A method for improving mechanical properties of additively manufactured hastelloy x alloy

Abstract

The application provides a method for improving the mechanical properties of an additive manufacturing Hastelloy X alloy, and specifically comprises sequentially performing solid solution treatment and stress relief annealing treatment on the additive manufacturing Hastelloy X alloy; the solid solution treatment and stress relief annealing treatment are performed under the protection of an argon atmosphere, the solid solution treatment temperature is 1100 DEG C to 1140 DEG C, the solid solution treatment time is 70 min to 90 min, and the Hastelloy X alloy is air-cooled to room temperature after the solid solution treatment; the stress relief annealing treatment temperature is 750 DEG C to 770 DEG C, and the stress relief annealing treatment time is 15 min to 35 min. The method improves the plasticity of the additive manufacturing Hastelloy X alloy, reduces the influence of thermal stress, reduces the generation of microcracks, and improves the strength and elongation of the Hastelloy X alloy.

Description

Technical Field

[0001] This invention provides a method for improving the mechanical properties of Hastelloy X additively manufactured products, belonging to the field of additive manufacturing technology. Background Technology

[0002] Selective Laser Melting (SLM), a metal additive manufacturing technology, differs from traditional material processing methods such as turning, milling, and forging. Additive manufacturing is a production method that creates parts by adding material. This technology relies on a computer-generated three-dimensional digital model to create a model of the part, then selects suitable parts as a base for layering and slicing, using a layer-by-layer fabrication method to bond and form the applied materials. It possesses enormous application potential due to its advantages such as eliminating the need for molds, saving raw materials, and achieving high precision.

[0003] High-temperature alloys are metallic materials based on metallic elements that can operate for extended periods under certain stress in high-temperature environments above 600°C. Hastelloy X is a nickel-based high-temperature alloy with Cr and Mo as solid solution reinforcing elements and a high iron content. Current machining methods struggle to achieve integral forming of complex parts. SLM (Sequencing and Molding) technology provides a new solution for the rapid manufacturing and integral forming of complex Hastelloy X components. Since the plasticity of workpieces formed by SLM is often unsatisfactory, post-processing is necessary to improve its plasticity.

[0004] CN113042755 A discloses a heat treatment method for GH3536 high-temperature alloy used in additive manufacturing. The heat treatment method includes: hot isostatic pressing of the GH3536 high-temperature alloy under a protective atmosphere, followed by a first-stage cooling treatment; solution treatment and a second-stage cooling treatment of the cooled GH3536 high-temperature alloy under vacuum conditions, followed by a third-stage cooling treatment. This invention's heat treatment method improves the performance of GH3536 high-temperature alloy used in additive manufacturing by controlling the process conditions during heat treatment, bringing its performance close to that of forgings. However, this method also requires multiple cooling treatments, resulting in a long production cycle. Furthermore, the plasticity of the transverse and longitudinal samples of this invention is not very high, which is not conducive to industrial application.

[0005] CN109014215 A discloses a heat treatment method for additive manufacturing of single-crystal nickel-based superalloys. The method includes: performing solution treatment, aging heat treatment, and cooling steps on the additive-manufactured single-crystal nickel-based superalloy to be treated in a heat treatment furnace; preparing slices of the treated single-crystal nickel-based superalloy; and determining the effectiveness of the heat treatment method based on microstructure characterization and crystal orientation analysis, and the presence or absence of recrystallization in the heat-affected zone and epitaxial growth zone. This method requires multiple cooling and aging treatments, resulting in a long aging time, excessively long production cycle, and low productivity. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving the mechanical properties of additively manufactured Hastelloy X alloys. This method improves the plasticity of additively manufactured Hastelloy X alloys while reducing the influence of thermal stress, reducing the generation of microcracks, and improving the strength and elongation of Hastelloy X alloys.

[0007] The technical solution adopted by the present invention to achieve its purpose is: a method for improving the mechanical properties of additively manufactured Hastelloy X alloy, specifically including performing solution treatment and stress-relieving annealing treatment on the additively manufactured Hastelloy X alloy in sequence;

[0008] The solution treatment and stress-relief annealing were carried out under an argon atmosphere. The solution treatment temperature was 1100℃-1140℃ and the solution treatment time was 70min-90min. After the solution treatment, the Hastelloy X alloy was air-cooled to room temperature. The stress-relief annealing temperature was 750℃-770℃ and the stress-relief annealing time was 15min-35min.

[0009] The principle and beneficial effects of this invention are as follows:

[0010] Hastelloy X alloy is manufactured using additive manufacturing. Metal powder is melted point-by-point, overlapped line-by-line, and solidified layer by layer, forming molten pools between layers. The morphology of the molten pool is determined by its orientation: strip-shaped molten pools in the printing direction and fish-scale-shaped molten pools in the construction direction. Regardless of the molten pool morphology, the interior of the molten pool consists of uniformly distributed slender columnar microcrystals. These microcrystals ensure the high strength and good plasticity of the additively manufactured sample. However, the molten pool boundary significantly affects the plasticity of the laser-melted sample. Since the bonding strength of the molten pool boundary is inherently weaker than that of the grain boundary, and there are local "coarse-grained regions" at the molten pool boundary, it becomes a weak point in the sample's performance. When the additively manufactured sample undergoes plastic deformation, it preferentially slips along the molten pool boundary. Furthermore, due to the extremely high cooling rate of additive manufacturing and the significant temperature gradient of the formed sample, the internal thermal stress of the sample is extremely high, resulting in defects such as microcracks.

[0011] This invention first involves treating the Hastelloy X alloy obtained through additive manufacturing at a solution temperature of 1100-1140℃ for 70-90 minutes. This process promotes the dissolution of fish-scale and strip-shaped molten pools that appear in the Hastelloy X alloy during the additive manufacturing process, thus preventing M... 23 The excessive formation of carbides such as C6 and M6C, and the complete recrystallization of grains, along with grain growth and grain boundary migration, result in large grains engulfing small grains, making the grain size more uniform. At the same time, the microstructure becomes more homogeneous, and elements such as Cr and Mo can be fully dissolved, playing a role in solid solution strengthening and improving the plasticity and tensile strength of the alloy during post-processing.

[0012] Then, this invention involves stress-relief annealing of the solution-treated alloy at a temperature of 750℃-770℃ for 15min-35min, which allows the topologically close-packed components in the matrix to dissolve equally, resulting in a homogeneous supersaturated solid solution. Simultaneously, finely precipitated, uniformly distributed carbides, such as Mo- and Cr-rich M, are formed. 23 C6, M6C, and other precipitates are uniformly and continuously distributed at the grain boundaries, playing a role in grain boundary strengthening, which improves the tensile strength and elongation of the material.

[0013] Furthermore, the additive manufacturing method for Hastelloy X alloy described in this invention includes selective laser melting, laser powder bed melting, and laser melting deposition modeling.

[0014] Furthermore, the additive manufacturing method for Hastelloy X alloy described in this invention is selective laser melting forming, and the preparation process parameters are: spot area 2.5-3.5mm, layer thickness 25-35μm, laser power 160-190W, scanning speed 1000-1100mm / s, and scanning spacing 0.08-0.11mm.

[0015] Furthermore, the solution treatment temperature of the solution treatment described in this invention is 1100℃-1120℃.

[0016] Furthermore, the solution treatment time of the solid solution treatment described in this invention is 75 min to 85 min.

[0017] Furthermore, the specific operation of the solution treatment described in this invention involves placing the additively manufactured Hastelloy X alloy in a heat treatment furnace, heating it to the solution treatment temperature at a heating rate of 8°C / min-10°C / min, and holding it at that temperature for the duration of the solution treatment.

[0018] Furthermore, the stress-relief annealing time described in this invention is 20-30 minutes.

[0019] Furthermore, before performing solution treatment on the additively manufactured Hastelloy X alloy, the present invention performs a pre-heating treatment on the additively manufactured Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additively manufactured Hastelloy X alloy in a heat treatment furnace and heat it to 790℃-810℃ at a heating rate of 8℃ / min-10℃ / min, and hold it for 20min-30min.

[0020] Pre-heating treatment can ensure that the internal and surface temperatures of the Hastelloy X alloy are consistent, preventing temperature differences between the set temperature and the sample. However, if the treatment time is too long, phases such as μ and σ may be generated, affecting the alloy's properties.

[0021] Furthermore, the specific operation of the solution treatment described in this invention is to continue heating the additively manufactured Hastelloy X alloy in the heat treatment furnace after pre-heating treatment, heating it to the solution treatment temperature at a heating rate of 8℃ / min-10℃ / min, and then holding it at that temperature for the duration of the solution treatment. Attached Figure Description

[0022] Figure 1 These are optical micrographs of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Embodiment 1 of the invention.

[0023] Figure 2 These are scanning electron microscope (SEM) images of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Embodiment 1 of the invention.

[0024] Figure 3 The image shows the tensile curves of Hastelloy X alloy before and after solution treatment and stress-relief annealing in Embodiment 1 of the invention.

[0025] Figure 4 The images show optical micrographs of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Comparative Example 1.

[0026] Figure 5 The images show scanning electron microscope (SEM) images of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Comparative Example 1.

[0027] Figure 6 The images show optical micrographs of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Comparative Example 2.

[0028] Figure 7 The images show optical micrographs of the transverse and longitudinal samples of the Hastelloy X alloy obtained in Comparative Example 3. Detailed Implementation

[0029] Example 1

[0030] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3mm, layer thickness 30μm, laser power 170W, scanning speed 1050mm / s, and scanning spacing 0.09mm.

[0031] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0032] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 20min.

[0033] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1120°C at a heating rate of 8°C / min, and then held at the temperature for 80 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0034] The stress-relief annealing treatment temperature is 760℃, and the stress-relief annealing treatment time is 20min.

[0035] In this embodiment, transverse and longitudinal samples were taken from the Hastelloy X alloy for characterization. Using the printed substrate as the base surface, samples taken parallel to the printed substrate direction are considered transverse samples, exhibiting a strip-like molten pool morphology. Samples taken perpendicular to the printed substrate are considered longitudinal samples, exhibiting a fish-scale-like molten pool morphology. The microstructure of the transverse and longitudinal samples of the Hastelloy X alloy obtained in this embodiment was characterized using optical microscopy and scanning electron microscopy. The characterization results are as follows: Figure 1 and Figure 2 As shown. From Figure 1 and Figure 2It can be seen that although there are microcracks at the grain boundaries of the transverse and longitudinal samples, they are distributed throughout the grain boundaries. No obvious carbide phase was observed inside the grains. The carbides are distributed uniformly and continuously in a chain-like manner on the grain boundaries, which improves the plasticity of the samples. The grains of the longitudinal samples all grow along the construction direction. Figure 3 Table 1 shows the tensile properties of Hastelloy X alloys before and after solution treatment and stress-relief annealing in this embodiment. Table 1 summarizes the tensile property test results of the Hastelloy X alloys treated in Examples 1 to 4 and Comparative Examples 1 to 3. Figure 3 As can be seen from Table 1, after solution treatment and stress-relief annealing in this embodiment, the yield tensile strength of the transverse sample increased by 23.37%, the ultimate tensile strength increased by 12.76%, and the plasticity reached 26.48%; the yield tensile strength of the longitudinal sample increased by 5.42%, the ultimate tensile strength increased by 13.61%, and the plasticity significantly increased to 76.7%.

[0036] Example 2

[0037] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3mm, layer thickness 30μm, laser power 170W, scanning speed 1050mm / s, and scanning spacing 0.09mm.

[0038] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0039] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0040] The specific operation of the solution treatment is to continue heating the additive manufacturing Hastelloy X alloy in the heat treatment furnace after pre-heating treatment, and raise the temperature to the solution treatment temperature of 1100°C at a heating rate of 8°C / min, hold it at the temperature for 75 minutes, and then open the heat treatment furnace to allow the Hastelloy X alloy to cool naturally to room temperature.

[0041] The stress-relief annealing temperature is 770℃, and the stress-relief annealing time is 30 minutes.

[0042] Example 3

[0043] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3mm, layer thickness 30μm, laser power 170W, scanning speed 1050mm / s, and scanning spacing 0.09mm.

[0044] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0045] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0046] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy, which has undergone pre-heating treatment, is heated in the heat treatment furnace at a heating rate of 8°C / min to the solution treatment temperature of 1110°C, and then held at that temperature for 85 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0047] The stress-relief annealing treatment temperature is 750℃, and the stress-relief annealing treatment time is 30min.

[0048] Example 4

[0049] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3mm, layer thickness 30μm, laser power 170W, scanning speed 1050mm / s, and scanning spacing 0.09mm.

[0050] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0051] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0052] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1130°C at a heating rate of 8°C / min, and then held at that temperature for 70 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0053] The stress-relief annealing treatment temperature is 750℃, and the stress-relief annealing treatment time is 15min.

[0054] Comparative Example 1

[0055] Hastelloy X alloy was prepared by selective laser melting (SLM). The preparation process parameters were: spot area 3 mm, layer thickness 30 μm, laser power 170 W, scanning speed 1050 mm / s, and scanning spacing 0.09 mm. The Hastelloy X alloy sample printed by SLM was slightly sanded on all six sides to remove the surface oxide film generated by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relief annealing treatment in sequence.

[0056] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0057] The specific operation of the solution treatment is to continue heating the additive manufacturing Hastelloy X alloy in the heat treatment furnace after pre-heating treatment, and raise the temperature to the solution treatment temperature of 1160°C at a heating rate of 8°C / min, hold it at the temperature for 80 minutes, and then open the heat treatment furnace to allow the Hastelloy X alloy to cool naturally to room temperature.

[0058] The stress-relief annealing treatment temperature is 760℃, and the stress-relief annealing treatment time is 20min.

[0059] Transverse and longitudinal samples were taken from the Hastelloy X alloy obtained in this comparative example for characterization. Using the printed substrate as the base surface, samples taken parallel to the printed substrate direction are considered transverse samples, exhibiting a strip-like molten pool morphology. Samples taken perpendicular to the printed substrate are considered longitudinal samples, exhibiting a fish-scale-like molten pool morphology. The microstructure of the transverse and longitudinal samples of the Hastelloy X alloy obtained in this comparative example was characterized using optical microscopy and scanning electron microscopy. The characterization results are as follows: Figure 4 and Figure 5 As shown. From Figure 4 and Figure 5 As can be seen, at this solid solution temperature, grains continue to grow, and the increased size leads to a decrease in material strength. The hindering effect of grain boundaries on dislocations weakens, making dislocation movement easier. Furthermore, excessively high solid solution temperatures cause some phases, such as M... 23 Low-melting-point phases such as C6 and M6C precipitate at grain boundaries, reducing strength and hardness. The grain boundaries in the longitudinal sample widen significantly, and the grain boundaries and intragranular areas contain more of other phases, weakening solid solution strengthening and affecting mechanical properties. As shown in Table 1, after the solution treatment and stress-relief annealing treatment in this embodiment, although the plasticity of the Hastelloy X alloy increased to 27.04% in the transverse sample and only to 27.15% in the longitudinal sample compared to before treatment, the tensile strength only slightly improved.

[0060] Comparative Example 2

[0061] Hastelloy X alloy was prepared by selective laser melting (SLM). The preparation process parameters were: spot area 3 mm, layer thickness 30 μm, laser power 170 W, scanning speed 1050 mm / s, and scanning spacing 0.09 mm. The Hastelloy X alloy sample printed by SLM was slightly sanded on all six sides to remove the surface oxide film generated by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relief annealing treatment in sequence.

[0062] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0063] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1120°C at a heating rate of 8°C / min, and then held at the temperature for 80 minutes. After the holding time is completed, it is cooled to room temperature at a cooling rate of 10°C / min.

[0064] The stress-relief annealing treatment temperature is 750℃, and the stress-relief annealing treatment time is 15min.

[0065] Transverse and longitudinal samples were taken from the Hastelloy X alloy obtained in this comparative example for characterization. Using the printed substrate as the base surface, samples taken parallel to the printed substrate were designated as transverse samples, exhibiting a strip-like molten pool morphology. Samples taken perpendicular to the printed substrate were designated as longitudinal samples, exhibiting a fish-scale-like molten pool morphology. The microstructure of the transverse and longitudinal samples of the Hastelloy X alloy obtained in this comparative example was characterized using an optical microscope. The characterization results are as follows: Figure 6 As shown. Figure 6It can be seen that the transverse sample grains show a slightly uniform trend, which is a result of cooling at a rate of 10℃ / min. The grains grow naturally along the temperature gradient, and cracks are generated at the grain boundaries in both directions. Table 1 shows that, after solution treatment and stress-relief annealing in this embodiment, the Hastelloy X alloy exhibits a 17.82% increase in transverse plasticity and a 41.32% increase in longitudinal plasticity compared to before treatment. The tensile strength of the transverse sample only shows a slight increase.

[0066] Comparative Example 3

[0067] Hastelloy X alloy was prepared by selective laser melting (SLM). The preparation process parameters were: spot area 3 mm, layer thickness 30 μm, laser power 170 W, scanning speed 1050 mm / s, and scanning spacing 0.09 mm. The Hastelloy X alloy sample printed by SLM was slightly sanded on all six sides to remove the surface oxide film generated by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relief annealing treatment in sequence.

[0068] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0069] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1120°C at a heating rate of 8°C / min, and then held for 80 minutes. After the holding time is completed, the additive manufacturing Hastelloy X alloy is taken out and placed in room temperature water for water cooling.

[0070] The stress-relief annealing treatment temperature is 750℃, and the stress-relief annealing treatment time is 15min.

[0071] Transverse and longitudinal samples were taken from the Hastelloy X alloy obtained in this comparative example for characterization. Using the printed substrate as the base surface, samples taken parallel to the printed substrate were designated as transverse samples, exhibiting a strip-like molten pool morphology. Samples taken perpendicular to the printed substrate were designated as longitudinal samples, exhibiting a fish-scale-like molten pool morphology. The microstructure of the transverse and longitudinal samples of the Hastelloy X alloy obtained in this comparative example was characterized using an optical microscope. The characterization results are as follows: Figure 7 As shown. Figure 7 As can be seen, the grains in the transverse sample are highly uneven. Due to the rapid cooling rate of water cooling, the internal thermal stress of the sample cannot be released, resulting in a large number of microcracks inside the sample. The longitudinal sample has a large number of twins, which hinder dislocation movement, thus exhibiting good plasticity. As shown in Table 1, after solution treatment and stress-relief annealing in this embodiment, compared with before treatment, the plasticity of the Hastelloy X alloy in the transverse sample increased to 18.81%, and the plasticity of the longitudinal sample increased to 70.36%, but the tensile strength of the transverse and longitudinal samples only increased to a small extent.

[0072] Table 1. Tensile property test results of the Hastelloy X alloys treated in the above embodiments and comparative examples.

[0073]

[0074] Example 5

[0075] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3mm, layer thickness 30μm, laser power 170W, scanning speed 1050mm / s, and scanning spacing 0.09mm.

[0076] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0077] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 800°C at a heating rate of 8°C / min, and hold it for 30min.

[0078] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1140°C at a heating rate of 8°C / min, and then held at that temperature for 90 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0079] The stress-relief annealing temperature is 750℃, and the stress-relief annealing time is 35 minutes.

[0080] Example 6

[0081] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 2.5 mm, layer thickness 25 μm, laser power 160 W, scanning speed 1000 mm / s, and scanning spacing 0.08 mm.

[0082] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0083] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 790°C at a heating rate of 10°C / min, and hold it for 25 minutes.

[0084] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy, which has undergone pre-heating treatment, is heated in the heat treatment furnace at a heating rate of 10℃ / min to the solution treatment temperature of 1140℃, and then held at that temperature for 90 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0085] The stress-relief annealing temperature is 750℃, and the stress-relief annealing time is 25 minutes.

[0086] Example 7

[0087] A method for improving the mechanical properties of additively manufactured Hastelloy X alloy, wherein the additive manufacturing method for Hastelloy X alloy is selective laser melting forming, and the preparation process parameters are: spot area 3.5 mm, layer thickness 35 μm, laser power 190 W, scanning speed 1100 mm / s, and scanning spacing 0.11 mm.

[0088] The Hastelloy X alloy sample, which was printed by selective laser melting, was lightly sanded on all six sides with sandpaper to remove the surface oxide film produced by natural aging. Then, it was ultrasonically cleaned for 40-60 seconds to remove surface waste powder. After drying, it was placed in a crucible and then placed in a tube furnace. Argon gas was introduced for 10 minutes to remove oxygen and other impurities in the tube furnace and to ensure an argon atmosphere. Under the protection of the argon atmosphere, the additively manufactured Hastelloy X alloy was subjected to solution treatment and stress-relieving annealing treatment in sequence.

[0089] Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace, heat it to 810°C at a heating rate of 9°C / min, and hold it for 25 minutes.

[0090] The specific operation of the solution treatment is as follows: the additive manufacturing Hastelloy X alloy that has undergone pre-heating treatment in the heat treatment furnace is heated to the solution treatment temperature of 1140°C at a heating rate of 9°C / min, and then held at that temperature for 90 minutes. After that, the heat treatment furnace is opened to allow the Hastelloy X alloy to cool naturally to room temperature.

[0091] The stress-relief annealing temperature is 750℃, and the stress-relief annealing time is 25 minutes.

Claims

1. A method for improving the mechanical properties of additively manufactured Hastelloy X alloys, characterized in that, Specifically, this involves sequentially performing solution treatment and stress-relief annealing on the additively manufactured Hastelloy X alloy; the solution treatment and stress-relief annealing are performed under an argon atmosphere. Before performing solution treatment on the additive manufacturing Hastelloy X alloy, a pre-heating treatment is performed on the additive manufacturing Hastelloy X alloy. The specific operation of the pre-heating treatment is to place the additive manufacturing Hastelloy X alloy in a heat treatment furnace and heat it to 790℃-810℃ at a heating rate of 8℃ / min-10℃ / min, and hold it for 20min-30min. The specific operation of the solution treatment is to continue heating the additively manufactured Hastelloy X alloy in the heat treatment furnace after pre-heating treatment, heating it to 1100℃-1140℃ at a heating rate of 8℃ / min-10℃ / min, holding it at that temperature for 75min-85min, and then air cooling it to room temperature. The stress-relief annealing temperature is 750℃-770℃, and the stress-relief annealing time is 20min-30min.

2. The method for improving the mechanical properties of additively manufactured Hastelloy X alloy according to claim 1, characterized in that: The additive manufacturing method for the Hastelloy X alloy includes selective laser melting.

3. The method for improving the mechanical properties of additively manufactured Hastelloy X alloy according to claim 1, characterized in that: The solution treatment temperature is 1100℃-1120℃.

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