pickle the Ti6Al4V wire; finally, they were washed with water to remove the pickling solution and dried for later use) to remove surface oil and oxide film. Then, a multi-strand stranded welding wire was prepared using a stranding machine (twisting machine). The twist pitch T during the preparation process was 1.6 mm, the twist pitch multiple m was 2, and the corresponding helix angle was 17.66°, thus obtaining a 1×7 structure titanium-based composite multi-strand wire. Based on the above-mentioned filaments, a laser power of 1200W and a scanning speed of 300mm / min were used. An RC-LDM8060 powder-feed laser additive manufacturing equipment was employed, using a reciprocating deposition strategy, where the deposition direction of each subsequent layer is opposite to that of the previous layer. This additive manufacturing method suffers from drawbacks. Due to the low twist ratio of the helical strands, the cross-sectional area of ​​the multiple filaments varies significantly, which is detrimental to the stability of filament feeding. Consequently, the distribution of reinforcement in the prepared in-situ self-reinforced titanium matrix composite material is uneven and difficult to precisely control, resulting in poor mechanical property stability and anisotropy, thus hindering the further development and application of additively manufactured integrated titanium matrix composite structural components.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 1 is that an alternating feed of one core wire and one peripheral wire is used in the additive manufacturing process. A 1 wt.% TiB2 / Al composite ingot was prepared using a mixed salt method. The raw materials used were industrial pure aluminum, 99% pure potassium fluoroborate (KBF4), and 98% pure potassium fluorotitanate (K2TiF6). The mixed salt was injected into the molten aluminum in several batches using a bell jar at a Ti:B molar ratio of 1:2. The mass ratio of the mixed salt to the molten aluminum was KBF4:K2TiF6:Al = 126:101:3500. The ingots obtained through a casting process with a melt temperature of 800℃ and a reaction time of 60 min were first subjected to homogenization heat treatment: the temperature was raised to 350℃ in a vacuum heat treatment furnace at a heating rate of 10℃ / min and held for 2 hours, followed by furnace cooling. Then, a wire blank was obtained through drawing, and subsequent drawing was performed multiple times to finally obtain an aluminum-based composite wire with a diameter of 0.8 mm as the core wire. The volume fraction of TiB2 in the aluminum-based composite wire was 1 wt.%. Simultaneously, commercially available Ti6Al4V titanium alloy wire with a diameter of 0.8 mm was selected as the outer wire. Using process parameters of 1200W laser power and a scanning speed of 300 mm / min, and with an RC-LDM8060 powder-feed laser additive manufacturing equipment, the first layer was deposited as aluminum-based composite wire, and the second layer as titanium alloy wire. The titanium-based composite material was deposited through an alternating wire feeding method. Using this additive manufacturing method, because the aluminum-based composite filaments and titanium alloy filaments are deposited alternately, it is impossible to guarantee the uniformity of the material along the width travel direction, and the chemical reaction of the in-situ self-generated reinforcement cannot proceed fully. At the same time, the difference in heat dissipation conditions between the two ends and the middle stable section of the additive body will cause changes in the remelting depth, which in turn affects the precise control of the reaction ratio of the aluminum-based composite layer and the titanium alloy layer. This may lead to the formation of brittle phases such as titanium-aluminum intermetallic compounds, which seriously deteriorates the mechanical properties of the additive body.

[0076] In summary, the additive manufacturing method provided by this invention refines the matrix grains and reinforcement size through in-situ autogenous reactions during the melting and solidification process of multi-strand titanium-based composite materials. This enables precise control of the reinforcement size distribution, thereby significantly improving the strength and toughness of additively manufactured titanium-based composite materials. This method and technology can help guide the direct preparation of high-strength and high-toughness titanium-based composite materials and their components using fused wire additive manufacturing, and has important application value in the fields of aerospace and other major equipment.

[0077] It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

Claims

1. A method for in-situ self-generated titanium-based composite additive manufacturing based on multi-strand filaments, characterized in that, Includes the following steps: A. Aluminum-based composite material wire is used as the core wire; B. Use pure titanium or titanium alloy wire as the outer wire; C. Mix and twist the core wire and the outer wire together into one piece; D. In-situ self-reinforced titanium-based composite materials are prepared using a fused wire additive manufacturing method; wherein: The diameter of the core wire in step A is 0.08~2.4 mm, and the aluminum-based composite material wire includes a matrix and a reinforcing phase; The diameter of the outer wire mentioned in step B is 0.01~1.2 mm; The twisting method described in step C includes: the core wire is located in the middle, and the outer wires are spirally twisted; the spiral twisting structure includes one of 1×3, 1×7, and 3+3. The twist pitch T of the peripheral filaments in step C is m x (d 外 +d 核 ) / 2, where m is the twist pitch multiplier, d 外 is the diameter of the peripheral filaments, d 核 is the diameter of the core filaments, and 3.2 < m < 20.

2. The method according to claim 1, characterized in that, The matrix comprises pure aluminum or an aluminum alloy, and the reinforcing phase comprises at least one of TiB2, TiC, and SiC.

3. The method according to claim 1, characterized in that, The reinforcing phase is uniformly distributed within the aluminum matrix composite filament, and the mass fraction of the reinforcing phase in the aluminum matrix composite filament is 0.1~5 wt.%.

4. The method according to claim 1, characterized in that, The spiral angle of the outer yarn mentioned in step C is α, where α = arctan(m / 2π), and m is the twist ratio. 3.2 <m<20,26.99°<α<72.56°。 5. The method according to claim 1, characterized in that, The fused wire additive manufacturing method described in step D includes one of arc fused wire additive manufacturing, laser fused wire additive manufacturing, and electron beam fused wire additive manufacturing.

6. An in-situ self-reinforced titanium-based composite material prepared by the method according to any one of claims 1-5.

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