Additive manufacturing method and system for metal matrix fiber composite materials

Abstract

The present invention provides an additive manufacturing method and system for metal-based fiber composite materials, which adopts a fused deposition molding process to print a continuous fiber reinforcement layer on each substrate deposition layer, and uses a print head and a substrate that can move in a three-dimensional direction to perform multi-dimensional and multi-directional molding to improve processing efficiency. The continuous fibers are three-dimensionally woven to form a grid fiber structure, and the molded parts are processed by a laser-assisted sintering method to improve the density. The continuous fibers form a three-dimensional network structure in the final structure, greatly improving the performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing of metal-based continuous fiber composite materials, and in particular to an additive manufacturing method and system for metal-based fiber composite materials. Background Art

[0002] The aircraft landing gear is an accessory device at the bottom of the aircraft used to support the aircraft and move on the ground during takeoff, landing or ground taxiing. It is a key component that is subjected to force during takeoff and landing. It must absorb and dissipate the impact energy generated by the aircraft and the ground during landing and taxiing to ensure the safety of the aircraft during ground movement. Therefore, this requires the landing gear to have excellent performance.

[0003] The traditional material of landing gear is generally low-alloy high-strength steel, which has defects such as short service life and easy fracture. It is also increasingly difficult to meet the use requirements of new aircraft and their landing gear. Titanium alloy has the characteristics of high strength, high thermal strength, good corrosion resistance, low resonance coefficient, high elastic modulus, etc. It has good mechanical properties. At the same time, the density of titanium is usually about 4.51g / cm 3 , only 60% of steel, lighter, can be a good substitute for low alloy high strength steel. However, due to the high chemical activity and high strength of titanium, it is difficult to process by traditional forging and turning methods.

[0004] Additive manufacturing technology is to use the raw materials to form the final product by layer-by-layer accumulation. Compared with traditional manufacturing technology, the application of additive manufacturing technology to the manufacture of titanium alloys can solve the problem of titanium alloy processing difficulties to a certain extent. At the same time, the use of additive manufacturing technology to obtain components has a high material utilization rate, can form complex structures, and has a simple process, which can effectively reduce production costs.

[0005] However, the performance of titanium alloy parts produced by additive manufacturing is currently poor, and even after post-processing, it is difficult to meet the use requirements. Adding a reinforcing phase to the titanium alloy substrate can improve the mechanical properties of the material. For example, using particle-reinforced titanium-based composites, the mechanical properties are improved by adding SiC, TiC, etc., but particle reinforcement has limited effect on the improvement of the mechanical properties of the material. Adding continuous fibers to the titanium alloy substrate can also improve the mechanical properties of the material, but the two-dimensional woven structure currently used still has limited effect on improving the material performance, and the interface bonding strength of the composite material is not good. Summary of the invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and provide a novel additive manufacturing method and system for metal-based fiber composite materials. The method adopts a fused deposition molding process to print a continuous fiber reinforcement layer on each substrate deposition layer. A print head and a substrate that can move in three dimensions are used to perform multi-dimensional and multi-directional molding to improve processing efficiency. The continuous fibers are three-dimensionally woven to form a grid fiber structure. The molded parts are processed by a laser-assisted sintering method to improve the density. The continuous fibers form a three-dimensional network structure in the final structure, greatly improving the performance of the material.

[0007] A first aspect of the present invention relates to a method for additive manufacturing of a metal-based fiber composite material, comprising the following steps:

[0008] S1. Raw material silk making

[0009] Putting the metal substrate powder and the binder into a vacuum reactor in proportion, heating them under protective gas conditions, and mixing them to obtain a mixture by keeping the temperature and pressure, extruding the mixture to obtain a substrate wire material for later use;

[0010] After the surface of the continuous fiber is impregnated with a binder, a reinforcement wire material is obtained and is ready for use;

[0011] S2, Fused Deposition Modeling

[0012] The substrate filament and the reinforcement filament obtained in step S1 are respectively fed into the first print head and the second print head of the printer, and printing is started by using the fused deposition modeling process according to the preset program. The printing process is as follows:

[0013] S21, the first print head deposits the base material filament on the substrate according to the planned path to obtain a bottom base material deposition layer;

[0014] S22, the first print head deposits a single path of substrate filament along the edge of the bottom substrate deposition layer according to the planned path, and a single path of substrate deposition layer is obtained at the edge of the substrate deposition layer, and the deposition length is not less than 1 / 2 of the circumference of the bottom substrate deposition layer;

[0015] S23, the second printing head deposits a single reinforcement wire material on the single substrate deposition layer according to the printing path of the single substrate deposition layer to obtain a single reinforcement layer;

[0016] S24, alternately repeating steps S22 and S23 on a single reinforcement layer, accumulating layer by layer until the deposition is completed, to obtain a side deposition layer;

[0017] S25, a second print head deposits reinforcement filaments on the bottom substrate deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the bottom substrate deposition layer;

[0018] The second print head deposits reinforcement filaments on the side deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the side deposition layer;

[0019] S26, repeating steps S21, S22, S23, S24 and S25 in sequence on the bottom substrate deposition layer having the grid fiber structure, accumulating layer by layer until the deposition is completed, to obtain a formed blank;

[0020] S3, post-processing

[0021] The formed green body obtained in step S2 is subjected to laser-assisted sintering after part of the binder is removed to obtain a final component, wherein the continuous fibers form a three-dimensional network structure in the final component.

[0022] In an alternative embodiment, the metal substrate is titanium or a titanium alloy;

[0023] The continuous fiber is a mixture of one or more of carbon fiber, glass fiber, Kevlar fiber, carbon nanotube fiber, aramid fiber, basalt fiber, ceramic fiber and metal fiber.

[0024] In alternative embodiments, the binder is PEG and / or PMMA.

[0025] In an optional embodiment, specific parameters of the first print head include:

[0026] The printing temperature is 240-260°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0027] In an optional embodiment, specific parameters of the second print head include:

[0028] The printing temperature is 240-260°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0029] In an optional embodiment, the process parameters of laser assisted sintering include:

[0030] The preheating temperature is 60-120°C, the laser power is 20-30W, the scanning time is 1-2h, the scanning rate is 1500-2500mm / s, and the scanning spacing is 0.1-0.2mm.

[0031] In an optional embodiment, the manufacturing method further comprises:

[0032] The binder is heated and extruded to obtain a binder filament, which is then fed into the third print head of the printer. When the printed component has a structure that requires support, the third print head prints the support structure to a preset degree, and then continues printing along a preset path to obtain a molded body. The support structure is removed before laser-assisted sintering.

[0033] In an optional embodiment, specific parameters of the third print head include:

[0034] The printing temperature is 180-220°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0035] A second aspect of the present invention relates to a metal-based fiber composite material prepared according to the aforementioned additive manufacturing method.

[0036] The third aspect of the present invention also relates to an aircraft landing gear using the above-mentioned metal matrix fiber composite material.

[0037] A fourth aspect of the present invention also relates to an additive manufacturing system for a metal-based fiber composite material, comprising:

[0038] substrate;

[0039] A printing system disposed above the substrate is provided with at least three print heads, including a first print head for printing the metal substrate, a second print head for printing the reinforcement, and a third print head for printing the support structure;

[0040] The substrate and each print head can move in three dimensions, and multi-dimensional and multi-directional molding can be achieved to realize three-dimensional weaving of the reinforcement.

[0041] The feeding system is provided with at least three wire feeding mechanisms, which are respectively connected to the printing heads, and each wire material is fed into the corresponding printing head through the wire feeding mechanisms.

[0042] In summary, the additive manufacturing method and system of the metal-based fiber composite material proposed in the present invention have the following advantages:

[0043] The present invention adopts a fused deposition modeling process, uses multiple print heads, and combines a multi-dimensional processing strategy to enable the continuous fibers as a reinforcement phase to form a grid fiber structure on each layer of matrix deposition layer, and finally form a three-dimensional network structure in the molded part. The continuous fibers form a three-dimensional network structure in the metal matrix, which can better bear the load, provide strength and rigidity. The three-dimensional network structure can concentrate the residual stress of the material on the interface between the fiber and the matrix, so that the residual stress distribution from the fiber to the matrix is ​​relatively gentle and uniform, which affects the initiation and expansion of microcracks. The three-dimensional network structure has a good interface with the substrate, thereby affecting the macroscopic mechanical properties of the composite material, greatly improving the mechanical properties of the material, and processing the molded part in combination with the laser-assisted sintering method to improve the density and the physical properties of the molded part.

[0044] The system proposed in the present invention can enable the print head and the substrate to move in three-dimensional directions, and can perform multi-dimensional and multi-directional molding, thereby improving work efficiency. The continuous fibers can be three-dimensionally woven to form a grid fiber structure, and ultimately a three-dimensional network structure of the continuous fibers can be obtained, thereby realizing three-dimensional weaving in the integrated 3D printing process.

[0045] The system of the present invention is also provided with a support structure print head, which uses a binder as a support material, and can be directly removed frequently by a water-soluble method in the future. The removal efficiency is good, the removal effect is good, and the printer can be prevented from being polluted, so that the printer has better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the additive manufacturing process of the additive manufacturing system of the metal-based fiber composite material of the present invention.

[0047] Figure 2 It is a partial structural schematic diagram of an exemplary additive manufacturing system for metal-based fiber composite materials of the present invention.

[0048] Figure 3 It is a schematic diagram of the process flow of the additive manufacturing method of the metal-based fiber composite material of the present invention.

[0049] Figure 4 It is a schematic diagram of an exemplary process of printing parts without support bodies according to the present invention.

[0050] Figure 5 It is a schematic diagram of an exemplary process of printing a part requiring a support body according to the present invention.

[0051] Figure 6 It is a schematic diagram of the parts structure printed in Example 3 of the present invention. DETAILED DESCRIPTION

[0052] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0053] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways.

[0054] The fused deposition modeling (FDM) process is to granulate powder and binder, and then use a wire making machine to form a special wire for metal materials. The metal wire is fed into the printing nozzle to heat and melt the binder. The sample is obtained by 3D printing layer by layer, and then the binder in the product is removed by a degreasing process. Finally, sintering is performed to obtain the final sample.

[0055] Based on this, the present invention provides a method for additive manufacturing of metal-based continuous fiber composite materials, which adopts a three-print head printing method to print the matrix material, reinforcing material, and binder respectively. The three print heads and the substrate are controlled by three-dimensional forming manufacturing software and can move in the X, Y, and Z directions. Multi-dimensional and multi-directional forming can be achieved to improve processing efficiency. At the same time, the three-dimensional forming software can generate multiple processing strategies, so that the print head can move in three-dimensional directions to perform three-dimensional weaving of continuous fibers to form a grid fiber structure, thereby greatly improving the performance of the material.

[0056] Additive Manufacturing Systems for Metal Matrix Fiber Composites

[0057] Combination Figure 1 and Figure 2 The additive manufacturing system of the metal matrix fiber composite material of the exemplary embodiment shown includes:

[0058] The substrate 10 is used as a working platform for printing components.

[0059] The printing system 20 disposed above the substrate 10 is provided with at least three print heads, including a first print head 21 for printing the metal substrate, a second print head 22 for printing the reinforcement, and a third print head 23 for printing the support structure; the print head can be a commercially available FDM general print head.

[0060] The substrate 10 and each print head can move in three dimensions. In a specific embodiment, Figure 2 As shown, a robotic arm can be used to achieve movement in three-dimensional directions, thereby achieving multi-dimensional and multi-directional forming in the additive manufacturing process and achieving three-dimensional weaving of the reinforcement.

[0061] The feeding system 30 is provided with at least three wire feeding mechanisms 31, which are respectively connected to the printing heads. Each wire material is fed into the corresponding printing head through the wire feeding mechanism 31; the wire feeding mechanism can adopt the wire feeding mechanism commonly used in the field of additive manufacturing.

[0062] Additive manufacturing method for metal matrix fiber composites

[0063] Combination Figure 3 The process shown in the figure, combined with the additive manufacturing system of the metal-based fiber composite material of the aforementioned embodiment of the present invention, uses the additive manufacturing process of the metal-based fiber composite material to include the following steps:

[0064] S1. Raw material silk making

[0065] Putting the metal substrate powder and the binder into a vacuum reactor in proportion, heating them under protective gas conditions, and mixing them to obtain a mixture by keeping the temperature and pressure, extruding the mixture to obtain a substrate wire material for later use;

[0066] After the surface of the continuous fiber is impregnated with a binder, a reinforcement wire material is obtained and is ready for use;

[0067] S2, Fused Deposition Modeling

[0068] The substrate filament and the reinforcement filament obtained in step S1 are respectively fed into the first print head and the second print head of the printer, and printing is started by using the fused deposition modeling process according to the preset program. The printing process is as follows:

[0069] S21, the first print head deposits the base material filament on the substrate according to the planned path to obtain a bottom base material deposition layer;

[0070] S22, the first print head deposits a single path of substrate filament along the edge of the bottom substrate deposition layer according to the planned path, and a single path of substrate deposition layer is obtained at the edge of the substrate deposition layer, and the deposition length is not less than 1 / 2 of the circumference of the bottom substrate deposition layer;

[0071] It can be understood that the principle of selecting the deposition length is to keep the final side from collapsing;

[0072] S23, the second printing head deposits a single reinforcement wire material on the single substrate deposition layer according to the printing path of the single substrate deposition layer to obtain a single reinforcement layer;

[0073] S24, alternately repeating steps S22 and S23 on a single reinforcement layer, accumulating layer by layer until the deposition is completed, to obtain a side deposition layer;

[0074] S25, a second print head deposits reinforcement filaments on the bottom substrate deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the bottom substrate deposition layer;

[0075] The second print head deposits reinforcement filaments on the side deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the side deposition layer;

[0076] It can be understood that the reinforcement wires may be crisscrossed orthogonally or non-orthogonally, as long as a grid structure is formed.

[0077] S26, repeating steps S21, S22, S23, S24 and S25 in sequence on the bottom substrate deposition layer having the grid fiber structure, accumulating layer by layer until the deposition is completed, to obtain a formed blank;

[0078] S3, post-processing

[0079] The formed green body obtained in step S2 is subjected to laser-assisted sintering after part of the binder is removed to obtain a final component, wherein the continuous fibers form a three-dimensional network structure in the final component.

[0080] In an optional embodiment, the manufacturing method further comprises:

[0081] The binder is heated and extruded to obtain a binder filament, which is then fed into the third print head of the printer. When the printed component has a structure that requires support, the third print head prints the support structure to a preset degree, and then continues printing along a preset path to obtain a molded body. The support structure is removed before laser-assisted sintering.

[0082] As a specific example, combining Figure 4 The process shown in the figure takes the preparation of a cube part as an example. The additive manufacturing method of metal matrix fiber composite materials mainly includes the following steps:

[0083] 1. Prepare three types of silk materials respectively

[0084] [Preparation of matrix wire]

[0085] After the metal powder is dried, the binder and the metal powder are put into a stainless steel reactor with a jacket according to a certain proportion, and the reactor is sealed, evacuated, and protected with nitrogen.

[0086] The temperature was gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure were maintained for 2 hours. Under vigorous stirring, the mixture was evenly mixed to obtain a mixture. The mixture was extruded into wires with a diameter of 0.5mm to 2mm on a hydraulic press, and then the wires used for 3D printing were quickly cooled by an air cooling device.

[0087] [Preparation of reinforcement wire]

[0088] Continuous fiber tows of 5-8 μm are selected and pre-impregnated in a binder, and then prepared into continuous pre-impregnated fiber tows.

[0089] 2. Insert different filaments into the corresponding printer heads (the print head for printing the metal substrate is defined as the first print head, and the print head for printing the reinforcement is defined as the second print head), perform structural design of composite parts on the host computer, and output the printed part model in STL format through 3D software. Slice the 3D model through slicing software, plan the trajectory, and generate a G code file containing the entire design information.

[0090] The 3D printing control system receives the design instructions from the host computer and compiles them into control signals. The control system completes the decoding of the G code and provides servo instructions to the servo driver. At the same time, it communicates with the auxiliary module through the serial port to control the temperature control module. The printer hardware executes the printing task according to the control signal of the printing control system.

[0091] 3. Body forming

[0092] Step 3-1: The substrate moves upward, and the first print head starts to print the base material to form a bottom surface.

[0093] Step 3-2: The first print head prints a layer along the X and Y directions of the bottom surface, and then the second print head prints a layer of fiber material along the path of the first print head. After printing the city, the second print head prints the base material along the printing path of the first print head, and repeats the process of one layer of fiber material and one layer of base material, accumulating layer by layer until two vertical surfaces are printed, which can be defined as surface 1 and surface 2.

[0094] Step 3-3: Then the second print head prints the fiber material on the bottom surface and surfaces 1 and 2 respectively. The fiber material is printed on each surface in an alternating and overlapping path to form a grid fiber distribution on each surface.

[0095] Step 3-4: Repeat steps 3-1, 3-2, and 3-3 in sequence to gradually accumulate into a block part blank.

[0096] 4. Finally, the continuous fiber reinforced composite material printed body is obtained through layer-by-layer 3D printing, and the final product is obtained through post-processing operations such as deburring and laser-assisted sintering.

[0097] In another specific example, combining Figure 5 The process shown in the figure takes the preparation of an italic part as an example. The additive manufacturing method of the metal matrix fiber composite material mainly includes the following steps:

[0098] 1. Prepare three types of silk materials respectively

[0099] [Preparation of matrix wire]

[0100] After the metal powder is dried, the binder and the metal powder are put into a stainless steel reactor with a jacket according to a certain proportion, and the reactor is sealed, evacuated, and protected with nitrogen.

[0101] The temperature was gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure were maintained for 2 hours. Under vigorous stirring, the mixture was evenly mixed to obtain a mixture. The mixture was extruded into wires with a diameter of 0.5mm to 2mm on a hydraulic press, and then the wires used for 3D printing were quickly cooled by an air cooling device.

[0102] [Preparation of reinforcement wire]

[0103] Continuous fiber tows of 5-8 μm are selected and pre-impregnated in a binder, and then prepared into continuous pre-impregnated fiber tows.

[0104] [Preparation of binder wire]

[0105] The binder is also prepared into 0.5 mm to 2 mm wires by heating and extruding.

[0106] 2. Insert different filaments into the corresponding printer heads (the print head for printing the metal substrate is defined as the first print head, the print head for printing the reinforcement is defined as the second print head, and the print head for printing the binder support is defined as the third print head), perform structural design of composite parts on the host computer, and output the printed part model in STL format through 3D software. Slice the 3D model through slicing software, plan the trajectory, and generate a G code file containing the entire design information.

[0107] The 3D printing control system receives the design instructions from the host computer and compiles them into control signals. The control system completes the decoding of the G code and provides servo instructions to the servo driver. At the same time, it communicates with the auxiliary module through the serial port to control the temperature control module. The printer hardware executes the printing task according to the control signal of the printing control system.

[0108] 3. Body forming

[0109] Step 3-1: The substrate moves upward, and the first print head starts to print the base material to form a bottom surface; at the same time, according to the angle of the inclined surface, the third print head prints the adhesive support.

[0110] Step 3-2: The first print head prints a layer along the X and Y directions of the bottom surface, and then the second print head prints a layer of fiber material along the path of the first print head. After printing the city, the second print head prints the base material along the printing path of the first print head, and repeats the process of one layer of fiber material and one layer of base material, accumulating layer by layer until two vertical surfaces are printed, which can be defined as surface 1 and surface 2.

[0111] Step 3-3: Then the second print head prints the fiber material on the bottom surface and surfaces 1 and 2 respectively. The fiber material is printed on each surface in an alternating and overlapping path to form a grid fiber distribution on each surface.

[0112] Step 3-4: Repeat steps 3-1, 3-2, and 3-3 in sequence to gradually accumulate into a block part blank.

[0113] 5. Finally, the continuous fiber reinforced composite material printed part is obtained through layer-by-layer 3D printing, and the final product is obtained through post-processing operations such as deburring, binder support degreasing, and laser-assisted sintering.

[0114] In an alternative embodiment, the metal substrate is titanium or a titanium alloy;

[0115] The continuous fiber is a mixture of one or more of carbon fiber, glass fiber, Kevlar fiber, carbon nanotube fiber, aramid fiber, basalt fiber, ceramic fiber and metal fiber.

[0116] It should be understood that the particle size of the metal substrate powder and the diameter of the wire can be selected according to actual conditions and are not further limited herein.

[0117] In an optional embodiment, the binder is PEG and / or PMMA, and a water-soluble binder is used. A water bath heating method is used to remove most of the binder components before laser-assisted sintering, because C and Ti will react to produce titanium carbide, which will reduce the strength and affect the mechanical properties of the material. Removing most of the binder can reduce the contamination of elements C and O to titanium alloy parts, and reduce the impact of the binder on the quality of the printer.

[0118] It is understandable that when a binder is needed to print the support part, the selected binder can be the same as the binder composition used in the metal powder wire making process, or it can be different, but a water-soluble binder should be used, and most of the binder should be removed by water bath heating after the blank is formed. The support part will also be partially removed by water bath heating and become loose. At this time, you only need to take away the remaining part directly. The temperature and time of water bath heating can be determined according to actual conditions and are not further limited here.

[0119] In another optional embodiment, a binder component is prepared by using 65-85% PEG+10-25% PMMA+1-10% SA in a mass fraction, wherein SA is a powder surfactant and a lubricant.

[0120] It can be understood that the ratio of metal powder to binder is generally that the metal powder content is higher, which can be determined according to the actual process and is not further limited here.

[0121] In a preferred embodiment, the process parameters of additive manufacturing and laser-assisted sintering are determined according to the parameters of the titanium alloy workpiece.

[0122] In an optional embodiment, specific parameters of the first print head include:

[0123] The printing temperature is 240-260°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0124] In an optional embodiment, specific parameters of the second print head include:

[0125] The printing temperature is 240-260°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0126] In an optional embodiment, the process parameters of laser assisted sintering include:

[0127] The preheating temperature is 60-120°C, the laser power is 20-30W, the scanning time is 1-2h, the scanning rate is 1500-2500mm / s, and the scanning spacing is 0.1-0.2mm.

[0128] In an optional embodiment, specific parameters of the third print head include:

[0129] The printing temperature is 180-220°C, the temperature of the hot bed is 60-120°C, the feed speed is 1-10cm / s, and the layer lifting amount is 0.1-0.5mm.

[0130] The present invention also provides a metal-based fiber composite material prepared according to the aforementioned additive manufacturing method, and an aircraft landing gear using the metal-based fiber composite material. The obtained aircraft landing gear can meet the use requirements and has excellent mechanical properties.

[0131] For better understanding, the present invention is further described below in conjunction with several specific examples, but the processing technology is not limited thereto, and the content of the present invention is not limited thereto.

[0132] The following examples and comparative examples use TC4 titanium alloy powder as the metal substrate, with a particle size of 53 to 250 μm. The specific composition is shown in Table 1.

[0133] The carbon fiber is T700 with a diameter of 7 μm; the silicon carbide fiber is SCS-UItra with a diameter of 140 μm.

[0134] Table 1 Chemical composition of TC4 alloy powder (wt.%)

[0135] Brand Ti Al V Fe C N H TC4 margin 5.50-6.75 3.5-4.5 ＜0.30 ＜008 ＜0.05 ＜0.015

[0136] Example 1

[0137] Printing size of 30mm×30mm×30mm cubic parts, the binder formula is 85% PEG+14% PMMA+1% SA

[0138] Step 1: After the continuous carbon fiber tow is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. The impregnated filament is then extruded from the nozzle by a single screw extrusion movement. The filament used for 3D printing is quickly cooled by an air cooling device.

[0139] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0140] Step 2: Insert different filaments into the corresponding printer heads, and the printer hardware executes the printing task according to the control signal of the printing control system. The parameters of print head 1 and print head 2 are: printing temperature is 240℃, hot bed temperature is 100℃, feed speed is 2cm / s, and single printing layer thickness is 0.1mm.

[0141] ① The substrate moves upward, and the first print head starts to print the base material to form a bottom surface.

[0142] ② The first print head prints a layer along the X and Y directions of the bottom surface, and then the second print head prints a layer of fiber material along the path of the first print head. After printing the city, the second print head prints the base material along the printing path of the first print head, and repeats the process of one layer of fiber material and one layer of base material, accumulating layer by layer until two vertical surfaces are printed, which can be defined as surface 1 and surface 2.

[0143] ③Then the second print head prints the fiber material on the bottom surface and surfaces 1 and 2 respectively. The fiber material is printed on each surface in an alternating and overlapping path to form a grid fiber distribution on each surface.

[0144] ④ Repeat steps ①, ②, and ③ in sequence to gradually accumulate into a block part blank.

[0145] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, and then place the deburred printed part in an 80°C water bath for 2 hours to remove 60% PEG and most of the SA, and reduce the contamination of elements C and O to the titanium alloy parts.

[0146] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 82°C, laser power 25W, time 1.5h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0147] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0148] Example 2

[0149] Printing size of 30mm×30mm×30mm cubic parts, the binder formula is 70% PEG+20% PMMA+10% SA

[0150] Step 1: After the continuous silicon carbide fiber bundle is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. Then the impregnated filament is extruded from the nozzle through a single screw extrusion movement, and the filament used for 3D printing is quickly cooled by an air cooling device.

[0151] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0152] Step 2: Insert different filaments into the corresponding printer heads, and the printer hardware executes the printing task according to the control signal of the printing control system. The parameters of print head 1 and print head 2 are: printing temperature is 260℃, hot bed temperature is 120℃, feed speed is 5cm / s, and single printing layer thickness is 0.1mm.

[0153] ① The substrate moves upward, and the first print head starts to print the base material to form a bottom surface.

[0154] ② The first print head prints a layer along the X and Y directions of the bottom surface, and then the second print head prints a layer of fiber material along the path of the first print head. After printing the city, the second print head prints the base material along the printing path of the first print head, and repeats the process of one layer of fiber material and one layer of base material, accumulating layer by layer until two vertical surfaces are printed, which can be defined as surface 1 and surface 2.

[0155] ③Then the second print head prints the fiber material on the bottom surface and surfaces 1 and 2 respectively. The fiber material is printed on each surface in an alternating and overlapping path to form a grid fiber distribution on each surface.

[0156] ④ Repeat steps ①, ②, and ③ in sequence to gradually accumulate into a block part blank.

[0157] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, and then place the deburred printed part in an 80°C water bath for 2 hours to remove 60% PEG and most of the SA, and reduce the contamination of elements C and O to the titanium alloy parts.

[0158] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 100°C, laser power 25W, time 2h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0159] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0160] Example 3

[0161] like Figure 6 As shown, the printed size is 20mm×20mm×50mm, the tilt angle is 45°, and the binder formula is 70% PEG+20% PMMA+10% SA

[0162] Step 1: After the continuous silicon carbide fiber bundle is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. Then the impregnated filament is extruded from the nozzle through a single screw extrusion movement, and the filament used for 3D printing is quickly cooled by an air cooling device.

[0163] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0164] After the adhesive is prepared according to the formula of 70% PEG+20% PMMA+10% SA, it is poured into a single-screw extruder to be extruded into a wire with a diameter of 2 mm, and then quickly cooled by an air cooling device.

[0165] Step 2: Insert different filaments into the corresponding printer heads, and the printer hardware executes the printing task according to the control signal of the printing control system. The parameters of print head 1 and print head 2 are: printing temperature is 260℃, hot bed temperature is 120℃, feed speed is 5cm / s, and single printing layer thickness is 0.1mm; the parameters of print head 3 are: printing temperature is 220℃, hot bed temperature is 100℃, feed speed is 5cm / s, and single printing layer thickness is 0.1mm.

[0166] ① The substrate moves upward, and the first print head starts to print the base material to form a bottom surface; at the same time, according to the angle of the inclined surface, the third print head prints the adhesive support.

[0167] ② The first print head prints a layer along the X and Y directions of the bottom surface, and then the second print head prints a layer of fiber material along the path of the first print head. After printing the city, the second print head prints the base material along the printing path of the first print head, and repeats the process of one layer of fiber material and one layer of base material, accumulating layer by layer until two vertical surfaces are printed, which can be defined as surface 1 and surface 2.

[0168] ③Then the second print head prints the fiber material on the bottom surface and surfaces 1 and 2 respectively. The fiber material is printed on each surface in an alternating and overlapping path to form a grid fiber distribution on each surface.

[0169] ④ Repeat steps ①, ②, and ③ in sequence to gradually accumulate into a block part blank.

[0170] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, then place the deburred printed part in an 80℃ water bath for 2 hours to remove 60% PEG and most of the PA, and then use tweezers to remove the support.

[0171] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 100°C, laser power 25W, time 2h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0172] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0173] Comparative Example 1

[0174] The printed parts and materials used are the same as those in Example 1.

[0175] Step 1: After the continuous carbon fiber tow is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. The impregnated filament is then extruded from the nozzle by a single screw extrusion movement. The filament used for 3D printing is quickly cooled by an air cooling device.

[0176] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0177] Step 2: Use a traditional dual-nozzle FDM printer to insert different filaments into their corresponding printer heads. The printer hardware executes the printing task according to the control signal of the printing control system. Print head No. 1 first prints a layer of base material on the substrate, and then nozzle No. 2 prints a grid-like fiber material on the base material. Repeat the overlapping printing until the deposition is completed.

[0178] The parameters of print head 1 and print head 2 are: printing temperature is 240°C, the temperature of the hot bed is 100°C, the feed speed is 2cm / s, and the single printing layer thickness is 0.1mm.

[0179] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, and then place the deburred printed part in an 80°C water bath for 2 hours to remove 60% PEG and most of the SA, and reduce the contamination of elements C and O to the titanium alloy parts.

[0180] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 82°C, laser power 25W, time 1.5h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0181] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0182] Comparative Example 2

[0183] The printed parts and materials used are the same as those in Example 1.

[0184] Step 1: After the continuous carbon fiber tow is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. The impregnated filament is then extruded from the nozzle by a single screw extrusion movement. The filament used for 3D printing is quickly cooled by an air cooling device.

[0185] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0186] Step 2: Use a traditional dual-nozzle FDM printer to insert different filaments into their corresponding printer heads. The printer hardware executes the printing task according to the control signal of the printing control system. Print head No. 1 first prints a layer of base material on the substrate, and then nozzle No. 2 prints a U-shaped fiber material on the base material. Repeat the overlapping printing until the deposition is completed.

[0187] The parameters of print head 1 and print head 2 are: printing temperature is 240°C, the temperature of the hot bed is 100°C, the feed speed is 2cm / s, and the single printing layer thickness is 0.1mm.

[0188] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, and then place the deburred printed part in an 80°C water bath for 2 hours to remove 60% PEG and most of the SA, and reduce the contamination of elements C and O to the titanium alloy parts.

[0189] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 82°C, laser power 25W, time 1.5h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0190] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0191] Comparative Example 3

[0192] The printed parts and materials used are the same as those in Example 3.

[0193] Step 1: After the continuous silicon carbide fiber bundle is dried, it is driven by a roller into an impregnation tank containing a binder for impregnation. The roller moves at a speed of 2m / min. Then the impregnated filament is extruded from the nozzle through a single screw extrusion movement, and the filament used for 3D printing is quickly cooled by an air cooling device.

[0194] After drying the TC4 powder, the binder and metal powder are put into a jacketed stainless steel reactor in a ratio of 1:2. The reactor is sealed, evacuated, and protected with nitrogen. The temperature is gradually raised to 250°C at a rate of 2°C / min, and the temperature and pressure are maintained for 2 hours. Under vigorous stirring, the mixture is evenly mixed to obtain a mixture, which is extruded into a wire with a diameter of 2mm on a single screw extruder, and then the wire used for 3D printing is quickly cooled by an air cooling device.

[0195] After the adhesive is prepared according to the formula of 70% PEG+20% PMMA+10% SA, it is poured into a single-screw extruder to be extruded into a wire with a diameter of 2 mm, and then quickly cooled by an air cooling device.

[0196] Step 2: Use a traditional dual-nozzle FDM printer to insert different filaments into their corresponding printer heads. The printer hardware executes the printing task according to the control signal of the printing control system. Print head No. 1 first prints a layer of base material on the substrate, head No. 3 prints the support body, and nozzle No. 2 prints a grid-like fiber material on the base material. Repeat the overlapping printing until the deposition is completed.

[0197] The parameters of print head 1 and print head 2 are: printing temperature is 240℃, hot bed temperature is 100℃, feed speed is 2cm / s, and single print layer thickness is 0.1mm; the parameters of print head 3 are: printing temperature is 220℃, hot bed temperature is 100℃, feed speed is 5cm / s, and single print layer thickness is 0.1mm.

[0198] Step 3: After printing, perform simple surface treatment on the printed part to remove burrs, then place the deburred printed part in an 80℃ water bath for 2 hours to remove 60% PEG and most of the PA, and then use tweezers to remove the support.

[0199] Step 4: Place the printed part completed in step 3 into a laser sintering furnace for laser-assisted sintering. The set process parameters are: preheating temperature 100°C, laser power 25W, time 2h, scanning rate 2000mm / s, and scanning spacing 0.15mm.

[0200] Step 5: After sintering is completed and completely cooled, turn off the cooling system and remove the printed continuous fiber composite part.

[0201] test

[0202] The molded parts of Examples 1-3 and Comparative Examples 1-3 were subjected to strength tests such as tensile tests. The test results are shown in Table 2.

[0203] Table 2

[0204]

[0205] The results show that the parts printed by the method of the present invention have good strength and modulus, are corrosion-resistant, have a small linear expansion coefficient, good flexibility, and better wettability between the part reinforcement and the matrix. This is because the reinforcement phase forms a three-dimensional network structure in the molded part, and the continuous fibers form a three-dimensional network structure in the metal matrix that can better bear the load, provide strength and stiffness. The three-dimensional network structure can concentrate the residual stress of the material on the interface between the fiber and the matrix, so that the residual stress distribution from the fiber to the matrix is ​​relatively gentle and uniform, which affects the initiation and expansion of microcracks. The three-dimensional network structure has a good interface bonding with the substrate, thereby affecting the macroscopic mechanical properties of the composite material. Compared with the two-dimensional structure, it greatly improves the mechanical properties of the material.

[0206] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A method for additive manufacturing of a metal-based fiber composite material, characterized in that: The following steps are involved: S1. Raw material silk making Putting the metal substrate powder and the binder into a vacuum reactor in proportion, heating them under protective gas conditions, and mixing them to obtain a mixture by keeping the temperature and pressure, extruding the mixture to obtain a substrate wire material for later use; After the surface of the continuous fiber is impregnated with a binder, a reinforcement wire material is obtained and is ready for use; S2, Fused Deposition Modeling The substrate filament and the reinforcement filament obtained in step S1 are respectively fed into the first print head and the second print head of the printer, and printing is started by using the fused deposition modeling process according to the preset program. The printing process is as follows: S21, the first print head deposits the base material filament on the substrate according to the planned path to obtain a bottom base material deposition layer; S22, the first print head deposits a single path of substrate filament along the edge of the bottom substrate deposition layer according to the planned path, and a single path of substrate deposition layer is obtained at the edge of the substrate deposition layer, and the deposition length is not less than 1 / 2 of the circumference of the bottom substrate deposition layer; S23, the second printing head deposits a single reinforcement wire material on the single substrate deposition layer according to the printing path of the single substrate deposition layer to obtain a single reinforcement layer; S24, alternately repeating steps S22 and S23 on a single reinforcement layer, accumulating layer by layer until the deposition is completed, to obtain a side deposition layer; S25, a second print head deposits reinforcement filaments on the bottom substrate deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the bottom substrate deposition layer; The second print head deposits reinforcement filaments on the side deposition layer, wherein the reinforcement filaments are crisscrossed to form a grid fiber structure on the side deposition layer; S26, repeating steps S21, S22, S23, S24 and S25 in sequence on the bottom substrate deposition layer having the grid fiber structure, accumulating layer by layer until the deposition is completed, to obtain a formed blank; S3, post-processing The formed green body obtained in step S2 is subjected to laser-assisted sintering after part of the binder is removed to obtain a final component, wherein the continuous fibers form a three-dimensional network structure in the final component.

2. The additive manufacturing method of metal matrix fiber composite material according to claim 1, characterized in that: The metal substrate is titanium or titanium alloy; The continuous fiber is a mixture of one or more of carbon fiber, glass fiber, Kevlar fiber, carbon nanotube fiber, aramid fiber, basalt fiber, ceramic fiber and metal fiber.

3. The additive manufacturing method of the metal matrix fiber composite material according to claim 1, characterized in that: The binder is PEG and / or PMMA.

4. The additive manufacturing method of the metal matrix fiber composite material according to claim 1, characterized in that: The specific parameters of the first print head include: The printing temperature is 240~260℃, the temperature of the hot bed is 60~120℃, the feed speed is 1~10cm / s, and the layer lifting amount is 0.1~0.5mm.

5. The additive manufacturing method of metal matrix fiber composite material according to claim 1, characterized in that: The specific parameters of the second print head include: The printing temperature is 240~260℃, the temperature of the hot bed is 60~120℃, the feed speed is 1~10cm / s, and the layer lifting amount is 0.1~0.5mm.

6. The additive manufacturing method of metal matrix fiber composite material according to claim 1, characterized in that: The process parameters of laser-assisted sintering include: The preheating temperature is 60~120℃, the laser power is 20~30 W, the scanning time is 1~2h, the scanning rate is 1500~2500 mm / s, and the scanning spacing is 0.1~0.2mm.

7. The additive manufacturing method of metal matrix fiber composite material according to claim 1, characterized in that: The manufacturing method further comprises: The binder is heated and extruded to obtain a binder filament, which is then fed into the third print head of the printer. When the printed component has a structure that requires support, the third print head prints the support structure to a preset degree, and then continues printing along a preset path to obtain a molded body. The support structure is removed before laser-assisted sintering.

8. The additive manufacturing method of metal matrix fiber composite material according to claim 7, characterized in that: The specific parameters of the third print head include: The printing temperature is 180~220℃, the temperature of the hot bed is 60~120℃, the feed speed is 1~10cm / s, and the layer lifting amount is 0.1~0.5mm.

9. A metal-based fiber composite material prepared by the additive manufacturing method according to any one of claims 1 to 8.

10. An aircraft landing gear using the metal matrix fiber composite material according to claim 9.

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