Method for heat treatment of laser powder bed fusion formed nickel-based alloys and applications thereof

Abstract

The present application relates to the technical field of nickel-based alloy, in particular to a heat treatment method of laser powder bed fusion formed nickel-based alloy and application thereof. The heat treatment method of laser powder bed fusion formed nickel-based alloy comprises: after heating the laser powder bed fusion formed nickel-based alloy at 817-1142.3 DEG C, placing it in liquid nitrogen for preservation, taking out the nickel-based alloy and restoring it to room temperature, and then performing aging heat treatment. The present application introduces a large amount of compressive stress into the alloy through a large temperature difference, which can relieve the phenomenon of residual stress unevenness of LPBF formed components, greatly improve the strength of the nickel-based alloy, and ensure its elongation rate; and the large compressive stress causes lattice shrinkage, makes the lattice distorted, and the dislocation of atomic arrangement leads to a large number of crystal defects, such as subgrain boundary, deformation twin and dislocation pile-up, so that the alloy has obvious dislocation strengthening and fine-grain strengthening effect.

Description

Technical Field

[0001] This invention relates to the field of nickel-based alloy technology, and more specifically, to a heat treatment method for nickel-based alloys formed by laser powder bed melting and its application. Background Technology

[0002] Nickel-based alloys possess excellent mechanical properties and oxidation resistance, making them widely used in turbine blades, combustion chambers, and other high-temperature components of aero-engines. In recent years, advancements in additive manufacturing technology have propelled the research progress of nickel-based superalloys. Among these, laser powder bed melting (LPBF) technology, due to its significant advantages in achieving extremely high manufacturing precision and accommodating complex designs, has been widely applied to the forming of complex cavity-shaped nickel-based superalloy components. LPBF-formed nickel-based alloys exhibit unique ultra-high solid solubility, a non-equilibrium microstructure with high-density dislocations, and complex non-uniform residual stress. Current LPBF-formed nickel-based alloys generally employ solution treatment to homogenize the microstructure, followed by aging treatment to control the size and morphology of the constituent phases to optimize alloy properties. The main objectives of solution heat treatment are twofold: firstly, to dissolve the strengthening and harmful phases, thereby making the dominant strengthening phase γ... Solution treatment serves two purposes: first, it eliminates unevenly distributed secondary carbides and borides at grain boundaries, resulting in a homogeneous supersaturated solid solution; second, it reduces or eliminates segregation, homogenizing the microstructure and preventing uneven distribution of strengthening phases due to microstructure segregation. Aging heat treatment is performed after solution heat treatment to further precipitate fine γ-rays. Phases are used to adjust the quantity and morphology of strengthening phases, thereby enhancing the strength of the alloy.

[0003] The widely used solution treatment process is inherited from the heat treatment scheme of deformed or cast nickel-based alloys. Due to the slow solidification rate of traditional processing, alloying elements (such as Al, Ti, Nb, Ta, etc.) have ample time to diffuse and precipitate from the nickel γ matrix, forming coarse enriched phases (such as γ' phase, carbides, Laves phase, etc.). These phases are also unevenly distributed at grain boundaries and between dendrites. LPBF directly prints a near-perfect, uniform, fine-grained supersaturated solid solution microstructure. Therefore, solution treatment suitable for conventionally formed nickel-based alloys is not suitable for LPBF. Studies have shown that the ultra-high solid solubility of LPBF-formed components is beneficial to mechanical properties. The HX alloy microstructure optimized based on non-equilibrium solidification characteristics exhibits excellent creep resistance. However, the microstructure requirements for creep and instantaneous stretching at room temperature are difficult to reconcile. Currently, there is a lack of exploration into optimizing the ultra-solid solution microstructure of LPBF-formed nickel-based alloys to achieve even better performance. Furthermore, when the aging temperature exceeds 350℃, dislocations in nickel-based alloys exhibit significant recovery, weakening the dislocation strengthening effect. Therefore, direct high-temperature heat treatment cannot achieve optimal strength in LPBF-formed nickel-based alloys and may even lead to a sharp decrease in the plasticity of the alloy.

[0004] To address these challenges, deep cooling (DCT) processes introduce micro-stress and crystal defects into the crystal at low temperatures, serving as a means to enhance LPBF forming alloys. DCT pre-introduces numerous crystal defects such as dislocations, stacking faults (SFs), deformation twins, and nanograins into the alloy, improving the thermal stability of dislocations during aging heat treatment (AHT) through a pinning effect. This suppresses dislocation recovery and promotes the nucleation and uniform distribution of the second phase. Furthermore, due to their multi-element nature, FCC alloys (face-centered cubic alloys) typically have low stacking fault energies (SFEs), which decrease with increasing temperature. This provides favorable conditions for activating stacking faults (SFs) or deformation twins (DTs) through DCT.

[0005] However, the partial compressive residual stress caused by microplasticity resulting from defects in environments ranging from room temperature to -77K can suppress crack propagation and thus improve the ductility of the alloy. However, the method of significantly improving strength without sacrificing ductility still needs to be explored.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a heat treatment method for nickel-based alloys formed by laser powder bed fusion (LPBF). By introducing a large amount of compressive stress into the alloy through a significant temperature difference, the method can alleviate the uneven residual stress in LPBF-formed components, significantly improve the strength of the nickel-based alloy, and ensure its elongation. Furthermore, the large compressive stress causes lattice contraction, resulting in lattice distortion and atomic misalignment, leading to numerous crystal defects such as subgrain boundaries, deformed twins, and dislocation pile-ups. This results in significant dislocation strengthening and grain refinement effects in the alloy.

[0008] A second objective of this invention is to provide the application of a heat treatment method for nickel-based alloys formed by laser powder bed melting in the preparation of nickel-based alloy products.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: The present invention first provides a heat treatment method for nickel-based alloys formed by laser powder bed melting, comprising the following steps: heating the nickel-based alloy formed by laser powder bed melting at 817~1142.3℃, storing it in liquid nitrogen, taking out the nickel-based alloy and restoring it to room temperature, and then performing aging heat treatment.

[0010] Furthermore, the heating time is 5 to 30 minutes.

[0011] Furthermore, the storage time in liquid nitrogen is 3 to 24 hours.

[0012] Furthermore, the heat treatment method does not include solution treatment.

[0013] Furthermore, the temperature of the aging heat treatment is 817~1142.3℃.

[0014] Furthermore, the holding time for the aging heat treatment is 6 to 20 hours.

[0015] Furthermore, the room temperature is 10~30℃.

[0016] Furthermore, the nickel-based alloy includes solid solution-strengthened nickel-based alloys and / or precipitation-strengthened nickel-based alloys.

[0017] Furthermore, after being treated by the aforementioned heat treatment method, the nickel-based alloy exhibits a yield strength ≥1000MPa, an ultimate tensile strength ≥1400MPa, and an elongation ≥10.5%.

[0018] The present invention also provides the application of the above-mentioned heat treatment method for nickel-based alloys formed by laser powder bed melting in the preparation of nickel-based alloy products.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The heat treatment method provided by the present invention introduces a large amount of compressive stress into the alloy through a large temperature difference, which can alleviate the phenomenon of uneven residual stress in LPBF molded components and greatly improve the performance of nickel-based alloys. Furthermore, the large compressive stress causes lattice shrinkage, which causes lattice distortion and atomic misalignment, resulting in a large number of crystal defects, such as subgrain boundaries, deformed twins and dislocation pile-up, which makes the alloy exhibit obvious dislocation strengthening and fine grain strengthening effects.

[0020] (2) This invention breaks the traditional mindset that nickel-based alloys must be heat-treated by first solution treatment and then aging. It innovatively introduces a large number of crystal defects such as dislocations, stacking faults, deformed twins and nanocrystals into the alloy in advance, which improves the thermal stability of dislocations during the AHT process and promotes the nucleation of the second phase and the uniformity of its distribution, resulting in a nickel-based alloy with exceptionally good performance, high strength and high ductility. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 The phase composition-temperature diagram of ZGH4142 alloy was calculated using Pandat software; Figure 2 The images show a comparison of XRD patterns of nickel-based alloy workpieces treated in Comparative Examples 1-3 and Example 1. Figure 3 The images show the EBSD diagrams of nickel-based alloy workpieces after treatment in Comparative Examples 1-3 and Example 1; where (a) is the EBSD diagram of the nickel-based alloy workpiece formed by laser powder bed melting in Comparative Example 1; (b) is the EBSD diagram of the nickel-based alloy workpiece after treatment in Comparative Example 2; (c) is the EBSD diagram of the nickel-based alloy workpiece after treatment in Comparative Example 3; and (d) is the EBSD diagram of the nickel-based alloy workpiece after treatment in Example 1. Figure 4 The diagram shows a comparison of the engineering stress-strain curves of nickel-based alloy workpieces after treatment in Comparative Examples 1-3 and Example 1. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] In a first aspect, the present invention provides a heat treatment method for nickel-based alloys formed by laser powder bed melting, specifically a high-performance forming method for nickel-based alloys based on the non-equilibrium solidification characteristics of laser powder bed melting and post-heat treatment processes, comprising the following steps: A nickel-based alloy formed by laser powder bed melting is heated to 817~1142.3℃ for a period of time, then stored in liquid nitrogen for a period of time. Afterwards, the nickel-based alloy is removed and allowed to return to room temperature, followed by aging heat treatment. After cooling, the treated nickel-based alloy is obtained. The heating temperature includes, but is not limited to, any one of 817℃, 820℃, 830℃, 850℃, 880℃, 900℃, 920℃, 950℃, 980℃, 1000℃, 1050℃, 1100℃, 1120℃, and 1142.3℃, or a range between any two.

[0025] This invention breaks with the traditional mindset that nickel-based alloy heat treatment must first involve solution treatment followed by aging. It innovatively introduces numerous crystal defects such as dislocations, stacking faults (SF), deformed twins, and nanocrystals into the alloy beforehand, improving the thermal stability of dislocations during the AHT process and promoting the nucleation and uniformity of the second phase distribution. By overcoming technical biases, the heat treatment method of this invention yields nickel-based alloys with exceptionally high performance, exhibiting high strength and high ductility. Their performance far surpasses that of nickel-based alloys obtained using traditional manufacturing methods and / or heat treatment methods, laying an important foundation for the subsequent production and use of nickel-based alloys.

[0026] The heat treatment method provided by this invention can significantly improve the performance of nickel-based alloys formed by LPBF (Liquid-Based Plastic Fiber) without damaging plasticity, compared to traditional heat treatment methods. The large temperature difference introduces a significant amount of compressive stress into the alloy, alleviating the uneven residual stress in LPBF formed components. Furthermore, the large compressive stress causes lattice contraction, resulting in lattice distortion and atomic misalignment, leading to numerous crystal defects such as subgrain boundaries, deformed twins, and dislocation pile-ups. This results in a significant dislocation strengthening and grain refinement effect in the alloy.

[0027] In some specific embodiments, for the heat treatment method of the nickel-based alloy formed by laser powder bed fusion provided by the present invention, without any solution treatment, the yield strength of the nickel-based alloy can be increased by up to 39%, the tensile strength can be increased by up to 36%, and the elongation remains almost unchanged.

[0028] In some specific embodiments, the heating time is 5 - 30 min, including but not limited to any point value among 5 min, 10 min, 15 min, 20 min, 25 min, 30 min or the range value between any two of them. This is beneficial to further improve the performance of the nickel-based alloy.

[0029] In some specific embodiments, the time for storing in liquid nitrogen is 3 - 24 h, including but not limited to any point value among 3 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 24 h or the range value between any two of them. This is beneficial to further improve the performance of the nickel-based alloy.

[0030] In some specific embodiments, the nickel-based alloy includes a solid solution strengthened nickel-based alloy and / or a precipitation strengthened nickel-based alloy.

[0031] In some specific embodiments, the heat treatment method does not include solution treatment.

[0032] The nickel-based alloy used in the present invention includes a solid solution strengthened nickel-based alloy and / or a precipitation strengthened nickel-based alloy, and a large number of second phases are contained inside the alloy. The purpose of solution treatment is to dissolve these phases into the matrix. And the solution temperature must be higher than the complete dissolution temperature of various phases to ensure complete dissolution of the phases. As Figure 1 shown in the phase composition - temperature diagram of ZGH4142 alloy calculated by Pandat software. It can be seen that the complete dissolution of the phase requires at least more than 1142.3 °C. Therefore, the solution temperature range is between the dissolution temperature of the γ phase and the primary dissolution temperature of the alloy (1142.3 °C < ST < 1369.6 °C). Therefore, the heating at 817 - 1142.3 °C in the heat treatment method of the present application is not solution treatment. That is, the heat treatment method of the present application has no solution treatment step.

[0033] In some specific embodiments, the temperature of the aging heat treatment is 817 - 1142.3 °C, including but not limited to any point value among 817 °C, 820 °C, 830 °C, 850 °C, 880 °C, 900 °C, 920 °C, 950 °C, 980 °C, 1000 °C, 1050 °C, 1100 °C, 1120 °C, 1142.3 °C or the range value between any two of them.

[0034] In some specific embodiments, the holding time of the aging heat treatment is 6 to 20 hours, including but not limited to any one of 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 16 hours, 18 hours, and 20 hours, or any range between two of them.

[0035] In some specific embodiments, the room temperature is 10~30℃, including but not limited to any one of 10℃, 12℃, 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, and 30℃, or a range between any two.

[0036] In some specific embodiments, the heating is carried out in an inert atmosphere, such as an argon atmosphere, but is not limited thereto.

[0037] In some specific embodiments, after the nickel-based alloy is treated by the heat treatment method, the yield strength is ≥1000MPa, the ultimate tensile strength is ≥1400MPa, and the elongation is ≥10.5%; preferably, after the nickel-based alloy is treated by the heat treatment method, the yield strength is ≥1300MPa, the ultimate tensile strength is ≥1700MPa, and the elongation is ≥13%.

[0038] Secondly, the present invention provides the application of the above-mentioned heat treatment method for nickel-based alloys formed by laser powder bed melting in the preparation of nickel-based alloy products.

[0039] The heat treatment method provided by this invention can obtain nickel-based alloys with exceptionally high performance, including high strength and high ductility, which far exceed the performance of nickel-based alloys obtained by traditional manufacturing methods and / or heat treatment methods, laying an important foundation for the subsequent production and use of nickel-based alloys.

[0040] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0041] Example 1 The heat treatment method for nickel-based alloys formed by laser powder bed melting provided in this embodiment includes the following steps: (1) Using GH4142 nickel-based superalloy powder (precipitation-strengthened nickel-based alloy), it was loaded into the powder feeding chamber of the EOS M 290 3D metal printer. The substrate was preheated to 80°C, the laser power was 2500W, the scanning speed was 800mm / s, and the scanning spacing was set to 0.10mm. Two sets of printing were performed on the substrate. A nickel-based alloy workpiece with a diameter of 12mm × 400mm was obtained by laser powder bed melting.

[0042] (2) Under an argon protective atmosphere, the nickel-based alloy workpiece formed by the above laser powder bed melting is heated at 900°C for 10 minutes. Then, the nickel-based alloy workpiece is immediately placed in liquid nitrogen and left to stand for 6 hours. After that, the nickel-based alloy workpiece is taken out and after the temperature of the nickel-based alloy workpiece returns to room temperature (25°C), it is subjected to aging heat treatment at 900°C for 16 hours to obtain the treated nickel-based alloy workpiece, which is numbered DCTC.

[0043] Example 2 The heat treatment method for the nickel-based alloy formed by laser powder bed melting in this embodiment is basically the same as that in embodiment 1, except that in step (2), the heating temperature is replaced with 850°C.

[0044] Example 3 The heat treatment method for the nickel-based alloy formed by laser powder bed melting in this embodiment is basically the same as that in embodiment 1, except that in step (2), the heating temperature is replaced with 1000℃.

[0045] Example 4 The heat treatment method for nickel-based alloys formed by laser powder bed melting in this embodiment is basically the same as that in embodiment 1, except that in step (2), the heating and holding time is replaced with 30 min.

[0046] Example 5 The heat treatment method for the nickel-based alloy formed by laser powder bed melting in this embodiment is basically the same as that in embodiment 1, except that in step (2), the standing time in liquid nitrogen is replaced with 12h.

[0047] Example 6 The heat treatment method for the nickel-based alloy formed by laser powder bed melting in this embodiment is basically the same as that in embodiment 1, except that in step (2), the aging heat treatment is to keep it at 1000℃ for 12 hours.

[0048] Example 7 The heat treatment method for the nickel-based alloy formed by laser powder bed melting provided in this embodiment is basically the same as that in embodiment 1, except that in step (1), GH4142 nickel-based superalloy powder is replaced with Rene 142 nickel-based alloy powder (precipitation-strengthened nickel-based alloy).

[0049] Comparative Example 1 The nickel-based alloy workpiece obtained by laser powder bed melting and forming directly using step (1) of Example 1 is numbered As built.

[0050] Comparative Example 2 The nickel-based alloy workpiece obtained by laser powder bed melting and forming in step (1) of Example 1 was directly subjected to aging heat treatment at 900℃ for 16h to obtain the treated nickel-based alloy workpiece, which was numbered AT.

[0051] Comparative Example 3 The nickel-based alloy workpiece obtained by laser powder bed melting in step (1) of Example 1 was placed directly in liquid nitrogen and left to stand for 6 hours. Then the nickel-based alloy workpiece was taken out and after the temperature of the nickel-based alloy workpiece returned to room temperature (25°C), it was subjected to aging heat treatment at 900°C for 16 hours to obtain the treated nickel-based alloy workpiece, which was numbered DCT.

[0052] Comparative Example 4 The nickel-based alloy workpiece formed by laser powder bed melting in step (1) of Example 1 was kept at 900°C for 10 min under an argon protective atmosphere, then cooled to room temperature (25°C), and then subjected to aging heat treatment at 900°C for 16 h to obtain the treated nickel-based alloy workpiece.

[0053] Experimental Example Figure 2 The XRD test results are shown for the nickel-based alloy workpieces treated in Comparative Examples 1-3 and Example 1. Table 1 shows the γ matrix lattice constants calculated from the XRD data. Figure 2 The XRD results showed no significant changes in the phase composition of the four workpiece samples, with the main phases being γ' phase, MC carbides, and γ matrix. However, their lattice constants differed significantly. First, the lattice constant of the LPBF-formed ZGH412 alloy (As built) (Comparative Example 1) was 3.5749 Å. In contrast, the lattice constant of pure nickel was only 3.52 Å, indicating that the extremely rapid non-equilibrium solidification during LPBF caused atoms within the alloy to remain in the matrix and form a supersaturated solid solution before they could precipitate. Therefore, compared to traditionally extruded and cast nickel-based alloys, the solution treatment step can be omitted for LPBF-formed nickel-based alloys. Furthermore, the lattice constant of the AT sample (Comparative Example 2) was smaller than that of the As built sample (Comparative Example 1). However, the lattice constants of the DCT sample (Comparative Example 3) and the DCTC sample (Example 1) were only 3.5711 Å and 3.5713 Å, respectively, indicating that the samples underwent severe lattice shrinkage deformation upon entering liquid nitrogen. When the lattice contracts, it causes local atomic misalignment and dislocation aggregation, resulting in a dislocation strengthening effect in the sample, thereby enhancing the performance of the workpiece sample.

[0054] Table 1. Statistics of lattice constants

[0055] Figure 3 The images show the EBSD images of nickel-based alloy workpieces after treatment in Comparative Examples 1-3 and Example 1. Regarding average grain size, the grain sizes of the As-built (Comparative Example 1) and AT (Comparative Example 2) workpiece samples were 10.1 μm and 10.35 μm, respectively, showing no significant difference. However, the grain sizes of the DCT (Comparative Example 3) and DCTC (Example 1) workpiece samples were 11.72 μm and 12.11 μm, respectively, slightly larger than those of the As-built (Comparative Example 1) workpiece sample. This is because the low-temperature treatment of the workpiece samples resulted in more dislocations and twins, providing additional driving force for grain growth and accelerating the grain boundary migration process. Conversely, the DCTC (Example 1) workpiece sample had a higher proportion of small-angle grain boundaries (31.9%) than the AT (Comparative Example 2) workpiece sample (26.1%). This may be because dislocations accumulate during propagation and sliding to form dislocation walls, and the numerous dislocation walls together form smaller subgrains, thus achieving a grain refinement strengthening effect.

[0056] Figure 4 The tensile results of nickel-based alloy workpieces treated with Comparative Examples 1-3 and Example 1 are shown. The stress-strain curves show that the mechanical properties of the DCTC (Example 1) workpiece sample are significantly improved compared to those of Comparative Examples 1-3.

[0057] In addition, the strength and elongation test results of the nickel-based alloy workpieces after treatment in each embodiment and comparative example are shown in Table 2.

[0058] Table 2. Test results of strength and elongation of various nickel-based alloy workpieces.

[0059] As can be seen from Table 2, compared with the comparative examples, the nickel-based alloy workpieces treated in each example have higher yield strength and tensile strength, while also maintaining high elongation; especially Examples 1 and 2, with yield strength ≥1250MPa, ultimate tensile strength ≥1600MPa, and elongation ≥12%.

[0060] In summary, this invention introduces a large amount of compressive stress into the alloy through a significant temperature difference, which can alleviate the uneven residual stress in LPBF molded components and greatly improve the performance of nickel-based alloys. Furthermore, the large compressive stress causes lattice contraction, resulting in lattice distortion and atomic misalignment, leading to a large number of crystal defects such as subgrain boundaries, deformed twins, and dislocation pile-ups, which result in significant dislocation strengthening and grain refinement effects in the alloy.

[0061] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A heat treatment method for nickel-based alloys formed by laser powder bed melting, characterized in that, The heat treatment method includes the following steps: It does not include solution treatment. The nickel-based alloy formed by laser powder bed melting was heated to 817~1142.3℃ and then stored in liquid nitrogen. After the nickel-based alloy was taken out and restored to room temperature, it was subjected to aging heat treatment. The heating time is 5-30 minutes; The storage time in liquid nitrogen is 3~24 hours; The aging heat treatment temperature is 817~1142.3℃; The holding time for the aging heat treatment is 6~20h; The room temperature is 10~30℃; After being treated by the heat treatment method, the nickel-based alloy has a yield strength ≥1000MPa, an ultimate tensile strength ≥1400MPa, and an elongation ≥10.5%.

2. The heat treatment method for nickel-based alloys formed by laser powder bed melting according to claim 1, characterized in that, The nickel-based alloys include solid solution-strengthened nickel-based alloys and / or precipitation-strengthened nickel-based alloys.

3. The application of the heat treatment method for nickel-based alloys formed by laser powder bed melting as described in any one of claims 1 to 2 in the preparation of nickel-based alloy products.

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