An in-situ oxygen-controlled composite scraper and a laser selective melting device equipped with the in-situ oxygen-controlled composite scraper.

Abstract

This invention belongs to the technical field of additive manufacturing technology and discloses an in-situ oxygen-controlled composite scraper and a laser selective melting device equipped with the in-situ oxygen-controlled composite scraper. The bottom of the composite scraper includes a second scraper (16), an air jet unit, and a first scraper (18) arranged sequentially along the powder spreading direction. It has an internal gas storage chamber (15) and a powder drop chamber (19). The first scraper is used to evenly spread the powder raw material to form an initial powder layer. The air jet unit performs in-situ oxidation treatment on the surface of the initial powder layer by spraying oxygen-containing gas. The second scraper is used to level and compact the powder layer after the in-situ oxidation treatment. This invention improves the composition and structure of the composite scraper and utilizes the overall cooperation of the first scraper, the air jet unit, and the second scraper to generate a synergistic mechanism of powder spreading, in-situ oxidation, and secondary compaction, breaking through the process limitation that it is difficult to construct oxide dispersion-strengthened structures in-situ during additive manufacturing.

Description

Technical Field

[0001] This invention belongs to the technical field of additive manufacturing technology, and more specifically, relates to an in-situ oxygen-controlled composite scraper and a laser selective melting device equipped with the in-situ oxygen-controlled composite scraper. Background Technology

[0002] Oxide dispersion strengthening (ODS) is an important strengthening method that significantly improves the overall performance of materials by uniformly dispersing stable nanoscale oxide particles in a metal matrix. These oxide particles typically possess high melting points, high thermal stability, and low diffusion coefficients, enabling them to remain stable for extended periods at high temperatures. They effectively pin dislocations and grain boundaries, inhibiting grain growth and high-temperature creep, thereby significantly improving the material's high-temperature strength, creep resistance, and thermal stability. Compared to traditional solid solution strengthening or precipitation strengthening mechanisms, ODS strengthening is temperature-insensitive, maintaining excellent mechanical properties even at temperatures close to the material's melting point. Therefore, it has significant application value in aerospace, nuclear energy, gas turbines, and structural components operating in extreme environments. Furthermore, oxide particles in ODS materials can act as heterogeneous nucleation sites, promoting the formation of fine-grained structures and improving the strength-toughness balance. For powder metallurgy and additive manufacturing systems, the ODS structure can also effectively improve the uniformity and stability of the formed microstructure, reducing susceptibility to hot cracking and the risk of microstructure segregation. Especially in high-energy beam rapid prototyping processes such as selective laser melting (SLM), if precise control of oxygen content and oxidation behavior can be achieved, it is expected that stable and controllable dispersed oxide structures can be directly constructed during the forming process without introducing complex post-processing, thereby expanding the design and preparation space of high-performance metal materials.

[0003] Currently, the preparation of ODS materials mainly relies on traditional powder metallurgy processes such as mechanical alloying combined with hot isostatic pressing or high-temperature sintering. These processes are complex, time-consuming, and costly, and have significant limitations in terms of component size, shape freedom, and microstructure controllability. Although metal additive manufacturing technologies such as selective laser melting (SLM) have shown significant advantages in the integrated forming of complex structures, most existing mainstream equipment adopts a highly inert forming atmosphere control strategy. Their design goals are mainly focused on suppressing oxidation, reducing oxygen content fluctuations, and ensuring forming stability, rather than functionally controlling oxidation behavior. Specifically, the powder spreading blades or roller spreading devices in existing SLM equipment only perform powder spreading and leveling functions. Their structural design is usually solid or simple hollow, lacking the ability to introduce, distribute, and release gas in a directional manner, and cannot achieve fine adjustment of the local oxygen partial pressure of the powder layer during powder spreading or forming. Under these conditions, the powder can only be passively oxidized or completely avoided under the overall atmosphere control of the forming chamber, making it difficult to achieve precise control over the degree, location, and time of oxidation. This "globally inert" equipment design concept objectively limits the in-situ construction of ODS structures during additive manufacturing, making it impossible to effectively realize the technical path of directly controlling the oxide dispersed phase through the forming process. Therefore, there is an urgent need for a novel powder spreading and gas control device that can achieve localized and controllable oxidation of the powder layer without compromising the overall forming atmosphere stability, in order to overcome the limitations of existing technologies in in-situ control of ODS.

[0004] In summary, existing additive manufacturing equipment systems generally employ an overall inert atmosphere and passive anti-oxidation strategy for forming and powder spreading devices. Their structural functions are limited to powder spreading and surface leveling, lacking the ability to actively control the local oxygen partial pressure and oxidation behavior of the powder layer. It is difficult to achieve precise control over the degree of powder oxidation, the area of ​​action, and the time window during the forming process. As a result, it is impossible to construct a stable and controllable oxide dispersion reinforcement structure in situ inside the formed component, which restricts the degree of freedom in microstructure design and the potential for performance control of high-temperature service metal materials and functionally graded reinforced components under additive manufacturing conditions. Summary of the Invention

[0005] Existing additive manufacturing processes generally employ overall inert atmosphere control during the forming process, making it difficult to precisely regulate the oxidation behavior of the powder layer locally during the powder spreading stage. The purpose of this invention is to provide an in-situ oxygen-controlled composite scraper and a laser selective melting device equipped with the in-situ oxygen-controlled composite scraper. By improving the composition and structure of the composite scraper, the overall cooperation of the first scraper, the jet unit, and the second scraper generates a synergistic mechanism of powder spreading, in-situ oxidation, and secondary compaction, thus overcoming the process limitation that it is difficult to construct oxide dispersion-strengthened structures in-situ during additive manufacturing.

[0006] To achieve the above objectives, according to one aspect of the present invention, an in-situ oxygen-controlled composite scraper is provided, characterized in that the bottom of the composite scraper includes a second scraper (16), an air jet unit, and a first scraper (18) arranged sequentially along the powder spreading direction. The interior of the composite scraper is provided with an air storage chamber (15) and a powder drop chamber (19), wherein the powder drop chamber (19) is used to transfer laser selective melting powder raw material conveyed through the powder drop channel (20) to the powder outlet of the first scraper (18); the first scraper (18) is used to uniformly spread the powder raw material on the surface of the forming substrate to form an initial powder layer, thereby realizing the first scraper spreading powder; the air storage chamber (15) is used to transfer oxygen-containing gas with controlled oxygen content conveyed through the ventilation channel (14) to the air jet unit, and the air jet unit performs in-situ oxidation treatment on the surface of the initial powder layer by spraying out oxygen-containing gas; the second scraper (16) is used to level and compact the powder layer after the in-situ oxidation treatment is completed.

[0007] As a further preferred embodiment of the present invention, the jet unit is a multi-micro-hole jet device (17), which has multiple interconnected gas channels inside and a micro-hole gas outlet structure at the bottom, with the micro-holes evenly distributed along the length direction of the first scraper (18).

[0008] As a further preferred embodiment of the present invention, the oxygen content in the oxygen-containing gas is regulated by a flow-controlled gas distribution valve (6). The inlet of the flow-controlled gas distribution valve (6) is connected to at least two gas cylinders via a vent pipe, and the outlet is connected to the venting channel (14) via a main vent pipe (3). At least one of these gas cylinders stores O2, and each gas cylinder contains a different gas. The flow-controlled gas distribution valve (6) is used to regulate the partial pressure ratio of each gas input from these gas cylinders, mix them to form the oxygen-containing gas with controlled oxygen content, and regulate the overall flow rate of the oxygen-containing gas. Preferably, there are two gas cylinders, which store oxygen and argon respectively; or, there are four gas cylinders, which store oxygen, argon, nitrogen and carbon dioxide respectively.

[0009] As a further preferred embodiment of the present invention, the forming substrate is a heatable forming substrate, and a heating device is provided below it, which can raise the temperature under the action of the heating device to provide a controllable thermal environment for the powder layer, thereby synergistically regulating the temperature and degree of the powder oxidation reaction.

[0010] As a further preferred embodiment of the present invention, the heating device is an electric heating device or an induction heating device, and the heating temperature can be adjusted within a preset range; Preferably, the heating device is connected to the power supply box (10) via a power-conducting wire (11), and the power supply box (10) is used to supply power to the heating device.

[0011] As a further preferred embodiment of the present invention, both the powder drop channel (20) and the ventilation channel (14) are located at the top of the composite scraper.

[0012] According to another aspect of the present invention, the present invention provides a laser selective melting device with an in-situ oxygen-controlled composite scraper, characterized in that it includes a printing platform, a forming substrate, a laser (1) and the above-mentioned in-situ oxygen-controlled composite scraper, wherein the forming substrate and the printing platform are on the same horizontal plane.

[0013] According to another aspect of the present invention, the present invention provides a laser selective melting forming method for oxide dispersion-strengthened components based on the above-mentioned laser selective melting equipment equipped with an in-situ oxygen-controlled composite scraper, characterized in that it includes the following steps: S1: Based on the parameter requirements of the target oxide dispersion-strengthened component, set the moving speed V1 of the in-situ oxygen-controlled composite scraper, the partial pressure ratio of each gas component in the oxygen-containing gas, and the ventilation flow rate V2 of the oxygen-containing gas. S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature conditions of the formed substrate are controlled by the power supply box. S3: Set the laser power P, scanning spacing h, layer thickness t and scanning speed V3 according to the printing parameters of the target oxide dispersion-strengthened component sample; S4: Without starting the laser, start the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, and the jet unit sprays oxygen-containing gas to oxidize the powder in situ. At the same time, the second scraper levels and compacts the powder after in-situ oxidation. S5: The laser is activated to print oxide dispersion reinforced components on the powder layer formed by in-situ oxygen-controlled composite doctor blade operation.

[0014] Compared with the prior art, the above-described technical solutions conceived in this invention can achieve the following beneficial effects: 1. This invention integrates and decouples the processes of powder spreading, in-situ oxygen control, and powder leveling and compaction by setting up a multi-segment composite powder spreading scraper. Without changing the overall structure of the existing selective laser melting equipment, it achieves active control of powder oxidation behavior during the powder spreading stage, providing a new process path for the in-situ construction of oxide dispersion-strengthened structures.

[0015] The composite scraper of this invention comprises a second scraper, an air jet unit, and a first scraper arranged sequentially along the powder spreading direction, forming a multi-segment structure. The first scraper is used to uniformly spread metal powder onto the surface of the forming substrate to form an initial powder layer. The air jet unit is positioned after the first scraper unit and before the second scraper unit. The air jet unit, through the internal ventilation structure of the composite scraper, locally introduces oxygen-containing gas with controlled oxygen content into the powder layer that has been spread but not compacted, performing in-situ oxidation treatment on the powder surface. The second compaction scraper levels and compacts the powder layer after the oxidation treatment. In addition to the controllable oxygen content of the oxygen-containing gas, the forming substrate used in conjunction with the composite scraper can preferably provide a controllable thermal environment to the powder layer through a heating device, thereby synergistically regulating the temperature and degree of the powder oxidation reaction. Thus, by controlling the oxygen content and temperature, precise and controllable regulation of the powder layer oxidation behavior can be achieved during the powder spreading stage.

[0016] 2. In the process of spreading powder, the present invention introduces oxygen-containing gas locally (the oxygen content of these oxygen-containing gases is controlled, for example, by adjusting the oxygen content through a flow control valve), and achieves in-situ oxidation treatment of the powder layer through an intermediate ventilation unit. Compared with the traditional method that relies on overall atmosphere control or subsequent heat treatment, it has the advantages of clear action area, fast control response, and simplified process, and effectively improves the controllability of oxygen content and oxidation degree.

[0017] This invention utilizes an in-situ oxygen-controlled composite doctor blade to provide oxygen-containing gas with controlled oxygen content. Through structures or components such as ventilation channels, main ventilation pipes, and gas storage chambers, the oxygen is confined to the interior of the composite doctor blade and a localized area of ​​the powder layer below the jet unit. This allows for directional release without disrupting the inert atmosphere of other parts of the SLM printing chamber (i.e., the SLM forming chamber) or altering the overall structure of existing selective laser melting equipment.

[0018] 3. By limiting the in-situ oxygen regulation process to the powder spreading stage and setting a secondary compaction scraper unit thereafter, the present invention effectively avoids the adverse effects of airflow disturbance on the stability of the powder layer and the forming quality, ensuring the consistency of powder layer thickness and density, which is beneficial to improving the uniformity of the structure and the forming stability of the formed components.

[0019] 4. When applied to SLM printing, the composite doctor blade of this invention can achieve coupled and controllable adjustment of the powder layer oxygen partial pressure n, the reaction time t (determined by the moving speed V1 of the composite doctor blade and the gas flow rate V2), and the oxidation temperature T. This invention can achieve multi-parameter coupled adjustment of powder oxidation reaction temperature, oxidation time, and oxygen partial pressure by regulating the flow control valve, the in-situ oxygen-controlled composite doctor blade moving speed, and the substrate heating device, utilizing their synergy (wherein, the in-situ oxidation time can be controlled by adjusting the moving speed V1 of the composite doctor blade and / or the gas flow rate V2). The oxygen control strategy can be flexibly adjusted according to different material systems and performance requirements, thereby expanding the application scope of selective laser melting (SLM) in the preparation of high-performance metallic materials and functionally graded structures.

[0020] 5. Traditional approaches often treat powder oxidation and powder spreading as two independent processes, or attempt to achieve this through overall atmosphere control in the forming chamber. However, this easily leads to uncontrollable oxidation reactions, low efficiency, and difficulty in coordinating with other process parameters (such as temperature), thus failing to achieve an effective breakthrough. This invention overcomes these difficulties through unique structural design and system integration: First, the second scraper, jet unit, and first scraper are integrated along the powder spreading direction at the bottom of the same composite scraper, achieving integrated continuous operation of "powder spreading-oxidation-leveling"; second, by setting up a gas storage chamber and a powder drop chamber inside the composite scraper, the powder raw material transport and oxygen-containing gas transport are physically isolated, avoiding cross-interference; third, a flow control valve can be introduced to precisely regulate the partial pressure ratio of each gas component in the oxygen-containing gas and the overall flow rate of the oxygen-containing gas, and combined with a heatable forming substrate, it achieves dual precise control of "oxygen concentration-thermal environment" for the oxidation reaction, thereby effectively suppressing solidification cracks and ensuring uniform dispersion of oxides. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a preferred embodiment of a laser selective melting device with an in-situ oxygen-controlled composite scraper, according to the present invention, viewed from both the front and back sides. Figure 1 (a) in the image corresponds to a frontal oblique view. Figure 1 (b) in the image corresponds to the oblique rear view.

[0022] Figure 2 This is a schematic diagram of the structure of a preferred in-situ oxygen-controlled composite scraper according to the present invention, viewed from two different perspectives: top and bottom. Figure 2 (a) in the image corresponds to the oblique view of the bottom surface. Figure 2 (b) in the diagram corresponds to the oblique view of the top surface.

[0023] Figure 3 This is a schematic diagram of the internal structure of a preferred in-situ oxygen-controlled composite scraper according to the present invention.

[0024] Figure 4 It is the Inconel 718 oxygen regulation component with a lateral gradient according to the preferred embodiment 1 of the present invention.

[0025] Figure 5 It is a CuCrZr oxygen regulation component with a longitudinal gradient according to the preferred embodiment 2 of the present invention.

[0026] Figure 6 It is the AlMgScZr oxygen regulation component with a longitudinal gradient according to the preferred embodiment 3 of the present invention.

[0027] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-laser; 2-in-situ oxygen-controlled composite scraper; 3-main vent pipe; 4-first gas cylinder; 5-second gas cylinder; 6-flow control valve; 7-powder drop pipe; 8-powder drop container; 9-second vent pipe; 10-electric box; 11-electric wire; 12-heatable substrate; 13-first vent pipe; 14-venting channel; 15-gas storage chamber; 16-second scraper; 17-multi-micro-hole jet device; 18-first scraper; 19-powder drop container; 20-powder drop channel. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. The process parameters, equipment components, and other technical elements involved in this solution can be modularly integrated under the premise of satisfying the principle of non-interference.

[0029] The in-situ oxygen-regulating composite scraper of this invention has an in-situ oxygen regulation function, such as... Figure 3 As shown, the system includes a ventilation channel 14, an air storage chamber 15, a second scraper 16, a multi-micro-hole jet device 17, a first scraper 18, a powder drop chamber 19, and a powder drop channel 20. During the printing process, it performs powder spreading, in-situ oxygen control, and powder compaction. The in-situ oxygen control composite scraper is arranged with the second scraper 16, the multi-micro-hole jet device 17, and the first scraper 18 sequentially along the powder spreading direction. The first scraper 18 is located at the front end of the powder spreading direction and is used to evenly spread the metal powder to the forming area to form an initial powder layer. A multi-micro-hole jet device 17 (e.g., ...) is disposed between the first scraper 18 and the second scraper 16. Figure 2As shown, the micro-pore gas outlet structure of the multi-micro-pore jet device 17 can be uniformly distributed along the length of the first scraper 18. The gas is input through the main vent pipe 3, transmitted to the gas storage chamber 15 through the venting channel 14, and sprayed onto the powder layer through the micro-pore gas outlet array (i.e., the multi-micro-pore jet device 17) set at the bottom of the scraper, so as to perform in-situ oxygen control treatment on the metal powder during the powder spreading process. The oxygen partial pressure and gas flow rate can be regulated at the front end of the main vent pipe 3 through the flow control valve 6. The second scraper 16 is set after the multi-micro-pore jet device 17 and is used to compact and level the powder layer after the powder has undergone in-situ oxygen control treatment, so as to improve the density of the powder bed and the uniformity of powder spreading.

[0030] Correspondingly, laser selective melting equipment equipped with in-situ oxygen-controlled composite scrapers, such as... Figure 1 As shown, in addition to the laser 1 and the aforementioned in-situ oxygen-controlled composite scraper, the system also includes: a first gas cylinder 4 (containing a gas denoted as the first gas, for example, pure oxygen), a second gas cylinder 5 (containing a gas denoted as the second gas, for example, pure argon), a flow control valve 6, a main vent pipe 3, a second vent pipe 9, and a first vent pipe 13, which can regulate the gas flow rate and the partial pressure of oxygen and argon; an electrical box 10 and a heatable substrate 12, wherein the heatable substrate 12 has a heating function and can precisely control the temperature of the powder in-situ oxygen regulation, thereby synergistically controlling the oxidation kinetics of the powder in the in-situ oxygen regulation process and realizing the coupled regulation of temperature and oxygen content.

[0031] During the powder spreading and in-situ oxygen control process, the laser 1 does not work. After the powder spreading, oxygen control and compaction process in the single-layer forming plane (XY plane) is completed, the laser 1 is started to perform selective laser melting and forming, so as to avoid the laser energy interfering with the powder oxidation process.

[0032] In addition, the oxygen content in the oxygen-dispersion-enhanced sample is synergistically controlled by the powder spreading speed of the in-situ oxygen-regulated composite scraper 2, the oxygen partial pressure of the mixed gas, the jetting speed of the multi-micro-hole jetting device 17, and the substrate heating temperature.

[0033] A preset gap is maintained between the multi-micro-hole jet device 17 and the heatable substrate 12 so that the airflow acts only on the powder surface layer without disturbing the already formed powder bed structure, ensuring the consistency of powder thickness and the quality of interlayer forming.

[0034] The laser selective melting device of this invention, equipped with an in-situ oxygen-controlled composite scraper, can be operated according to the following steps: S1: Based on actual parameter requirements, design the in-situ oxygen-controlled composite scraper 2 moving speed V1, oxygen / argon partial pressure n, and ventilation flow rate V2.

[0035] S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature conditions of the heatable substrate 12 are adjusted by the power supply box 10. The oxygen dispersion is strengthened by adjusting the oxidation conditions. The occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient (i.e., the temperature difference between the substrate and the forming molten pool).

[0036] S3: Design the laser power P, scanning spacing h, layer thickness t, and scanning speed V3 based on the sample printing parameters.

[0037] S4: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays oxygen-containing gas with controlled oxygen content (e.g., low-pressure oxygen-containing gas) to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0038] S5: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0039] S6: Based on the design scheme, repeat S1-S5 continuously until the oxygen dispersion reinforced component printing is completed.

[0040] The following are specific examples: Example 1: like Figure 4 As shown, the Inconel 718 component includes two oxygen content regions: region A is black, indicating an Inconel 718 oxygen content of 1000 ppm, and region B is gray, indicating an Inconel 718 oxygen content of 800 ppm. The fabrication direction is along the Z-axis as shown in the figure, and this component is a composition gradient material in the XY plane. Using Inconel 718 15-53μm spherical powder as raw material, the laser selective melting forming steps are as follows: S1: Based on actual parameter requirements, the in-situ oxygen-controlled composite scraper 2 is designed with a moving speed of 1000ppm-Inconel 718, a zone of V1=200 mm / s, oxygen / argon partial pressure n=1, and a ventilation flow rate of V2=5 m³ / s. 3 / s (All flow rates mentioned in this invention correspond to standard conditions); 800ppm - Inconel 718 region: V1=150 mm / s, oxygen / argon partial pressure n=1 and ventilation flow rate V2=4 m 3 / s.

[0041] S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=600 ℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0042] S3: Based on the sample printing parameters, the laser power is designed to be 275 W, the scanning spacing is h = 0.11 mm, the layer thickness is t = 0.05 mm, and the scanning speed is V3 = 700 mm / s.

[0043] S4: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0044] S5: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0045] S6: Based on the design scheme, repeat S1-S5 continuously until the oxygen dispersion reinforced component printing is completed.

[0046] Example 2: like Figure 5 As shown, a CuCrZr Gyroid-solid lattice component includes four oxygen content regions: 600 ppm, 800 ppm, 1000 ppm, and 1200 ppm, with gradient distributions as illustrated. This component is a composition gradient material varying along the Z-direction. Using CuCrZr 15-53 μm spherical powder as raw material, the laser selective melting forming steps are as follows: S1: Based on actual parameter requirements, the in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1=100 mm / s, oxygen / argon partial pressure n=0.8, and ventilation flow rate V2=5 m³ / s. 3 / s.

[0047] S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=300℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the solidification cracking in the component is suppressed by adjusting the temperature gradient.

[0048] S3: Based on the sample printing parameters, design the laser power P=400 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm and scanning speed V3=500 mm / s.

[0049] S4: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0050] S5: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0051] S6: Based on the design scheme, repeat S4-S5 continuously until the 600ppm-CuCrZr part of the printing work is completed.

[0052] S7: Design the in-situ oxygen-controlled composite scraper 2 with a moving speed of V1=80 mm / s, oxygen / argon partial pressure n=1, and ventilation flow rate V2=6 m³ / s. 3 / s.

[0053] S8: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=400℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0054] S9: Based on the sample printing parameters, design the laser power P=400 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm and scanning speed V3=500 mm / s.

[0055] S10: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0056] S11: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0057] S12: Based on the design scheme, repeat S10-S11 continuously until the 800ppm-CuCrZr part of the printing work is completed.

[0058] S13: Design the in-situ oxygen-controlled composite scraper 2 with a moving speed V1 = 70 mm / s, oxygen / argon partial pressure n = 1.2, and ventilation flow rate V2 = 7 m³ / s. 3 / s.

[0059] S14: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature condition T=350℃ of the heatable substrate 12 is adjusted by the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0060] S15: Based on the sample printing parameters, design the laser power P=400 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm and scanning speed V3=500 mm / s.

[0061] S16: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0062] S17: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0063] S18: Based on the design scheme, repeat S16-S17 until the 1000ppm-CuCrZr part of the printing work is completed.

[0064] S19: Based on actual parameter requirements, the in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1 = 60 mm / s, an oxygen / argon partial pressure n = 1.4, and a ventilation flow rate V2 = 8 m³ / s. 3 / s.

[0065] S20: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=400℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0066] S21: Based on the sample printing parameters, design the laser power P=400 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm and scanning speed V3=500 mm / s.

[0067] S22: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0068] S23: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0069] S24: Based on the design scheme, repeat S22-S23 continuously until the 1200 ppm CuCrZr partial printing is completed.

[0070] Example 3: like Figure 6 As shown, an AlMgScZr gyroid-sheet lattice component with four oxygen content regions (600 ppm, 800 ppm, 1000 ppm, and 1200 ppm) is constructed, exhibiting a gradient distribution as shown in the figure. This component is a composition gradient material varying along the Z-direction. Using AlMgScZr 15-53 μm spherical powder as raw material, the laser selective melting forming process is as follows: S1: Based on actual parameter requirements, the in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1 = 140 mm / s, an oxygen / argon partial pressure n = 0.6, and a ventilation flow rate V2 = 5 m³ / s. 3 / s.

[0071] S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=150 ℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0072] S3: Based on the sample printing parameters, the laser power is designed to be 425 W, the scanning spacing is h = 0.11 mm, the layer thickness is t = 0.05 mm, and the scanning speed is V3 = 1200 mm / s.

[0073] S4: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0074] S5: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0075] S6: Based on the design scheme, repeat S4-S5 continuously until the 600ppm-AlMgScZr partial printing is completed.

[0076] S7: The in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1 = 130 mm / s, an oxygen / argon partial pressure n = 0.7, and a ventilation flow rate V2 = 6 m³ / s. 3 / s.

[0077] S8: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=200 ℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0078] S9: Based on the sample printing parameters, the laser power is designed to be 425 W, the scanning spacing is h = 0.11 mm, the layer thickness is t = 0.05 mm, and the scanning speed is V3 = 1125 mm / s.

[0079] S10: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0080] S11: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0081] S12: Based on the design scheme, repeat S10-S11 continuously until the 800ppm-AlMgScZr partial printing is completed.

[0082] S13: The in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1 = 120 mm / s, an oxygen / argon partial pressure n = 0.6, and a ventilation flow rate V2 = 7 m³ / s. 3 / s.

[0083] S14: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature of the heatable substrate 12 is adjusted to T=250 ℃ through the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0084] S15: Based on the sample printing parameters, the laser power P=425 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm, and scanning speed V3=1125 mm / s were designed.

[0085] S16: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0086] S17: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0087] S18: Based on the design scheme, repeat S16-S17 until the 1000ppm-AlMgScZr partial printing is completed.

[0088] S19: Based on actual parameter requirements, the in-situ oxygen-controlled composite scraper 2 is designed with a moving speed V1 = 110 mm / s, an oxygen / argon partial pressure n = 0.7, and a ventilation flow rate V2 = 8 m³ / s. 3 / s.

[0089] S20: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature condition T=275 ℃ of the heatable substrate 12 is adjusted by the power supply box 10. The oxidation conditions are adjusted to strengthen the oxygen dispersion of the component, and the occurrence of solidification cracks in the component is suppressed by adjusting the temperature gradient.

[0090] S21: Based on the sample printing parameters, the laser power P=425 W, scanning spacing h=0.11 mm, layer thickness t=0.05 mm, and scanning speed V3=1125 mm / s were designed.

[0091] S22: Activate the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, while the multi-micro-hole jet device 17 sprays low-pressure oxygen-containing gas to oxidize the powder in situ. The second scraper compacts the powder at the same time. The laser does not operate at this time.

[0092] S23: After the powder is spread, the laser is started to print the sample with oxygen dispersion enhancement.

[0093] S24: Based on the design scheme, repeat S22-S23 until the 1200 ppm AlMgScZr partial printing is completed.

[0094] The above embodiments are merely examples. For instance, in addition to using argon and oxygen cylinders, the types of gas can be changed or more cylinders can be introduced as needed (for example, oxygen, argon, nitrogen and carbon dioxide cylinders can be used simultaneously, as long as at least one cylinder stores O2). The number of input ports of the flow control valve 6 can also be adjusted accordingly.

[0095] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An in-situ oxygen-regulated composite scraper, characterized in that, The bottom of the composite scraper includes a second scraper (16), an air jet unit, and a first scraper (18) arranged sequentially along the powder spreading direction. The interior of the composite scraper is provided with an air storage chamber (15) and a powder drop chamber (19). The powder drop chamber (19) is used to transfer the laser selective melting powder material transported through the powder drop channel (20) to the powder outlet of the first scraper (18). The first scraper (18) is used to evenly spread the powder material on the surface of the forming substrate to form an initial powder layer, thereby realizing the first scraper spreading the powder. The air storage chamber (15) is used to transfer oxygen-containing gas with controlled oxygen content transported through the ventilation channel (14) to the air jet unit. The air jet unit sprays out oxygen-containing gas to perform in-situ oxidation treatment on the surface of the initial powder layer. The second scraper (16) is used to level and compact the powder layer after the in-situ oxidation treatment is completed.

2. The in-situ oxygen-controlled composite scraper as described in claim 1, characterized in that, The jet unit is a multi-micro-hole jet device (17), which has multiple interconnected gas channels inside and a micro-hole gas outlet structure at the bottom. The micro-holes are evenly distributed along the length direction of the first scraper (18).

3. The in-situ oxygen-controlled composite scraper as described in claim 1, characterized in that, The oxygen content in the oxygen-containing gas is regulated by a flow-controlled gas distribution valve (6). The inlet of the flow-controlled gas distribution valve (6) is connected to at least two gas cylinders via a vent pipe, and the outlet is connected to the ventilation channel (14) via a main vent pipe (3). At least one of these gas cylinders stores O2, and each gas cylinder contains a different gas. The flow-controlled gas distribution valve (6) is used to regulate the partial pressure ratio of each gas input from these gas cylinders, mix them to form the oxygen-containing gas with controlled oxygen content, and regulate the overall flow rate of the oxygen-containing gas. Preferably, the gas cylinder consists of two cylinders, which store oxygen and argon respectively; Alternatively, the gas cylinders may consist of four cylinders, storing oxygen, argon, nitrogen, and carbon dioxide respectively.

4. The in-situ oxygen-controlled composite scraper as described in claim 1, characterized in that, The forming substrate is a heatable forming substrate with a heating device disposed below it. The heating device can raise the temperature to provide a controllable thermal environment for the powder layer, thereby synergistically regulating the temperature and degree of the powder oxidation reaction.

5. The in-situ oxygen-controlled composite scraper as described in claim 4, characterized in that, The heating device is an electric heating device or an induction heating device, and the heating temperature can be adjusted within a preset range; Preferably, the heating device is connected to the power supply box (10) via a power-conducting wire (11), and the power supply box (10) is used to supply power to the heating device.

6. The in-situ oxygen-controlled composite scraper as described in claim 1, characterized in that, Both the powder drop channel (20) and the ventilation channel (14) are located at the top of the composite scraper.

7. A laser selective melting device equipped with an in-situ oxygen-controlled composite scraper, characterized in that, It includes a printing platform, a forming substrate, a laser (1), and an in-situ oxygen-controlled composite scraper as described in any one of claims 1-6, wherein the forming substrate and the printing platform are on the same horizontal plane.

8. A laser selective melting forming method for oxide dispersion-strengthened components based on a laser selective melting device with an in-situ oxygen-controlled composite scraper as described in claim 7, characterized in that, Includes the following steps: S1: Based on the parameter requirements of the target oxide dispersion-strengthened component, set the moving speed V1 of the in-situ oxygen-controlled composite scraper, the partial pressure ratio of each gas component in the oxygen-containing gas, and the ventilation flow rate V2 of the oxygen-containing gas. S2: Based on the requirements for suppressing solidification cracks and the oxidation conditions of metal powder, the temperature conditions of the formed substrate are controlled by the power supply box. S3: Set the laser power P, scanning spacing h, layer thickness t and scanning speed V3 according to the printing parameters of the target oxide dispersion-strengthened component sample; S4: Without starting the laser, start the in-situ oxygen-controlled composite scraper. The first scraper spreads the powder, and the jet unit sprays oxygen-containing gas to oxidize the powder in situ. At the same time, the second scraper levels and compacts the powder after in-situ oxidation. S5: The laser is activated to print oxide dispersion reinforced components on the powder layer formed by in-situ oxygen-controlled composite doctor blade operation.

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