Method for inhibiting cracks in additive manufacturing of high-gamma-'-content nickel-based superalloy
By preheating the substrate and powder bed, combining with the powder melting scanning process, the temperature gradient is regulated, and the problem of cracks that nickel-based high-temperature alloys are easily generated in additive manufacturing is solved, and crack-free of nickel-based high-temperature alloys with high γ' content is achieved Forming, simplifies the preparation process and improves the forming quality.
Patent Information
- Application Number
- CN202411303736.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2024-12-27
AI Technical Summary
During the additive manufacturing process, nickel-based high-temperature alloys are prone to cracks, especially nickel-based high-temperature alloys with high γ′ content, which affects their forming quality. The existing methods require increasing equipment functions or combining with other equipment assistance, which increases complexity and cost.
By preheating the substrate and preheating multiple times before and after melting each layer of powder bed, combined with the powder melting scanning process, the temperature gradient is regulated to relieve thermal stress and avoid cracks. Near spherical or spherical powder with a particle size of less than 150μm is used and powder bed selection zone melted electron beam additive manufacturing technology.
The cracks caused by internal thermal stress of the high γ′ content nickel-based high-temperature alloy are effectively avoided, the forming quality is improved, the preparation process is simplified, the cost is reduced, and the preparation of high γ′ content nickel-based high-temperature alloy components without cracks is realized.
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Figure CN119187604A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal additive manufacturing, and in particular relates to a method for suppressing cracks in additive manufacturing of a nickel-based high-temperature alloy with a high γ′ content. Background Art
[0002] Nickel-based superalloys can maintain good high-temperature mechanical properties and structural stability at 600°C and are widely used in hot-end components of aerospace engines. The preparation of traditional nickel-based superalloy components mainly includes casting, deformation and other processes, which face problems such as cumbersome manufacturing processes and difficulty in forming complex components, which restrict the engineering application of nickel-based superalloy parts. The additive manufacturing technology that has emerged in recent years has the advantage of integrated forming of complex components, opening up a new way for the manufacture of complex components of nickel-based superalloys.
[0003] Metal additive manufacturing technology sets up a forming plan based on a three-dimensional model, and uses high-energy beams such as lasers, electron beams, and arcs to quickly melt and solidify powders and wires, and stack them layer by layer to form additive products. However, during the additive manufacturing process, additive products undergo a process of rapid melting and solidification and repeated remelting, resulting in large temperature gradients, large internal thermal stresses in the formed parts, and easy cracking, especially for nickel-based high-temperature alloys with high γ′ content, which seriously affects the forming quality of additively manufactured nickel-based high-temperature alloy components.
[0004] Therefore, how to control the cracks of additively manufactured nickel-based high-temperature alloys has become the key to promoting the engineering application of additively manufactured high-temperature alloy complex components. In response to the above problems, domestic and foreign research has been carried out, including the introduction of ultrasonic external fields, laser shot peening and other methods, or the subsequent hot isostatic pressing, stress relief annealing and other methods to reduce and eliminate stress to control cracks, but the above methods require the addition of equipment functions or the combination of other equipment, which not only increases the complexity of the preparation process, but also increases the preparation cost. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with a high γ′ content. The preparation method is used to regulate the temperature gradient of the forming process of the high γ′ content nickel-based high-temperature alloy to relieve thermal stress by preheating the substrate and preheating the powder bed multiple times during the preparation process. At the same time, combined with the powder melting scanning process, it can avoid the internal thermal stress of the high γ′ content nickel-based high-temperature alloy causing cracks, solving the problem that the existing technology needs to increase equipment functions or combine with other equipment to suppress internal cracks in high γ′ content nickel-based high-temperature alloys.
[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for suppressing cracks in additively manufacturing a nickel-based high-temperature alloy with a high γ′ content, characterized in that the preparation method comprises the following steps:
[0007] Step 1: Place high γ′ content nickel-based high-temperature alloy powder into a powder bin of an additive manufacturing device and evacuate the powder bin;
[0008] Step 2: Establish a three-dimensional CAD model of a high-γ′ content nickel-based high-temperature alloy component, perform layered slicing processing in the forming height direction of the three-dimensional CAD model, and then import the slicing data into the additive manufacturing equipment in step 1;
[0009] Step 3: preheat the substrate to the target temperature and keep it warm;
[0010] Step 4: evenly laying high γ′ content nickel-based high-temperature alloy powder on the substrate preheated in step 3 to form a powder bed;
[0011] Step 5: preheating the powder bed formed in step 4;
[0012] Step 6: setting the additive manufacturing parameters in the additive manufacturing equipment, and melting and solidifying the high-γ′ content nickel-based high-temperature alloy powder in the powder bed area one by one;
[0013] Step 7: preheating the powder bed solidified in step 6;
[0014] Step 8: Repeat steps 4 to 7 for multiple times until a high-γ′-content nickel-based high-temperature alloy component is formed.
[0015] The present invention performs two preheating treatments on the powder bed for each layer, so that the temperature of the high-γ′-content nickel-based high-temperature alloy powder can be raised in advance during the powder laying process of the next layer, thereby avoiding an instantaneous and substantial temperature rise when the high-γ′-content nickel-based high-temperature alloy powder is melted, thereby causing thermal stress. At the same time, it can avoid that the melting temperature difference between the high-γ′-content nickel-based high-temperature alloy solidified in the previous layer and the newly laid high-γ′-content nickel-based high-temperature alloy powder is too large, which is not conducive to metallurgical bonding between the layers.
[0016] The above-mentioned method for suppressing cracks in additive manufacturing of a nickel-based high-temperature alloy with a high γ′ content is characterized in that the molar percentage of the γ′ phase in the nickel-based high-temperature alloy powder with a high γ′ content in step one is greater than 50%.
[0017] The above-mentioned method for suppressing cracks in additively manufacturing a nickel-based high-temperature alloy with a high γ′ content is characterized in that the high γ′ content nickel-based high-temperature alloy powder in step one is a nearly spherical or spherical powder with a particle size of less than 150 μm.
[0018] The present invention controls the particle size of the high-γ' content nickel-based high-temperature alloy powder to be less than 150 μm, so that the high-γ' content nickel-based high-temperature alloy powder is easier to melt, which is beneficial to improving the alloy forming quality.
[0019] The above-mentioned method for suppressing cracks in additive manufacturing of high γ′ content nickel-based high-temperature alloys is characterized in that the additive manufacturing equipment in step one is a powder bed selective melting electron beam additive manufacturing equipment.
[0020] The above-mentioned method for suppressing cracks in additive manufacturing of a nickel-based high-temperature alloy with a high γ′ content is characterized in that the vacuum in step 1 is evacuated to a vacuum degree of no more than 5×10 -2 Pa.
[0021] The above-mentioned method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with a high γ′ content is characterized in that the target temperature of the substrate in step three is 950° C. to 1150° C., and the substrate insulation time is 10 min to 30 min.
[0022] The above-mentioned method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with a high γ′ content is characterized in that the powder bed preheating process in step five and step seven is: heating the powder bed to 950° C. to 1150° C. after 10s to 15s.
[0023] The above-mentioned method for suppressing cracks in an additively manufactured nickel-based high-temperature alloy with a high γ′ content is characterized in that the additive manufacturing parameters described in step six are: the electron beam acceleration voltage is 60 kV, the electron beam current is 4 mA to 10 mA, the scanning speed is 1 m / s to 8 m / s, the scanning line spacing is 40 μm to 100 μm, the powder layer thickness is 40 μm to 50 μm, and the interlayer rotation is 90°.
[0024] The invention controls the electron beam acceleration voltage to 60 kV, thereby providing the electron beam with sufficient energy to melt the nickel-based high-temperature alloy powder with a high γ′ content, and accurately controls the energy input, which is helpful to realize a fine microstructure; controls the powder layer thickness to 40 μm to 50 μm, so that the penetration depth of the electron beam acceleration voltage of 60 kV is moderate, ensures that the powder is completely melted and forms a good metallurgical bond, and avoids excessive penetration leading to damage to the substrate or excessive heat loss; controls the electron beam current to a lower value, thereby helping to reduce the heat-affected zone, reduce the concentration of thermal stress and the cracking tendency, and improve the dimensional accuracy and surface quality of the nickel-based high-temperature alloy with a high γ′ content; controls the scanning speed to a faster range, thereby shortening the preparation time, improving the production efficiency, and helping to reduce the heat accumulation; controls the scanning line spacing range, thereby preventing the scanning line spacing from being too large to reduce the fusibility of the nickel-based high-temperature alloy powder with a high γ′ content, and preventing the scanning line spacing from being too short to form an overmelting phenomenon, thereby affecting the molding quality of the nickel-based high-temperature alloy with a high γ′ content; controls the interlayer rotation by 90 degrees, thereby helping to disperse the residual stress generated in the preparation process, and reducing the cracks and deformation caused by stress concentration.
[0025] Compared with the prior art, the present invention has the following advantages:
[0026] 1. The present invention preheats the substrate and preheats each layer of powder bed before and after melting to regulate the temperature gradient of the forming process of the high γ′ content nickel-based high-temperature alloy to relieve thermal stress. At the same time, combined with the powder melting scanning process, it can avoid the internal thermal stress of the high γ′ content nickel-based high-temperature alloy causing cracks, and prepare high γ′ content nickel-based high-temperature alloy components with no internal cracks.
[0027] 2. The present invention is based on powder bed selective melting electron beam additive manufacturing technology. By combining the powder melting scanning process with the substrate and powder bed preheating temperature control, crack control is achieved in the preparation process of high γ′ content nickel-based high-temperature alloys. There is no need to combine with other equipment to assist in alleviating the cracks of additive parts, thereby reducing the complexity of the manufacturing process.
[0028] 3. The present invention can promote the melting, solidification and metallurgical bonding of high γ′ content nickel-based high-temperature alloy powder by comprehensively controlling parameters such as electron beam, scanning speed and scanning spacing, thereby improving the forming quality of the high γ′ content nickel-based high-temperature alloy component preparation process.
[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 This is a metallographic microstructure diagram of the nickel-based high-temperature alloy component prepared in Example 1 of the present invention.
[0031] Figure 2 This is a metallographic microstructure diagram of the nickel-based high-temperature alloy component prepared in Comparative Example 1 of the present invention.
[0032] Figure 3 This is a metallographic microstructure diagram of the nickel-based high-temperature alloy component prepared in Example 2 of the present invention. DETAILED DESCRIPTION
[0033] Example 1
[0034] The preparation method of this embodiment comprises the following steps:
[0035] Step 1: Place the nearly spherical or spherical Mar-M247 nickel-based high-temperature alloy powder with a particle size of less than 150 μm into the powder bin of the additive manufacturing equipment and evacuate it to a vacuum degree of no more than 5×10 -2 Pa; the molar percentage content of γ′ in the Mar-M247 nickel-based high-temperature alloy powder is greater than 50%;
[0036] Step 2: Establish a three-dimensional CAD model of a high-γ′ content nickel-based high-temperature alloy component, perform layered slicing processing in the forming height direction of the three-dimensional CAD model, and then import the slicing data into the additive manufacturing equipment in step 1;
[0037] Step 3: Heat the substrate to 1000°C-1100°C and keep it warm for 20 minutes;
[0038] Step 4: evenly spread Mar-M247 nickel-based high-temperature alloy powder on the substrate preheated in step 3 to form a powder bed;
[0039] Step 5: heating the powder bed formed in step 4 to 1000°C to 1100°C for 12 seconds;
[0040] Step 6: Set the electron beam acceleration voltage in the additive manufacturing equipment to 60 kV, the electron beam current to 4 mA, the scanning speed to 1.5 m / s, the scanning line spacing to 100 μm, the powder layer thickness to 40 μm, and the interlayer rotation to 90°, and melt and solidify the Mar-M247 nickel-based high-temperature alloy powder in the target area of the powder bed one by one;
[0041] Step 7: The powder bed solidified in step 6 is heated to 1000°C to 1100°C for 12 seconds;
[0042] Step 8: After the platform is lowered, steps 4 to 7 are repeated multiple times until the Mar-M247 nickel-based high-temperature alloy component is formed.
[0043] The Mar-M247 nickel-based high-temperature alloy component prepared in this embodiment was separated from the substrate and the internal microscopic morphology was analyzed. Figure 1 As shown, the Mar-M247 nickel-based high-temperature alloy component prepared in this embodiment has no cracks inside.
[0044] Comparative Example 1
[0045] The difference between this comparative example and Example 1 is that: in step three, the preheating temperature of the substrate is 900℃~950℃; in step six, the electron beam current is 12mA, the scanning speed is 6m / s, the scanning interval is 100μm, and the powder layer thickness is 50μm; in steps five and seven, the powder bed is heated to 800℃~900℃ after 9s.
[0046] The Mar-M247 nickel-based high-temperature alloy component prepared in this comparative example was separated from the substrate and the internal microscopic morphology was analyzed. Figure 2 As shown, there are multiple cracks inside the Mar-M247 nickel-based high-temperature alloy component prepared in this comparative example. By comparing the internal structure of the Mar-M247 nickel-based high-temperature alloy component prepared in Example 1, it is shown that the present invention can effectively suppress the generation of cracks in the preparation process of the high γ′ content nickel-based high-temperature alloy component by controlling the manufacturing parameters of the high γ′ content nickel-based high-temperature alloy component.
[0047] Example 2
[0048] The preparation method of this embodiment comprises the following steps:
[0049] Step 1: Place the nearly spherical or spherical Mar-M247 nickel-based high-temperature alloy powder with a particle size of less than 150 μm into the powder bin of the additive manufacturing equipment and evacuate it to a vacuum degree of no more than 5×10 -2 Pa; the molar percentage content of γ′ in the Mar-M247 nickel-based high-temperature alloy powder is greater than 50%;
[0050] Step 2: Establish a three-dimensional CAD model of a high-γ′ content nickel-based high-temperature alloy component, perform layered slicing processing in the forming height direction of the three-dimensional CAD model, and then import the slicing data into the additive manufacturing equipment in step 1;
[0051] Step 3, heating the substrate to 1050°C to 1150°C and keeping the temperature for 30 minutes;
[0052] Step 4: evenly spread Mar-M247 nickel-based high-temperature alloy powder on the substrate preheated in step 3 to form a powder bed;
[0053] Step 5: heating the powder bed formed in step 4 to 1050°C to 1150°C for 15 seconds;
[0054] Step 6: Set the electron beam acceleration voltage in the additive manufacturing equipment to 60 kV, the electron beam current to 5 mA, the scanning speed to 4 m / s, the scanning line spacing to 40 μm, the powder layer thickness to 40 μm, and the interlayer rotation to 90°, and melt and solidify the Mar-M247 nickel-based high-temperature alloy powder in the target area of the powder bed one by one;
[0055] Step 7: Heat the powder bed solidified in step 6 to 1050°C to 1150°C for 15 seconds;
[0056] Step 8: After the platform is lowered, steps 4 to 7 are repeated multiple times until the Mar-M247 nickel-based high-temperature alloy component is formed.
[0057] The Mar-M247 nickel-based high-temperature alloy component prepared in this embodiment was separated from the substrate and the internal microscopic morphology was analyzed. Figure 3 As shown, the Mar-M247 nickel-based high-temperature alloy component prepared in this embodiment has no cracks inside.
[0058] Example 3
[0059] The preparation method of this embodiment comprises the following steps:
[0060] Step 1: Place the nearly spherical or spherical Mar-M247 nickel-based high-temperature alloy powder with a particle size of less than 150 μm into the powder bin of the additive manufacturing equipment and evacuate it to a vacuum degree of no more than 5×10 -2Pa; the molar percentage content of γ′ in the Mar-M247 nickel-based high-temperature alloy powder is greater than 50%;
[0061] Step 2: Establish a three-dimensional CAD model of a high-γ′ content nickel-based high-temperature alloy component, perform layered slicing processing in the forming height direction of the three-dimensional CAD model, and then import the slicing data into the additive manufacturing equipment in step 1;
[0062] Step 3, heating the substrate to 950°C to 1050°C and keeping the temperature for 10 minutes;
[0063] Step 4: evenly spread Mar-M247 nickel-based high-temperature alloy powder on the substrate preheated in step 3 to form a powder bed;
[0064] Step 5: The powder bed formed in step 4 is heated to 950°C to 1050°C for 10 seconds;
[0065] Step 6: Set the electron beam acceleration voltage in the additive manufacturing equipment to 60 kV, the electron beam current to 10 mA, the scanning speed to 8 m / s, the scanning line spacing to 50 μm, the powder layer thickness to 50 μm, and the interlayer rotation to 90°, and melt and solidify the Mar-M247 nickel-based high-temperature alloy powder in the target area of the powder bed one by one;
[0066] Step 7: heating the powder bed solidified in step 6 to 950°C to 1050°C for 10 seconds;
[0067] Step 8: After the platform is lowered, steps 4 to 7 are repeated multiple times until the Mar-M247 nickel-based high-temperature alloy component is formed.
[0068] After testing, it was found that there was no crack inside the Mar-M247 nickel-based high-temperature alloy component prepared in this embodiment.
[0069] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.
Claims
1. A method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with a high γ′ content, characterized in that: The preparation method comprises the following steps: Step 1: Place high γ′ content nickel-based high-temperature alloy powder into a powder bin of an additive manufacturing device and evacuate the powder bin; Step 2: Establish a three-dimensional CAD model of a high-γ′ content nickel-based high-temperature alloy component, perform layered slicing processing in the forming height direction of the three-dimensional CAD model, and then import the slicing data into the additive manufacturing equipment in step 1; Step 3: preheat the substrate to the target temperature and keep it warm; Step 4: evenly laying high γ′ content nickel-based high-temperature alloy powder on the substrate preheated in step 3 to form a powder bed; Step 5: preheating the powder bed formed in step 4; Step 6: setting the additive manufacturing parameters in the additive manufacturing equipment, and melting and solidifying the high-γ′ content nickel-based high-temperature alloy powder in the powder bed area one by one; Step 7: preheating the powder bed solidified in step 6; Step 8: Repeat steps 4 to 7 for multiple times until a high-γ′-content nickel-based high-temperature alloy component is formed.
2. The method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with high γ′ content according to claim 1, characterized in that: The molar percentage content of the γ′ phase in the high γ′ content nickel-based high-temperature alloy powder in step 1 is greater than 50%.
3. The method for suppressing cracks in additively manufactured high-γ′ content nickel-based high-temperature alloy according to claim 1, characterized in that: The high γ′ content nickel-based high-temperature alloy powder in step 1 is a nearly spherical or spherical powder with a particle size less than 150 μm.
4. The method for suppressing cracks in additively manufactured high-γ′ content nickel-based high-temperature alloy according to claim 1, characterized in that: The additive manufacturing equipment described in step one is a powder bed selective melting electron beam additive manufacturing equipment.
5. The method for suppressing cracks in additively manufactured high-γ′ content nickel-based high-temperature alloy according to claim 1, characterized in that: The vacuum in step 1 is evacuated to a vacuum degree of no more than 5×10 -2 Pa.
6. The method for suppressing cracks in additively manufactured high-γ′ content nickel-based high-temperature alloy according to claim 1, characterized in that: In step 3, the target temperature of the substrate is 950° C. to 1150° C., and the substrate insulation time is 10 min to 30 min.
7. The method for suppressing cracks in additively manufactured nickel-based high-temperature alloys with high γ′ content according to claim 1, characterized in that: The powder bed preheating process described in step 5 and step 7 is: heating the powder bed to 950° C. to 1150° C. after 10s to 15s.
8. The method for suppressing cracks in additively manufactured high-γ′ content nickel-based high-temperature alloy according to claim 1, characterized in that: The additive manufacturing parameters described in step six are: electron beam acceleration voltage of 60 kV, electron beam current of 4 mA to 10 mA, scanning speed of 1 m / s to 8 m / s, scanning line spacing of 40 μm to 100 μm, powder layer thickness of 40 μm to 50 μm, and interlayer rotation of 90°.