High-forming-quality volatile light alloy laser additive and manufacturing method therefor

Abstract

Disclosed in the present invention are a high-forming-quality volatile light alloy laser additive and a manufacturing method therefor. The additive comprises a light alloy matrix and a micron-sized ceramic reinforcement phase dispersed in the light alloy matrix, wherein the light alloy matrix is a magnesium alloy or an aluminum alloy; and the micron-sized ceramic reinforcement phase is TiC, and the TiC ceramic reinforcement phase accounts for 2-6 wt.% of the light alloy matrix, and the micron-sized ceramic reinforcement phase TiC is tightly adhered to the surface of light alloy matrix powder by means of a low-energy ball milling method. Due to low melting points, metal elements such as magnesium and aluminum in a light alloy are prone to volatilize under the irradiation of high-energy laser beams, resulting in metallurgical defects such as spattering and pores, thereby reducing the forming quality and mechanical properties of the light alloy. By adding an appropriate amount of matching reinforcement phase, the present invention reduces the momenta of volatile light alloy powders such as magnesium alloys and aluminum alloys during laser forming, reduces the spattering of alloy powders and improves the forming quality of the alloys, thereby achieving the effect of improving the laser formability and mechanical properties of the light alloy and finally obtaining a light alloy having high forming quality and high performance.

Description

A high-quality, easily evaporable lightweight alloy laser additive manufacturing method and its production process Technical Field

[0001] This invention belongs to the field of laser additive manufacturing of easily evaporable light alloys, and specifically relates to a high-quality easily evaporable light alloy laser additive manufacturing method and its manufacturing method. Background Technology

[0002] Light alloys such as magnesium and aluminum alloys are widely used in aerospace, automotive, and medical industries due to their high specific strength and corrosion resistance. Laser additive manufacturing technology can directly utilize digital models to freely manufacture complex components, offering advantages such as design flexibility and high material utilization. However, light alloys like magnesium and aluminum alloys contain low-melting-point metallic elements such as Mg and Al, which are prone to rapid evaporation under high-energy laser beams, leading to metallurgical defects such as spatter and porosity, thus reducing the forming quality of the light alloys. By incorporating an appropriate amount of matching reinforcing phase into the light alloy, the laser absorption of the powder in the powder bed can be improved. Simultaneously, during laser forming, high-melting-point ceramic particles partially melt. At the high initial velocity of the metal vapor jet, unmelted ceramic particles are ejected into the metal vapor. Due to their relatively high density, the momentum of the metal vapor can be absorbed and reduced by the ejected ceramic particles, reducing powder spatter in the alloy powder bed and improving the stability of the powder bed. This, in turn, reduces the formation of defects such as porosity and spheroidization, ultimately improving the laser forming quality and mechanical properties of the alloy. Summary of the Invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a manufacturing method for high-quality, easily evaporable light alloy laser additive manufacturing, which addresses the shortcomings of the prior art, so as to give full play to the positive effects of the adaptive reinforcement on laser absorption and powder bed stability, thereby improving the forming quality of the material.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A high-quality, easily evaporable light alloy laser additive manufacturing process includes a light alloy matrix and a micron-sized ceramic reinforcement phase dispersed within the light alloy matrix. The light alloy matrix is ​​a magnesium alloy or an aluminum alloy. The micron-sized ceramic reinforcement phase is TiC, and the TiC ceramic reinforcement phase accounts for 2-6 wt.% of the light alloy matrix. The micron-sized ceramic reinforcement phase TiC is tightly adhered to the surface of the light alloy matrix powder by a low-energy ball milling method.

[0006] As one option, the magnesium alloy is a Mg-Al alloy, wherein the Al content is 8.2-9.0 wt.%.

[0007] Alternatively, the aluminum alloy is an Al-Mg alloy, wherein the Mg content is 3.9-5.5 wt.%.

[0008] Preferably, the micron-sized ceramic reinforcing phase TiC dispersed in the magnesium alloy matrix has a content of 2-5 wt.%, a particle size distribution range of 2-5 μm, and a purity greater than 99.5%.

[0009] Preferably, the micron-sized ceramic reinforcing phase TiC dispersed in the aluminum alloy matrix has a content of 3-6 wt.%, a particle size distribution range of 2-5 μm, and a purity greater than 99.5%.

[0010] In this invention, TiC ceramics exhibit low lattice mismatch rates with metallic elements such as Mg and Al, demonstrating excellent interfacial compatibility and making them ideal reinforcing materials. TiC particles possess a high laser absorption rate (>90%), which promotes the full melting and spreading of high-laser-reflectivity light alloys during laser additive manufacturing. Furthermore, the relatively high density of ceramic particles reduces powder momentum during powder splashing, thereby minimizing powder splashing and improving powder bed stability and the quality of light alloy laser forming.

[0011] Furthermore, the present invention also provides a method for manufacturing the above-mentioned high-quality, easily evaporable lightweight alloy laser additive, comprising the following steps:

[0012] (1) Micron-sized TiC ceramic powder and light alloy matrix powder are mixed uniformly by low-energy ball milling under inert gas protection to obtain composite powder; the light alloy matrix is ​​a magnesium alloy or an aluminum alloy.

[0013] (2) Establish a three-dimensional solid geometric model of the part to be formed, then slice the geometric model into layers and plan the laser scanning path, discretize the three-dimensional solid into a series of two-dimensional data, save and import it into the laser powder bed melting forming equipment;

[0014] (3) The laser powder bed melting and forming equipment melts and solidifies the composite powder in step (1) layer by layer according to the data imported in step (2), and finally forms high-quality light alloy parts.

[0015] As one option, in step (1), the light alloy matrix powder is Mg-Al alloy powder, wherein the Al content is 8.2-9.0 wt.% and the powder particle size ranges from 23 to 53 μm; the micron-sized ceramic reinforcing phase TiC accounts for 2-5 wt.% of the light alloy matrix.

[0016] As another option, in step (1), the light alloy matrix powder is Al-Mg alloy powder, wherein the Mg content is 3.9-5.5 wt.%, the powder particle size range is 21-56 μm, and the micron-sized ceramic reinforcing phase TiC accounts for 3-6 wt.% of the light alloy matrix.

[0017] Preferably, in step (3), when the light alloy matrix is ​​a magnesium alloy, the laser power used in the laser powder bed melting forming equipment is 120-180W, the laser scanning speed is 300-600mm / s, the scanning spacing is 90μm, the powder thickness is 40μm, and the laser powder bed melting forming equipment adopts an XY cross scanning strategy with adjacent layers rotating 90°.

[0018] Preferably, in step (3), when the light alloy matrix is ​​aluminum alloy, the laser power used in the laser powder bed melting forming equipment is 300-400W, the laser scanning speed is 500-900mm / s, the scanning spacing is 60μm, the powder thickness is 40μm, and the laser powder bed melting forming equipment adopts an XY cross scanning strategy with adjacent layers rotating 90°.

[0019] The laser powder bed melting process is as follows: (a) The powder spreading device evenly spreads the powder to be processed on the forming substrate. The laser beam scans the sliced ​​area layer by layer according to the pre-designed scanning path, causing the powder layer to melt / solidify rapidly, thereby obtaining the first two-dimensional plane of the part to be formed; (b) The computer control system lowers the forming substrate by one powder layer thickness, while the piston of the powder supply cylinder rises by a certain powder layer thickness. The powder spreading device spreads a new layer of powder to be processed. The high-energy laser beam completes the second layer of powder scanning according to the sliced ​​information to obtain the second two-dimensional plane of the part to be formed; (c) Repeat step (b) to form the powder layer by layer until the part to be formed is completed.

[0020] The laser parameters mentioned above were determined after process optimization. Based on the microstructure and performance characteristics of easily evaporable light alloys, laser process parameters can be rationally selected to effectively adjust the morphology, size and distribution of the reinforcing type, thus successfully preparing light alloys with good forming quality and excellent comprehensive performance. Beneficial effects:

[0021] (1) In this invention, micron-sized TiC ceramic particles are added to light alloy powder and tightly adhered to the matrix. Due to the high melting temperature, the ceramic particles partially melt. Under the high initial velocity of the metal vapor, the unmelted ceramic particles are ejected into the metal vapor. Considering its relatively high density compared to magnesium and aluminum alloys, the momentum of the metal vapor can be absorbed and reduced by the ejected ceramic particles, thereby reducing the amount of alloy powder sputtering, improving the stability of the powder bed, reducing powder sputtering in the powder bed, thus reducing the formation of defects such as pores, significantly reducing the source of cracks, and improving the laser forming quality. At the same time, the ceramic reinforcing phase improves the laser absorption rate of the alloy powder, which is conducive to the full melting and spreading of the powder, and improves the forming quality of the alloy.

[0022] (2) This invention involves uniformly mixing micron-sized TiC ceramic powder with Mg-Al alloy powder and Al-Mg alloy powder using low-energy ball milling under inert gas protection to obtain a composite powder with uniform ceramic reinforcing phase distribution, good flow properties, high laser absorption rate, and suitability for laser additive manufacturing. The preparation method is simple and cost-effective. Using laser additive manufacturing to prepare easily evaporable light alloys not only shortens the production cycle and improves product production efficiency, but also allows for the formation of parts with complex geometries with almost no subsequent machining processing.

[0023] (3) The present invention can adjust the laser energy density by changing the laser power and laser scanning speed. As the laser energy input of the powder bed changes, the thermodynamic and kinetic characteristics of the molten pool formed by the interaction between the laser and the powder bed also change. By rationally selecting laser process parameters and adjusting the laser energy input, the volatilization of low melting point elements and powder splashing are reduced, the generation of metallurgical defects is reduced, and finally high forming quality is obtained. Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0025] Figure 1 shows the sputtering process of preparing 3 wt.% TiC / Mg-Al powder by laser additive manufacturing in Example 1.

[0026] Figure 2 shows the sputtering process of Mg-Al magnesium alloy powder prepared by laser additive manufacturing in Example 1.

[0027] Figure 3 shows an OM image of a 3wt.% TiC / Mg-Al composite material sample prepared by laser additive manufacturing in Example 1.

[0028] Figure 4 shows a SEM image of the surface of the 3wt.% TiC / Mg-Al composite material prepared by laser additive manufacturing in Example 1.

[0029] Figure 5 shows a SEM image of the surface of the Mg-Al magnesium alloy sample prepared by laser additive manufacturing in Comparative Example 1.

[0030] Figure 6 shows the surface roughness of the 4wt.% TiC / Al-Mg composite material prepared by laser additive manufacturing in Example 2.

[0031] Figure 7 shows the surface roughness of Al-Mg magnesium alloy prepared by laser additive manufacturing in Example 2.

[0032] Figure 8 shows an OM image of the 5 wt.% TiC / Mg-Al composite material prepared by laser additive manufacturing in Example 3.

[0033] Figure 9 shows the surface roughness of the 1 wt.% TiC / Mg-Al composite material prepared by laser additive manufacturing in Comparative Example 2. Detailed Implementation

[0034] The present invention can be better understood from the following embodiments.

[0035] In the following examples, when the lightweight alloy matrix used is a Mg-Al alloy, the Al content is 8.2-9.0 wt.%, and the powder particle size ranges from 23 to 53 μm; when the lightweight alloy matrix used is an Al-Mg alloy, the Mg content is 3.9-5.5 wt.%, and the powder particle size ranges from 21 to 56 μm. The TiC ceramic powder used has a particle size distribution range of 2-5 μm and a purity of not less than 99.5%.

[0036] Example 1

[0037] (1) Micron-sized TiC ceramic powder and Mg-Al alloy powder were uniformly mixed by low-energy ball milling under inert gas protection to obtain composite powder. The ceramic mass accounted for 3 wt.% of the total powder mass. A ceramic jar was used in this process, and ceramic grinding balls with diameters of 6 mm, 8 mm, and 10 mm were used as the milling media. The ball milling process parameters were set as follows: ball-to-powder ratio of 5:1, high-energy ball milling speed of 200 rpm, and ball milling time of 3 h. This ball milling process required argon protection to prevent the Mg-Al alloy powder from being oxidized or contaminated during the ball milling process. After ball milling, the powder maintained good sphericity, and the TiC ceramic particles were uniformly distributed on the alloy surface with a tight bond between the two.

[0038] (2) Target part modeling and slicing

[0039] A three-dimensional solid geometric model of the target part was created using Solidworks software on a computer. Then, Magics software was used to perform layer slicing and scan path planning on the three-dimensional solid model, discretizing the three-dimensional solid into a series of two-dimensional data. This data was saved and imported into the laser powder bed melting forming equipment. The laser process parameters were set as follows: laser power of 120W, laser scanning speed of 300mm / s, scanning interval of 90μm, powder thickness of 40μm, and an XY cross-scan strategy with adjacent layers rotated by 90°.

[0040] (3) Laser powder bed melting process

[0041] The composite powder obtained in step (1) is used for laser powder bed melting and forming. (a) The powder spreading device evenly spreads the powder to be processed on the forming substrate. The laser beam scans the slice area layer by layer according to the pre-designed scanning path, so that the powder layer melts / solidifies rapidly, thereby obtaining the first two-dimensional plane of the part to be formed; (b) The computer control system lowers the forming substrate by one powder layer thickness, while the piston of the powder supply cylinder rises by a certain powder layer thickness. The powder spreading device spreads a new layer of powder to be processed. The high-energy laser beam completes the second layer of powder scanning according to the slice information to obtain the second two-dimensional plane of the part to be formed; (c) Repeat step (b) until a solid sample is obtained by forming layer by layer.

[0042] (4) A multiphysics model was established using DEM and CFD to simulate the interaction between powder and fluid during LPBF. DEM was used to simulate particle motion and collisions, while CFD was used to simulate the thermal fluid behavior of metal vapor and surrounding gas. Powder sputtering is primarily driven by metal vapor generated in the melt pool and the surrounding gas above the powder bed; this model effectively captures the metal vapor jet and its interaction with the powder. The amount of sputtered powder particles in the theoretical simulation was ~71 (Figure 1). Compared to the number of sputtered powder particles in pure Mg-Al alloy without reinforcing phase (~119), this represents a reduction of ~40% (Figure 2), indicating that adding an appropriate amount of reinforcing phase can effectively reduce the amount of powder sputtering, resulting in improved manufacturing quality, significantly different from pure magnesium alloys.

[0043] After forming, the part and substrate were separated by wire cutting to obtain the Mg-Al / TiC sample. The sample was then ground, polished, and etched according to standard metallographic sample preparation methods. OM observation showed that the Mg-Al / TiC sample prepared by laser powder bed melting had no obvious cracks or pores (Figure 3), and its density reached 99.6%. The three-dimensional surface morphology of the artificial sample was examined using a laser scanning confocal microscope. The surface roughness of the Mg-Al / TiC sample was measured to be ~10.6 μm, which is 65% lower than that of pure Mg-Al alloy (~30.6 μm). Combined with observation of the sample surface microstructure (Figures 4-5), the surface forming quality of the Mg-Al / TiC sample was significantly better. The amount of powder splash in the simulation corresponded to the surface forming quality, further confirming the accuracy of the simulation results.

[0044] Example 2

[0045] (1) Micron-sized TiC ceramic powder and Al-Mg alloy powder were uniformly mixed by low-energy ball milling under inert gas protection to obtain a composite powder. The ceramic mass accounted for 4 wt.% of the total powder mass. A ceramic jar was used in this process, and ceramic grinding balls with diameters of 6 mm, 8 mm, and 10 mm were used as the milling media. The ball milling process parameters were set as follows: ball-to-powder ratio of 4:1, high-energy ball milling speed of 200 rpm, and ball milling time of 4 h. This ball milling process required argon protection to prevent the Al-Mg alloy powder from being oxidized or contaminated during the ball milling process. After ball milling, the powder maintained good sphericity, and the ceramic particles were uniformly distributed on the alloy surface with a tight bond between the two.

[0046] (2) Target part modeling and slicing

[0047] A three-dimensional solid geometric model of the target part was created using Solidworks software on a computer. Then, Magics software was used to perform layer slicing and scan path planning on the three-dimensional solid model, discretizing the three-dimensional solid into a series of two-dimensional data. This data was saved and imported into the laser powder bed melting forming equipment. The laser process parameters were set as follows: laser power of 300W, laser scanning speed of 700mm / s, scanning interval of 60μm, powder thickness of 40μm, and an XY cross-scan strategy with adjacent layers rotated by 90°.

[0048] (3) Laser powder bed melting process

[0049] The composite powder obtained in step (1) is used for laser powder bed melting and forming. (a) The powder spreading device evenly spreads the powder to be processed on the forming substrate. The laser beam scans the slice area layer by layer according to the pre-designed scanning path, so that the powder layer melts / solidifies rapidly, thereby obtaining the first two-dimensional plane of the part to be formed; (b) The computer control system lowers the forming substrate by one powder layer thickness, while the piston of the powder supply cylinder rises by a certain powder layer thickness. The powder spreading device spreads a new layer of powder to be processed. The high-energy laser beam completes the second layer of powder scanning according to the slice information to obtain the second two-dimensional plane of the part to be formed; (c) Repeat step (b) until a solid sample is obtained by forming layer by layer.

[0050] (4) A multiphysics model was established using the discrete element method (DEM) and computational fluid dynamics (CFD) to simulate the interaction between powder and fluid during laser powder bed melting (LPBF). DEM was used to simulate particle motion and collisions, while CFD was used to simulate the thermal fluid behavior of metal vapor and surrounding gas. Powder sputtering is primarily driven by metal vapor generated in the melt pool and the surrounding gas above the powder bed; this model effectively captures the metal vapor jet and its interaction with the powder. The amount of sputtered powder particles in the theoretical simulation was ~68. Compared to the number of sputtered powder particles in pure Al-Mg alloy without reinforcing phase (~115), this represents a reduction of ~41%, indicating that adding an appropriate amount of reinforcing phase can effectively reduce the number of sputtered powder particles, resulting in improved manufacturing quality, significantly different from pure aluminum alloys.

[0051] After forming, the part and substrate were separated by wire cutting to obtain the Al-Mg / TiC sample. The sample was then ground, polished, and etched according to standard metallographic sample preparation methods. OM observation showed that the Al-Mg / TiC sample prepared by laser powder bed melting had no obvious pores, a regular melt pool, and a density of 99.5%. The three-dimensional surface morphology of the artificial sample was examined using a laser scanning confocal microscope. The surface roughness of the Al-Mg / TiC sample was measured to be ~8.4 μm, which is 67% lower than that of pure Al-Mg alloy (~25.7 μm), indicating a significant improvement in forming quality (Figures 6-7). The amount of powder spatter in the simulation corresponded to the surface forming quality, confirming the accuracy of the simulation results.

[0052] Example 3

[0053] (1) Micron-sized TiC ceramic powder and Mg-Al alloy powder were uniformly mixed by low-energy ball milling under inert gas protection to obtain composite powder. The ceramic mass accounted for 5 wt.% of the total powder mass. A ceramic jar was used in this process, and ceramic grinding balls with diameters of 6 mm, 8 mm, and 10 mm were used as the milling media. The ball milling process parameters were set as follows: ball-to-powder ratio of 5:1, high-energy ball milling speed of 250 rpm, and milling time of 4 h. This ball milling process required argon protection to prevent oxidation or contamination of the alloy powder during the milling process. After ball milling, the powder maintained good sphericity, and the TiC ceramic particles were uniformly distributed on the alloy surface with a tight bond between the two.

[0054] (2) Target part modeling and slicing

[0055] A three-dimensional solid geometric model of the target part was created using Solidworks software on a computer. Then, Magics software was used to perform layer slicing and scan path planning on the three-dimensional solid model, discretizing the three-dimensional solid into a series of two-dimensional data. This data was saved and imported into the laser powder bed melting forming equipment. The laser process parameters were set as follows: laser power of 180W, laser scanning speed of 600mm / s, scanning interval of 90μm, powder thickness of 40μm, and an XY cross-scan strategy with adjacent layers rotated by 90°.

[0056] (3) Laser powder bed melting process

[0057] The composite powder obtained in step (1) is used for laser powder bed melting and forming. (a) The powder spreading device evenly spreads the powder to be processed on the forming substrate. The laser beam scans the slice area layer by layer according to the pre-designed scanning path, so that the powder layer melts / solidifies rapidly, thereby obtaining the first two-dimensional plane of the part to be formed; (b) The computer control system lowers the forming substrate by one powder layer thickness, while the piston of the powder supply cylinder rises by a certain powder layer thickness. The powder spreading device spreads a new layer of powder to be processed. The high-energy laser beam completes the second layer of powder scanning according to the slice information to obtain the second two-dimensional plane of the part to be formed; (c) Repeat step (b) until a solid sample is obtained by forming layer by layer.

[0058] (4) A multiphysics model was established using DEM and CFD to simulate the interaction between powder and fluid during LPBF. DEM was used to simulate particle motion and collisions, while CFD was used to simulate the thermal fluid behavior of metal vapor and surrounding gas. Powder sputtering is primarily driven by metal vapor generated in the melt pool and the surrounding gas above the powder bed; this model effectively captures the metal vapor jet and its interaction with the powder. The amount of sputtered powder particles in the theoretical simulation was ~76. Compared to the number of sputtered powder particles in pure Mg-Al alloy without reinforcing phase (~119), this represents a reduction of ~36%, indicating that adding an appropriate amount of reinforcing phase can effectively reduce the amount of powder sputtering, resulting in improved manufacturing quality, significantly different from pure magnesium alloys.

[0059] After forming, the part and substrate were separated by wire cutting to obtain the Mg-Al / TiC sample. The sample was then ground, polished, and etched according to standard metallographic sample preparation methods. OM observation showed that the Mg-Al / TiC sample prepared by laser powder bed melting had no obvious cracks or pores. The density reached 99.3% (Figure 8). The three-dimensional surface morphology of the artificial sample was examined using a laser scanning confocal microscope. The surface roughness of the Mg-Al / TiC sample was measured to be ~11.7 μm, which is 61.8% lower than that of pure Mg-Al alloy (~30.6 μm), indicating a significant improvement in forming quality. The amount of powder spatter in the simulation corresponded to the surface forming quality, confirming the accuracy of the simulation results.

[0060] Comparative Example 1

[0061] This comparative example follows the same steps as Example 1, except that in step (1), no TiC ceramic reinforcing phase was added; instead, only Mg-Al alloy powder was used for laser powder bed melting. The theoretical simulation of the alloy without the TiC ceramic reinforcing phase showed a spatter count of ~119 (Figure 2). After laser powder bed melting, due to its low laser absorption rate and low laser energy input, metallurgical defects such as pores were generated during the forming process, resulting in poor sample quality, severe surface spheroidization (Figure 5), a density reduction to 96.0%, and a surface roughness of ~30.6 μm. This is because low-melting-point elements in the Mg-Al alloy have a high evaporation tendency under high-power laser irradiation. On one hand, the upward flow of these vapors causes dynamic changes in melt flow and vapor flow that interact with the ambient gas, forming a complex flow field that propels powder particles outwards to form spatter. On the other hand, some vapor that cannot escape due to rapid cooling remains inside the sample, forming metallurgical defects such as pores, reducing the material's forming quality.

[0062] Comparative Example 2

[0063] This comparative example follows the same steps as Example 1, except that in step (1), the added TiC ceramic reinforcing phase accounts for 1 wt.% of the total mass of the composite powder. It was found that in theoretical simulations with a lower TiC reinforcing phase content, the amount of spattered powder increased to ~10⁴. Observations of the sample after laser powder bed melting revealed some pores and a surface roughness of ~29.4 μm (Figure 9). This is likely because the 1 wt.% TiC particles are relatively dispersed in the matrix, with insufficient bonding between themselves and the matrix, failing to effectively restrict melt flow and thus having limited spatter suppression. Furthermore, the 1 wt.% TiC addition has a relatively small impact on laser energy absorption and conduction, and a limited effect on the kinetic behavior of the molten pool. The molten pool remains easily disturbed by metal vapor and surrounding gas, leading to more powder spatter and thus minimal improvement in forming quality.

[0064] Comparative Example 3

[0065] This comparative example follows the same steps as Example 1, except that in step (1), the added TiC ceramic reinforcing phase accounts for 10 wt.% of the total mass of the composite powder. Theoretical simulations with a higher TiC reinforcing phase content showed an increase in the number of splashed powder particles to approximately 112. Numerous pores were observed in the laser-formed samples, likely due to severe agglomeration caused by excessive TiC particles during powder mixing. These TiC agglomerates are difficult to fully melt with the laser, leading to an unstable molten pool and the formation of pores and cracks. Agglomerates also affect the uniform absorption of laser energy, causing localized overheating and increasing the risk of splashing. Furthermore, excessive TiC particles significantly reduce the plastic deformation capacity of the magnesium alloy matrix. During laser melting, the fluidity of the molten pool is restricted, making it difficult for the melt to fully fill, resulting in defects such as pores and cracks, thus reducing the forming quality.

[0066] As shown in Examples 1-3 and Comparative Examples 1-3, the addition of an appropriate amount of TiC ceramic reinforcing phase to easily evaporable light alloys via laser additive manufacturing significantly reduces metallurgical defects such as spatter and porosity, resulting in a marked improvement in forming quality. This is mainly because the addition of the TiC reinforcing phase increases the laser absorption rate, promoting the full melting and spreading of the high laser reflectivity light alloy during the laser additive manufacturing process, thus improving the alloy's forming quality. Furthermore, during laser forming, unmelted ceramic particles are ejected into the metal vapor. Due to their relatively high density, the momentum of the metal vapor is absorbed and reduced by the ejected ceramic particles, reducing powder spatter in the alloy powder bed and improving its stability. This, in turn, reduces the formation of defects such as porosity and spheroidization, ultimately improving the laser forming quality of the alloy.

[0067] This invention provides a concept and method for high-quality, easily evaporable lightweight alloy laser additive manufacturing and its manufacturing process. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A high formability quality evaporable light alloy laser additive, characterized in that, It includes a light alloy matrix and a micron-sized ceramic reinforcing phase dispersed in the light alloy matrix; the light alloy matrix is ​​a magnesium alloy or an aluminum alloy; the micron-sized ceramic reinforcing phase is TiC, and the TiC ceramic reinforcing phase accounts for 2-6 wt.% of the light alloy matrix. The micron-sized ceramic reinforcing phase TiC is tightly adhered to the surface of the light alloy matrix powder by low-energy ball milling.

2. The high formability quality evaporable light alloy laser additive of claim 1, wherein, The magnesium alloy is a Mg-Al alloy, wherein the Al content is 8.2-9.0 wt.%.

3. The high formability quality evaporable light alloy laser additive of claim 1, wherein, The aluminum alloy is an Al-Mg alloy, wherein the Mg content is 3.9-5.5 wt.%.

4. The high formability quality evaporable light alloy laser additive of claim 2, wherein, The micron-sized ceramic reinforcing phase TiC dispersed in the magnesium alloy matrix has a content of 2-5 wt.%, a particle size distribution range of 2-5 μm, and a purity greater than 99.5%.

5. The high formability quality evaporable light alloy laser additive of claim 3, wherein, The micron-sized ceramic reinforcing phase TiC dispersed in the aluminum alloy matrix has a content of 3-6 wt.%, a particle size distribution range of 2-5 μm, and a purity greater than 99.5%.

6. The method of claim 1, wherein the high formability quality evaporable light alloy laser additive manufacturing is characterized by, Includes the following steps: (1) Micron-sized TiC ceramic powder and light alloy matrix powder are mixed uniformly by low-energy ball milling under inert gas protection to obtain composite powder; the light alloy matrix is ​​a magnesium alloy or an aluminum alloy. (2) Establish a three-dimensional solid geometric model of the part to be formed, then slice the geometric model into layers and plan the laser scanning path, discretize the three-dimensional solid into a series of two-dimensional data, save and import it into the laser powder bed melting forming equipment; (3) The laser powder bed melting and forming equipment melts and solidifies the composite powder in step (1) layer by layer according to the data imported in step (2), and finally forms high-quality light alloy parts.

7. The method of claim 6, wherein the high formability quality evaporable light alloy laser additive manufactured is characterized by, In step (1), the light alloy matrix powder is Mg-Al alloy powder, wherein the Al content is 8.2-9.0 wt.% and the powder particle size range is 23-53 μm; the micron-sized ceramic reinforcing phase TiC accounts for 2-5 wt.% of the light alloy matrix.

8. The method of claim 6, wherein the high formability quality evaporable light alloy laser additive manufactured is characterized by, In step (1), the light alloy matrix powder is Al-Mg alloy powder, wherein the Mg content is 3.9-5.5 wt.%, the powder particle size range is 21-56 μm, and the micron-sized ceramic reinforcing phase TiC accounts for 3-6 wt.% of the light alloy matrix.

9. The method of claim 6, wherein the high formability quality evaporable light alloy laser additive manufactured is characterized by, In step (3), when the light alloy matrix is ​​magnesium alloy, the laser power used in the laser powder bed melting forming equipment is 120-180W, the laser scanning speed is 300-600mm / s, the scanning spacing is 90μm, the powder thickness is 40μm, and the laser powder bed melting forming equipment adopts an XY cross scanning strategy with adjacent layers rotating 90°.

10. The method of claim 6, wherein the high formability quality evaporable light alloy laser additive manufactured is characterized by, In step (3), when the light alloy matrix is ​​aluminum alloy, the laser power used in the laser powder bed melting forming equipment is 300-400W, the laser scanning speed is 500-900mm / s, the scanning spacing is 60μm, the powder thickness is 40μm, and the laser powder bed melting forming equipment adopts an XY cross scanning strategy with adjacent layers rotating 90°.

Images