A method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys

Abstract

This invention provides a method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys, comprising the following steps: S1, placing high-oxygen nickel-based recycled alloy powder into the first channel of a feeding hopper, and low-oxygen nickel-based alloy powder into the second channel of the feeding hopper; S2, activating the first feeding tray of the first channel and the second feeding tray of the second channel for continuous feeding, obtaining a layer-by-layer stacked mixed printing powder; S3, simultaneously activating the printing equipment to print layer by layer, obtaining a nickel-based superalloy sample with a gradient change in oxygen content; wherein, as the number of layers increases, the mass percentage of high-oxygen nickel-based recycled alloy powder gradually increases from 0% to 100%, and the mass percentage of low-oxygen nickel-based alloy powder gradually decreases from 100% to 0%. The gradient material with continuously changing oxygen content prepared by the method of this invention can provide prototype materials for high-throughput rapid characterization of the effect of oxygen content on the microstructure and properties of nickel-based superalloys.

Description

Technical Field

[0001] This invention belongs to the field of nickel-based superalloy technology, specifically relating to a method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys. Background Technology

[0002] Powdered nickel-based superalloys possess characteristics such as fine grains, uniform microstructure, absence of macrosegregation, and excellent hot working and mechanical properties, making them a new generation of superalloys with promising application prospects.

[0003] In the powder preparation process of nickel-based superalloys, coarse powder recyclables with unacceptable dimensions and composition are inevitably generated. In the actual production of nickel-based superalloys, castings with serious defects, such as runners, sprues, and risers, are unavoidable and cannot be used to manufacture finished parts. The processing also generates waste materials such as chips, scrap, and discarded parts. This results in the final weight of the finished parts often only accounting for 30% of the original smelted alloy weight. Therefore, the processing of nickel-based superalloys generates a significant amount of recyclable material.

[0004] High-temperature alloy recycled materials experience increased oxygen content due to prolonged exposure to air, while the content of alloying elements remains relatively unchanged. Therefore, improving the reuse rate of high-temperature alloy recycled materials can directly enhance the recycling and utilization of important metal resources, while simultaneously reducing production costs and energy consumption, achieving a win-win situation for resources and energy, and thus possessing significant strategic importance.

[0005] To investigate the effect of oxygen content on the microstructure and mechanical properties of high-temperature alloys, traditional techniques involve a trial-and-error approach, preparing alloys with different oxygen contents in batches, followed by comparative analysis to draw conclusions. This process is time-consuming, labor-intensive, and increases experimental costs. Therefore, preparing gradient materials with different oxygen contents through selective laser melting is of great significance for exploring the threshold of oxygen-induced degradation of alloy mechanical properties. Summary of the Invention

[0006] This invention uses high-oxygen-content nickel-based superalloy recycled material and low-oxygen pure nickel-based superalloy powder as raw materials, and uses selective laser melting technology to process recycled material with different mass fractions to obtain gradient alloys. It can prepare gradient materials with continuously varying oxygen content, and can provide prototype materials for high-throughput rapid characterization of the effect of oxygen content on the microstructure and properties of nickel-based superalloys.

[0007] This invention provides a method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys, comprising the following steps:

[0008] S1. Place the high-oxygen nickel-based recycled alloy powder into the first channel of the feeding hopper, and the low-oxygen nickel-based alloy powder into the second channel of the feeding hopper.

[0009] S2. Start the first feeding tray of the first channel and the second feeding tray of the second channel. Control the amount of high oxygen nickel-based return alloy powder added in different positions of the gradient material by adjusting the feeding speed of the powder feeding tray. Continuously discharge the powder and send the high oxygen nickel-based return alloy powder and low oxygen nickel-based alloy powder to the printing table to obtain mixed printing powder stacked layer by layer.

[0010] S3. While continuously discharging the material, start the printing equipment to laser melt the mixed printing powder and print layer by layer to obtain a nickel-based high-temperature alloy sample with a gradient change in oxygen content.

[0011] Among them, as the number of layers increases in the mixed printing powder, the mass percentage of high-oxygen nickel-based recycled alloy powder gradually increases from 0% to 100%, while the mass percentage of low-oxygen nickel-based alloy powder gradually decreases from 100% to 0%.

[0012] Preferably, the height of the sample is H, the layer-by-layer printing speed is v, and the total printing time is T. As the number of layers increases in the mixed printing powder, the mass percentage of high-oxygen nickel-based recycled alloy powder to low-oxygen nickel-based alloy powder is y%: (100-y)%, y=kf(t), t∈[0,T], where y% is the mass percentage of high-oxygen nickel-based recycled alloy powder, t is a certain time point in the printing process, and k is a constant.

[0013] Preferably, k = 1, t∈[0,T], the value of y is a continuous value. As time goes by or the height increases, the content of high oxygen return alloy powder in the sample increases continuously, and the distribution of oxygen content also gradually increases.

[0014] Preferably, k = 5. t∈[0,T]. Where y is a common multiple of 5 and is a positive integer. In this case, within a certain time period, the proportion of high-oxygen nickel-based recycled alloy powder in the mixed printing powder remains unchanged as the number of layers increases. As the printed sample accumulates over time, the oxygen concentration is constant in a certain region (within a certain numerical height range), but changes in the next time region.

[0015] The content of high-oxygen nickel-based recycled alloy powder in the mixed printing powder changes stepwise with the increase of the number of layers. For example, in the first section layer, the proportion of high-oxygen nickel-based recycled alloy powder is 0%, and the proportion of low-oxygen nickel-based alloy powder is 100%; in the second section layer, the proportion of high-oxygen nickel-based recycled alloy powder is 5%, and the proportion of low-oxygen nickel-based alloy powder is 95%; in the third section layer, the proportion of high-oxygen nickel-based recycled alloy powder is 10%, and the proportion of low-oxygen nickel-based alloy powder is 90%, and so on.

[0016] Preferably, the particle size of both the high-oxygen nickel-based recycled alloy powder and the low-oxygen nickel-based alloy powder is 50–70 μm.

[0017] Preferably, the oxygen content of the high-oxygen nickel-based recycled alloy powder is 800–1000 ppm. It is a powder processed from the nickel-based high-temperature alloy recycled material described in the background art.

[0018] Preferably, the oxygen content of the low-oxygen nickel-based alloy powder is 100–300 ppm.

[0019] Preferably, the high-oxygen recycled nickel-based alloy powder and the low-oxygen nickel-based alloy powder are both nickel-based high-temperature alloys, selected from any one or different types of FGH95, FGH96, FGH97, FGH98, FGH981, and FGH99.

[0020] Preferably, in step S3, the laser power during the laser melting process is 350-480W, and the printing speed is 0.1-2cm / s.

[0021] Preferably, in step S2, the total feeding speed of the first feeding tray and the second feeding tray is 3-8 g / min.

[0022] It should be noted that at different times, the total amount of material fed out by the first and second feed trays in different layers is constant, while the proportion of high-oxygen nickel-based recycled alloy powder and low-oxygen nickel-based alloy powder in the total material is constantly changing.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] (1) This invention uses high-oxygen nickel-based superalloy recycled material and low-oxygen pure nickel-based superalloy powder as raw materials, and processes them using selective laser melting technology to obtain gradient alloys with different mass fractions of recycled material. This allows for the preparation of gradient materials with continuous or discontinuous changes in oxygen content, achieving a stable gradient distribution of oxygen content in nickel-based alloys. This provides prototype materials for high-throughput rapid characterization of oxygen content and its impact on the microstructure and properties of nickel-based superalloys.

[0025] (2) The method described in this invention can quickly study the influence of oxygen concentration in alloy materials on the microstructure and mechanical properties of nickel-based superalloys;

[0026] (3) The method described in this invention can quickly study the influence of oxygen concentration in alloy materials on the content of inclusions in nickel-based superalloys;

[0027] (3) This invention improves the reuse rate of nickel-based superalloys by analyzing the influence of the addition of recycled materials on the oxygen of nickel-based superalloys and their impurities, thereby reducing costs and energy consumption and achieving efficient utilization of resources and energy. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating a method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys, provided in a specific embodiment of the present invention.

[0029] Figure 2 This is a secondary ion mass spectrometry (SIMS) image of the sample prepared in Example 1 of the present invention;

[0030] Figure 3 This is a scanning electron microscope (SEM) image of the sample prepared in Example 1 of the present invention;

[0031] Figure 4 This is a SEM image of the sample prepared in Example 2 of the present invention;

[0032] Figure 5 This is a SEM image of the sample prepared in Comparative Example 1 of this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys includes the following steps:

[0036] S1. A dual-channel feeding hopper is used. High-oxygen nickel-based recycled alloy powder with a particle size of 50μm is placed into the first channel of the feeding hopper, and low-oxygen nickel-based alloy powder with a particle size of 70μm is placed into the second channel of the feeding hopper. The oxygen content of the high-oxygen nickel-based recycled alloy powder is 800ppm, and the oxygen content of the low-oxygen nickel-based alloy powder is 100ppm.

[0037] S2. Start the first feeding tray of the first channel and the second feeding tray of the second channel. By adjusting the feeding speed of the powder feeding tray, control the amount of high oxygen nickel-based return alloy powder added at different positions of the gradient material. The total feeding speed of the first feeding tray and the second feeding tray is 3g / min, and continuous discharge is carried out. The high oxygen nickel-based return alloy powder and the low oxygen nickel-based alloy powder are sent to the printing table to obtain mixed printing powder stacked layer by layer.

[0038] S3. While continuously discharging the material, the printing equipment is started to laser melt the mixed printing powder. The printing is carried out layer by layer in an argon atmosphere. The laser power is 350W and the printing speed is 0.1cm / s to obtain a nickel-based superalloy sample with a gradient of oxygen content.

[0039] In the mixed printing powder, as the number of layers increases, the mass percentage of high-oxygen nickel-based recycled alloy powder gradually increases from 0% to 100%, while the mass percentage of low-oxygen nickel-based alloy powder gradually decreases from 100% to 0%.

[0040] The height of the sample is H, the layer-by-layer printing speed is v, and the total printing time is T. In the mixed printing powder, as the number of layers increases, the mass percentage of high-oxygen nickel-based recycled alloy powder to low-oxygen nickel-based alloy powder is y%:(100-y)%. t∈[0,T], and y takes continuous values. As time progresses or the altitude increases, the content of high-oxygen nickel-based recycled alloy powder in the sample continuously increases, and the oxygen content distribution also gradually increases.

[0041] A 1*1*1cm cube sample was cut from the printed sample using wire cutting. The sampling location was... Figure 1 The sample box location is shown. SIMS analysis was performed, and the results are as follows... Figure 2 As shown, where Figure 2 The side above corresponds to the side with a higher content of high-oxygen nickel-based recycled alloy powder. Figure 2 The lower section corresponds to the side with a lower content of high-oxygen nickel-based recycled alloy powder. It can be observed that... Figure 2 The oxygen content changes continuously from top to bottom.

[0042] Figure 3 This is a SEM image of the sample prepared in this embodiment. Elemental analysis was performed using energy dispersive spectroscopy, and the selected positions were... Figure 3 The results of the four equidistant test points are shown in Table 1. It can be observed that the oxygen content exhibits a continuous change, indicating that the oxygen content varies continuously in the sample prepared through this embodiment.

[0043] Example 2

[0044] A method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys includes the following steps:

[0045] S1. A dual-channel feeding hopper is used. High-oxygen nickel-based recycled alloy powder with a particle size of 70μm is placed into the first channel of the feeding hopper, and low-oxygen nickel-based alloy powder with a particle size of 50μm is placed into the second channel of the feeding hopper. The oxygen content of the high-oxygen nickel-based recycled alloy powder is 1000ppm, and the oxygen content of the low-oxygen nickel-based alloy powder is 300ppm.

[0046] S2. Start the first feeding tray of the first channel and the second feeding tray of the second channel. By adjusting the feeding speed of the powder feeding tray, control the amount of high oxygen nickel-based return alloy powder added at different positions of the gradient material. The total feeding speed of the first feeding tray and the second feeding tray is 8g / min, and continuous material is discharged. The high oxygen nickel-based return alloy powder and the low oxygen nickel-based alloy powder are sent to the printing table to obtain mixed printing powder stacked layer by layer.

[0047] S3. While continuously discharging material, the printing equipment is started to laser melt the mixed printing powder. The printing is carried out layer by layer in an argon atmosphere. The laser power is 480W and the printing speed is 2cm / s to obtain a nickel-based high-temperature alloy sample with a gradient of oxygen content.

[0048] In the mixed printing powder, as the number of layers increases, the mass percentage of high-oxygen nickel-based recycled alloy powder gradually increases from 0% to 100%, while the mass percentage of low-oxygen nickel-based alloy powder gradually decreases from 100% to 0%.

[0049] The height of the sample is H, the layer-by-layer printing speed is v, and the total printing time is T. In the mixed printing powder, as the number of layers increases, the mass percentage of high-oxygen nickel-based recycled alloy powder to low-oxygen nickel-based alloy powder is y%:(100-y)%. t∈[0,T], where y is a common multiple of 5 and is a positive integer. In this case, within a certain time period, the proportion of high-oxygen nickel-based recycled alloy powder in the mixed printing powder remains unchanged as the number of layers increases. As the printed sample accumulates over time, the oxygen concentration is constant within a certain region (within a certain numerical height range), but changes in the next time region.

[0050] In this mixed printing powder, the content of high-oxygen nickel-based recycled alloy powder changes in a stepwise manner with the increase of the number of layers. For example, the area printed within the time interval 0-t1 is the first region layer, during which the proportion of high-oxygen nickel-based recycled alloy powder remains constant. This pattern continues to the second, third, and so on, resulting in the second, third, and so on region layers. In the first region layer, the proportion of high-oxygen nickel-based recycled alloy powder is 0%, and the proportion of low-oxygen nickel-based alloy powder is 100%; in the second region layer, the proportion of high-oxygen nickel-based recycled alloy powder is 5%, and the proportion of low-oxygen nickel-based alloy powder is 95%; in the third region layer, the proportion of high-oxygen nickel-based recycled alloy powder is 10%, and the proportion of low-oxygen nickel-based alloy powder is 90%, and so on.

[0051] Figure 4 This is a SEM image of the sample prepared in this embodiment. Elemental analysis was performed using energy dispersive spectroscopy, and the selected positions were... Figure 4The results of the four equidistant test points are shown in Table 2. A gradient change in oxygen content can be observed, indicating a gradient variation in oxygen content within the sample prepared in this embodiment.

[0052] Comparative Example 1

[0053] This comparative example follows the same procedure as Example 1. The difference is that in this comparative example, both the dual-channel hoppers contain high-oxygen nickel-based recycled alloy powder with an oxygen content of 900 ppm and a particle size of 50 μm.

[0054] Figure 5 This is a SEM image of the sample prepared in this comparative example. Elemental analysis was performed using energy dispersive spectroscopy (EDS), with the selected positions being... Figure 5 The results of the four equidistant test points are shown in Table 3. It can be observed that the oxygen content is similar, indicating that oxygen is uniformly distributed in the samples prepared using this comparative example.

[0055] Table 1. Elemental distribution of the samples in Example 1

[0056]

[0057] Table 2 Elemental distribution of the samples in Example 2

[0058]

[0059] Table 3 Elemental distribution of the samples in Comparative Example 1

[0060]

[0061] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for studying the effect of oxygen content on the microstructure and properties of nickel-based superalloys, characterized in that, Includes the following steps: S1. High-oxygen nickel-based recycled alloy powder is placed into the first channel of the feeding hopper, and low-oxygen nickel-based alloy powder is placed into the second channel of the feeding hopper. The oxygen content of the high-oxygen nickel-based recycled alloy powder is 800~1000 ppm, and the oxygen content of the low-oxygen nickel-based alloy powder is 100~300 ppm. S2. Start the first feeding tray of the first channel and the second feeding tray of the second channel to continuously discharge materials, and send the high oxygen nickel-based return alloy powder and the low oxygen nickel-based alloy powder to the printing table to obtain mixed printing powder stacked layer by layer. S3. While continuously discharging the material, start the printing equipment to laser melt the mixed printing powder and print layer by layer to obtain a nickel-based high-temperature alloy sample with a gradient change in oxygen content. Among them, as the number of layers increases in the mixed printing powder, the mass percentage of high oxygen nickel-based recycled alloy powder gradually increases from 0% to 100%, while the mass percentage of low oxygen nickel-based alloy powder gradually decreases from 100% to 0%. The height of the sample is H, the layer-by-layer printing speed is v, and the total printing time is T, where T = As the number of layers increases in the mixed printing powder, the mass percentage of high-oxygen nickel-based recycled alloy powder to low-oxygen nickel-based alloy powder is y%: (100-y)%, y=kf(t), t∈[0,T], where y% is the mass percentage of high-oxygen nickel-based recycled alloy powder, t is a certain time point in the printing process, and k is a constant; When k=1, y=(100× ), t∈[0,T]; When k=5, y=5[100× ], t∈[0,T], y is a common multiple of 5.

2. The method according to claim 1, characterized in that, The particle size of both the high-oxygen nickel-based recycled alloy powder and the low-oxygen nickel-based alloy powder is 50~70μm.

3. The method according to claim 1, characterized in that, In step S3, the laser power during the laser melting process is 350-480W, and the layer-by-layer printing speed is 0.1~2cm / s.

4. The method according to claim 1, characterized in that, In step S2, the total feeding speed of the first feeding tray and the second feeding tray is 3-8 g / min.

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