A method of composite additive manufacturing of metal matrix composites

Abstract

The present application relates to the technical fields of laser additive manufacturing, and discloses a kind of metal matrix composite composite additive manufacturing methods, comprising: the mixing of pre-prepared composite powder, substrate pretreatment, laser bottom layer cladding preparation bottom layer structure;Electron beam selective melting additive preparation main functional layer, obtain rough parts;Rough parts post-processing.The present application improves the wettability between metal matrix and TiC reinforcing phase through the transition effect of laser cladding bottom layer and hot isostatic pressing post-processing, improves the interface bonding strength, avoids the interface peeling problem under load;Through laser cladding, realize rapid bottom layer forming, electron beam selective melting ensures high-precision functional layer manufacturing, and is suitable for the integrated manufacturing of complex structure (such as hollow, thin-walled) metal matrix composite parts.

Description

Technical Field

[0001] This invention relates to the field of laser additive manufacturing technology, and more specifically, to a method for composite additive manufacturing of metal matrix composite materials. Background Technology

[0002] Currently, additive manufacturing processes for metal matrix composites mainly include single processes such as selective laser melting (SLM), electron beam melting (EBM), and laser cladding. Among them, selective laser melting has the advantages of high forming accuracy and high part density, but it suffers from low manufacturing efficiency and difficulty in controlling the dispersion of reinforcing phase particles, which easily leads to the agglomeration of reinforcing phases. Electron beam melting is suitable for manufacturing high-melting-point metal matrix composites and has relatively low thermal stress during forming, but it is prone to interfacial reactions with highly reactive reinforcing phases (such as ceramic particles), which reduces material properties, and the equipment operating cost is relatively high. Laser cladding has the advantages of high manufacturing efficiency and high coating-matrix bonding strength, but the forming accuracy is low, making it difficult to meet the manufacturing requirements of complex and precision structural parts.

[0003] In practical applications, existing technologies do not offer additive manufacturing processes that integrate laser cladding and electron beam melting (EBM). Only one of these processes is used for additive manufacturing. However, when using a single additive manufacturing process to prepare metal matrix composites, the following technical bottlenecks are commonly encountered: poor interfacial wettability between the metal matrix and the reinforcing phase, easily forming interfacial voids or brittle reaction layers, resulting in low interfacial bonding strength; uneven dispersion of the reinforcing phase in the metal matrix, forming localized enrichment zones, affecting the consistency of material properties; rapid solidification of the molten pool, easily generating internal defects such as pores and microcracks, reducing the fatigue life and reliability of the parts; and the difficulty of simultaneously meeting the dual requirements of "rapid prototyping" and "high precision and high performance" with a single process, limiting the large-scale application of complex structure high-performance metal matrix composite parts.

[0004] Therefore, developing an additive manufacturing method for metal matrix composites that can achieve uniform dispersion of reinforcing phases, excellent interfacial bonding performance, controllable internal defects, and strong process compatibility has become a technical problem that urgently needs to be solved in this field.

[0005] Therefore, proposing a composite additive manufacturing method for metal matrix composite materials has significant practical implications. Summary of the Invention

[0006] In view of this, the present invention proposes a method for composite additive manufacturing of metal matrix composite materials, which aims to solve at least one of the problems in the background art.

[0007] This invention proposes a method for composite additive manufacturing of metal matrix composite materials, comprising the following steps:

[0008] Select the appropriate alloy powder as the metal matrix powder according to the material of the target part;

[0009] TiC ceramic particles and the metal matrix powder were ball-milled and then vacuum-dried to obtain a pre-prepared composite powder.

[0010] Using an alloy plate of the same material as a substrate, the substrate is polished and ultrasonically cleaned, dried and then vacuum preheated. The preheated substrate is then laser-clad with the pre-made composite powder to obtain the underlying structure.

[0011] The underlying structure is subjected to electron beam selective melting additive manufacturing using the pre-made composite powder in a vacuum environment according to the target part size, while ultrasonic vibration is performed simultaneously to obtain the rough-added part;

[0012] The roughened part is subjected to hot isostatic pressing, then heated and held at a certain temperature, and then cooled to obtain the target part.

[0013] Preferably, the ball milling medium for the ball milling and mixing process is anhydrous ethanol, the ball-to-material ratio is 8:1, the ball milling speed is 300-350 r / min, and the ball milling time is 4-6 h.

[0014] Preferably, the vacuum drying temperature is 60-80℃ and the drying time is 8-10h.

[0015] Preferably, the cleaning solution used in the ultrasonic cleaning is an acetone solution, the ultrasonic frequency is 40-50kHz, and the ultrasonic power is 150-200W.

[0016] Preferably, the vacuum preheating treatment is as follows: in a vacuum environment with a vacuum degree of less than or equal to 10 Pa, preheating to 300-350°C in an argon atmosphere and holding for 2 hours.

[0017] Preferably, the laser power of the laser cladding layer is 1800-2000W, the scanning speed is 8-10mm / s, the spot diameter is 3-5mm, the powder feeding speed is 20-25g / min, the protective gas is argon, the protective gas flow rate is 20-25L / min, the number of cladding layers is 2-3, and the thickness of a single layer is 0.3-0.5mm.

[0018] Preferably, in the electron beam selective melting additive manufacturing process, the accelerating voltage of the electron beam is 60kV, the beam current is 20-30mA, the scanning strategy is island scanning, the island size is 5×5mm, the scanning spacing is 0.1-0.15mm, and the single-layer additive thickness is 0.05-0.08mm.

[0019] Preferably, the ultrasonic vibration has an ultrasonic frequency of 20-30 kHz and an amplitude of 5-10 μm.

[0020] Preferably, the hot isostatic pressing treatment is performed at a temperature of 920-950℃, a pressure of 100-120MPa, and a holding time of 3-4h.

[0021] Preferably, the heating temperature for the heating and heat preservation is 700-750℃, and the heat preservation time is 2 hours.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) This invention first achieves rapid bottom layer forming through laser cladding, and then ensures high-precision functional layer manufacturing through electron beam selective melting. It is suitable for integrated manufacturing of complex structure (such as hollow, thin-walled) metal matrix composite parts. By combining laser cladding process with electron beam selective melting process, an additive manufacturing process that takes into account both "rapid prototyping" and "high precision and high performance" is realized.

[0024] (2) The present invention improves the wettability between the metal matrix and the TiC reinforced phase through the transition effect of laser cladding and hot isostatic pressing post-treatment, thereby enhancing the interfacial bonding strength and avoiding the problem of interfacial peeling under load.

[0025] (3) The present invention breaks up the reinforcing phase agglomerates by introducing online ultrasonic vibration, so that TiC particles are uniformly dispersed in the metal matrix, reducing the material anisotropy coefficient and ensuring the consistency of performance.

[0026] (4) The present invention reduces the internal porosity of the parts, reduces the crack density, and significantly improves the fatigue life by combining composite additive manufacturing with hot isostatic pressing post-treatment. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0028] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] This invention provides a method for composite additive manufacturing of metal matrix composite materials, comprising the following steps:

[0033] Select the appropriate alloy powder as the metal matrix powder according to the material of the target part;

[0034] TiC ceramic particles and the metal matrix powder were ball-milled and then vacuum-dried to obtain a pre-prepared composite powder.

[0035] Using an alloy plate of the same material as a substrate, the substrate is polished and ultrasonically cleaned, dried and then vacuum preheated. The preheated substrate is then laser-clad with the pre-made composite powder to obtain the underlying structure.

[0036] The underlying structure is subjected to electron beam selective melting additive manufacturing using the pre-made composite powder in a vacuum environment according to the target part size, while ultrasonic vibration is performed simultaneously to obtain the rough-added part;

[0037] The roughened part is subjected to hot isostatic pressing, then heated and held at a certain temperature, and then cooled to obtain the target part.

[0038] Specifically, the particle size of the metal matrix powder is preferably 20-50 μm, the particle size of the TiC ceramic particles is preferably 5-15 μm, and the mass ratio of the TiC ceramic particles to the metal matrix powder is (1-1.5):10.

[0039] Specifically, after vacuum drying, the pre-made composite powder is passed through a 100-mesh sieve to obtain a uniformly dispersed powder.

[0040] Specifically, when polishing the substrate, 400#, 800#, and 1200# sandpaper are used in sequence to remove surface oxide scale and oil stains.

[0041] It is understood that the present invention improves the wettability between the metal matrix and the TiC reinforced phase through the transition effect of laser cladding and hot isostatic pressing post-treatment, thereby enhancing the interfacial bonding strength and avoiding the problem of interfacial peeling under load.

[0042] Understandably, this invention breaks up the reinforcing phase agglomerates by introducing online ultrasonic vibration, which allows TiC particles to be uniformly dispersed in the metal matrix, reduces the anisotropy coefficient of the material, and ensures consistent performance.

[0043] It is understandable that this invention, through composite additive manufacturing combined with hot isostatic pressing post-treatment, reduces the internal porosity of parts, lowers crack density, and significantly improves fatigue life.

[0044] It is understood that this invention achieves rapid bottom-layer forming through laser cladding and ensures high-precision functional layer manufacturing through selective electron beam melting, making it suitable for the integrated manufacturing of complex structures (such as hollowed-out, thin-walled) metal matrix composite parts.

[0045] In this invention, the ball milling medium for the ball milling and mixing process is preferably anhydrous ethanol, the ball-to-material ratio is preferably 8:1, the ball milling speed is preferably 300-350 r / min, and the ball milling time is preferably 4-6 h.

[0046] Specifically, TiC ceramic particles and the metal matrix powder are placed in a planetary ball mill, anhydrous ethanol is used as the ball milling medium, the mass ratio of stainless steel grinding balls to powder is 8:1, the ball milling speed is 300-350 r / min, the ball milling time is 4-6 h, and argon gas is introduced during the ball milling process to prevent powder oxidation.

[0047] Understandably, using anhydrous ethanol as the ball milling medium can prevent powder drying and agglomeration. Combined with a ball-to-powder mass ratio of 8:1, a ball milling speed of 300-350 r / min, and a ball milling time of 4-6 h, it can achieve thorough mixing and appropriate refinement of the metal matrix powder and the reinforcing phase powder, ensuring the uniformity of the pre-formed composite powder composition. At the same time, the introduction of argon gas during the ball milling process can effectively isolate air and prevent the powder from oxidizing and deteriorating during the ball milling process. This provides a pre-formed powder with pure composition and good dispersibility for subsequent additive manufacturing, laying the foundation for improving the interfacial bonding performance and mechanical property stability of the final composite material.

[0048] In this invention, the drying temperature of the vacuum drying is preferably 60-80℃, and the drying time is preferably 8-10h.

[0049] Specifically, after ball milling, the slurry is vacuum dried (vacuum degree ≤ 5Pa, drying temperature 60-80℃, drying time 8-10h), and then passed through a 100-mesh sieve to obtain a uniformly dispersed pre-composite powder.

[0050] Understandably, vacuum drying, with a high vacuum of ≤5Pa, a suitable temperature of 60-80℃, and a sufficient time of 8-10 hours, can efficiently remove anhydrous ethanol from the slurry, while preventing the powder from oxidizing or deteriorating and agglomerating due to excessive temperature during the drying process. Subsequent sieving through a 100-mesh sieve can further screen out powder with uniform particle size, removing any large particles or insufficiently dispersed agglomerates, ultimately obtaining a pre-formed composite powder with excellent dispersibility and particle size uniformity. This lays the foundation for uniform powder feeding and stable molten pool formation during subsequent laser cladding and selective electron beam melting, ensuring the consistency and stability of the final composite material parts' performance.

[0051] In this invention, the cleaning solution for ultrasonic cleaning is acetone solution, the ultrasonic frequency is preferably 40-50kHz, and the ultrasonic power is preferably 150-200W.

[0052] Specifically, the polished substrate is placed in an acetone solution for ultrasonic cleaning for 30-40 minutes at an ultrasonic frequency of 40-50 kHz and an ultrasonic power of 150-200 W. Then it is rinsed with anhydrous ethanol 2-3 times and air-dried at room temperature.

[0053] Understandably, a 40-50kHz ultrasonic frequency and 150-200W ultrasonic power combined with a 30-40 minute cleaning time can efficiently remove oil and residual oxide scale from the substrate surface through cavitation effect, resulting in thorough cleaning without damaging the substrate surface. Subsequent anhydrous ethanol rinsing can quickly remove residual acetone medium, avoiding adverse effects of chemical residues on subsequent cladding bonding. Room temperature drying can prevent secondary contamination or oxidation of the substrate during the drying process, ultimately providing clean and activated surface conditions for a tight bond between the laser cladding underlayer and the substrate, ensuring the bonding strength of the underlayer.

[0054] In this invention, the vacuum preheating treatment is as follows: under a vacuum environment with a vacuum degree of less than or equal to 10 Pa, preheating to 300-350°C in an argon atmosphere and holding for 2 hours.

[0055] Specifically, the dried substrate is placed in a vacuum heating furnace with a vacuum degree ≤10Pa, preheated to 300-350℃ in an argon atmosphere, and held for 2 hours.

[0056] Understandably, a vacuum heating furnace with a vacuum level of ≤10Pa, combined with an argon atmosphere, can effectively isolate air and prevent the substrate from oxidizing during preheating to form a new oxide scale, thus ensuring the cleanliness of the substrate surface. A preheating temperature of 300-350℃ and a holding time of 2 hours can effectively eliminate the internal stress generated by the substrate in the early processing while avoiding overheating and deformation. At the same time, it can make the overall temperature of the substrate uniform, reduce the temperature difference and thermal stress between the substrate and the cladding layer during subsequent laser cladding, provide stable temperature conditions for the tight bonding between the bottom cladding and the substrate, and further improve the interfacial bonding strength.

[0057] In this invention, the laser power of the laser cladding layer is preferably 1800-2000W, the scanning speed is preferably 8-10mm / s, the spot diameter is preferably 3-5mm, the powder feeding speed is preferably 20-25g / min, the protective gas is preferably argon, the protective gas flow rate is preferably 20-25L / min, the number of cladding layers is preferably 2-3 layers, and the thickness of a single layer is preferably 0.3-0.5mm.

[0058] Specifically, the dried substrate is fixed on a laser cladding stage, and a CO2 laser (wavelength 10.6μm) is used for the bottom layer cladding. The laser power is set to 1800-2000W, the scanning speed is 8-10mm / s, the spot diameter is 3-5mm, the powder feed rate is 20-25g / min, the protective gas is argon, and the flow rate is 20-25L / min. During the cladding process, the pre-made composite powder is uniformly fed into the molten pool through an inert gas nozzle. The number of cladding layers is 2-3, and the thickness of each layer is controlled at 0.3-0.5mm, forming a bottom layer structure with a thickness of 0.6-1.5mm.

[0059] Understandably, using a 10.6μm wavelength CO2 laser facilitates efficient absorption of laser energy by the metal substrate. The combination of parameters—1800-2000W power, 8-10mm / s scanning speed, and 3-5mm spot diameter—allows for precise control of the molten pool temperature and solidification rate, reducing defects such as porosity and cracks. A powder feed rate of 20-25g / min, combined with inert gas nozzle feeding, ensures that the pre-prepared composite powder enters the molten pool uniformly, guaranteeing the compositional uniformity of the cladding layer. Argon protection at a flow rate of 20-25L / min effectively isolates the powder and molten pool from air, preventing oxidation of the powder and molten pool during the cladding process. The arrangement of 2-3 layers, each 0.3-0.5mm thick, forms a 0.6-1.5mm thick bottom layer structure, ensuring a tight bond with the pre-treated substrate and providing a flat and solid transition substrate for the subsequent electron beam selective melting of the functional layer, thus improving the interlayer bonding strength of the overall structure.

[0060] In this invention, the accelerating voltage of the electron beam in the electron beam selective melting additive manufacturing is preferably 60kV, the beam current is preferably 20-30mA, the scanning strategy is preferably island scanning, the island size is preferably 5×5mm, the scanning spacing is preferably 0.1-0.15mm, and the single-layer additive thickness is preferably 0.05-0.08mm.

[0061] Specifically, the substrate with the laser-coated underlayer is transferred to the vacuum chamber of the electron beam selective melting equipment, and the vacuum level is evacuated to 5×10⁻⁶. -3 Below Pa; the pre-fabricated composite powder is selectively melted using an electron beam (accelerating voltage 60kV, beam current 20-30mA), with an island scanning strategy, island size 5×5mm, and scanning interval 0.1-0.15mm; during the melting process, an online ultrasonic vibration device is simultaneously activated, with an ultrasonic frequency of 20-30kHz, amplitude of 5-10μm, and ultrasonic vibration direction perpendicular to the substrate surface, wherein the thickness of a single layer of additive material is 0.05-0.08mm, and layers are stacked one by one according to the part design dimensions until completion.

[0062] Understandably, the vacuum level was evacuated to 5×10 -3 Below Pa, air is effectively isolated, preventing oxidation and contamination of the molten pool and powder. Electron beam parameters of 60kV acceleration voltage and 20-30mA beam current allow for precise control of energy input, ensuring full melting of the pre-formed composite powder and preventing overheating damage to the highly active reinforcing phase. The combination of island scanning (island size 5×5mm) and 0.1-0.15mm scanning spacing reduces thermal stress concentration and lowers the risk of part deformation and cracking. Simultaneously initiated vertical ultrasonic vibration at a frequency of 20-30kHz and an amplitude of 5-10μm strongly promotes molten pool convection, breaking up reinforcing phase aggregates and achieving uniform dispersion. A single-layer additive thickness of 0.05-0.08mm combined with layer-by-layer stacking ensures the forming accuracy and density of the functional layer, ultimately providing high-quality metal matrix composite functional layers with uniform performance and excellent precision for complex structural parts.

[0063] In this invention, the ultrasonic frequency of the ultrasonic vibration is 20-30kHz and the amplitude is 5-10μm.

[0064] Specifically, the ultrasonic frequency is 20-30kHz, the amplitude is 5-10μm, and the ultrasonic vibration direction is perpendicular to the substrate surface. Ultrasonic vibration promotes molten pool convection, breaks up the agglomerates of the reinforcing phase, and achieves uniform dispersion of TiC particles.

[0065] In this invention, the preferred temperature for the hot isostatic pressing treatment is 920-950℃, the preferred pressure is 100-120MPa, and the preferred holding time is 3-4h.

[0066] Specifically, the coarse additive is cut and separated from the substrate using wire cutting at a speed of 1-2 mm / min to avoid thermal damage. The part is then placed in a hot isostatic press and held at 920-950℃ and 100-120 MPa for 3-4 hours to eliminate internal pores and microcracks.

[0067] Understandably, a temperature of 920-950℃ and a pressure of 100-120MPa, combined with a holding time of 3-4 hours, can provide a sufficient high-temperature and high-pressure densification environment for the parts. This can effectively promote the closure of internal pores and the healing of microcracks, significantly reducing the internal defect rate of the parts. At the same time, this process can also improve the interfacial bonding between the metal matrix and the reinforcing phase, further enhancing the material density and structural integrity. This lays a good foundation for subsequent heat treatment to control the microstructure and improve mechanical properties, ensuring the fatigue life and reliability of the parts.

[0068] In this invention, the heating temperature for heating and heat preservation is preferably 700-750℃, and the heat preservation time is preferably 2h.

[0069] Specifically, the parts are heated to 700-750℃, held at that temperature for 2 hours, and then cooled to room temperature in the furnace.

[0070] Understandably, a heating temperature of 700-750℃ and a holding time of 2 hours can promote the recovery and recrystallization of the metal matrix, refining the grain structure, while avoiding excessive growth of the reinforcing phase or intensification of interfacial reactions. The furnace cooling method can achieve slow cooling, effectively reducing the thermal stress generated during the cooling process, preventing deformation or cracking of parts, and ultimately further controlling the microstructure of the material, optimizing the matching of strength and toughness, and ensuring the stability of the mechanical properties and reliability of the parts.

[0071] Example 1

[0072] S1. Select TC4 titanium alloy powder with a particle size of 20-50μm as the metal matrix powder and TiC ceramic particles with a particle size of 5-15μm as the reinforcing phase powder. Mix TiC ceramic particles and TC4 titanium alloy powder at a mass ratio of 1.2:10. Place the mixed powder in a planetary ball mill, use anhydrous ethanol as the ball milling medium, and the mass ratio of stainless steel grinding balls to powder is 8:1. The ball milling speed is 330r / min, and the ball milling time is 5h. Argon gas is introduced for protection during the ball milling process. After ball milling, the slurry is vacuum dried (vacuum degree ≤5Pa, drying temperature 70℃, drying time 9h) and passed through a 100-mesh sieve to obtain the pre-made composite powder.

[0073] S2. TC4 titanium alloy plate with a thickness of 13mm was selected as the substrate. The surface of the substrate was polished with 400#, 800# and 1200# sandpaper in sequence to remove the surface oxide scale and oil. Then, the substrate was ultrasonically cleaned in acetone solution for 35 minutes at an ultrasonic frequency of 45kHz and an ultrasonic power of 180W. It was then rinsed twice with anhydrous ethanol and air-dried at room temperature. Finally, the substrate was placed in a vacuum heating furnace with a vacuum degree ≤10Pa and preheated to 330℃ in an argon atmosphere for 2 hours for later use.

[0074] S3. Fix the processed substrate on the laser cladding stage and perform bottom layer cladding using a CO2 laser (wavelength 10.6μm); the laser power is set to 1900W, the scanning speed is 9mm / s, the spot diameter is 4mm, the powder feed rate is 23g / min, the protective gas is argon, and the flow rate is 23L / min; during the cladding process, the pre-made composite powder is uniformly fed into the molten pool through an inert gas nozzle, the number of cladding layers is 3, the thickness of each layer is controlled at 0.4mm, forming a bottom layer structure with a thickness of 1.2mm;

[0075] S4. Transfer the substrate with the bottom cladding completed to the vacuum chamber of the electron beam selective melting equipment, and evacuate the vacuum level to 5×10⁻⁶. -3 Below Pa; the pre-fabricated composite powder is selectively melted using an electron beam (accelerating voltage 60kV, beam current 25mA). The scanning strategy is island scanning, with an island size of 5×5mm, a scanning interval of 0.13mm, and a single-layer additive thickness of 0.06mm, until the additive process is completed, resulting in a rough part. During the melting process, an online ultrasonic vibration device is simultaneously activated with an ultrasonic frequency of 25kHz, an amplitude of 8μm, and an ultrasonic vibration direction perpendicular to the substrate surface.

[0076] S5. Cut the rough part from the substrate using wire cutting at a speed of 1.5 mm / min to avoid thermal damage. Then place the part in a hot isostatic press and hold it at 930°C and 110 MPa for 3.5 hours. Finally, perform heat treatment by heating the part to 730°C and holding it for 2 hours. Then, cool it to room temperature in the furnace to obtain the target part.

[0077] Example 2

[0078] S1. Select TC4 titanium alloy powder with a particle size of 20-50μm as the metal matrix powder and TiC ceramic particles with a particle size of 5-15μm as the reinforcing phase powder. Mix TiC ceramic particles and TC4 titanium alloy powder at a mass ratio of 1:10. Place the mixed powder in a planetary ball mill, use anhydrous ethanol as the ball milling medium, and the mass ratio of stainless steel grinding balls to powder is 8:1. The ball milling speed is 300r / min, and the ball milling time is 4h. Argon gas is introduced for protection during the ball milling process. After ball milling, the slurry is vacuum dried (vacuum degree ≤5Pa, drying temperature 60℃, drying time 8h) and passed through a 100-mesh sieve to obtain the pre-made composite powder.

[0079] S2. TC4 titanium alloy plate with a thickness of 10mm is selected as the substrate. The surface of the substrate is polished with 400#, 800# and 1200# sandpaper in sequence to remove the surface oxide scale and oil. Then, the substrate is ultrasonically cleaned in acetone solution for 30 minutes at an ultrasonic frequency of 40kHz and an ultrasonic power of 150W. It is then rinsed twice with anhydrous ethanol and air-dried at room temperature. Finally, the substrate is placed in a vacuum heating furnace with a vacuum degree ≤10Pa and preheated to 300℃ in an argon atmosphere for 2 hours for later use.

[0080] S3. Fix the processed substrate on the laser cladding stage and perform bottom layer cladding using a CO2 laser (wavelength 10.6μm); the laser power is set to 1800W, the scanning speed is 8mm / s, the spot diameter is 3mm, the powder feed rate is 20g / min, the protective gas is argon, and the flow rate is 20L / min; during the cladding process, the pre-made composite powder is uniformly fed into the molten pool through an inert gas nozzle, the number of cladding layers is 3, the thickness of each layer is controlled at 0.4mm, forming a bottom layer structure with a thickness of 1.2mm;

[0081] S4. Transfer the substrate with the bottom cladding completed to the vacuum chamber of the electron beam selective melting equipment, and evacuate the vacuum level to 5×10⁻⁶. -3 Below Pa; the pre-fabricated composite powder is selectively melted using an electron beam (accelerating voltage 60kV, beam current 20mA). The scanning strategy is island scanning, with an island size of 5×5mm, a scanning interval of 0.1mm, and a single-layer additive thickness of 0.05mm, until the additive process is completed to obtain a rough part. During the melting process, an online ultrasonic vibration device is simultaneously started with an ultrasonic frequency of 20kHz, an amplitude of 5μm, and an ultrasonic vibration direction perpendicular to the substrate surface.

[0082] S5. Cut the rough part from the substrate using wire cutting at a speed of 1 mm / min to avoid thermal damage. Then place the part in a hot isostatic press and hold it at 920℃ and 100MPa for 3 hours. Finally, perform heat treatment by heating the part to 700℃ and holding it for 2 hours. Then, cool it to room temperature in the furnace to obtain the target part.

[0083] Example 3

[0084] S1. Select TC4 titanium alloy powder with a particle size of 20-50μm as the metal matrix powder and TiC ceramic particles with a particle size of 5-15μm as the reinforcing phase powder. Mix TiC ceramic particles and TC4 titanium alloy powder at a mass ratio of 1.5:10. Place the mixed powder in a planetary ball mill, use anhydrous ethanol as the ball milling medium, and the mass ratio of stainless steel grinding balls to powder is 8:1. The ball milling speed is 350r / min, and the ball milling time is 6h. Argon gas is introduced for protection during the ball milling process. After ball milling, the slurry is vacuum dried (vacuum degree ≤5Pa, drying temperature 80℃, drying time 10h) and passed through a 100-mesh sieve to obtain the pre-made composite powder.

[0085] S2. TC4 titanium alloy plate with a thickness of 15mm is selected as the substrate. The surface of the substrate is polished with 400#, 800# and 1200# sandpaper in sequence to remove the surface oxide scale and oil. Then, the substrate is ultrasonically cleaned in acetone solution for 40 minutes at an ultrasonic frequency of 50kHz and an ultrasonic power of 200W. It is then rinsed three times with anhydrous ethanol and air-dried at room temperature. Finally, the substrate is placed in a vacuum heating furnace with a vacuum degree ≤10Pa and preheated to 350℃ in an argon atmosphere for 2 hours for later use.

[0086] S3. Fix the processed substrate on the laser cladding stage and perform bottom layer cladding using a CO2 laser (wavelength 10.6μm); the laser power is set to 2000W, the scanning speed is 10mm / s, the spot diameter is 5mm, the powder feed rate is 25g / min, the protective gas is argon, and the flow rate is 25L / min; during the cladding process, the pre-made composite powder is uniformly fed into the molten pool through an inert gas nozzle, the number of cladding layers is 3, the thickness of each layer is controlled at 0.4mm, forming a bottom layer structure with a thickness of 1.2mm;

[0087] S4. Transfer the substrate with the bottom cladding completed to the vacuum chamber of the electron beam selective melting equipment, and evacuate the vacuum level to 5×10⁻⁶. -3 Below Pa; the pre-fabricated composite powder is selectively melted using an electron beam (accelerating voltage 60kV, beam current 30mA). The scanning strategy is island scanning, with an island size of 5×5mm, a scanning interval of 0.15mm, and a single-layer additive thickness of 0.08mm, until the additive process is completed, resulting in a rough part. During the melting process, an online ultrasonic vibration device is simultaneously activated with an ultrasonic frequency of 30kHz, an amplitude of 10μm, and an ultrasonic vibration direction perpendicular to the substrate surface.

[0088] S5. Cut the rough part from the substrate using wire cutting at a speed of 2 mm / min to avoid thermal damage. Then place the part in a hot isostatic press and hold it at 950℃ and 120MPa for 4 hours. Finally, perform heat treatment by heating the part to 750℃ and holding it for 2 hours. Then, cool it to room temperature in the furnace to obtain the target part.

[0089] Effect test

[0090] TC4 titanium alloy powder (20-50μm) and TiC ceramic particles (5-15μm) were selected as raw materials and mixed at a mass ratio of 10:1.2. Samples with dimensions of 100mm×10mm×5mm were prepared using four processes: the method of Example 1 of this invention, selective laser melting (SLM), electron beam melting (EBM), and laser cladding. Performance tests were performed on each sample, and the test methods and results are shown in Table 1.

[0091] Table 1 Test methods and results

[0092]

[0093] As can be seen from Table 1 above, the parts prepared by the present invention are significantly superior to those prepared by traditional single processes in terms of core performance indicators such as interfacial bonding strength, enhanced phase dispersion uniformity, porosity and fatigue life. At the same time, with manufacturing efficiency close to that of laser cladding, the material utilization rate is higher, achieving synergistic optimization of "high performance" and "high efficiency and low cost", which fully demonstrates the beneficial effects of the present invention.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for composite additive manufacturing of metal matrix composite materials, characterized in that, Includes the following steps: Select the appropriate alloy powder as the metal matrix powder according to the material of the target part; TiC ceramic particles and the metal matrix powder were ball-milled and then vacuum-dried to obtain a pre-prepared composite powder. Using an alloy plate of the same material as a substrate, the substrate is polished and ultrasonically cleaned, dried and then vacuum preheated. The preheated substrate is then laser-clad with the pre-made composite powder to obtain the underlying structure. The underlying structure is subjected to electron beam selective melting additive manufacturing using the pre-made composite powder in a vacuum environment according to the target part size, while ultrasonic vibration is performed simultaneously to obtain the rough-added part; The roughened part is subjected to hot isostatic pressing, then heated and held at a certain temperature, and then cooled to obtain the target part.

2. The method for composite additive manufacturing of metal matrix composite materials according to claim 1, characterized in that, The ball milling medium used in the ball milling and mixing process is anhydrous ethanol, the ball-to-material ratio is 8:1, the ball milling speed is 300-350 r / min, and the ball milling time is 4-6 h.

3. The method for composite additive manufacturing of metal matrix composite materials according to claim 2, characterized in that, The vacuum drying process is carried out at a temperature of 60-80℃ for 8-10 hours.

4. The method for composite additive manufacturing of metal matrix composite materials according to claim 3, characterized in that, The ultrasonic cleaning solution is acetone solution, the ultrasonic frequency is 40-50kHz, and the ultrasonic power is 150-200W.

5. The method for composite additive manufacturing of metal matrix composite materials according to claim 4, characterized in that, The vacuum preheating treatment is as follows: under a vacuum environment with a vacuum degree of less than or equal to 10 Pa, preheat to 300-350℃ in an argon atmosphere and keep warm for 2 hours.

6. The method for composite additive manufacturing of metal matrix composite materials according to claim 5, characterized in that, The laser power for the laser cladding of the substrate is 1800-2000W, the scanning speed is 8-10mm / s, the spot diameter is 3-5mm, the powder feeding speed is 20-25g / min, the protective gas is argon, the protective gas flow rate is 20-25L / min, the number of cladding layers is 2-3, and the thickness of a single layer is 0.3-0.5mm.

7. The method for composite additive manufacturing of metal matrix composite materials according to claim 6, characterized in that, In the electron beam selective melting additive manufacturing process, the accelerating voltage of the electron beam is 60kV, the beam current is 20-30mA, the scanning strategy is island scanning, the island size is 5×5mm, the scanning spacing is 0.1-0.15mm, and the single-layer additive thickness is 0.05-0.08mm.

8. The method for composite additive manufacturing of metal matrix composite materials according to claim 7, characterized in that, The ultrasonic vibration has an ultrasonic frequency of 20-30kHz and an amplitude of 5-10μm.

9. The method for composite additive manufacturing of metal matrix composite materials according to claim 8, characterized in that, The hot isostatic pressing treatment is performed at a temperature of 920-950℃, a pressure of 100-120MPa, and a holding time of 3-4 hours.

10. The method for composite additive manufacturing of metal matrix composite materials according to claim 9, characterized in that, The heating temperature for the heating and heat preservation process is 700-750℃, and the heat preservation time is 2 hours.

Images