Additive manufacturing method for unsupported thin-wall component based on ultrafast laser strengthening
By using shock waves induced by ultrafast laser beams to strengthen each deposition layer in situ during powder bed additive manufacturing, the problems of insufficient molding reliability and mechanical properties of overhanging thin-walled parts in the unsupported printing process are solved, and efficient molding and comprehensive performance optimization of unsupported thin-walled components are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2026-01-28
- Publication Date
- 2026-05-26
AI Technical Summary
Unsupported printing of suspended thin-walled parts presents problems such as deposition layer collapse, warping, weak interlayer bonding, uneven heat accumulation, and uneven performance, resulting in insufficient molding reliability and comprehensive mechanical properties.
An ultrafast laser strengthening method is used to perform in-situ strengthening treatment on each deposited layer during powder bed additive manufacturing by using shock waves induced by an ultrafast laser beam, thereby improving the interlayer bonding strength and plasticity.
Without adding a supporting structure, the molding reliability and comprehensive mechanical properties of unsupported overhanging thin-walled components are significantly improved, especially plasticity and elongation, solving the problems of insufficient plasticity and performance anisotropy.
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Figure CN122076995A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the fields of additive manufacturing and laser processing technology, specifically to a method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening. Background Technology
[0002] In the aerospace field, lightweight cooling blades for aircraft engines, spacecraft grid panels, and satellite honeycomb support structures extensively employ thin-walled designs with complex internal cavities and external overhangs to minimize weight while ensuring thermal management or mechanical performance. Supportless printing of overhanging thin-walled components not only eliminates subsequent removal processes and avoids damage to the support contact surface, but also achieves complete closure and freeform forming of internal cavities, a feat unattainable with traditional printing methods.
[0003] The unsupported printing process for overhanging thin-walled parts presents several challenges: First, an excessively high overhang angle causes the melt to fall due to gravity, leading to layer collapse, flow, or severe geometric distortion. Second, the thin-walled region has a low heat capacity and a rapid cooling rate, making it prone to severe shrinkage and warping during printing due to large temperature differences between the inside and outside. Furthermore, the interlayer bonding in the overhanging region is weak, making it susceptible to peeling or cracking under stress. Third, the lack of heat dissipation from the underlying solid layer in the overhanging region leads to significant heat accumulation, exacerbating melt pool instability and the risk of collapse. Meanwhile, rapid heat loss at the thin-walled edges results in excessively low melt pool temperatures, affecting interlayer bonding and density.
[0004] In addition, unsupported printing of overhanging thin-walled parts presents performance deficiencies. For example, the underside of the overhanging surface suffers from severe dimensional deviations due to the "step effect" and "melt sagging"; the overhanging area is prone to voids and unfused defects due to insufficient fusion, significantly reducing density; and overheating or undercooling in the overhanging thin-walled area can lead to coarse or excessively fine grains, resulting in uneven performance.
[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure and may therefore contain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention
[0006] To address the problems existing in the prior art, this disclosure provides a method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening. By using ultrafast laser to strengthen the deposited layer layer by layer during the powder bed additive manufacturing process, the comprehensive mechanical properties of the unsupported thin-walled components are improved.
[0007] This disclosure provides the following technical solutions:
[0008] A method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening includes the following steps:
[0009] Step S100: Deposit a layer of metal powder onto the substrate or the formed deposited layer;
[0010] Step S200: Selectively melt the metal powder using a first laser beam to form a deposition layer;
[0011] Step S300: After the deposition layer is formed and before the next layer of metal powder is laid, the deposition layer is scanned with an ultrafast laser beam, and the deposition layer is strengthened in situ using the shock wave induced by the ultrafast laser beam.
[0012] Step S400: Repeat steps S100 to S300, layer by layer, until the unsupported thin-walled component is formed.
[0013] In the method described, the metal powder in step S100 is a high-temperature alloy powder.
[0014] In the method described, the high-temperature alloy powder is a cobalt-based high-temperature alloy powder.
[0015] In the method described, the cobalt-based high-temperature alloy powder is GH5188 alloy powder.
[0016] In the method described, the thickness of the laid metal powder layer is 30-50 μm.
[0017] In the method described, in step S200, the rotation angle between the selected melting scan paths of adjacent deposition layers is 67°.
[0018] In the method described, the ultrafast laser beam in step S300 is a femtosecond laser beam.
[0019] In the method described, the first laser beam is generated by a continuous laser, and the ultrafast laser beam is generated by an ultrafast laser.
[0020] In the method described, the power of the ultrafast laser beam in step S300 is 10-50 W, and the scanning speed is 800-1200 mm / s.
[0021] An unsupported thin-walled component is formed by layer-by-layer deposition of metal powder through an additive manufacturing process. During the forming process of the component, after each deposition layer is formed and before the next layer of powder is laid, in-situ strengthening treatment is performed using shock waves induced by an ultrafast laser beam.
[0022] Compared with the prior art, the beneficial effects of this disclosure are as follows:
[0023] This disclosure provides a method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening. Through an integrated manufacturing method of "additive forming - ultrafast laser in-situ strengthening", the forming reliability and overall performance of unsupported overhanging thin-walled components are improved without adding a support structure. In addition, by using femtosecond laser-induced shock waves to hammer each deposition layer in situ, the plasticity (elongation) of the component can be significantly improved with almost no impact on the component strength. This effectively solves the common problems of insufficient plasticity and performance anisotropy in additive manufacturing of unsupported thin-walled parts, and achieves optimization of comprehensive mechanical properties.
[0024] The description provided is merely an overview of the technical solution of this disclosure. To make the technical means of this disclosure clearer and more understandable, to the point that those skilled in the art can implement it according to the content of the specification, and to make the described and other objects, features, and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are illustrated below. (See accompanying drawings.)
[0025] Various other advantages and benefits of this disclosure will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0026] Figure 1 This is a schematic diagram of an additive manufacturing method for unsupported thin-walled components based on ultrafast laser strengthening, as provided in this disclosure.
[0027] Figure 2 A photograph of the completed printing of a suspended thin-walled part obtained under one embodiment of the present disclosure;
[0028] Figure 3 The stress-strain curve of a suspended thin-walled part along the vertical direction is provided as a comparative example for this disclosure.
[0029] Figure 4 The stress-strain curve of a suspended thin-walled part along the vertical direction is obtained when the strengthening power is 16W in one embodiment of this disclosure.
[0030] Figure 5 The stress-strain curve of a suspended thin-walled part along the vertical direction is obtained when the strengthening power is 40W in one embodiment provided in this disclosure. Detailed Implementation
[0031] The following will be combined with the appendix Figures 1 to 5The embodiments described herein are provided in detail and are intended to explain, rather than limit, this disclosure. While specific embodiments of this disclosure are shown in the accompanying drawings, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.
[0032] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions of preferred embodiments of this disclosure are for the purpose of implementing the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.
[0033] To facilitate understanding of the embodiments of this disclosure, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of this disclosure.
[0034] A method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening, see [link to relevant documentation]. Figure 1 It includes the following steps:
[0035] Step S100: Deposit a layer of metal powder onto the substrate or the formed deposited layer;
[0036] Step S200: Selectively melt the metal powder using a first laser beam to form a deposition layer;
[0037] Step S300: After the deposition layer is formed and before the next layer of metal powder is laid, the deposition layer is scanned with an ultrafast laser beam, and the deposition layer is strengthened in situ using the shock wave induced by the ultrafast laser beam.
[0038] Step S400: Repeat steps S100 to S300, layer by layer, until the unsupported thin-walled component is formed.
[0039] In a preferred embodiment of the method, the metal powder in step S100 is a high-temperature alloy powder.
[0040] In a preferred embodiment of the method, the high-temperature alloy powder is a cobalt-based high-temperature alloy powder.
[0041] In a preferred embodiment of the method, the cobalt-based high-temperature alloy powder is GH5188 alloy powder.
[0042] In a preferred embodiment of the method, the thickness of the laid metal powder layer is 30-50 μm.
[0043] It should be noted that the thickness of the metal powder layer must meet the following constraints: the thickness of the metal powder layer needs to match the powder particle size distribution to ensure uniform powder spreading, complete penetration of the laser energy into the powder layer to achieve stable metallurgical bonding, and compatibility with the effective depth of the ultrafast laser shock wave. If the metal powder layer thickness is too thin (e.g., <30μm), it can easily lead to interlayer adhesion and excessive heat input, resulting in low manufacturing efficiency; if the metal powder layer thickness is too thick (e.g., >50μm), it can easily lead to insufficient fusion, increased porosity and defects, and a significant decrease in interlayer bonding strength.
[0044] In a preferred embodiment of the method, in step S200, the rotation angle between the selected melting scan paths of adjacent deposition layers is 67°.
[0045] In a preferred embodiment of the method, the ultrafast laser beam in step S300 is a femtosecond laser beam.
[0046] In a preferred embodiment of the method, the first laser beam is generated by a continuous laser, and the ultrafast laser beam is generated by an ultrafast laser.
[0047] In a preferred embodiment of the method, the power of the ultrafast laser beam in step S300 is 10-50 W, and the scanning speed is 800-1200 mm / s.
[0048] Specifically, the power of the ultrafast laser beam must meet the following constraints: the power of the ultrafast laser beam needs to work in conjunction with the pulse width and spot size to generate a sufficiently high peak power density, ensuring the instantaneous formation of high-temperature, high-pressure plasma on the material surface and inducing an effective shock wave effect. If the power is too low (e.g., <10W), the peak power density is insufficient, making it difficult to generate a plasma shock wave with sufficient pressure, resulting in negligible strengthening effect; if the power is too high (e.g., >50W), it can easily cause excessive ablation, remelting, or the formation of an unfavorable heat-affected zone on the material surface, leading to a decrease in the geometric accuracy of the component.
[0049] The scanning speed of the ultrafast laser beam must meet the following constraints: the scanning speed of the ultrafast laser beam needs to be matched with the laser power, pulse frequency, and spot overlap rate to ensure that sufficient shock wave superposition and strengthening effect can be generated between adjacent action points on the scanning trajectory. If the scanning speed is too low (e.g., <800 mm / s), the action time per unit area is too long, the heat accumulation effect is aggravated, and it is easy to cause local annealing or even micro-melting, resulting in low processing efficiency; if the scanning speed is too high (e.g., >1200 mm / s), the action time at a single point is too short, and it is easy to fail to form a stable plasma shock wave, leaving unstrengthened weak areas.
[0050] In a preferred embodiment of the method, the strengthening treatment increases the elongation of the unsupported thin-walled member by more than 20% compared to the unstrengthened member, while the decrease in strength does not exceed 5%.
[0051] On the other hand, this disclosure provides an unsupported thin-walled component, which is formed by layer-by-layer deposition of metal powder through an additive manufacturing process. During the forming process of the component, after each deposition layer is formed and before the next layer of powder is laid, in-situ strengthening treatment is performed using shock waves induced by an ultrafast laser beam.
[0052] In one embodiment, the metal powder is a high-temperature alloy powder, the high-temperature alloy powder is a cobalt-based high-temperature alloy powder, and the cobalt-based high-temperature alloy powder is GH5188 alloy powder.
[0053] The thickness of the metal powder layer laid on the component is 30-50 μm, and the rotation angle between the selected area melting scanning paths of adjacent deposition layers is 67°.
[0054] The ultrafast laser beam is a femtosecond laser beam. The power of the ultrafast laser beam is 10-50 W, and the scanning speed is 800-1200 mm / s.
[0055] The strengthening treatment of the component increases the elongation of the component by more than 20% compared with the unstrengthened component, and the strength decreases by no more than 5%.
[0056] To better understand this disclosure, the following more specific embodiments are provided to illustrate the technical effects brought about by this disclosure.
[0057] Comparative Example
[0058] A layer of metal powder was deposited on a GH5188 alloy substrate with dimensions of 20 mm × 20 mm × 10 mm. The metal powder was GH5188 alloy powder prepared by gas atomization, and its chemical composition is shown in Table 1. The powder particle size distribution was between 15-53 μm, and it had high sphericity and surface smoothness.
[0059] Table 1. Composition of GH5188 alloy powder (wt.%)
[0060]
[0061] A first laser beam generated by a continuous fiber laser with a wavelength of 1064 nm and a maximum power of 500 W is used to selectively melt and scan the currently laid metal powder layer. In this embodiment, the process parameters of the additive laser are set as follows: laser power 300 W, scanning speed 960 mm / s, scanning line overlap rate 50%, spot diameter approximately 80 μm, and auxiliary powder layer thickness 50 μm. The scanning path is preset based on the three-dimensional model slice data of the target component (an unsupported thin-walled structure with a wall thickness of approximately 1.2 mm and a cantilever angle of 40°), and a scanning strategy of 67° interlayer rotation and 100 μm line spacing is adopted to optimize stress distribution. The entire printing process is carried out in a sealed chamber with a protective atmosphere that has been replaced with high-purity argon and kept flowing, and the oxygen content is always below 50 ppm. The first laser beam is used to selectively melt the metal powder of the current layer to form a deposition layer.
[0062] Repeat the powder-spreading-melting cycle to ultimately obtain a geometrically complete, internally reinforced, unsupported thin-walled component. (See attached image) Figure 2 .
[0063] After the components are printed, they are cooled to room temperature in the furnace. Samples are then taken perpendicular to the components and processed into standard tensile specimens. Uniaxial tensile tests are performed at room temperature according to national standards to determine their mechanical properties.
[0064] The stress-strain curve along the vertical direction of the unsupported thin-walled component prepared in this embodiment is shown in [reference]. Figure 3 Its room temperature tensile properties in the vertical direction are: tensile strength 880 MPa, elongation after fracture 28%.
[0065] Example 1
[0066] A layer of metal powder was deposited on a GH5188 alloy substrate with dimensions of 20 mm × 20 mm × 10 mm. The metal powder was GH5188 alloy powder prepared by gas atomization, and its chemical composition is shown in Table 1. The powder particle size distribution was between 15-53 μm, and it had high sphericity and surface smoothness.
[0067] A first laser beam generated by a continuous fiber laser with a wavelength of 1064 nm and a maximum power of 500 W is used to selectively melt and scan the currently laid metal powder layer. In this embodiment, the process parameters of the additive laser are set as follows: laser power 300 W, scanning speed 960 mm / s, scanning line overlap rate 50%, spot diameter approximately 80 μm, and auxiliary powder layer thickness 50 μm. The scanning path is preset based on the three-dimensional model slice data of the target component (an unsupported thin-walled structure with a wall thickness of approximately 1.2 mm and a cantilever angle of 40°), and a scanning strategy of 67° interlayer rotation and 100 μm line spacing is adopted to optimize stress distribution. The entire printing process is carried out in a sealed chamber with a protective atmosphere that has been replaced with high-purity argon and kept flowing, and the oxygen content is always below 50 ppm. The first laser beam is used to selectively melt the metal powder of the current layer to form a deposition layer.
[0068] Immediately after the current deposition layer has formed and solidified, and before the next step of laying a new powder layer begins, an ultrafast laser beam generated by a femtosecond ultrafast laser with a wavelength of 1030 nm, a pulse width of 500 fs, and a maximum average power of 40 W is used to scan the surface of the newly formed deposition layer. In this embodiment, the process parameters of the femtosecond strengthening laser are set as follows: average power 16 W, scanning speed 1000 mm / s, and scan line overlap rate 50%. The interaction between the laser and the material generates a shock wave, which performs in-situ strengthening of the deposition layer.
[0069] The process of powder spreading, melting, and strengthening is repeated until the entire 3D digital model is layered and simultaneously strengthened, ultimately resulting in a geometrically complete, internally strengthened, unsupported thin-walled component. After printing, the component is cooled to room temperature in the furnace. Subsequently, samples are taken along the vertical direction of the component and processed into standard tensile specimens. Uniaxial tensile tests are conducted at room temperature according to national standards to determine its mechanical properties.
[0070] The stress-strain curve along the vertical direction of the unsupported thin-walled component prepared in this embodiment is shown in [reference]. Figure 4 Compared to a control component using the exact same additive manufacturing equipment, materials, and process parameters but without ultrafast laser strengthening, the tensile strength of the strengthened component was 860 MPa, a decrease of only about 2.3% compared to the unstrengthened component (880 MPa), indicating that the strength was essentially maintained. Furthermore, the elongation after fracture of the strengthened component reached 35%, a significant increase of approximately 25% compared to the unstrengthened control component (28%).
[0071] Example 2
[0072] A layer of metal powder was deposited on a GH5188 alloy substrate with dimensions of 20 mm × 20 mm × 10 mm. The metal powder was GH5188 alloy powder prepared by gas atomization, and its chemical composition is shown in Table 1. The powder particle size distribution was between 15-53 μm, and it had high sphericity and surface smoothness.
[0073] A first laser beam generated by a continuous fiber laser with a wavelength of 1064 nm and a maximum power of 500 W is used to selectively melt and scan the currently laid metal powder layer. In this embodiment, the process parameters of the additive laser are set as follows: laser power 300 W, scanning speed 960 mm / s, scanning line overlap rate 50%, spot diameter approximately 80 μm, and auxiliary powder layer thickness 50 μm. The scanning path is preset based on the three-dimensional model slice data of the target component (an unsupported thin-walled structure with a wall thickness of approximately 1.2 mm and a cantilever angle of 40°), and a scanning strategy of 67° interlayer rotation and 100 μm line spacing is adopted to optimize stress distribution. The entire printing process is carried out in a sealed chamber with a protective atmosphere that has been replaced with high-purity argon and kept flowing, and the oxygen content is always below 50 ppm. The first laser beam is used to selectively melt the metal powder of the current layer to form a deposition layer.
[0074] Immediately after the current deposition layer has formed and solidified, and before the next step of laying a new powder layer begins, an ultrafast laser beam generated by a femtosecond ultrafast laser with a wavelength of 1030 nm, a pulse width of 500 fs, and a maximum average power of 40 W is used to scan the surface of the newly formed deposition layer. In this embodiment, the process parameters of the femtosecond strengthening laser are set as follows: average power 40 W, scanning speed 1000 mm / s, and scan line overlap rate 50%. The interaction between the laser and the material generates a shock wave, which performs in-situ strengthening of the deposition layer.
[0075] The process of powder spreading, melting, and strengthening is repeated until the entire 3D digital model is layered and simultaneously strengthened, ultimately resulting in a geometrically complete, internally strengthened, unsupported thin-walled component. After printing, the component is cooled to room temperature in the furnace. Subsequently, samples are taken along the vertical direction of the component and processed into standard tensile specimens. Uniaxial tensile tests are conducted at room temperature according to national standards to determine its mechanical properties.
[0076] The stress-strain curve along the vertical direction of the unsupported thin-walled component prepared in this embodiment is shown in [reference]. Figure 5Compared to a control component using the exact same additive manufacturing equipment, materials, and process parameters but without ultrafast laser strengthening, the tensile strength of the strengthened component was 854 MPa, a decrease of only about 3.0% compared to the unstrengthened component (880 MPa), indicating that the strength was essentially maintained. Furthermore, the elongation after fracture of the strengthened component reached 35%, a significant increase of approximately 25% compared to the unstrengthened control component (28%).
[0077] The method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening uses femtosecond laser-induced shock waves to hammer each deposition layer in situ. This significantly improves the plasticity (elongation) of the component with almost no impact on its strength, effectively solving common problems in additive manufacturing of unsupported thin-walled components such as insufficient plasticity and performance anisotropy, and achieving optimization of comprehensive mechanical properties.
[0078] Although the embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this disclosure is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the teachings of this specification and without departing from the scope of protection of the claims of this disclosure, and all of these are within the scope of protection of this disclosure.
Claims
1. A method for additive manufacturing of unsupported thin-walled components based on ultrafast laser strengthening, characterized in that, Includes the following steps: Step S100: Deposit a layer of metal powder onto the substrate or the formed deposited layer; Step S200: Selectively melt the metal powder using a first laser beam to form a deposition layer; Step S300: After the deposition layer is formed and before the next layer of metal powder is laid, the deposition layer is scanned with an ultrafast laser beam, and the deposition layer is strengthened in situ using the shock wave induced by the ultrafast laser beam. Step S400: Repeat steps S100 to S300, layer by layer, until the unsupported thin-walled component is formed.
2. The method according to claim 1, characterized in that, Preferably, the metal powder in step S100 is a high-temperature alloy powder.
3. The method according to claim 2, characterized in that, The high-temperature alloy powder is a cobalt-based high-temperature alloy powder.
4. The method according to claim 3, characterized in that, The cobalt-based high-temperature alloy powder is GH5188 alloy powder.
5. The method according to any one of claims 1 to 4, characterized in that, The thickness of the laid metal powder layer is 30-50 μm.
6. The method according to claim 1, characterized in that, In step S200, the rotation angle between the selected melting scan paths of adjacent deposition layers is 67°.
7. The method according to claim 1, characterized in that, The ultrafast laser beam mentioned in step S300 is a femtosecond laser beam.
8. The method according to claim 1 or 7, characterized in that, The first laser beam is generated by a continuous laser, and the ultrafast laser beam is generated by an ultrafast laser.
9. The method according to claim 1, characterized in that, The power of the ultrafast laser beam in step S300 is 10-50 W, and the scanning speed is 800-1200 mm / s.
10. An unsupported thin-walled component, characterized in that, The component is formed by layering metal powder through additive manufacturing process. During the forming process of the component, after each deposition layer is formed and before the next layer of powder is laid, in-situ strengthening treatment is carried out by shock wave induced by ultrafast laser beam.