Continuous pulse current solution treatment method for additive manufacturing of nickel-based superalloy

Abstract

The invention relates to a continuous pulse current solution treatment method for additive manufacturing of nickel-based superalloy, and relates to the technical field of solution treatment for additive manufacturing of nickel-based superalloy. According to the main technical scheme, solution treatment is carried out in the mode that continuous pulse current treatment is applied to the additive manufacturing nickel-based superalloy, so that dissolving of harmful phases such as Lave in the additive manufacturing nickel-based superalloy is promoted, and the additive manufacturing nickel-based superalloy subjected to solution treatment is obtained. Compared with a traditional heat treatment process, the grain size in the additive manufacturing nickel-based superalloy subjected to solution treatment is smaller; the method is low in treatment temperature, short in treatment time, more efficient and more energy-saving, and meets the requirements of current industrial green sustainable development. Therefore, the invention provides a new method for further improving the comprehensive mechanical properties of the nickel-based superalloy manufactured by laser, electric arc and other additive manufacturing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid solution treatment of additive manufacturing nickel-based superalloys, and particularly relates to a continuous pulse current solid solution treatment method for additive manufacturing nickel-based superalloys. BACKGROUND

[0002] Nickel-based superalloys have excellent comprehensive mechanical properties, high temperature resistance, good processing performance and corrosion resistance, and are widely used in key components such as working blades, turbine discs and combustion chambers of aero-engines. Due to the long-term service of aero-engines under high temperature, high pressure, high speed and alternating load conditions, some parts will inevitably be damaged. Therefore, in order to avoid a large amount of material waste, excellent repair technology is essential. Additive manufacturing has a series of advantages such as high forming precision, short process flow and good mechanical properties compared with other repair technologies, and is suitable for manufacturing and repairing some complex superalloy parts.

[0003] Although the additive manufacturing process (10 3 -10 6 K / s) has a faster cooling rate than the casting process (10 1 -10 2 K / s), but there is still a large amount of Nb element segregation in the interdendritic region during the manufacturing process, and a large number of continuous irregular Laves harmful phases are formed by eutectic reaction during solidification. It is well known that Laves harmful phase is a kind of hard and brittle micro-scale harmful phase, which often hinders dislocation movement during alloy deformation, causing stress concentration. At the same time, Laves harmful phase is not coherent with γ matrix, so the coordination deformation ability between Laves harmful phase and γ matrix is poor, and it is difficult to realize the good compatibility of strength and plasticity.

[0004] The prior art generally adopts the method of traditional high-temperature solid solution treatment to regulate the Laves harmful phase in the alloy, but the standard solid solution temperature cannot promote enough diffusion of the Nb element and dissolve the Laves harmful phase, and the Laves harmful phase with a larger size needs to be kept at a higher temperature for a long time to effectively decompose or eliminate the Laves harmful phase. At present, there are few reports on new treatment technologies for eliminating harmful phases in additive manufacturing nickel-based high-temperature alloy materials. Blackwell P L. found in the study of heat treatment of additive manufacturing Inconel 718 alloy (Journal of Materials Processing Technology, 2005, 170: 240-246.) that hot isostatic pressing at 1160℃ can completely dissolve the Laves harmful phase in the as-deposited sample, but the traditional hot isostatic pressing method inevitably leads to serious grain coarsening and performance degradation. Therefore, the high-temperature solid solution treatment technology of the traditional hot isostatic pressing and heat treatment method inevitably changes the microstructure state of the additive manufacturing alloy, which may promote the recrystallization process, induce abnormal grain growth and change the intracrystalline substructure, which will seriously harm the mechanical properties of the alloy. At the same time, these two treatment methods often require a long processing time and a high processing temperature, resulting in a large amount of energy loss. It is urgent to develop a new treatment method with low energy consumption, high efficiency, precise regulation and simple operation to improve the microstructure and performance of additive manufacturing alloys.

[0005] Patent ZL202110446493.1 discloses a new method for realizing the dissolution of strengthening phase γ' in ordinary nickel-based deformed high-temperature alloy by using pulse current method. However, this method uses special high-energy pulse current and cannot realize continuous pulse treatment. Moreover, this method releases several thousand joules of energy in a few milliseconds, which has great safety risks and uncontrollability, and encounters great difficulties in practical application. This method also does not involve additive manufacturing nickel-based high-temperature alloy materials. In addition, the special high-energy pulse current method still has great disadvantages in usability, popularization and safety. In addition, the above-mentioned technology is aimed at the strengthening phase γ' in ordinary nickel-based deformed high-temperature alloy, not at the Laves harmful phase in additive manufacturing nickel-based high-temperature alloy. Here, the Laves harmful phase in additive manufacturing nickel-based high-temperature alloy is different from the γ' phase in deformed nickel-based high-temperature alloy; the γ' phase is completely coherent with the γ matrix, the γ' phase forming elements are close to the γ matrix, and the dissolution temperature is low; but the Laves harmful phase is completely incoherent with the γ phase, and the Laves harmful phase forming elements are all refractory elements, resulting in a high dissolution temperature.

[0006] In summary, in order to further improve the comprehensive mechanical properties of additive manufacturing nickel-based high-temperature alloy, a more effective solid solution treatment new method is urgently needed. SUMMARY

[0007] Therefore, the application provides a continuous pulse current solid solution treatment method for additive manufacturing of nickel-based superalloys, which can effectively decompose or eliminate large-sized Laves harmful phases and avoid abnormal grain growth.

[0008] To achieve the above-mentioned purposes, the application mainly provides the following technical solutions.

[0009] In one aspect, the application provides a continuous pulse current solid solution treatment method for additive manufacturing of nickel-based superalloys, wherein the solid solution treatment is performed by applying a continuous pulse current to the additive manufacturing of nickel-based superalloys to promote the dissolution of Laves harmful phases in the additive manufacturing of nickel-based superalloys, thereby obtaining the additive manufacturing of nickel-based superalloys after solid solution treatment.

[0010] Preferably, the continuous distribution of long-chain Laves harmful phases in the additive manufacturing of nickel-based superalloys is converted into a dispersed distribution of granular after the continuous pulse current treatment.

[0011] Preferably, the continuous pulse current solid solution treatment method for additive manufacturing of nickel-based superalloys comprises the following steps.

[0012] Step 1), processing the additive manufacturing of nickel-based superalloys into a workpiece for continuous pulse current treatment;

[0013] Step 2), connecting the workpiece with a pulse power supply, turning on the pulse power supply, and applying a continuous pulse current to the workpiece for treatment;

[0014] Step 3), cooling the workpiece after the continuous pulse current treatment to obtain the additive manufacturing of nickel-based superalloys after solid solution treatment.

[0015] Preferably, in the step 1), the additive manufacturing of nickel-based superalloys is a deposited laser additive manufacturing of nickel-based superalloys or a deposited electric arc additive manufacturing of nickel-based superalloys.

[0016] Preferably, in the step 1), the additive manufacturing of nickel-based superalloys is subjected to cutting, grinding, and cleaning treatment to obtain a workpiece with a set size.

[0017] Preferably, the additive manufacturing of nickel-based superalloys is a laser additive manufacturing of nickel-based superalloys.

[0018] Preferably, the additive manufacturing of nickel-based superalloys is a laser melting deposition of nickel-based superalloys.

[0019] Preferably, the additive manufacturing of nickel-based superalloys has the following chemical composition in terms of weight percentage:

[0020] Fe: 1-35 wt%, Cr: 2-35 wt%, Mo: 0-10 wt%, Al: 0.1-5 wt%, Ti: 0-5 wt%, Nb: 2-10 wt%, Ta: 0-5 wt%, W: 0.5-5 wt%, Co: 1-20 wt%, Zr: 0-1 wt%, Hf: 0-1 wt%, C: 0-0.5 wt%, B: 0-0.05 wt%, Si: 0-0.05 wt%, Ni: balance.

[0021] Preferably, the parameters of the continuous pulse current treatment are as follows:

[0022] The continuous pulse current density is 50-1000 A / mm 2 , preferably the current density is 200-400 A / mm 2 ;

[0023] The continuous pulse current width is 1 us-10 ms, preferably the current width is 0.1-2 ms;

[0024] The continuous pulse current frequency is 5-100 Hz, preferably 40-80 Hz;

[0025] The duty cycle is 1-80%, preferably 10-65%;

[0026] The temperature of the continuous pulse current treatment is 1000-1150℃, the time of the continuous pulse current treatment is 2-15 min, preferably the temperature of the continuous pulse current treatment is 1050℃±2℃, the time of the continuous pulse current treatment is 10 min±2 min.

[0027] Preferably, the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy before the continuous pulse current treatment is 9-10%; the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy after the solid solution treatment is 0.2-4.5%, preferably 0.2-0.58%.

[0028] Preferably, the grain size of the additive manufacturing nickel-based superalloy before the continuous pulse current treatment is 160-200 pm; the grain size of the additive manufacturing nickel-based superalloy after the solid solution treatment is 135-240 pm.

[0029] In another aspect, the embodiment of the present application provides a continuous pulse current solid solution treated additive manufacturing nickel-based superalloy, wherein the solid solution treated additive manufacturing nickel-based superalloy is obtained by solid solution treatment of the additive manufacturing nickel-based superalloy using the solid solution treatment method of the additive manufacturing nickel-based superalloy according to any one of the above; preferably, the Laves harmful phase in the solid solution treated additive manufacturing nickel-based superalloy is in a dispersed distribution of granular shape; preferably, the solid solution treated additive manufacturing nickel-based superalloy is an additive manufacturing nickel-based superalloy; preferably, the additive manufacturing nickel-based superalloy is a laser melting deposition nickel-based superalloy; preferably, the volume fraction of the Laves harmful phase in the solid solution treated additive manufacturing nickel-based superalloy is 0.2-4.5%, preferably 0.2-0.58%; preferably, the size of the grain in the solid solution treated additive manufacturing nickel-based superalloy is 135-240 μm.

[0030] Compared with the prior art, the continuous pulse current solid solution treatment method of the additive manufacturing nickel-based superalloy of the present application has at least the following beneficial effects:

[0031] The embodiment of the present application provides a continuous pulse current solid solution treatment method of an additive manufacturing nickel-based superalloy, which performs solid solution treatment by applying continuous pulse current treatment to the additive manufacturing nickel-based superalloy, so as to promote the dissolution of the Laves harmful phase in the additive manufacturing nickel-based superalloy and obtain a solid solution treated additive manufacturing nickel-based superalloy. Here, it needs to be explained about the above-mentioned solution that the present application accelerates atomic movement under the coupling effect of thermal effect and non-thermal effect by applying continuous pulse current to the nickel-based superalloy after additive manufacturing, realizes rapid dissolution of the Laves harmful phase in the alloy, and ensures that the grain does not grow, so that the elongation of the alloy is greatly improved without reducing the strength of the alloy. Moreover, the application of continuous pulse current treatment to the additive manufacturing nickel-based superalloy can rapidly dissolve the Laves harmful phase in the alloy at a lower temperature, and since the continuous pulse current treatment time is short, the grain in the alloy does not have time to grow rapidly and retains a high grain boundary strengthening effect. In addition, most of the Laves harmful phase in the alloy is dissolved, and small granular Laves harmful phase is retained in a dispersed distribution, which plays a key role in improving the mechanical properties of the alloy. In summary, the present application uses continuous pulse current treatment technology to rapidly realize the dissolution of the Laves harmful phase in the additive manufacturing nickel-based superalloy at a lower temperature and in a shorter time, which has the advantages of high efficiency, energy saving and environmental protection, etc.

[0032] Further, the additive manufacturing nickel-based superalloy is a laser melting deposition nickel-based superalloy. The parameters of the continuous pulse current treatment are as follows: the continuous pulse current density is 100-600 A / mm 2The continuous pulse current frequency is 5-100 Hz, the duty cycle is 10-80%, the temperature of the continuous pulse current treatment is 1000-1150 DEG C, and the time of the continuous pulse current treatment is 2-15 min. It should be noted that: the application utilizes the electric effect and Joule heat effect of the pulse current to reduce the thermodynamic potential barrier in the Laves harmful phase dissolution process by changing the free energy of the system, thereby reducing the Laves harmful phase dissolution temperature and increasing the atomic diffusion flux to further improve the atomic diffusion rate. The pulse current parameters are set reasonably in combination with the Laves harmful phase dissolution temperature of the additive manufacturing nickel-based superalloy, so that the Laves harmful phase is effectively dissolved at a lower temperature and in a shorter time.

[0033] The above description is only a summary of the technical scheme of the application, in order to more clearly understand the technical means of the application, and the content of the specification can be implemented as follows. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The scanning electron microscope (SEM) picture (see (a) figure) and the grain size distribution graph (see (b) figure) of the microstructure of the additive manufacturing nickel-based superalloy without treatment.

[0035] Figure 2 The scanning electron microscope (SEM) picture of the microstructure of the additive manufacturing nickel-based superalloy treated by different solid solution treatment methods; wherein, (a) figure is the solid solution treatment method of continuous pulse current treatment for 2 min at a temperature of 1050 DEG C, (b) figure is the traditional solid solution treatment method of heating for 2 min at a temperature of 1050 DEG C.

[0036] Figure 3 The grain size distribution graph of the additive manufacturing nickel-based superalloy treated by different solid solution treatment methods; wherein, (a) figure is the solid solution treatment method of continuous pulse current treatment for 2 min at a temperature of 1050 DEG C, (b) figure is the traditional solid solution treatment method of heating for 2 min at a temperature of 1050 DEG C.

[0037] Figure 4 The scanning electron microscope (SEM) picture of the microstructure of the additive manufacturing nickel-based superalloy treated by different solid solution treatment methods; wherein, (a) figure is the solid solution treatment method of continuous pulse current treatment for 5 min at a temperature of 1050 DEG C, (b) figure is the traditional solid solution treatment method of heating for 5 min at a temperature of 1050 DEG C.

[0038] Figure 5(a) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a continuous pulsed current treatment at a temperature of 1050 °C for 5 min, and (b) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1050 °C for 5 min.

[0039] Figure 6 (a) is a scanning electron microscope (SEM) image of the microstructure of the additive manufactured nickel-based superalloy after being treated with a continuous pulsed current treatment at a temperature of 1050 °C for 10 min, and (b) is a scanning electron microscope (SEM) image of the microstructure of the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1050 °C for 10 min.

[0040] Figure 7 (a) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a continuous pulsed current treatment at a temperature of 1050 °C for 10 min, and (b) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1050 °C for 10 min.

[0041] Figure 8 (a) is a scanning electron microscope (SEM) image of the microstructure of the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1050 °C for 60 min.

[0042] Figure 9 (a) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1050 °C for 60 min.

[0043] Figure 10 (a) is a scanning electron microscope (SEM) image of the microstructure of the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1150 °C for 60 min.

[0044] Figure 11 (a) is a grain size distribution plot for the additive manufactured nickel-based superalloy after being treated with a traditional solution treatment at a temperature of 1150 °C for 60 min.

[0045] Figure 12 (a) is a scanning electron microscope (SEM) image of the microstructure of the additive manufactured nickel-based superalloy after being treated with a continuous pulsed current treatment at a temperature of 1200 °C for 10 min. DETAILED DESCRIPTION

[0046] To further clarify the technical means and effects taken by the present application to achieve the intended purpose, the following describes the specific embodiments, structures, features and effects according to the present application in detail with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0047] The embodiment of the present application provides a continuous pulse current solid solution treatment method for additive manufacturing of nickel-based superalloy. The continuous pulse current is applied to the nickel-based superalloy after additive manufacturing for solid solution treatment, so that the Laves harmful phase in the additive manufacturing nickel-based superalloy is dissolved into the gamma matrix phase at a lower temperature and a shorter time, and meanwhile, abnormal grain growth is not induced. The grain size of the additive manufacturing nickel-based superalloy obtained by the solid solution treatment method is smaller.

[0048] The prior art discloses a pulse current solid solution treatment technology for nickel-based deformed superalloy, which effectively eliminates the gamma prime phase in the deformed superalloy by using high-energy pulse current. It should be noted that: (1) The maximum peak current of the high-energy pulse current of the prior art can reach tens of thousands of amperes, which may endanger the health of the operator. (2) The Laves harmful phase in the additive manufacturing nickel-based superalloy is different from the gamma prime phase in the deformed nickel-based superalloy; wherein the gamma prime phase is completely coherent with the gamma matrix, the gamma prime phase forming elements are close to the gamma matrix, and the dissolution temperature is low; but the Laves harmful phase is completely incoherent with the gamma phase, the Laves harmful phase forming elements are all refractory elements, resulting in a high dissolution temperature. Therefore, the structure, element composition and dissolution temperature of the gamma prime phase and the Laves harmful phase are completely different, and the Laves harmful phase has a higher dissolution temperature. The high-energy pulse current outputs high-density current instantaneously, and it is difficult to control the treatment temperature. The treatment temperature is too high, which easily causes the alloy to be initially melted, seriously affecting the quality of the alloy. Based on the prior art in the field, the above-mentioned prior art is only for the gamma prime phase in the deformed superalloy, and cannot realize the solid solution of the Laves harmful phase in the additive manufacturing nickel-based superalloy.

[0049] The specific scheme of the present application is as follows:

[0050] Step 1), the additive manufacturing nickel-based superalloy is processed into a workpiece for continuous pulse current treatment.

[0051] Step 2), the workpiece is connected with a pulse power supply, the pulse power supply is turned on, and the continuous pulse current treatment is applied to the workpiece.

[0052] Step 3), the workpiece after the continuous pulse current treatment is cooled to room temperature (preferably, the cooling method is room temperature).

[0053] Preferably, the additive manufacturing nickel-based superalloy is a laser melting deposition nickel-based superalloy. Correspondingly, the parameters of the continuous pulse current treatment are as follows: the continuous pulse current density is 50-1000 A / mm 2 , preferably, the current density is 200-400 A / mm 2 ; the continuous pulse current width is 1 us-10 ms, preferably, the current width is 0.1-2 ms; the continuous pulse current frequency is 5-100 Hz, preferably 40-80 Hz; the duty cycle is 1-80%, preferably 10-65%; the continuous pulse current treatment temperature is 1000-1150℃, the continuous pulse current treatment time is 2-15 min, preferably, the continuous pulse current treatment temperature is 1050℃±2℃, and the continuous pulse current treatment time is 10 min±2 min.

[0054] Preferably, the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy before the continuous pulse current treatment is 9-10%; after the continuous pulse current treatment, the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy is 0.2-4.5%, preferably, the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy after the solution treatment is 0.58%. The grain size of the additive manufacturing nickel-based superalloy after the solution treatment is 135-240 um, preferably, the grain size of the additive manufacturing nickel-based superalloy after the solution treatment is 231.1 um.

[0055] Here, the above-mentioned solutions of the present application need to be explained as follows:

[0056] 1) The present application accelerates atomic movement under the coupling of thermal effect and non-thermal effect by applying continuous pulse current to the nickel-based superalloy after additive manufacturing, realizes rapid dissolution of Laves harmful phase in the alloy, ensures that the grain does not grow, and greatly improves the elongation of the alloy under the premise of ensuring that the strength of the alloy does not decrease.

[0057] 2) The present application applies continuous pulse current treatment to the additive manufacturing nickel-based superalloy, which can rapidly dissolve Laves harmful phase in the alloy at a lower temperature. Because the continuous pulse current treatment time is short, the grain in the alloy does not have time to grow rapidly and retains a high grain boundary strengthening effect. In addition, most of the Laves harmful phase in the alloy is dissolved, and small particle-shaped Laves harmful phase is retained, which plays a key role in improving the mechanical properties of the alloy.

[0058] Compared with the traditional solid solution heat treatment technology, the Laves harmful phase in the additive manufacturing nickel-based superalloy can be quickly dissolved at a lower temperature and for a shorter time by using the continuous pulse current treatment technology, and the method has the advantages of high efficiency, energy saving, environmental protection and the like.

[0059] The application will be further described below through specific experimental examples as follows:

[0060] In the following examples and comparative examples, the alloy powder used for printing is prepared by a plasma rotating electrode (PREP) method, and the laser additive manufacturing nickel-based superalloy is printed by a coaxial powder feeding device, wherein the printing process parameters are as follows: laser power: 900 w; laser scanning speed: 8 mm / s; powder feeding amount: 7 g / min; and Z-axis lifting height: 0.7 mm. It should be noted that the scheme of the application is mainly proposed for the additive manufacturing nickel-based superalloy to promote the dissolution of the Laves harmful phase in the alloy, and is not limited to the above printing process parameters. As long as the additive manufacturing nickel-based superalloy has the Laves harmful phase, the scheme of the application can be used for solid solution treatment.

[0061] In addition, the temperature of the laser additive manufacturing nickel-based superalloy is recorded in real time by an infrared temperature measuring instrument. The temperature rise caused by the joule heating effect of the continuous pulse current is considered to be uniform on the cross section.

[0062] In addition, the composition of the laser additive manufacturing nickel-based superalloy in the following examples and comparative examples is shown in Table 1. In order to intuitively reflect the superiority of the continuous pulse current treatment of the application, the alloy with the composition shown in Table 1 is subjected to traditional solid solution treatment in a box-type resistance furnace for comparison, so as to analyze the advantages of the continuous pulse current treatment method.

[0063] Table 1 shows the alloy composition (wt%) used in the examples of the application

[0064] Element Al Ti Nb W Mo Cr Co Fe C Ni wt% 1.5 0.9 5.4 1.1 2.5 18.1 9.2 9.5 0.02 balance

[0065] Example 1

[0066] In this example, the laser additive manufacturing nickel-based superalloy is subjected to solid solution treatment by means of continuous pulse current treatment. The main steps are as follows:

[0067] 1) The laser additive manufacturing nickel-based superalloy is processed into a workpiece sample for continuous pulse current treatment.

[0068] The strip-shaped workpiece sample is cut from the as-deposited sample of the laser additive manufacturing nickel-based superalloy, and the surface is polished with 400-mesh, 800-mesh, 1200-mesh and 2000-mesh sandpaper in sequence to eliminate the wire cutting marks and ensure no obvious macroscopic defects, so as to ensure good contact between the workpiece sample and the electrode.

[0069] 2) Connect the sample to the pulse power supply, turn on the pulse power supply, and apply continuous pulse current to the workpiece sample.

[0070] Fix the workpiece sample to the output end of the power supply using a fixture (connect the two poles of the pulse power supply to the two ends of the sample to form a circuit).

[0071] The process involves applying a continuous pulsed current to a nickel-based superalloy workpiece manufactured using laser additive manufacturing, with a continuous pulsed current density of 260 A / mm². 2 The continuous pulse current width is 1ms; the continuous pulse current frequency is 55Hz; and the duty cycle is 50%. The continuous pulse current is processed for 2 minutes at 1050℃.

[0072] 3) The dissolution of the harmful Laves phase in the pulse-treated sample was observed using a scanning electron microscope. The central part of the pulse-treated sample was taken and mechanically polished after being polished with sandpaper of 240 grit, 600 grit, 1200 grit and 2000 grit in sequence.

[0073] 4) After chemical etching, the distribution of the harmful Laves phase was observed using scanning electron microscopy. The results of the scanning electron microscopy observations are shown in [reference needed]. Figure 2 Figure (a) shows the grain size distribution. Figure 3 Figure (a) in the middle.

[0074] In addition, the distribution of the Laves harmful phase was observed using scanning electron microscopy in both untreated samples and samples treated with conventional solution treatment at 1050°C for 2 min; the scanning electron microscopy results are shown in [reference to relevant documentation]. Figure 1 (a) Figure and Figure 2 See Figure (b) for grain size distribution. Figure 1 Figure (b) in the middle and Figure 3 Figure (b) in the middle.

[0075] It is evident that the untreated sample contained a large amount of harmful Laves phase, with a volume fraction of 9.42%. The volume fraction of harmful Laves phase in the sample treated with conventional solution treatment (6.21%) was still lower than that in the sample treated with continuous pulsed current (4.21%). Because the continuous pulsed current treatment parameters in Example 1 were not within the preferred range (while the parameters in Example 3 were within the preferred range), the treatment effect on the harmful Laves phase was not optimal. Furthermore, compared to the untreated sample (grain size 167.8 μm), the grain size in both the sample treated with conventional solution treatment (grain size 155.5 μm) and the sample treated with continuous pulsed current (grain size 163.8 μm) did not change significantly.

[0076] Example 2

[0077] This embodiment utilizes a continuous pulsed current treatment method to perform solution treatment on a laser additive manufacturing nickel-based superalloy. The main steps are as follows:

[0078] 1) Laser additive manufacturing of nickel-based superalloys is used to process workpiece samples for continuous pulse current processing.

[0079] Strip-shaped workpiece samples were cut from the deposited samples of nickel-based superalloys produced by laser additive manufacturing. The surfaces were then polished sequentially with 400-grit, 800-grit, 1200-grit, and 2000-grit sandpaper to eliminate wire cutting marks while ensuring no obvious macroscopic defects, thus ensuring good contact between the workpiece sample and the electrode.

[0080] 2) Connect the sample to the pulse power supply, turn on the pulse power supply, and apply continuous pulse current to the workpiece sample.

[0081] Fix the workpiece sample to the output end of the power supply using a fixture (connect the two poles of the pulse power supply to the two ends of the sample to form a circuit).

[0082] The process involves applying a continuous pulsed current to a nickel-based superalloy workpiece manufactured using laser additive manufacturing, with a continuous pulsed current density of 340 A / mm². 2 The continuous pulse current width is 1.2 ms; the continuous pulse current frequency is 55 Hz; and the duty cycle is 55%. The continuous pulse current is processed for 5 minutes at 1050℃.

[0083] 3) The dissolution of the harmful Laves phase in the sample after continuous pulse treatment was observed using a scanning electron microscope. The central part of the pulse-treated sample was taken and mechanically polished after being polished with sandpaper of 240 grit, 600 grit, 1200 grit and 2000 grit in sequence.

[0084] 4) After chemical etching, the distribution of the harmful Laves phase was observed using scanning electron microscopy. The results of the scanning electron microscopy observations are shown in [reference needed]. Figure 4 Figure (a) shows the grain size distribution. Figure 5 Figure (a) in the middle.

[0085] In addition, the distribution of the Laves harmful phase was observed using scanning electron microscopy on the sample after conventional solution treatment at 1050℃ for 5 min; the scanning electron microscopy results are shown in [reference needed]. Figure 4 See Figure (b) for grain size distribution. Figure 5 Figure (b) in the middle.

[0086] It can be seen that the volume fraction of Laves harmful phase in the sample after continuous pulse current treatment (the volume fraction of Laves harmful phase is 2.17%) is obviously lower than that in the sample after traditional solid solution heat treatment (the volume fraction of Laves harmful phase is 5.79%). At the same time, the grain size in the sample after continuous pulse current treatment (the grain size is 138.9 μm) is equivalent to that in the sample after traditional solid solution heat treatment (the grain size is 142.9 μm). It is worth mentioning that the recrystallization of the alloy after solid solution treatment leads to the decrease of the grain size.

[0087] Example 3

[0088] In this example, the solid solution treatment is performed by means of continuous pulse current treatment on the laser additive manufactured nickel-based superalloy. The main steps are as follows:

[0089] 1) The laser additive manufactured nickel-based superalloy is processed into a workpiece sample for continuous pulse current treatment.

[0090] The strip-shaped workpiece sample is cut from the as-deposited sample, and the surface is polished with 400 mesh, 800 mesh, 1200 mesh and 2000 mesh sandpaper in sequence to eliminate the wire cutting marks while ensuring no obvious macroscopic defects, so as to ensure good contact between the workpiece sample and the electrode.

[0091] 2) The workpiece sample is connected with the pulse power supply, and the pulse power supply is turned on to apply continuous pulse current treatment to the workpiece sample.

[0092] The workpiece sample is fixed on the output end of the power supply (the two poles of the pulse power supply are connected with the two ends of the sample to form a loop).

[0093] The power supply is turned on to apply continuous pulse current treatment to the workpiece sample, wherein the continuous pulse current density is 300 A / mm 2 ; the continuous pulse current width is 0.8 ms; the continuous pulse current frequency is 60 Hz; and the duty cycle is 60%. The continuous pulse current treatment is performed at a temperature of 1050℃ for 10 min.

[0094] 3) The dissolution of Laves harmful phase after continuous pulse current treatment is observed by scanning electron microscope.

[0095] The center part of the pulse treated sample is polished with 240 mesh, 600 mesh, 1200 mesh and 2000 mesh sandpaper in sequence and then mechanically polished.

[0096] 4) After chemical etching, the distribution of Laves harmful phase is observed by scanning electron microscope. The scanning electron microscope observation result is shown in FIG. 1(a) of the drawings, and the grain size distribution is shown in FIG. 1(a) of the drawings. Figure 6 Figure 7 ​​

[0097] In addition, the sample after traditional solid solution treatment at 1050 °C for 10 min was observed by scanning electron microscope to observe the distribution of Laves harmful phase. The scanning electron microscope observation results are shown in FIG. 2(b) of the accompanying drawings, and the grain size distribution is shown in FIG. 2(c) of the accompanying drawings. Figure 6 Figure 7

[0098] Most of the Laves harmful phase in the sample after continuous pulse current treatment (the volume fraction of Laves harmful phase is 0.58%) has been basically eliminated, and the elimination effect is obviously better than that of the sample after traditional solid solution treatment (the volume fraction is 4.74%). The grain size of the sample after continuous pulse current treatment slightly increases (the grain size is 231.1 μm), but still retains a high grain boundary strengthening effect. It can be seen that the process parameters of continuous pulse current treatment have a significant influence on the treatment effect.

[0099] Comparative Example 1

[0100] Comparative Example 1 performs traditional solid solution treatment on the laser additive manufacturing nickel-based superalloy workpiece, specifically as follows: heating at 1050 °C for 60 min to perform traditional solid solution treatment.

[0101] The sample after traditional solid solution treatment is subjected to standard metallographic treatment, and the distribution of Laves harmful phase is observed by scanning electron microscope after chemical etching. The scanning electron microscope observation results are shown in FIG. 3(a) of the accompanying drawings, and the grain size distribution is shown in FIG. 3(b) of the accompanying drawings. Figure 8 Figure 9

[0102] It is found that: after the laser additive manufacturing nickel-based superalloy of Comparative Example 1 is subjected to traditional solid solution treatment at a temperature of 1050 °C for 60 min, most of the Laves harmful phase (the volume fraction of Laves harmful phase is 4.59%) still exists in the sample, and the elimination effect is quite different from that of the sample after continuous pulse current treatment at 1050 °C for 10 min as described in the above examples. It can be seen that prolonging the heating time cannot effectively eliminate the Laves harmful phase.

[0103] Comparative Example 2

[0104] Comparative Example 2 performs traditional solid solution treatment on the laser additive manufacturing nickel-based superalloy workpiece, specifically as follows: heating at 1150 °C for 60 min to perform traditional solid solution treatment.

[0105] The sample after traditional solid solution treatment is subjected to standard metallographic treatment, and the distribution of Laves harmful phase is observed by scanning electron microscope after chemical etching. The scanning electron microscope observation results are shown in FIG. 4(a) of the accompanying drawings, and the grain size distribution is shown in FIG. 4(b) of the accompanying drawings. Figure 10 Figure 11 ​​​​​​

[0106] Findings: In Comparative Example 2, the laser additive manufacturing of nickel-based superalloys, after conventional solution treatment at 1150°C for 60 min, showed that most of the harmful Laves phases in the sample were essentially eliminated (Laves harmful phase volume fraction was 0.19%). This elimination effect was essentially consistent with that described in the previous examples after continuous pulsed current treatment at 1050°C for 10 min. However, the grain size of the sample in Comparative Example 2 after conventional solution treatment had significantly increased (grain size was 609.8 μm). This indicates that continuous pulsed current treatment reduces both the treatment temperature and time, while also inhibiting grain growth.

[0107] Comparative Example 3

[0108] Comparative Example 3 describes a solution treatment performed on a laser-additively manufactured nickel-based superalloy workpiece using continuous pulsed current processing. The main steps are as follows:

[0109] 1) The laser additive manufacturing nickel-based superalloy is processed into a workpiece sample for continuous pulse current processing.

[0110] Strip-shaped workpiece samples were cut from the sedimentary sample, and the surface was polished in sequence with 400-grit, 800-grit, 1200-grit, and 2000-grit sandpaper to eliminate wire cutting marks while ensuring no obvious macroscopic defects, so as to ensure good contact between the workpiece sample and the electrode.

[0111] 2) Connect the workpiece sample to the pulse power supply, turn on the pulse power supply, and apply continuous pulse current to the workpiece sample.

[0112] Fix the workpiece sample to the output end of the power supply using a fixture (connect the two poles of the pulse power supply to the two ends of the sample to form a circuit).

[0113] A continuous pulse current was applied to the workpiece sample after the power was turned on, wherein the continuous pulse current density was 1100 A / mm². 2 The continuous pulse current width is 1.5ms; the continuous pulse current frequency is 65Hz; and the duty cycle is 50%. The continuous pulse current is applied at 1200℃ for 10 minutes.

[0114] 3) Observe the dissolution of the harmful Laves phase after continuous pulsed current treatment using scanning electron microscopy.

[0115] Take the central part of the sample treated with continuous pulse current, and polish it mechanically after grinding it with sandpaper of 240 grit, 600 grit, 1200 grit and 2000 grit in sequence.

[0116] 4) After chemical etching, the distribution of the harmful Laves phase was observed using scanning electron microscopy. The results of the scanning electron microscopy observations are shown in [reference needed]. Figure 12 As shown.

[0117] The Laves harmful phase in the sample after the continuous pulse current treatment is not effectively eliminated, and the incipient melting phenomenon is observed. Compared with the embodiments, the parameters of the continuous pulse current treatment are unreasonable, and the ideal effect of eliminating the Laves harmful phase cannot be achieved. The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still belong to the scope of the technical scheme of the present application.

Claims

1. A continuous pulse current solid solution treatment method of additive manufacturing nickel-based superalloy, characterized in that, By applying continuous pulse current treatment to the additive manufacturing nickel-based superalloy, the solid solution treatment is carried out to promote the dissolution of Laves harmful phase in the additive manufacturing nickel-based superalloy, and the additive manufacturing nickel-based superalloy after solid solution treatment is obtained.

2. The continuous pulsed current solutionizing process for additive manufacturing of nickel- based superalloys of claim 1, wherein, After continuous pulse current treatment, the continuous distribution of long chain Laves harmful phase in the additive manufacturing nickel-based superalloy is converted into dispersed distribution of granular.

3. The continuous pulsed galvanostatic solution treatment method of additively manufactured nickel-base superalloy according to claim 1 or 2, characterized in that, The continuous pulse current solid solution treatment method of the additive manufacturing nickel-based superalloy comprises the following steps: Step 1), the additive manufacturing nickel-based superalloy is processed into a workpiece for continuous pulse current treatment; Step 2), the workpiece is connected with pulse power supply, the pulse power supply is turned on, and the workpiece is subjected to continuous pulse current treatment; Step 3), after the workpiece after continuous pulse current treatment is cooled, the additive manufacturing nickel-based superalloy after solid solution treatment is obtained.

4. The continuous pulsed current solutionizing process for additive manufacturing of nickel- based superalloys of claim 3, wherein, In the step 1), The additive manufacturing nickel-based superalloy is a deposited state laser additive manufacturing nickel-based superalloy or a deposited state electric arc additive manufacturing nickel-based superalloy.

5. The continuous pulsed current solutionizing process for additive manufacturing of nickel- based superalloys of claim 3, wherein, In the step 1), The additive manufacturing nickel-based superalloy is subjected to cutting, grinding and cleaning treatment to obtain a workpiece with a set size.

6. The continuous pulsed galvanostatic solution treatment method of additively manufactured nickel-base superalloys according to any one of claims 1 to 5, characterized in that, The additive manufacturing nickel-based superalloy is a laser additive manufacturing nickel-based superalloy; Preferably, the additive manufacturing nickel-based superalloy is a laser melting deposition nickel-based superalloy; Preferably, the chemical composition of the additive manufacturing nickel-based superalloy is as follows in terms of weight percentage: Fe: 1-35wt%, Cr: 2-35wt%, Mo: 0-10wt%, Al: 0.1-5wt%, Ti: 0-5wt%, Nb: 2-10wt%, Ta: 0-5wt%, W: 0.5-5wt%, Co: 1-20wt%, Zr: 0-1wt%, Hf: 0-1wt%, C: 0-0.5wt%, B: 0-0.05wt%, Si: 0-0.05wt%, Ni: balance.

7. The continuous pulsed galvanostatic solution treatment method of additively manufactured nickel-base superalloys of claim 6, wherein, The parameters of the continuous pulse current treatment are as follows: the continuous pulse current density is 50-1000 A / mm 2 , preferably, the current density is 200-400 A / mm 2 ; The continuous pulse current width is 1us-10ms, preferably the current width is 0.1-2ms; The continuous pulse current frequency is 5-100Hz, preferably 40-80Hz; The duty cycle is 1-80%, preferably 10-65%; The temperature of continuous pulse current treatment is 1000-1150℃, the time of continuous pulse current treatment is 2-15min, preferably the temperature of continuous pulse current treatment is 1050℃±2℃, the time of continuous pulse current treatment is 10min±2min.

8. The continuous pulse current solid solution treatment method of additive manufacturing nickel-based superalloy according to claim 6 or 7, characterized in that, Before continuous pulse current treatment, the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy is 9-10%; the volume fraction of Laves harmful phase in the additive manufacturing nickel-based superalloy after solid solution treatment is 0.2-4.5%, preferably 0.2-0.58%.

9. The continuous pulse current solid solution treatment method of the additive manufactured nickel-based superalloy according to claim 6 or 7, characterized in that, the grain size of the additive manufactured nickel-based superalloy before the continuous pulse current treatment is 160-200 μm; and the grain size of the additive manufactured nickel-based superalloy after the solid solution treatment is 135-240 μm.

10. A solution treated additive manufactured nickel-based superalloy, characterized in that, the additive manufactured nickel-based superalloy after the solid solution treatment is obtained by the continuous pulse current solid solution treatment method of the additive manufactured nickel-based superalloy according to any one of claims 1-9; preferably, the Laves harmful phase in the additive manufactured nickel-based superalloy after the solid solution treatment is in a dispersed distribution of granular shape; preferably, the additive manufactured nickel-based superalloy after the solid solution treatment is an additive manufactured nickel-based superalloy; and preferably, the additive manufactured nickel-based superalloy is a laser melting deposition nickel-based superalloy; preferably, the volume fraction of the Laves harmful phase in the additive manufactured nickel-based superalloy after the solid solution treatment is 0.2-4.5%, preferably 0.2-0.58%; preferably, the grain size of the additive manufactured nickel-based superalloy after the solid solution treatment is 135-240 μm.

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