Method for interlayer microalloying of metal material layers by electric arc additive manufacturing

Abstract

The application belongs to the technical field of metal material additive manufacturing, and discloses an electric arc additive manufacturing metal material interlayer micro-alloying method, which comprises the following steps: (1) mixing additive powder and solvent to form a mixed slurry; (2) preparing an arc-shaped metal foil strip with a rough surface and coating the slurry; (3) in the electric arc additive manufacturing of metal materials, after completing one pass of electric arc additive manufacturing of metal materials and obtaining one solidified metal layer, the rough surface of the metal foil strip with the adhesive slurry component is directly laid and attached to the solidified metal layer; the above steps are repeated to obtain the interlayer in-situ micro-alloyed composite material by layer-by-layer accumulation. Through the improvement of the introduction mode of the key interlayer additive and the corresponding overall process design, the in-situ micro-alloying component can be adjusted, controlled, improved and optimized, the microstructure of the material is improved, and finally the performance of the formed material is improved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology for metal materials, and more specifically, relates to a method for interlayer microalloying of metal materials using electric arc additive manufacturing. Background Technology

[0002] Arc additive manufacturing of metallic materials originated from welding technology. It uses the heat of a burning electric arc to melt wires of materials such as aluminum alloys, titanium alloys, and steel, forming molten droplets. These droplets then form a molten pool on a metal substrate along a pre-defined path, solidifying to form solidified metal layers. These layers are stacked to ultimately create a three-dimensional structure. Arc additive manufacturing of metallic materials is characterized by high efficiency and high performance. Furthermore, it allows for material design and in-situ alloy preparation by changing the wire material or using powder-core wire. This method has already been widely applied in aerospace, shipbuilding, and military industries. However, the following problems still exist in the arc additive manufacturing of metal materials, mainly reflected in: (1) the metal wire grades are based on their welding material grades, and there is a lack of types. The preparation of high-performance, high-alloy material wires, especially the drawing and forming, is difficult; (2) the performance of arc additive materials formed from single metal wires is insufficient. They are prone to grain coarsening and anisotropic structure under the action of arc thermal cycling, and need to be improved by alloying treatment; (3) although powder core wires can better realize material composition design and in-situ alloying, the preparation cost of powder core wires is very high, the equipment requirements are stringent, the powder core is prone to moisture, and the storage is difficult. Moreover, the arc process performance of powder core wires is difficult to control, which can easily cause arc instability and spatter. In-situ alloying to improve the structure and properties of metal materials is an effective means and method for arc additive manufacturing of high-performance metal materials. However, the existing methods have problems such as a limited variety of wires, high operation difficulty, and high alloying cost.

[0003] In in-situ alloying materials for metal arc additive manufacturing, commonly used materials include ceramic powders, alloy powders, rare earth elements and their oxides, fluoride powders, and graphene powders. These powder materials can be effectively driven by the Marangoni flow field within the flowing molten pool, undergoing a full metallurgical reaction, precipitating strengthening phases or solid solution phases, and distributing them relatively uniformly in the solidified metal, thereby achieving the purpose of improving and designing material properties. These powder materials can be directly melted using the powder-core wire method. However, as mentioned earlier, when powder materials pass through the arc space, due to their large specific surface area and high reactivity, deflagration is easily caused, leading to arc instability and significant loss of beneficial elements. Furthermore, the preparation process of powder-core wires is complex, difficult, and costly. The composition and purity of powder-core wires produced by most domestic manufacturers are unstable, resulting in significant differences in the performance of the formed materials. Alternatively, powder materials can be fed via coaxial feeding, as is the case with laser cladding. However, for arc additive manufacturing, the sprayed powder also affects the stability of the arc combustion. Furthermore, due to flowability issues, this method can only feed coarse-grained powders (powder diameter > 80 μm), while nano- and submicron-sized powders are prone to clogging at the feeding pipes and nozzles. Numerous studies have shown that coarse-grained powders cannot effectively refine the microstructure, are difficult to fully undergo metallurgical reactions, and introduce numerous micro-interfaces, causing stress concentration.

[0004] Studies have also shown that in-situ alloying can be achieved using interlayer powder slurry coating. This involves preparing the required powder into a slurry, applying it to the surface of the previous cladding metal layer using a brush, and then applying the next layer of metal using arc additive manufacturing. This method is very simple to operate, the alloying composition is adjustable, and it can improve the material's microstructure and properties to some extent. However, our research group has found several unresolved problems with this method. First, the solidified metal surface is not smooth. The slurry applied in real-time (i.e., a wet slurry is manually applied after each layer of arc additive manufacturing) is prone to flowing and sliding off the edges of the cladding metal if the slurry's viscosity is insufficient (this is because each layer of arc additive manufacturing results in an arc shape, which exacerbates the flow), making it impossible to add sufficient alloying powder. Second, during the process, because the welding torch is directly pointed at the coating, the slurry flies around during arc initiation, affecting uniformity. Furthermore, existing coating techniques often use manual application with a brush, which may result in an uneven coating, also affecting arc initiation. More importantly, the real-time application of the slurry is equivalent to water quenching the freshly solidified metal, which can easily cause cracking and failure. The above problems have a significant impact on its alloying effect. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, the present invention aims to provide a method for interlayer microalloying of metallic materials using arc additive manufacturing. This method improves the introduction of key interlayer additives and the overall process design. A pre-mixed slurry is uniformly coated onto the surface of a rough metal foil strip. After drying, it participates in the arc additive manufacturing process, placed on the surface of each layer of solidified metal. Residual heat adheres the additive powder, and the arc heat melts the metal foil strip and the surface of the previous solidified metal layer, carrying the additive powder into the molten pool and causing it to melt. This allows for in-situ microalloying with adjustable composition, controlling, improving, and optimizing the microstructure of the material, ultimately improving the performance of the formed material. In this invention, because the additive powder adheres to the metal foil and is used in arc additive manufacturing of metallic materials, the coating surface is in direct contact with the solidified metal layer, while the welding torch is directly pointed at the metal foil strip. Therefore, the coating is not blown away by the arc force but enters the molten pool with the molten metal and participates in the metallurgical reaction.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for interlayer microalloying of metallic materials using arc additive manufacturing is provided, characterized by comprising the following steps:

[0007] (1) The additive powder is mixed with a solvent to form a mixed slurry, wherein the solvent used in the mixed slurry is alcohol;

[0008] (2) Prepare a rough-surfaced arc-shaped metal foil strip, then coat the mixed slurry obtained in step (1) onto the rough surface of the metal foil strip and dry it to obtain a metal foil strip with the slurry components adhering to it.

[0009] (3) In the arc additive manufacturing of metal materials, except for the arc additive manufacturing of the last layer of metal materials, for the arc additive manufacturing of any other layer of metal materials, after each arc additive manufacturing of metal materials is completed and a solidified metal layer is obtained, the rough surface of the metal foil strip with the adhesive slurry obtained in step (2) is directly laid and bonded to the solidified metal layer; this is repeated, layer by layer, until the arc additive manufacturing of the last layer of metal materials is completed, and the composite material with in-situ microalloying between layers can be obtained.

[0010] As a further preferred embodiment of the present invention, in step (1), the mixed slurry further includes organic matter with binding and dispersing effects;

[0011] The organic material with binding and dispersing effects is preferably hydroxyethyl cellulose;

[0012] The mixed slurry is formed by mixing additive powder, solvent, and hydroxyethyl cellulose in a mass ratio of 1:0.5-2:0.05-0.2.

[0013] As a further preferred embodiment of the present invention, in step (2), the drying process is preferably carried out in an oven at a temperature of 75°C or higher.

[0014] As a further preferred embodiment of the present invention, in step (1), the additive powder is selected from elemental metal powder, alloy powder, nano-ceramic powder, rare earth oxide powder, and rare earth fluoride powder.

[0015] As a further preferred embodiment of the present invention, in the arc additive manufacturing of the metal material in step (3), the metal foil strip with adhesive slurry components is fixed on the forming path of the additive metal material.

[0016] As a further preferred embodiment of the present invention, in step (2), the rough-surfaced arc-shaped metal foil strip is obtained by sanding the surface of the metal foil strip with sandpaper and then pressing it on a cylindrical iron rod.

[0017] The metal foil strip is selected from aluminum foil, titanium foil, niobium foil, iron foil, and chromium foil;

[0018] The coating is applied by brushing or casting.

[0019] As a further preferred embodiment of the present invention, in step (3), the arc additive manufacturing is performed using TIG / MIG welding, GTA / GMA welding or CMT welding.

[0020] According to another aspect of the present invention, the present invention provides a composite material with in-situ interlayer microalloying obtained by the above method.

[0021] Compared with the prior art, the present invention, through the above-described technical solution, obtains a mixed slurry by thoroughly mixing pre-selected additive powders (e.g., nano-ceramic powders, rare earth oxides, fluorides, alloy powders, elemental metal powders, etc.) in an alcohol solvent. Optionally, organic materials with binding and dispersing properties, such as hydroxyethyl cellulose, can be added to the mixed slurry (this is optional because it allows consideration of whether the additive powders agglomerate in the solvent; if agglomeration occurs, adding hydroxyethyl cellulose ensures thorough dispersion; if agglomeration does not occur, it is unnecessary; simultaneously, the viscosity of hydroxyethyl cellulose reduces flow). Subsequently, the mixed slurry is uniformly coated onto a metal foil strip and used in the arc additive manufacturing of metal materials. In the arc additive manufacturing of metallic materials, a metal foil strip with adhesive paste is laid and adhered to the surface of solidified metal. During the arc additive manufacturing of the next layer of metallic material, the heat of the arc melts the metal foil strip and the surface of the previous solidified metal layer. Additive powder is carried into the molten pool and undergoes an in-situ metallurgical reaction with the molten metal, resulting in alloying, purification of the molten pool metal, and an increase in nucleation sites. As the arc additive manufacturing of metallic materials is carried out layer by layer, an arc additive manufactured metallic material with interlayer micro-alloying is ultimately obtained. This invention can optimize the microstructure and properties of arc additive manufactured metallic materials.

[0022] This invention utilizes a pre-fabricated metal strip with additives, adding additive powder to an electric arc additive manufacturing temperature field. The heat of the electric arc melts the metal foil strip and the surface of the solidified metal layer above. The additive powder components in the slurry are carried into the molten pool and melted, participating in the molten pool metallurgical reaction, thus achieving in-situ microalloying. The operation is simple, low-cost, does not affect the stability of the electric arc, and the cladding layer has stable dimensions. The resulting metal-based material has a fine structure, adjustable composition, and significantly improved mechanical properties.

[0023] Specifically, the present invention can achieve the following beneficial effects:

[0024] (1) Based on existing relatively mature electric arc additive manufacturing technology (such as dual-wire electric arc additive manufacturing technology), the present invention melts the metal foil strip and the surface of the solidified metal layer through the heat of the electric arc, and the additive powder is carried into the molten pool and melted, so as to achieve adjustable alloying composition, thereby controlling, improving and optimizing the microstructure of the material.

[0025] (2) This invention employs in-situ microalloying to incorporate additive powder into the metal matrix. Compared to existing interlayer direct coating techniques, this invention provides uniform coating, controllable slurry concentration, and reduces the impact on arc stability. See the comparison below. Figure 1As shown, the surface of the arc additive manufacturing product obtained by direct coating is irregular, and the quality and cladding efficiency after molding are low; while the arc additive manufacturing product obtained by using a metal foil strip with slurry based on the present invention has a smooth surface, high cladding efficiency, and improved quality of the material after molding.

[0026] The present invention also uses a foil strip pre-formed with alloy powder, which can preferably be dried first, to eliminate most of the solvent and produce much less pollution than direct coating.

[0027] (3) By covering the solidified metal surface with a metal foil strip, the residual heat of the solidified layer surface after arc additive manufacturing is used to locally melt the metal foil, thereby improving the adhesion of the additive powder to the solidified metal and making it difficult for the protective gas to blow away the additive powder.

[0028] (4) Compared with the prior art, the present invention uses a pre-made metal foil strip with attached alloying powder, which is placed between the cladding metal layers in arc additive manufacturing. The metal foil strip can be operated under room temperature and air conditions, and the slurry application is convenient (for example, it can be prepared in the laboratory and then brought to the factory), and the slurry concentration can be controlled. Therefore, this method is very effective in improving the existing in-situ alloying method in arc additive manufacturing.

[0029] (5) This invention is applicable to various additive powders and can be flexibly added according to actual needs. As described below. Figure 6 As shown, when CeF metal powder is added, the microalloyed metal material obtained by the method of this invention has fine grains and uniform composition, eliminating the original coarse columnar crystals and improving isotropy. Furthermore, this invention does not have requirements on the particle size of the additive powder; for example, any powder that has a beneficial effect on metal additive manufacturing can be added, regardless of whether it is coarse or fine.

[0030] In summary, this invention can effectively perform in-situ micro-alloying modification of arc additive manufacturing of metal-based materials. This invention utilizes metal foil strips pre-coated with additive powder, which participates in the arc additive manufacturing process, enabling in-situ micro-alloying of arc additive manufacturing of metal-based materials. This allows for adjustable in-situ micro-alloying composition, control, improvement, and optimization of the material's microstructure, ultimately improving the performance of the formed material. Attached Figure Description

[0031] Figure 1 This is a comparison diagram of the product manufactured by the interlayer microalloying dual-wire arc additive manufacturing process in Example 4 of the present invention and the product in Comparative Example 3; wherein, Figure 1 (a) corresponds to product of ratio 3. Figure 1 (b) in the example corresponds to the product of Example 4.

[0032] Figure 2The microstructure of the TiAl alloy obtained in Comparative Example 1 without added metal powder during arc additive manufacturing is shown below; Figure 2 (a) in the figure corresponds to a metallographic diagram (the scale bar in the figure represents 20 μm). Figure 2 (b) in the figure corresponds to the SEM image (the size scale in the figure represents 10 μm).

[0033] Figure 3 The microstructure of the Nb microalloyed TiAl alloy obtained in Example 1 is shown; wherein, Figure 3 (a) in the image corresponds to the SEM image (the size bar in the image represents 10 μm). Figure 3 (b) in the text corresponds to element Nb. Figure 3 (c) in the text corresponds to the Ti element. Figure 3 (d) in the text corresponds to the Al element.

[0034] Figure 4 The microstructure of the Y-microalloyed TiAl alloy obtained in Example 2 is shown in the figure; wherein, Figure 4 (a) in the image corresponds to the SEM image (the size bar in the image represents 10 μm). Figure 4 (b) in the text corresponds to the Al element. Figure 4 (c) in the text corresponds to the Ti element. Figure 4 (d) in the text corresponds to the Y element.

[0035] Figure 5 The compressive strength-strain curves are for the TiAl alloys of Example 1 (without additives), Example 2 (with Y microalloying), and Example 1 (with Nb microalloying).

[0036] Figure 6 These are micrographs of aluminum-based substrates with and without CeF; among them, Figure 6 (a) is the metallographic diagram of the product obtained in Example 2. Figure 6 (b) in the figure corresponds to the metallographic image of the product obtained in Example 3; both have the same magnification and the scale bar in the figure is 20 μm.

[0037] Figure 7 This is a flowchart of the processing according to an embodiment of the present invention. Detailed Implementation

[0038] 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.

[0039] Based on this invention, in actual operation, the following steps may be included:

[0040] (1) Mix the additive powder (e.g., nano-ceramic powder, rare earth oxide, fluoride powder, alloy powder, other metal element powder) with the solvent (i.e., alcohol) and stir with a glass rod to form a mixed slurry;

[0041] The ratio of additive powder to solvent can be flexibly adjusted. If the additive powder cannot form a good dispersion in the solvent, organic substances with binding and dispersing effects, such as hydroxyethyl cellulose, can be introduced into the mixed slurry (that is, the additive powder, solvent, and hydroxyethyl cellulose are mixed together). In this case, it is preferable to mix the additive powder, solvent, and hydroxyethyl cellulose in a mass ratio of 1:0.5-2:0.05-0.2.

[0042] (2) Cut metal foil strips with similar length, width and weld size, grind them to form a rough surface, place them on a cylindrical bar and press them to form a preset arc; then, using the mixed slurry obtained in step (1) as raw material, apply the slurry evenly to the surface of the ground metal foil strip with a brush (this surface is the inner surface of the arc-shaped foil strip, and the rough surface is also the inner surface of the arc-shaped foil strip).

[0043] Furthermore, it can undergo additional drying treatment (e.g., standing at room temperature for 5 minutes or drying at 100°C for 5 minutes). When the solvent is alcohol, there is virtually no alcohol residue after drying (in this case, the effects similar to water quenching are also avoided).

[0044] (3) The metal foil strip obtained in step (2) is placed on the solidified metal surface of the previous layer after being polished by a steel brush (the surface on which the slurry components of the metal foil strip are adhered to is in direct contact with this solidified metal layer) to perform arc additive manufacturing of the next layer of metal material.

[0045] Arc welding parameters can be set as follows: current 80-250A, welding speed 10-200mm / s; arc additive manufacturing can refer to relevant existing technologies and can be carried out under an argon protective atmosphere, with an argon flow rate of, for example, 10-20L / min (of course, depending on the actual situation, other gases, such as CO2, can also be added to the argon).

[0046] (4) Repeat steps (2) and (3) until multiple layers are stacked one by one to form an in-situ microalloyed reinforced metal matrix composite material.

[0047] The following are specific examples:

[0048] Example 1

[0049] The TiAl-based composite material in this embodiment is prepared according to the following steps:

[0050] (1) Weigh 2g of Nb metal powder, 0.1g of hydroxyethyl cellulose, and 1g of alcohol. First, mix the Nb metal powder with the alcohol, then add the hydroxyethyl cellulose and continue mixing.

[0051] (2) Cut an aluminum foil strip with a length of 120mm, a width of 12mm, and a thickness of 0.15mm. After polishing (it can be polished on one side only, and the polished surface will have a rough texture), place it on a cylindrical rod and press it to obtain an arc-shaped plate (the rough surface formed by polishing corresponds to the inner surface of the arc-shaped foil strip, the same below).

[0052] (3) Use the mixed slurry in step (1) as raw material, apply it evenly to the surface of the aluminum foil strip after it has been polished by brushing and dry it (of course, in actual batch operation, the drying effect can be that more than 95% of the alloy powder will not fall off when the foil strip is picked up vertically after drying).

[0053] (4) After the substrate is heated to 450°C, a pulse-free AC standard double-wire TIG welding method is used. The welding current is 120A and the welding speed is 30mm / s. Ti6Al4V wire and 4043Al-Si wire are selected respectively to form a solidified metal layer.

[0054] (5) Clean the surface immediately with a steel brush, and then place the aluminum foil strip with slurry obtained in step (3) on the surface of the solidified metal layer to carry out the next layer of arc additive manufacturing.

[0055] (6) Repeat steps (4-5) above until multiple layers are stacked one by one to form an arc additive manufacturing metal material with interlayer Nb microalloying.

[0056] Experimental results show that the metal powder in the metal foil strip coated with the mixed slurry is carried into the molten pool and undergoes an in-situ metallurgical reaction with the molten metal, resulting in alloying and uniform distribution in the matrix. The microstructure is as follows: Figure 3 As shown, corresponding to Comparative Example 1 below. Figure 2 Compared to the previous method, the microstructure was significantly altered, especially the α2+γ lath structure, which was noticeably refined. This contributes to improving the material's plasticity and strength. The compressive strength-strain curve is shown below. Figure 5 As shown, compared to the absence of added metal elements, its compressive strength increased by 16% and its plasticity increased by 22%.

[0057] Example 2

[0058] The titanium-aluminum based composite material in this embodiment is prepared according to the following steps:

[0059] (1) Weigh 1.5g of Y metal powder, 0.05g of hydroxyethyl cellulose, and 1g of alcohol. First, mix the Y metal powder with the alcohol, then add the hydroxyethyl cellulose and continue mixing.

[0060] (2) Cut an aluminum foil strip with a length of 120mm, a width of 12mm, and a thickness of 0.15mm. After polishing, place it on a cylindrical bar and press it down.

[0061] (3) The mixed slurry in step (1) is used as raw material, and is evenly coated on aluminum foil strip in the form of casting and dried.

[0062] (4) After the substrate is heated to 450°C, a pulseless AC standard dual-wire TIG welding method is adopted. The welding current is 110A, the welding speed is 30mm / s, and Ti6Al4V wire and 4043Al-Si wire are selected respectively to form a solidified metal layer.

[0063] (5) Clean the surface immediately with a steel brush, and then place the aluminum foil strip with slurry obtained in step (3) on the surface of the solidified metal layer to carry out the next layer of arc additive manufacturing.

[0064] (6) Repeat steps (4-5) above until multiple layers are stacked one by one to form an arc additive manufacturing metal material with interlayer Y microalloying.

[0065] The difference between the steps for preparing the aluminum-based composite material in this embodiment and those in Example 1 lies in the addition of different metal powders, the use of different welding currents, and the resulting material microstructure. Figure 4 As shown, corresponding to Comparative Example 1 below. Figure 2 In contrast, the addition of rare earth element Y did not significantly affect the α2+γ lath microstructure. Furthermore, the addition of Y significantly refined the second-phase size, resulting in numerous fine, short rod-shaped second-phase precipitates. Mechanical property testing results showed that, compared to the un-in-situ microalloyed sample, the compressive strength of the microalloyed sample increased by 8.5%, and the plasticity increased by 11% (similar to...). Figure 5 (As shown).

[0066] Example 3

[0067] The aluminum-based rare-earth microalloyed material in this embodiment is prepared according to the following steps:

[0068] (1) Weigh 2g of CeF3 powder, 0.2g of alcohol, and 0.05g of hydroxyethyl cellulose. Mix CeF3 powder and alcohol, then add hydroxyethyl cellulose and continue mixing.

[0069] (2) Cut an aluminum foil strip with a length of 120mm, a width of 12mm, and a thickness of 0.15mm. After polishing, place it on a cylindrical bar and press it down.

[0070] (3) The mixed slurry in step (1) is used as raw material, and is evenly coated on aluminum foil strip in the form of casting and dried.

[0071] (4) The cold metal transfer (CMT) mode is adopted, the welding current is 171A, the voltage is 21.5V, Φ1.2 (i.e., diameter is 1.2mm) 2319 aluminum alloy welding wire is used, the wire feeding speed is 8m / min, the wire extension is fixed at 15mm, and a solidified layer is formed on the surface of 1060 aluminum alloy substrate.

[0072] (5) Then place the aluminum foil strip with slurry obtained in step (3) on the surface of the solidified metal layer and perform the next layer of arc additive manufacturing.

[0073] (6) Repeat steps (4-5) to perform the next layer of arc additive manufacturing, until multiple layers are stacked one after another. The microstructure is shown in the figure below. Figure 6 As shown in (b) below, compared to Comparative Example 2 below... Figure 6 In (a) of this embodiment, since porosity is difficult to avoid in aluminum alloy additive manufacturing, in-situ alloying has no significant effect on the generation and distribution of porosity. However, microalloying has a significant grain-refining effect on the aluminum alloy matrix, transforming columnar crystals into equiaxed crystals, which is beneficial for suppressing crack generation and weakening anisotropy. This is mainly because CeF3 decomposes in the molten pool, precipitating Ce compounds and forming a heterogeneous nucleation effect.

[0074] Example 4

[0075] The titanium-aluminum based composite material in this embodiment is prepared according to the following steps:

[0076] (1) Weigh 1.5g of Y metal elemental powder and 1g of alcohol, and stir and mix the Y metal powder and alcohol.

[0077] (2) Cut an aluminum foil strip with a length of 120mm, a width of 12mm, and a thickness of 0.15mm. After polishing, place it on a cylindrical bar and press it down.

[0078] (3) The mixed slurry in step (1) is used as raw material and is evenly coated onto aluminum foil strip by brushing and then dried.

[0079] (4) After the substrate is heated to 450°C, a pulseless AC standard dual-wire TIG welding method is adopted. The welding current is 110A, the welding speed is 30mm / s, and Ti6Al4V wire and 4043Al-Si wire are selected respectively to form a solidified metal layer.

[0080] (5) Clean the surface immediately with a steel brush, and then place the aluminum foil strip with slurry obtained in step (3) on the surface of the solidified metal layer to carry out the next layer of arc additive manufacturing.

[0081] (6) Repeat steps (4-5) above until multiple layers are stacked one by one to form an arc additive manufacturing metal material with interlayer Y microalloying.

[0082] This embodiment uses an arc additive manufacturing product obtained from a metal foil strip coated with slurry, such as... Figure 1 As shown in (b), it can be seen that the product obtained by arc additive manufacturing of metal foil strips coated with slurry has a regular surface, high forming quality and high cladding efficiency.

[0083] Comparative Example 1:

[0084] The titanium-aluminum matrix composite material of this comparative example was prepared according to the following steps:

[0085] (1) Raise the temperature of the pure titanium substrate to 450°C.

[0086] (2) The standard double-wire TIG welding method without pulse is adopted. The welding current is 120A and the welding speed is 30mm / s. The welding wires are Ti6Al4V wire and 4043Al-Si wire respectively, forming the first solidified metal layer on the substrate surface.

[0087] (3) After cooling for 1 minute, perform the next layer of arc additive manufacturing according to the specifications of step (2).

[0088] (4) Repeat the above steps (2-3) until multiple layers are stacked one by one to form an arc additive manufacturing metal material.

[0089] Experimental results show that the microstructure of TiAl alloy arc additive manufacturing materials without the addition of interlayer alloying powder is as follows: Figure 2 As shown.

[0090] Comparative Example 2

[0091] The aluminum-based material in this comparative example was prepared according to the following steps:

[0092] (1) The cold metal transfer (CMT) mode is adopted, the welding current is 171A, the voltage is 21.5V, Φ1.2 2319 aluminum alloy welding wire is used, the wire feeding speed is 8m / min, the wire extension is fixed at 15mm, and a cladding layer is formed on the surface of 1060 aluminum alloy substrate.

[0093] (2) Repeat the above steps, applying the next layer of arc additive manufacturing to the surface of the previous layer of solidified metal, until multiple layers are deposited one by one. Its microstructure is shown in the figure. Figure 6 As shown in (a), the interlayer exhibits columnar crystal structure pointing towards the center of the melt pool, accompanied by a large number of linear θ phase precipitates, showing obvious anisotropy.

[0094] Comparative Example 3

[0095] The titanium-aluminum matrix composite material of this comparative example was prepared according to the following steps:

[0096] (1) Raise the temperature of the pure titanium substrate to 450°C.

[0097] (2) Weigh 1.5g of Y metal elemental powder and 1g of alcohol, and stir and mix the Y metal powder and alcohol.

[0098] (3) A pulseless AC standard double-wire TIG welding method is adopted, the welding current is 110A, the welding speed is 30mm / s, and Ti6Al4V wire and 4043Al-Si wire are selected respectively to form a solidified metal layer; then, the mixed slurry (wet state) in step (2) is used as raw material and applied to the surface of the solidified metal layer by steel brush.

[0099] (4) Repeat step (3) to perform the next layer of electric arc additive manufacturing until the number of layers reaches the preset requirement and the last solidified metal layer is formed. Finally, cool it down.

[0100] The effect after molding of this comparative model is as follows: Figure 1 As shown in (a) in the diagram. Through... Figure 1 (a) and Figure 1 As can be seen from comparison (b) in the figure, the arc additive manufacturing product obtained by direct coating has an irregular surface, and the quality and cladding efficiency after forming are low, such as Figure 1 As shown in (a); the arc additive manufacturing product obtained using a metal foil strip coated with slurry according to the present invention has a smooth surface, high cladding efficiency, and improved quality of the formed material, such as Figure 1 As shown in (b) of the diagram.

[0101] The above embodiments are merely examples and do not represent the optimal alloying effect. The type and content of the alloying powder, as well as the arc additive manufacturing parameters, can be adjusted according to the actual situation. For example, in addition to aluminum foil, the metal foil strip can also be titanium foil, niobium foil, iron foil, chromium foil, and other commonly used alloy materials that can be processed into metal foil. The specific material type is determined by the arc additive manufacturing material. Arc additive manufacturing can employ common arc additive manufacturing welding methods such as standard TIG / MIG welding, GTA / GMA welding, and CMT welding.

[0102] 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. A method for interlayer microalloying of metallic materials using electric arc additive manufacturing, characterized in that, Includes the following steps: (1) Using nano-ceramic powder, rare earth oxide powder, and rare earth fluoride powder as additive powders, the additive powders are mixed with solvents and organic substances with binding and dispersing effects to form a mixed slurry. The solvent used in the mixed slurry is alcohol. (2) Prepare a rough-surfaced arc-shaped metal foil strip, then coat the mixed slurry obtained in step (1) onto the rough surface of the metal foil strip and dry it to obtain a metal foil strip with the slurry components adhering to it; (3) In the arc additive manufacturing of metal materials, except for the arc additive manufacturing of the last layer of metal materials, for the arc additive manufacturing of any other layer of metal materials, after each arc additive manufacturing of metal materials is completed and a solidified metal layer is obtained, the rough surface of the metal foil strip with the adhesive slurry obtained in step (2) is directly laid and bonded to the solidified metal layer, and the additive powder is adhered by the residual heat of the solidified metal layer; this is repeated, layer by layer, until the arc additive manufacturing of the last layer of metal materials is completed, and the composite material with in-situ microalloying between layers can be obtained.

2. The method as described in claim 1, characterized in that, In step (1), the organic material with binding and dispersing effects is hydroxyethyl cellulose; The mixed slurry is formed by mixing additive powder, solvent, and hydroxyethyl cellulose in a mass ratio of 1:0.5-2:0.05-0.

2.

3. The method as described in claim 1, characterized in that, In step (2), the drying process involves drying in an oven at a temperature of 75°C or higher.

4. The method as described in claim 1, characterized in that, In the arc additive manufacturing of the metal material in step (3), the metal foil strip with adhesive slurry components is fixed on the forming path of the additive metal material.

5. The method as described in claim 1, characterized in that, In step (2), the rough-surfaced arc-shaped metal foil strip is obtained by sanding the surface of the metal foil strip with sandpaper and then pressing it on a cylindrical iron rod. The metal foil strip is selected from aluminum foil, titanium foil, niobium foil, iron foil, and chromium foil; The coating is applied by brushing or casting.

6. The method as described in claim 1, characterized in that, In step (3), the arc additive manufacturing is carried out by TIG / MIG welding, GTA / GMA welding or CMT welding.

Images