A laser composite additive manufacturing method based on pulsed laser control of molten pool flow

Abstract

The present application relates to the technical field of laser additive manufacturing, and discloses a laser composite additive manufacturing method based on pulse laser control of molten pool flow, comprising substrate processing, powder laying, additive manufacturing, remelting, forming and post-processing. In the additive manufacturing stage, the parameters of pulse laser and ultrasonic vibration are adjusted according to different stages of the molten pool, so that the molten pool convection is sufficient, the thermal stress in the solidification stage is significantly relieved, and the flow velocity is more uniform. Meanwhile, the present application also sets a remelting step, forms an excessive molten pool on the surface of the previous layer, reduces the thickness of the oxidation layer on the surface of the previous layer, and greatly improves the bonding strength between layers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser additive manufacturing, in particular to a laser composite additive manufacturing method based on pulse laser control of molten pool flow. BACKGROUND

[0002] Laser additive manufacturing (such as selective laser melting SLM, laser metal deposition LMD) has been widely used in the preparation of complex components due to its high forming freedom, but the existing technology has the following key defects:

[0003] 1. Molten pool flow is out of control: the existing continuous laser or fixed parameter pulse laser cannot adapt to the flow requirements of the three stages of "formation-expansion-solidification" of the molten pool, which easily leads to pores (insufficient convection of the molten pool), cracks (concentration of thermal stress in the solidification stage), and composition segregation (uneven flow speed);

[0004] 2. Weak interlayer bonding: when the layers are directly stacked, the surface oxidation layer and the excessive roughness of the previous layer lead to low interlayer bonding strength.

[0005] Therefore, it is of great practical significance to propose a laser composite additive manufacturing method based on pulse laser control of molten pool flow. SUMMARY

[0006] In view of this, the present application proposes a laser composite additive manufacturing method based on pulse laser control of molten pool flow, aiming to solve at least one of the background technologies.

[0007] The present application proposes a laser composite additive manufacturing method based on pulse laser control of molten pool flow, comprising the following steps:

[0008] Substrate treatment: selecting a substrate corresponding to the target metal component and pretreating the substrate;

[0009] Powder laying: fixing the pretreated substrate on the workbench of the additive manufacturing equipment, selecting metal powder of the same material as the substrate, and laying powder on the surface of the substrate using a powder laying device;

[0010] Additive manufacturing: presetting a laser scanning path, performing pulse laser scanning treatment and ultrasonic vibration treatment on the metal powder to form a molten pool, and adjusting the parameters of pulse laser scanning treatment and ultrasonic vibration treatment according to different periods of the molten pool until single-layer additive manufacturing is completed;

[0011] Remelting: remelting and cooling the single-layer additive using pulse laser;

[0012] Forming: laying powder on the surface of the remelted layer using a powder laying device, repeating the additive manufacturing step and the remelting step to form a powder-laying-additive-remelting cycle until the target metal component is formed;

[0013] Post-processing: the metal member after forming is post-processed.

[0014] Preferably, the pre-treatment specifically refers to:

[0015] The substrate is placed in anhydrous ethanol for ultrasonic cleaning, and after the end, the cleaned substrate surface is polished, and the substrate is vacuum preheated after polishing.

[0016] Preferably, the frequency of the ultrasonic cleaning is 40 kHz, and the cleaning time is 10-15 minutes; the vacuum degree of the vacuum preheating treatment is less than or equal to 5x10 -3 Pa, and the holding time is 30-60 min.

[0017] Preferably, the powder laying speed is 10 mm / s, and the powder thickness is 0.3 mm.

[0018] Preferably, the additive includes:

[0019] The peak temperature of the molten pool, the diameter of the molten pool, and the flow speed of the molten pool are collected in real time;

[0020] The pulsed laser scans the metal powder at a pulse frequency of 50 kHz and an energy density of 400 J / cm 2 The pulsed laser scans the metal powder at a pulse frequency of 50 kHz and an energy density of 400 J / cm

[0021] When the diameter of the molten pool is equal to 0.5 times the diameter of the laser spot, and the peak temperature of the molten pool is 200℃ above the melting point of the metal powder, the laser frequency of the pulsed laser scanning is increased to 150 kHz, and the energy density is reduced to 250 J / cm 2 , and the scanning speed is kept at 1500 mm / s;

[0022] When the flow speed of the molten pool is between 8 mm / s and 12 mm / s, the diameter of the molten pool is between 1-1.5 times the diameter of the laser spot, and the peak temperature of the molten pool is between 50-200℃ above the melting point of the metal powder, the laser frequency of the pulsed laser scanning is increased to 300 kHz, and the energy density is reduced to 100 J / cm 2 , and the scanning speed is kept at 1500 mm / s;

[0023] When the preset scanning path is completed and the peak temperature of the molten pool is 50℃ below the melting point of the metal powder, the flow speed of the molten pool is less than or equal to 1 mm / s, and the diameter of the molten pool is 0.3 mm, a single layer of additive is completed.

[0024] Preferably, the remelting specifically comprises: presetting a laser scanning path, adjusting the frequency of the pulsed laser to 250 kHz, and adjusting the energy density to 120 J / cm 2 The completed single layer surface is subjected to remelting.

[0025] Preferably, the preset laser scanning path during the remelting and the preset laser scanning path during the adding are crossed at 90°, the melting thickness is 5-10 μm, and the surface is cooled for 10 min after the remelting is completed.

[0026] Preferably, during the forming step, the average temperature of the surface is detected every 5 layers, if the temperature is less than 300℃, the forming is continued; if the temperature is greater than or equal to 300℃, the forming is performed after the surface is naturally cooled to 150℃.

[0027] Every 10 layers, the difference between the actual height of the forming and the target height is detected, wherein the target height = the number of cycles x 0.3 mm, and if the difference is greater than 0.05, the powder thickness of the next layer is adjusted.

[0028] Preferably, the post-processing specifically comprises: taking out the target metal component after the component is cooled to room temperature, performing low-temperature aging treatment, and then performing component separation and polishing treatment.

[0029] Preferably, Ar gas is continuously introduced at a flow rate of 15 L / min during the powder laying, adding, remelting and forming stages.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] (1) The present application adjusts the parameters of the pulsed laser and ultrasonic vibration according to different stages of the molten pool, so that the convection of the molten pool is sufficient, the thermal stress during the solidification stage is significantly relieved, and the flow velocity is more uniform.

[0032] (2) The present application forms an excessive molten pool on the surface of the previous layer by remelting, reduces the thickness of the oxidation layer on the surface of the previous layer, and greatly improves the bonding strength between the layers. DETAILED DESCRIPTION

[0033] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application. It should be understood that the terms described in the present application are only for describing the particular embodiments, and are not intended to limit the present application.

[0034] Also, for ranges of values, the disclosure herein also contemplates each and every value and sub-range within the range. For example, where a range of values is provided, it is intended to encompass every possible sub-range

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described herein.

[0036] Many modifications and variations of this application can be made without departing from its spirit or scope, which will be apparent to those skilled in the art. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0037] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed material or step.

[0038] The present application provides a laser composite additive manufacturing method based on pulsed laser control of molten pool flow, comprising the following steps:

[0039] Substrate treatment: selecting a substrate corresponding to the target metal component, and pretreating the substrate;

[0040] Powder laying: fixing the pretreated substrate on the workbench of the additive manufacturing equipment, selecting metal powder of the same material as the substrate, and laying powder on the surface of the substrate using a powder laying device;

[0041] Additive manufacturing: presetting a laser scanning path, and performing pulsed laser scanning and ultrasonic vibration treatment on the metal powder to form a molten pool, during which the parameters of the pulsed laser scanning and ultrasonic vibration treatment are adjusted according to different periods of the molten pool until single-layer additive manufacturing is completed;

[0042] Remelting: remelting and cooling the single-layer additive using pulsed laser;

[0043] Shaping: laying powder on the surface of the remelted layer using a powder laying device, repeating the additive manufacturing step and the remelting step, forming a powder-additive-remelting cycle, and shaping the target metal component until the target metal component is shaped;

[0044] Post-processing: post-processing the shaped metal component.

[0045] It can be understood that the present application makes the molten pool convection sufficient, the solidification stage thermal stress significantly alleviated and the flow velocity more uniform by adjusting the parameters of the pulsed laser and ultrasonic vibration for different stages of the molten pool.

[0046] It can be understood that the present application reduces the thickness of the oxidation layer on the surface of the previous layer by forming an excessive molten pool on the surface of the previous layer through remelting, and greatly improves the bonding strength between the layers.

[0047] In the present application, the pretreatment is specifically:

[0048] The substrate is placed in anhydrous ethanol for ultrasonic cleaning, and after the end, the cleaned substrate surface is polished, and the substrate is vacuum preheated after polishing.

[0049] The frequency of the ultrasonic cleaning is 40 kHz, and the cleaning time is 10-15 minutes; the vacuum degree of the vacuum preheating treatment is less than or equal to 5x10 -3 Pa, and the holding time is 30-60 min.

[0050] The ultrasonic cleaning step is preferably, a single-tank ultrasonic cleaning machine is selected, anhydrous ethanol is injected into the tank, and the injection amount is based on the liquid level height completely immersing the substrate; the substrate is placed in a 304 stainless steel cleaning basket, and the cleaning basket is placed in the ultrasonic tank to ensure that the substrate does not directly contact the tank wall; the frequency and cleaning time are set, and after the end, the substrate is taken out and nitrogen is used to blow along the surface of the substrate until there is no ethanol residue on the surface.

[0051] The polishing step is preferably, a handheld grinder is used to polish the cleaned substrate, and when polishing, 800 mesh sandpaper is used to polish the surface of the substrate, 3-5 times per square centimeter, and then 1200 mesh sandpaper is used for fine grinding, 5-8 times per square centimeter.

[0052] The vacuum preheating treatment step is preferably, the polished substrate is placed in the tray of a ZK-2 type vacuum furnace, the furnace door is closed, the vacuum pump is started, and the vacuum degree is less than or equal to 5x10 -3 Pa, and after reaching, the pressure is maintained for 5 min; the temperature of the substrate is increased at a rate of 5℃ / min (the specific temperature increase is determined according to the material quality of the substrate), and the holding time is 45 min; stop heating, keep vacuum state and naturally cool to below 150℃, introduce nitrogen to break the vacuum, take out the substrate, and cool to room temperature in a desiccator containing silica gel desiccant.

[0053] The substrate is sequentially subjected to ultrasonic cleaning, polishing and vacuum preheating, which can lay a stable foundation for subsequent additive manufacturing from three aspects of surface cleanliness, surface flatness, internal stress and temperature adaptability: the 40kHz ultrasonic wave cooperates with anhydrous ethanol cleaning to completely remove impurities such as oil stains and dust on the surface of the substrate (to avoid impurities forming inclusions or causing local oxidation in the molten pool, and reducing porosity defects); the 800-1200 mesh sandpaper polishing makes the surface roughness of the substrate reduce to Ra≤1.6μm (to ensure the uniformity of subsequent powder spreading, prevent uneven molten pool flow speed caused by surface concave-convex, and avoid component segregation); and the vacuum preheating with a vacuum degree less than or equal to 5×10 -3 Pa can not only eliminate the internal residual stress of the substrate (to avoid thermal shock cracks caused by large temperature difference between the molten pool and the substrate during additive manufacturing), but also remove the water vapor adsorbed on the surface of the substrate (to prevent bubbles caused by water vapor entering the molten pool), and the three synergistic effects ensure the good combination of the substrate and the molten pool, and provide key protection for the stable operation of subsequent pulse laser-ultrasonic composite additive manufacturing and the final quality of the component (such as mechanical properties and dimensional accuracy).

[0054] In the present application, the powder spreading speed is preferably 10mm / s, and the powder thickness is preferably 0.3mm.

[0055] The powder spreading step is preferably:

[0056] The metal powder of the same material as the substrate is selected, the metal powder is poured into a vacuum drying box to dry at a temperature of 90℃ and a vacuum degree of 50Pa for 3 hours, and after the end, the vacuum state is maintained to cool to below 50℃, nitrogen is introduced to break the vacuum, and the metal powder is taken out;

[0057] A scraper type powder spreader (material: tungsten carbide, scraper thickness: 5mm, blade flatness≤0.01mm) is selected, and the dried metal powder is poured into the powder spreader hopper for powder spreading.

[0058] It can be understood that the powder spreading speed of 10mm / s is in the medium speed range of industrial powder spreading, which can not only avoid uneven powder spreading caused by too high speed (such as local accumulation or missing spreading), but also avoid reducing the forming efficiency caused by too low speed, and ensure that the density fluctuation amplitude of the powder layer on the substrate surface is small, which lays a foundation for uniform molten pool formation; the powder spreading thickness of 0.3mm matches the laser spot diameter (0.3mm), which can make the pulse laser energy completely penetrate the powder layer and fully melt the powder, avoid the bottom layer powder not being fused caused by too thick thickness, and avoid the laser energy penetrating too much caused by too thin thickness (burning the substrate surface, affecting the bonding strength).

[0059] In the present application, the additive manufacturing includes:

[0060] The peak temperature of the molten pool, the diameter of the molten pool and the flow speed of the molten pool are collected in real time;

[0061] With a pulse frequency of 50kHz and a speed of 400J / cm 2 The metal powder is subjected to pulsed laser scanning at an energy density of 1500 mm / s, while the metal powder is subjected to ultrasonic vibration at a frequency of 80 kHz.

[0062] When the diameter of the molten pool is equal to 0.5 times the diameter of the laser spot, and the peak temperature of the molten pool is above 200°C (the melting point of the metal powder), the laser frequency of the pulsed laser scanning process is increased to 150 kHz, and the energy density is reduced to 250 J / cm². 2 The scanning speed is maintained at 1500 mm / s;

[0063] When the molten pool flow velocity is between 8 mm / s and 12 mm / s, the molten pool diameter is between 1 and 1.5 times the laser spot diameter, and the peak temperature of the molten pool is between 50 and 200°C higher than the melting point of the metal powder, the laser frequency of the pulsed laser scanning process is increased to 300 kHz, and the energy density is reduced to 100 J / cm³. 2 The scanning speed is maintained at 1500 mm / s;

[0064] When the preset scanning path is completed and the peak temperature of the molten pool is 50°C lower than the melting point of the metal powder, the flow velocity of the molten pool is less than or equal to 1 mm / s, and the diameter of the molten pool is 0.3 mm, the single-layer additive manufacturing is completed.

[0065] The additive manufacturing equipment is:

[0066] Pulsed laser generator (IPG YLR-1000-P type, wavelength 1064nm, maximum output power 1000W).

[0067] An ultrasonic vibration device (such as the JZ-200 model, with a maximum amplitude of 20μm) is fixed to the center of the bottom of the worktable (rigidly connected to the worktable).

[0068] The protective atmosphere system is supplied with Ar gas (purity 99.999%) at a flow rate of 15 L / min (monitored in real time by a flow meter, with an error ≤ ±0.5 L / min).

[0069] High-speed camera systems (such as the Phantom V2512, 1000fps) 4 fps, resolution 1280×800): Mounted on top of the work chamber, with the lens vertically aligned with the molten pool area, equipped with a 10x microscope lens (Navitar 12X), and the focus adjusted to clearly capture the molten pool in the range of 0.1-1mm;

[0070] Infrared temperature measuring instrument (such as Optris PI 450, temperature measuring range 500-3000℃): installed beside the high-speed camera system, measuring distance 300mm.

[0071] It can be understood that the present application can accurately capture the molten pool state by collecting the peak temperature, diameter and flow velocity of the molten pool in real time, provide data support for dynamic parameter adjustment, and avoid defects caused by blind regulation; during the formation period of the molten pool, the initial pulse frequency is 50kHz, the energy density is 400J / cm 2 The pulse laser with energy density (1500mm / s scanning speed) combined with 80kHz ultrasonic vibration processing can quickly melt the metal powder to form an initial molten pool, and at the same time, the initial bubble of the molten pool is broken by high-frequency ultrasonic waves to reduce the hidden danger of pores; when the diameter of the molten pool is 0.5 times the diameter of the laser spot and the peak temperature is 200℃ higher than the melting point of the metal, the molten pool enters the expansion period, and the laser frequency is increased to 50kHz and the energy density is reduced to 250J / cm 2 , which can accurately control the expansion rhythm of the molten pool and avoid excessive expansion of the molten pool to cause splashing or uneven convection; when the flow velocity of the molten pool is 8-12mm / s, the diameter is 1-1.5 times the diameter of the laser spot, and the peak temperature is 50-200℃ higher than the melting point, the molten pool enters the solidification period, and the laser frequency is further increased to 300kHz and the energy density is reduced to 100J / cm 2 , which can slow down the cooling rate of the molten pool, inhibit the growth of columnar crystals, and reduce the generation of cracks; finally, the single layer additive completion standard is that the preset scanning path is completed, the peak temperature of the molten pool is 50℃ lower than the melting point (to ensure complete solidification), the flow velocity is ≤1mm / s (no liquid flow), and the diameter is 0.3mm (matching the powder thickness), which can ensure stable single layer forming quality, avoid layer combination defects caused by incomplete solidification, and guarantee single layer size accuracy, laying a good foundation for subsequent multi-layer circulation and interlayer remelting, finally significantly reducing the problems of pores, cracks, composition segregation and the like of the component, and improving the mechanical properties and size accuracy of the component.

[0072] In the present application, the remelting specifically comprises: presetting a laser scanning path, adjusting the frequency of the pulse laser to 250kHz, and adjusting the energy density to 120J / cm 2 , and remelting the surface of the completed single layer.

[0073] The preset laser scanning path of the remelting and the preset laser scanning path of the additive are crossed at 90℃, the melting thickness is 5-10μm, and after completion, the cooling time is 10min.

[0074] The remelting is preferably: after the single layer additive is completed and naturally cooled to below 150 DEG C, presetting a laser scanning path, the preset laser scanning path and the preset laser scanning path during the additive are crossed at 90 DEG C (for example, the additive path is longitudinal, and the remelting path is transverse), the scanning range is consistent with the additive range, and the path spacing is 0.15 mm (0.5 times the spot diameter, to ensure that there is no missing melting area);

[0075] The frequency of the pulse laser generator is adjusted to 250 kHz, and the energy density is 120 J / cm 2 (lower than the additive stage, to avoid excessive melting), the scanning speed is 1200 mm / s (0.8 times the additive speed, to ensure sufficient remelting), the single layer surface is remelted, the melting thickness is 5-10 μm, and after completion, the cooling time is 10 min.

[0076] It can be understood that the interlayer pulse laser remelting in the present application does not need to additionally add equipment, directly uses the pulse laser device used for the additive, and through 250 kHz high frequency, 120 J / cm 2 low energy density, and 1200 mm / s scanning speed (and the scanning mode is crossed at 90 DEG C with the last layer additive path), the core defects of the prior art that the layers are directly overlapped can be efficiently solved: on the one hand, the 5-10 nm thick oxide layer on the surface of the last layer can be completely removed (reduced to below 1-2 nm), the surface roughness of the last layer is reduced, and the "barrier layer" of the layer combination is eliminated; on the other hand, the 5-10 μm deep area of the surface of the last layer can be remelted to form a "transition molten pool", the molten pool can be fully fused with the molten pool of the newly laid powder of the next layer, the interface separation between the layers is avoided, the layer combination strength is greatly improved, the flat remelted surface also provides protection for uniform spreading of the powder of the next layer, further reduces the problem of uneven molten pool flow of the subsequent additive, and forms a virtuous cycle of "interlayer quality-subsequent forming".

[0077] In the present application, when the forming step is performed, the average temperature of the surface is detected every 5 layers, if the temperature is less than 300 DEG C, the forming is continued; if the temperature is greater than or equal to 300 DEG C, the forming is performed after natural cooling to 150 DEG C;

[0078] Every 10 layers, the difference between the actual height of the forming height and the target height is detected, wherein the target height = the number of cycles x 0.3 mm, and when the difference is greater than 0.05, the powder laying thickness of the lower layer is adjusted.

[0079] The forming step is specifically: after the remelting is completed, the powder-laying-additive-remelting cycle is performed on the surface of the remelted layer with the same parameters until the target metal component is completely formed, during which the average temperature of the surface is detected every 5 layers, if the temperature is less than 300 DEG C, the forming is continued; if the temperature is greater than or equal to 300 DEG C, the forming is performed after natural cooling to 150 DEG C;

[0080] Detect the difference between the actual height and the target height of the forming height per 10 layers, wherein the target height = cycle number x 0.3 mm, when the actual height is less than the target height by 0.05 mm or less, adjust the powder laying thickness of the lower layer to 0.32 mm; when the actual height is greater than the target height by 0.05 mm or more, adjust the powder laying thickness of the lower layer to 0.28 mm.

[0081] It can be understood that the surface average temperature is detected per 5 layers per cycle, when the temperature < 300℃, continue to form, which can avoid unnecessary cooling waiting to balance production efficiency, and when the temperature ≥ 300℃, naturally cool to 150℃ before forming again, which can effectively relieve the accumulated thermal stress in the multi-layer additive process (prevent the molten pool from overheating to cause grain coarsening, component deformation or crack initiation), and maintain the stable thermal environment of the three stages of molten pool formation-expansion-solidification; per 10 layers, by comparing the actual forming height with the target height of "cycle number x 0.3 mm", when the difference > 0.05 mm, timely adjust the powder laying thickness of the lower layer, which can correct the slight size deviation caused by single layer powder laying or molten pool shrinkage (avoid the deviation accumulation to cause the final component height out of tolerance), and ensure the accuracy of the total height of the component after multi-layer forming. The two work together to avoid quality defects caused by heat accumulation, and prevent the gradual enlargement of size deviation, which significantly improves the quality consistency and batch stability of multi-layer components, and adapts to the large-scale manufacturing needs of complex high-precision components.

[0082] In the application, the post-processing is specifically: after the target metal component is cooled to room temperature, low-temperature aging treatment is carried out, and then component separation and polishing treatment are carried out.

[0083] The post-processing is preferably: after the forming is completed, the laser and ultrasonic device are turned off, the protective atmosphere (Ar gas flow is gradually reduced from 15 L / min to 5 L / min to avoid airflow disturbance of the component) is maintained, and the component is taken out with a high-temperature resistant glove after natural cooling to below 150℃, and is placed in a desiccator to cool to room temperature (25℃);

[0084] An SX2-12-10 box-type resistance furnace is selected, the component is placed in a tray in the furnace (graphite paper is laid on the tray to avoid adhesion), and Ar gas is introduced into the furnace (flow rate is 5 L / min to prevent oxidation);

[0085] The temperature is raised at a rate of 5℃ / min and is kept for a certain time (the temperature and the time are determined according to the material, for example, the temperature of TC4 titanium alloy is 550℃, and the time is 3 hours, and the temperature of GH4169 alloy is 620℃, and the time is 4 hours).

[0086] After the heat preservation is finished, the furnace is cooled to below 50℃, the component is taken out, the component is separated from the base material by a wire cutting machine, the surface of the component is manually polished by 1200 mesh sandpaper (the wire cutting trace is mainly removed), and then the surface of the component is finely polished by 2000 mesh sandpaper until Ra≤1.6 μm.

[0087] It can be understood that, in the post-processing of the application, the SX2-12-10 type box resistance furnace is selected, and the graphite paper is laid on the tray, so that the surface damage caused by the adhesion of the component to the tray is avoided, and the integrity of the component forming is ensured; 5L / min of Ar gas is introduced into the furnace, so that an inert protective atmosphere is formed to prevent the component from being oxidized during the heating and heat preservation process (to avoid the formation of an oxide layer on the surface to affect the mechanical properties); the component is heated at a slow rate of 5℃ / min, so that the temperature gradient inside and outside the component is reduced, new residual stress caused by uneven thermal expansion and cold contraction is prevented, the residual stress accumulated during the additive process is targetedly eliminated according to the material of the component, the microstructure of the component is optimized, and the stability of the mechanical properties is improved; after the heat preservation is finished, the furnace is cooled to below 50℃, so that stress concentration caused by rapid cooling is avoided, and the stability of the component structure is further ensured; the component and the base material are separated by wire cutting, so that the separation precision can be accurately controlled, and the damage of the component caused by mechanical separation is avoided; the wire cutting trace is removed by manually polishing with 1200 mesh sandpaper, and then the surface of the component is finely polished by 2000 mesh sandpaper, and the polishing rhythm is controlled every 10 min, so that the uniformity of polishing can be ensured, the size deviation caused by excessive polishing is prevented, and finally the surface roughness of the component is reduced to Ra≤1.6 μm, which not only meets the design accuracy requirement, but also provides a good surface quality for subsequent assembly or application of the component, and comprehensively ensures the final performance and use adaptability of the component.

[0088] In the application, Ar gas is continuously introduced at a flow rate of 15L / min during the powder laying, additive, remelting and forming stages.

[0089] Example 1

[0090] I. Target metal component

[0091] Material: TC4 titanium alloy;

[0092] Size: 100mm×100mm×10mm

[0093] II. Raw materials used

[0094] Base material: TC4 titanium alloy plate (110mm×110mm);

[0095] Metal powder: TC4 titanium alloy powder (particle size 15-45 μm, bulk density 4.8g / cm 3 , in line with GB / T 39265-2020)

[0096] III. Additive equipment

[0097] Pulsed laser generator (IPG YLR-1000-P, wavelength 1064 nm, maximum output power 1000 W):

[0098] Ultrasonic vibration device (JZ-200, maximum amplitude 20 μm): fixed at the center of the bottom of the workbench (rigidly connected with the workbench);

[0099] Protective atmosphere system: Ar gas (purity 99.999%) is introduced, flow rate 15 L / min;

[0100] High-speed camera system (Phantom V2512, frame rate 10 4 fps, resolution 1280×800), installed at the top of the work cabin, lens vertically aligned with the molten pool area, equipped with 10 times microscope lens (Navitar 12X), focal length adjusted to clearly capture the molten pool in the range of 0.1-1 mm;

[0101] Infrared temperature measuring instrument (Optris PI 450, temperature measuring range 500-3000℃): installed beside the high-speed camera system, measuring distance 300 mm.

[0102] Four, manufacturing method

[0103] S1, a single-tank ultrasonic cleaning machine (KQ-500VDE, power 500 W, tank size 500 mm×300 mm×300 mm) is selected, anhydrous ethanol (analytical pure, purity ≥99.7%) is injected into the tank, the liquid level is fully immersed in the substrate, the substrate is placed in a cleaning basket (made of 304 stainless steel to avoid reaction with ethanol), the cleaning basket is then placed in the ultrasonic tank, the ultrasonic cleaning machine is started, the frequency is set to 40 kHz, the power is set to 300 W, the cleaning time is 12 min, after the end, the substrate is taken out with clean forceps (304 stainless steel), nitrogen is used to uniformly blow along the surface of the substrate (speed 5 cm / s) until there is no ethanol residue on the surface (no wet marks are visible).

[0104] S2, the cleaned substrate is polished using a handheld grinder, during polishing, the surface of the substrate is polished with 800 mesh sandpaper, 4 times per square centimeter, then polished with 1200 mesh sandpaper, 6 times per square centimeter, the polished substrate is placed in a tray in a ZK-2 type vacuum furnace, the furnace door is closed, the vacuum pump is started, and the vacuum degree is less than or equal to 5×10 - 3 Pa, pressure is maintained for 5 min; the temperature of the substrate is increased to 250℃ at a rate of 5℃ / min, and the temperature is maintained for 45 min; heating is stopped, the vacuum state is maintained, and the substrate is naturally cooled to below 150℃, nitrogen is introduced to break the vacuum, the substrate is taken out, cooled to room temperature in a desiccator containing silica gel desiccant, and ready for use.

[0105] S3, pour the metal powder into the vacuum drying oven to dry at a temperature of 90℃ and a vacuum degree of 50Pa for 3 hours, and then cool to below 50℃ under vacuum, break the vacuum by introducing nitrogen, and take out the metal powder for standby.

[0106] S4, fix the substrate in the working table of the additive equipment, select a scraper powder spreader (material: tungsten carbide, scraper thickness: 5mm, blade flatness: ≤0.01mm), pour the dried metal powder into the powder spreader hopper, and uniformly spread the metal powder on the surface of the substrate at a speed of 10mm / s.

[0107] S5, start the protective atmosphere system (first introduce Ar gas for 10min to replace the air in the working cabin, and then proceed to the next step after the oxygen content is ≤50ppm), the ultrasonic vibration device, the high-speed camera and the infrared temperature measurement system (shoot a 10s blank video to confirm that the image is clear and the temperature measurement is stable);

[0108] S6, preset the longitudinal laser scanning path, and perform pulse laser scanning treatment on the metal powder at a pulse frequency of 50kHz and an energy density of 400J / cm 2 , and simultaneously perform ultrasonic vibration treatment on the metal powder at a frequency of 80kHz;

[0109] S7, when the melt pool diameter is equal to 0.5 times the laser spot diameter, and the melt pool peak temperature is 200℃ higher than the melting point temperature of the metal powder, increase the laser frequency of the pulse laser scanning treatment to 150kHz, and reduce the energy density to 250J / cm 2 , and keep the scanning speed at 1500mm / s; when the melt pool flow speed is between 8mm / s and 12mm / s, the melt pool diameter is between 1-1.5 times the laser spot diameter, and the melt pool peak temperature is 50-200℃ higher than the melting point of the metal powder, increase the laser frequency of the pulse laser scanning treatment to 300kHz, and reduce the energy density to 100J / cm 2 , and keep the scanning speed at 1500mm / s; when the preset scanning path is completed and the melt pool peak temperature is 50℃ lower than the melting point of the metal powder, the melt pool flow speed is less than or equal to 1mm / s, and the melt pool diameter is 0.3mm, a single layer of additive is completed.

[0110] S8, after the single layer of additive is completed and naturally cooled to below 150℃, preset the horizontal laser scanning path, the scanning range is consistent with the additive range, and the path spacing is 0.15mm; adjust the frequency of the pulse laser generator to 250kHz, and the energy density is 120J / cm 2Scan speed 1200 mm / s, remelt the surface of a single layer, melt thickness 8 μm, and cool for 10 min after completion.

[0111] S9, after remelting, powdering, adding, and remelting the surface of the remelted layer with the same parameters until the target metal component is completely formed, and detecting the average surface temperature every 5 layers during the process. If the temperature is less than 300℃, continue to form; if the temperature is greater than or equal to 300℃, naturally cool to 150℃ and then form; detect the difference between the actual height and the target height every 10 layers, and the target height = cycle number x 0.3 mm. When the actual height is less than the target height by 0.05 mm or less, adjust the powdering thickness of the lower layer to 0.32 mm; when the actual height is greater than the target height by 0.05 mm or more, adjust the powdering thickness of the lower layer to 0.28 mm.

[0112] S10, after the cycle forming is completed, turn off the laser and ultrasonic device, gradually reduce the Ar gas flow from 15 L / min to 5 L / min, naturally cool to 150℃ or below, take out the component, and place it in a desiccator to cool to room temperature (25℃).

[0113] S11, place the dried component in a tray in an SX2-12-10 box-type resistance furnace, introduce Ar gas into the furnace at a flow rate of 5 L / min, and heat to 550℃ at a rate of 5℃ / min, and hold for 3 hours. After the holding is completed, cool the furnace to 150℃ or below, take out the component, separate the component from the substrate using a wire cutting machine (DK7732 type), manually polish the surface of the component using 1200 mesh sandpaper, and then polish it using 2000 mesh sandpaper until Ra≤1.6 μm, to obtain the target metal component.

[0114] Example 2

[0115] I. Target Metal Component

[0116] Material: GH4169 alloy;

[0117] Size: 100 mm x 100 mm x 10 mm

[0118] II. Raw Materials Used

[0119] Substrate: GH4169 alloy plate (110 mm x 110 mm);

[0120] Metal powder: GH4169 alloy powder (particle size 20-50 μm, bulk density 4.6 g / cm 3 , in accordance with GJB 3807A-2021)

[0121] III. Additive Equipment

[0122] Pulsed laser generator (IPG YLR-1000-P, wavelength 1064 nm, maximum output power 1000 W):

[0123] Ultrasonic vibration device (JZ-200, maximum amplitude 20 μm): fixed at the center of the bottom of the workbench (rigidly connected with the workbench);

[0124] Protective atmosphere system: Ar gas (purity 99.999%) is introduced, flow rate 15 L / min;

[0125] High-speed camera system (Phantom V2512, frame rate 10 4 fps, resolution 1280×800), installed at the top of the work cabin, lens vertically aligned with the molten pool area, equipped with 10 times microscope lens (Navitar 12X), focal length adjusted to clearly capture the molten pool in the range of 0.1-1 mm;

[0126] Infrared temperature measuring instrument (Optris PI 450, temperature measurement range 500-3000℃): installed beside the high-speed camera system, measurement distance 300 mm.

[0127] Four, manufacturing method

[0128] S1, select a single-tank ultrasonic cleaning machine (KQ-500VDE, power 500 W, tank size 500 mm×300 mm×300 mm), inject anhydrous ethanol (analytically pure, purity ≥99.7%) into the tank, the liquid level height is completely immersed in the substrate, put the substrate into the cleaning basket (304 stainless steel material to avoid reaction with ethanol), then put the cleaning basket into the ultrasonic tank, start the ultrasonic cleaning machine, set the frequency to 40 kHz and the power to 300 W, the cleaning time is 12 min, after the end, use clean forceps (304 stainless steel material) to take out the substrate, use nitrogen gas to uniformly blow along the surface of the substrate (speed 5 cm / s) until there is no ethanol residue on the surface (no wet trace is visually observed).

[0129] S2, use a handheld grinder to polish the cleaned substrate, first polish the surface of the substrate with 800 mesh sandpaper, polish 4 times per square centimeter, then polish with 1200 mesh sandpaper, polish 6 times per square centimeter, put the polished substrate into the tray in the ZK-2 type vacuum furnace, close the furnace door, start the vacuum pump, and vacuumize to a vacuum degree less than or equal to 5×10 - 3 Pa, hold for 5 min; increase the substrate temperature to 200℃ at a rate of 5℃ / min, and keep it for 45 min; stop heating, keep vacuum state and naturally cool to below 150℃, introduce nitrogen gas to break the vacuum, take out the substrate, cool to room temperature in a desiccator containing silica gel desiccant, and reserve for use.

[0130] S3. Pour the metal powder into a vacuum drying oven and dry it at 90°C and 50Pa for 3 hours. After drying, keep it under vacuum and cool it to below 50°C. Then, introduce nitrogen to break the vacuum and remove the metal powder for later use.

[0131] S4. Fix the substrate in the worktable of the additive manufacturing equipment, select a scraper-type powder spreader (material is tungsten carbide, scraper thickness is 5mm, and blade flatness is ≤0.01mm), pour the dried metal powder into the hopper of the powder spreader, and spread the metal powder evenly on the surface of the substrate at a speed of 10mm / s.

[0132] S5. Activate the protective atmosphere system in sequence (first purge with Ar gas for 10 minutes to replace the air in the working chamber, and proceed to the next step after the oxygen content is ≤50ppm), ultrasonic vibration device, and high-speed camera and infrared temperature measurement system (shoot 10s blank video to confirm that the image is clear and the temperature measurement is stable).

[0133] S6. Preset longitudinal laser scanning path, with a pulse frequency of 50kHz and a speed of 400J / cm. 2 The metal powder is subjected to pulsed laser scanning at an energy density of 1500 mm / s, while the metal powder is subjected to ultrasonic vibration at a frequency of 80 kHz.

[0134] S7. When the diameter of the molten pool is equal to 0.5 times the diameter of the laser spot, and the peak temperature of the molten pool is above 200°C (the melting point temperature of the metal powder), the laser frequency of the pulsed laser scanning process is increased to 150kHz, and the energy density is reduced to 250J / cm². 2 The scanning speed is maintained at 1500 mm / s; when the molten pool flow velocity is between 8 mm / s and 12 mm / s, the molten pool diameter is between 1 and 1.5 times the laser spot diameter, and the peak temperature of the molten pool is between 50 and 200°C higher than the melting point of the metal powder, the laser frequency of the pulsed laser scanning process is increased to 300 kHz, and the energy density is reduced to 100 J / cm³. 2 The scanning speed is maintained at 1500 mm / s. When the preset scanning path is completed and the peak temperature of the molten pool is 50°C lower than the melting point of the metal powder, the flow velocity of the molten pool is less than or equal to 1 mm / s, and the diameter of the molten pool is 0.3 mm, the single-layer additive manufacturing is completed.

[0135] S8. After the single-layer additive manufacturing is completed and naturally cooled to below 150℃, a preset transverse laser scanning path is established, with the scanning range consistent with the additive manufacturing range and a path spacing of 0.15mm. The frequency of the pulsed laser generator is adjusted to 250kHz, and the energy density is 120J / cm². 2, the scanning speed is 1200 mm / s, the single layer surface is remelted, the melting thickness is 8 μm, and cooling is performed for 10 min after completion.

[0136] S9, after the remelting is completed, powder laying-additive-remelting cycles are performed on the surface of the remelted layer at the same parameters until the target metal component is completely formed, the average surface temperature is detected every 5 layers during the cycles, if the temperature is less than 300 DEG C, the forming is continued; if the temperature is greater than or equal to 300 DEG C, the forming is performed after natural cooling to 150 DEG C; the difference between the actual height and the target height is detected every 10 layers, wherein the target height = cycle number x 0.3 mm, when the actual height is less than the target height by 0.05 mm or less, the powder laying thickness of the lower layer is adjusted to 0.32 mm; when the actual height is greater than the target height by 0.05 mm or more, the powder laying thickness of the lower layer is adjusted to 0.28 mm.

[0137] S10, after the cycle forming is completed, the laser and the ultrasonic device are turned off, the Ar gas flow rate of the protective atmosphere is gradually reduced from 15 L / min to 5 L / min, and the component is taken out and placed in a desiccator to cool to room temperature (25 DEG C) after natural cooling to 150 DEG C or less.

[0138] S11, the dried component is placed in a tray in an SX2-12-10 type box resistance furnace, Ar gas is introduced into the furnace at a flow rate of 5 L / min, the temperature is raised to 620 DEG C at a rate of 5 DEG C / min, and the temperature is maintained for 4 hours, and the component is separated from the substrate by a wire cutting machine (DK7732 type) after the temperature is maintained and the furnace is cooled to 150 DEG C or less, the surface of the component is polished by hand with 1200 mesh sandpaper, and then the surface is polished with 2000 mesh sandpaper until Ra≤1.6 μm, and the target metal component is obtained.

[0139] Example 3

[0140] The difference between example 1 and example 3 is that the ultrasonic cleaner cleaning time in step S1 is 10 minutes, the holding time in step S2 is 30 minutes, and the melting thickness in step S8 is 5 μm.

[0141] Example 4

[0142] The difference between example 1 and example 4 is that the ultrasonic cleaner cleaning time in step S1 is 15 minutes, the holding time in step S2 is 60 minutes, and the melting thickness in step S8 is 10 μm.

[0143] Effect test

[0144] Test object: Select TC4 titanium alloy (typical material of aerospace load-bearing components) and GH4169 high-temperature alloy (typical material of high-temperature components) commonly used in additive manufacturing as test materials. Both materials meet industry standards (TC4 conforms to GB / T 3620.1-2022, and GH4169 conforms to GJB 2611-1996 "Specification for Cold Drawn Bars of High-Temperature Alloy for Aviation").

[0145] Control group 1: continuous laser group, laser power 300W, scanning speed 1500mm / s, no ultrasonic cooperation, no interlayer remelting;

[0146] Control group 2: fixed parameter pulsed laser group, pulse frequency 50kHz, energy density 250J / cm², scanning speed 1500mm / s, no ultrasonic cooperation, no interlayer remelting;

[0147] TC4 titanium alloy prepared by the preparation method of experimental group example 1 and GH4169 high-temperature alloy prepared by example 2;

[0148] Pattern preparation:

[0149] Defect detection test sample: 10mm x 10mm x 5mm (for metallographic analysis and CT scanning);

[0150] Mechanical property test sample: tensile test sample (according to GB / T 228.1-2021, gauge length section 50mm x 10mm x 4mm), interlayer tensile test sample (according to GB / T 35465.2-2017, size 20mm x 10mm x 8mm), impact test sample (according to GB / T 229-2020, U-shaped notch, 10mm x 10mm x 55mm);

[0151] Composition uniformity test sample: 20mm x 20mm x 3mm (for EDS area scanning);

[0152] Test results

[0153] 1. Melt pool flow control related performance test

[0154] The porosity of the samples prepared by the above-mentioned three preparation methods was tested by CT scanning method (according to GB / T 29062-2012), and the results are shown in Table 1:

[0155] Table 1 Porosity test results

[0156]

[0157] The porosity of the samples prepared by the above-mentioned three preparation methods was tested by CT scanning method (according to GB / T 29062-2012), and the results are shown in Table 1: 2The crack rates of the samples prepared by the above three preparation methods were tested, and the results are shown in Table 2:

[0158] Table 2 Crack rate test results

[0159]

[0160] The fluctuation of the main element content of the samples prepared by the above three preparation methods was analyzed by EDS area scanning, and the results are shown in Table 3:

[0161] Table 3 Composition uniformity test results

[0162]

[0163] From the porosity data in Table 1, the porosity of the TC4 titanium alloy prepared by the method of Example 1 (0.4%) is reduced by 81.8% compared with the existing continuous laser group (2.2%), and the porosity of the GH4169 alloy prepared by the method of Example 2 (0.5%) is reduced by 80% compared with the existing continuous laser group (2.5%), which proves that the present application can strengthen the convection of the molten pool and break the bubbles; from the crack rate data in Table 2, the crack rate of the TC4 titanium alloy prepared by the method of Example 1 (0.6%) is reduced by 78.6% compared with the existing continuous laser group (2.8%), which reflects that the preparation method of the present application can effectively alleviate the thermal stress concentration; from the composition uniformity data in Table 3, the fluctuation of Ti element in the TC4 titanium alloy prepared by Comparative Example 1 is ±5.2%, while the fluctuation of Ti element in the TC4 titanium alloy prepared by the method of Example 1 of the present application is ±1.5%, which proves that the present application optimally avoids the composition segregation caused by uneven flow speed and completely solves the problem of molten pool flow out of control.

[0164] 2. Interlayer bonding performance test

[0165] The interlayer oxidation layer thickness of the samples prepared by the above three preparation methods was tested by SEM cross-section observation method (according to GB / T 6462-2005), and the results are shown in Table 4:

[0166] Table 4 Interlayer oxidation layer thickness test results

[0167]

[0168] The interlayer surface roughness of the samples prepared by the above three preparation methods was tested by a stylus roughness meter (according to GB / T 3505-2009), and the results are shown in Table 5:

[0169] Table 5 Interlayer surface roughness test results

[0170]

[0171] The interlaminar tensile strength and interlaminar shear strength of the samples prepared by the above three groups of preparation methods were tested (the interlaminar tensile strength was tested according to GB / T 35465.2-2017, and the interlaminar shear strength was tested according to GB / T 35465.3-2017), and the results are shown in Table 6:

[0172] Table 6 Test results of interlaminar tensile strength and interlaminar shear strength

[0173]

[0174] According to Tables 4-6, the interlaminar oxide layer thickness of the preparation method of the present application is reduced from 7-10 nm of the prior art to 1.5-1.8 nm, and the roughness is reduced from 3.2-4.2 μm to 1.2-1.4 μm, which shows that the preparation method of the present application can effectively remove the oxide layer and reduce the roughness; in terms of interlaminar tensile strength, the TC4 titanium alloy is increased from 920 MPa to 1120 MPa, and the GH4169 alloy is increased from 880 MPa to 1080 MPa, and the strength gap from the forged piece is reduced from 22%-32% to 8%-10%, which shows that the preparation method of the present application strengthens the interlaminar fusion, completely breaks through the weak bottleneck of interlaminar bonding, and makes the mechanical properties of the component close to the level of the forged piece, thereby meeting the stringent requirements of high-end equipment on interlaminar performance.

[0175] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by the same, without departing from the spirit and scope of the present application. Any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow, characterized in that, Includes the following steps: Substrate preparation: Select a substrate corresponding to the target metal component and pre-treat the substrate; Powder spreading: The pretreated substrate is fixed on the worktable of the additive manufacturing equipment, and metal powder of the same material as the substrate is selected and spread on the surface of the substrate using a powder spreading device; Additive manufacturing: A preset laser scanning path is used to perform pulsed laser scanning and ultrasonic vibration processing on the metal powder to form a molten pool. During this process, the parameters of pulsed laser scanning and ultrasonic vibration processing are adjusted according to different stages of the molten pool until the single-layer additive manufacturing is completed. Remelting: The single-layer additive is remelted using a pulsed laser and then cooled; Forming: Powder is spread on the surface of the remelted layer using a powder spreading device. The additive manufacturing and remelting steps are repeated to form a powder spreading-additive manufacturing-remelting cycle until the target metal component is formed. Post-processing: The formed metal component undergoes post-processing; The additive manufacturing includes: Real-time acquisition of peak molten pool temperature, molten pool diameter, and molten pool flow velocity; With a pulse frequency of 50kHz and a speed of 400J / cm 2 The metal powder is subjected to pulsed laser scanning at an energy density of 1500 mm / s, while the metal powder is subjected to ultrasonic vibration at a frequency of 80 kHz. When the diameter of the molten pool is equal to 0.5 times the diameter of the laser spot, and the peak temperature of the molten pool is above 200°C (the melting point of the metal powder), the laser frequency of the pulsed laser scanning process is increased to 150 kHz, and the energy density is reduced to 250 J / cm². 2 The scanning speed is maintained at 1500 mm / s; When the molten pool flow velocity is between 8 mm / s and 12 mm / s, the molten pool diameter is between 1 and 1.5 times the laser spot diameter, and the peak temperature of the molten pool is between 50 and 200°C higher than the melting point of the metal powder, the laser frequency of the pulsed laser scanning process is increased to 300 kHz, and the energy density is reduced to 100 J / cm³. 2 The scanning speed is maintained at 1500 mm / s; When the preset scanning path is completed and the peak temperature of the molten pool is 50°C lower than the melting point of the metal powder, the flow velocity of the molten pool is less than or equal to 1 mm / s, and the diameter of the molten pool is 0.3 mm, the single-layer additive manufacturing is completed.

2. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 1, characterized in that, The preprocessing specifically includes: The substrate is placed in anhydrous ethanol for ultrasonic cleaning. After cleaning, the substrate is removed and its surface is polished. After polishing, the substrate is subjected to vacuum preheating treatment.

3. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 2, characterized in that, The ultrasonic cleaning frequency is 40kHz, and the cleaning time is 10-15 minutes; the vacuum degree of the vacuum preheating treatment is less than or equal to 5×10⁻⁶. -3 Pa, heat preservation time is 30-60 minutes.

4. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 3, characterized in that, The powder spreading speed is 10 mm / s, and the powder spreading thickness is 0.3 mm.

5. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 4, characterized in that, The remelting process specifically involves: pre-setting a laser scanning path, adjusting the frequency of the pulsed laser to 250kHz, and adjusting the energy density to 120J / cm². 2 The completed single-layer surface is then remelted.

6. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 5, characterized in that, The laser scanning path preset during remelting intersects the laser scanning path preset during additive manufacturing at a 90° angle, with a melting thickness of 5-10 μm, followed by cooling for 10 minutes after completion.

7. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 6, characterized in that, During the molding process, the average surface temperature is checked every 5 layers. If the temperature is less than 300°C, molding continues; if the temperature is greater than or equal to 300°C, the surface is allowed to cool naturally to 150°C before molding. Every 10 layers in a cycle, the difference between the actual height and the target height is measured, where the target height = number of cycles × 0.3 mm. When the difference is greater than 0.05, the thickness of the next layer of powder is adjusted.

8. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 7, characterized in that, The post-processing specifically involves: cooling the target metal component to room temperature, removing it, performing low-temperature aging treatment, and then separating and polishing the component.

9. The laser composite additive manufacturing method based on pulsed laser-controlled molten pool flow according to claim 8, characterized in that, Ar gas is continuously introduced at a flow rate of 15 L / min during the powder spreading, additive manufacturing, remelting, and forming stages.

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