Hydrogen embrittlement resistant nickel-based single crystal high-temperature alloy and preparation method thereof

Abstract

The invention belongs to the technical field of alloy hydrogen embrittlement resisting processes, and relates to a hydrogen embrittlement resisting nickel-based single crystal high-temperature alloy and a preparation method thereof. Comprising the following steps: weighing simple substance raw materials of Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C, smelting the raw materials for multiple times to obtain a mother alloy ingot of the nickel-based single crystal superalloy, processing the mother alloy ingot into a rod, cleaning, drying, heating to a preset temperature in an argon atmosphere, preserving heat for a preset time at the preset temperature, and cooling to obtain a nickel-based single crystal superalloy test rod; the method comprises the following steps: carrying out gradient solid solution heat treatment on a nickel-based single-crystal high-temperature alloy test bar, cooling to obtain a solid-solution nickel-based single-crystal high-temperature alloy test bar, and carrying out primary aging heat treatment to obtain the hydrogen embrittlement-resistant nickel-based single-crystal high-temperature alloy. The nickel-based single crystal superalloy prepared by the method disclosed by the invention can still keep relatively high elongation and reduction of area after being charged with hydrogen, the hydrogen embrittlement sensitivity of the nickel-based single crystal superalloy is obviously lower than that of a solid solution structure, and the nickel-based single crystal superalloy shows excellent comprehensive performance.

Description

Technical Field

[0001] This invention belongs to the field of alloy anti-hydrogen embrittlement technology, and relates to an anti-hydrogen embrittlement nickel-based single crystal superalloy and its preparation method. Background Technology

[0002] Nickel-based single-crystal superalloys are widely used in the manufacture of high-temperature components such as aero-engines and gas turbines due to their excellent high-temperature strength, creep resistance, and oxidation corrosion resistance. However, in high-temperature and high-pressure hydrogen environments, hydrogen atoms readily penetrate the alloy, leading to hydrogen embrittlement and significantly reducing the alloy's plasticity, toughness, and fatigue life. Hydrogen embrittlement primarily stems from the high diffusivity of hydrogen atoms in the alloy lattice and their aggregation under stress gradients. Hydrogen atoms tend to segregate at grain boundaries, phase interfaces, or microscopic defects, weakening interatomic bonding forces and promoting crack initiation and propagation.

[0003] In the prior art, two strategies are usually adopted to improve the hydrogen embrittlement resistance of nickel-based superalloys: one is to add certain specific elements through alloying design to capture hydrogen atoms or hinder their diffusion; the other is to optimize the heat treatment process and control the microstructure to reduce hydrogen trapping sensitive sites.

[0004] In alloying, existing research has explored the addition of rare earth elements (such as Re and Y) or strong carbide-forming elements (such as Nb, Ta, and Hf) to form stable hydrogen-trapping phases (such as carbides and oxides) or enhance grain boundary bonding. For example, some alloys incorporate refractory elements such as Re and W to slow hydrogen migration due to their low diffusion properties; other studies have promoted hydrogen growth by adding elements such as Ta and Nb. Phase precipitation occurs by capturing hydrogen atoms at the phase interface. However, excessive addition of these elements may lead to an expansion of the alloy's solidification range, increased segregation, or even the formation of harmful topologically dense phases, which in turn deteriorate mechanical properties and thermal stability.

[0005] In terms of heat treatment processes, while conventional solution treatment and aging treatment can optimize the microstructure to some extent, they often fail to completely eliminate dendrite segregation. The control over the size, distribution, and morphology of the phases is insufficient, and a large number of hydrogen diffusion channels and aggregation sites still exist. In particular, for highly alloyed single-crystal materials, how to achieve microstructure homogenization, refinement of strengthening phases, and optimization of interface structure through precise control of heat treatment parameters remains a technical challenge. Summary of the Invention

[0006] To address the problems in the prior art, this invention provides a hydrogen-resistant nickel-based single-crystal superalloy and its preparation method, which improves the elongation and reduction of area of ​​the nickel-based single-crystal superalloy after hydrogen charging.

[0007] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a nickel-based single-crystal superalloy resistant to hydrogen embrittlement, wherein the nickel-based single-crystal superalloy comprises, by weight percentage: 4.4wt%Cr, 8.9wt%Co, 2.0wt%Mo, 7.2wt%W, 6.8wt%Ta, 5.7wt%Al, 2.0wt%Re, 1.0wt%Nb, 0.1wt%Hf, 0.1wt%C, with the balance being Ni.

[0008] Secondly, the present invention provides a method for preparing a nickel-based single-crystal superalloy resistant to hydrogen embrittlement, comprising the following steps: S1. Weigh out the elemental raw materials Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C, and clean and dry the raw materials. S2. After the dried raw materials are smelted multiple times, a nickel-based single crystal high-temperature alloy master alloy ingot is obtained. S3. The nickel-based single crystal high-temperature alloy master alloy ingot is processed into a rod shape, and after cleaning and drying, it is heated to a preset temperature under an argon atmosphere and held at the preset temperature for a preset time. After cooling, a nickel-based single crystal high-temperature alloy test rod is obtained. S4. The nickel-based single crystal high-temperature alloy test rod is subjected to gradient solution heat treatment, and after cooling, a nickel-based single crystal high-temperature alloy test rod in a solid solution state is obtained. S5. Perform a first-stage aging heat treatment on the solid solution-state nickel-based single-crystal superalloy test bar to obtain the hydrogen-resistant nickel-based single-crystal superalloy.

[0009] Preferably, the mass ratio of the elemental Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C in S1 is 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1.

[0010] Preferably, the melting temperature of the raw materials in S2 is 1400~1600℃; and the melting time for each melting is 10~15min.

[0011] Preferably, after each melting in S2, the raw materials are cooled to room temperature and turned over before the next melting is carried out.

[0012] Preferably, the method described in S3 for heating to a preset temperature and holding at that temperature for a preset time is as follows: heating to 1600℃ at a heating rate of 20℃ / min and holding at 1600℃ for 60~80min.

[0013] Preferably, the gradient solution heat treatment method described in S4 is as follows: heating from room temperature to 1000-1100℃ at a heating rate of 8-10℃ / min, and holding at 1000-1100℃ for 10-15 min; then heating to 1280-1290℃ at a heating rate of 3-5℃ / min, and holding at 1280-1290℃ for 1-1.5 h; then heating to 1295-1300℃ at a heating rate of 1-2℃ / min, and holding at 1295-1300℃ for 2-2.5 h; finally heating to 1315℃ at a heating rate of 1-2℃ / min, and holding at 1315℃ for 4-5 h.

[0014] Preferably, the method for the first-stage aging heat treatment is as follows: the temperature is increased from room temperature to 1000-1050℃ at a heating rate of 8-10℃ / min, and held at 1000-1050℃ for 5-10 min, then increased to 1120℃ at a heating rate of 3-5℃ / min, and held at 1120℃ for 4-5 h, and then cooled to room temperature after the holding period.

[0015] Preferably, the method for the first-stage aging heat treatment is as follows: the temperature is increased from room temperature to 1000℃ at a heating rate of 10℃ / min, and held at 1000℃ for 10 min, then increased to 1120℃ at a heating rate of 5℃ / min, and held at 1120℃ for 4 h, and then cooled to room temperature after the holding period.

[0016] Preferably, the cooling method is air cooling.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention designs an excellent alloy composition by carefully adjusting the content of slow-diffusion elements such as Re, W, and Mo, as well as elements such as Ta, Nb, and Al. On the one hand, it utilizes refractory elements to effectively hinder the migration of hydrogen atoms and reduce their diffusion coefficient; on the other hand, it promotes a high volume fraction. The formation of the phase makes it an effective hydrogen trap to fix hydrogen atoms and prevent them from accumulating at grain boundaries or key interfaces, thus significantly improving the alloy's resistance to hydrogen embrittlement. Simultaneously, multiple vacuum melting processes ensure highly uniform composition of the parent alloy. High-quality, grain boundary-defect-free single-crystal specimens are obtained through precisely controlled directional solidification. Combined with a multi-stage gradient solution treatment and a first-stage aging heat treatment regime, micro-segregation is effectively eliminated, resulting in a fine-sized, uniformly distributed strengthening phase microstructure. This microstructure provides excellent high-temperature strength, and its uniformly distributed interfaces effectively trap hydrogen atoms, thus endowing the alloy with superior resistance to hydrogen embrittlement. Results show that the nickel-based single-crystal superalloy prepared by the method of this invention maintains high elongation and reduction of area after hydrogen charging, and its hydrogen embrittlement sensitivity is significantly lower than that of the solution-treated microstructure, exhibiting excellent comprehensive performance. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a microstructure diagram of the dendritic morphology of the nickel-based single-crystal superalloy test rod in Example 1; Figure 2 This is a partially enlarged view of the microstructure of the nickel-based single-crystal superalloy specimen in solid solution state, as shown in Example 1. Figure 3 This is a magnified view of the microstructure of the test bar after primary aging heat treatment in Example 1; Figure 4 This is a magnified view of the microstructure of the test bar after secondary aging heat treatment in Example 1; Figure 5 This is a tensile stress-strain curve of a nickel-based single-crystal superalloy specimen in solid solution state in Example 1, after being uncharged with hydrogen and after being charged with hydrogen for 72 hours, at room temperature with slow strain rate.

[0020] Figure 6 The figure shows the tensile stress-strain curves at room temperature and slow strain rate after the specimen under first-stage aging heat treatment in Example 1, without hydrogen charging and after 72 hours of hydrogen charging.

[0021] Figure 7 The figure shows the tensile stress-strain curves at slow strain rate at room temperature after the test bar under secondary aging heat treatment in Example 1, without hydrogen charging and after 72 hours of hydrogen charging.

[0022] Figure 8 The image shows the room temperature tensile fracture surface of the nickel-based single-crystal superalloy test bar in solid solution state of Example 1 after 72 hours of hydrogen charging.

[0023] Figure 9 The image shows the dislocation structure at the fracture surface of a nickel-based single-crystal superalloy specimen in solid solution state from Example 1 after being charged with hydrogen for 72 hours and then subjected to room temperature tensile testing. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0028] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings: The primary objective of this invention is to provide a hydrogen-resistant nickel-based single-crystal superalloy. This superalloy comprises, by mass percentage: 4.4 wt% Cr, 8.9 wt% Co, 2.0 wt% Mo, 7.2 wt% W, 6.8 wt% Ta, 5.7 wt% Al, 2.0 wt% Re, 1.0 wt% Nb, 0.1 wt% Hf, 0.1 wt% C, with the balance being Ni. Appropriate amounts of slow-diffusion elements such as Re, W, and Mo effectively hinder the migration and aggregation of hydrogen atoms within the crystal lattice, significantly reducing the hydrogen diffusion coefficient. Simultaneously, elements such as Ta, Nb, and Al promote a high volume fraction of hydrogen. The formation of these dispersed precipitates can act as efficient hydrogen traps, capturing and fixing hydrogen atoms and preventing them from accumulating at grain boundaries or phase interfaces to form stress concentrations. This inhibits the initiation and propagation of hydrogen-induced cracks from the source, allowing the alloy to maintain excellent mechanical properties and structural integrity in a hydrogen environment.

[0030] The second objective of this invention is to provide a method for preparing a nickel-based single-crystal superalloy resistant to hydrogen embrittlement, comprising the following steps: S1. Weigh the elemental raw materials Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C, and clean and dry the raw materials. S2. After the dried raw materials are smelted multiple times, a nickel-based single crystal high-temperature alloy master alloy ingot is obtained. S3. The nickel-based single crystal high-temperature alloy master alloy ingot is processed into a rod shape. After cleaning and drying, it is heated to a preset temperature under an argon atmosphere and held at the preset temperature for a preset time. After cooling, a nickel-based single crystal high-temperature alloy test rod is obtained. S4. The nickel-based single crystal high-temperature alloy test rod was subjected to gradient solution heat treatment and cooled to obtain a nickel-based single crystal high-temperature alloy test rod in a solid solution state. S5. The nickel-based single-crystal superalloy test bar in solid solution state is subjected to first-stage aging heat treatment to obtain a nickel-based single-crystal superalloy resistant to hydrogen embrittlement.

[0031] This invention utilizes a multi-stage vacuum melting process to significantly promote the full diffusion and homogenization of alloying elements, resulting in a highly homogeneous and dense master alloy ingot. This eliminates the risk of compositional segregation, paving the way for subsequent high-quality single crystal production. The crucial directional solidification step is performed under inert argon protection. By precisely controlling the heating temperature, holding time, and cooling process, single crystal specimens with consistent orientation and few defects are successfully prepared, eliminating rapid hydrogen diffusion pathways such as transverse grain boundaries. The subsequent multi-stage, graded solution heat treatment aims to fully dissolve the segregated phases generated during initial solidification and optimize the process. / Two-phase interface, for Uniform precipitation of the phase prepares an ideal matrix. Finally, a first-stage aging heat treatment precisely controls the precipitation. The size, morphology, distribution, and volume fraction of the phases enable them to form a controllable microstructure that can effectively hinder dislocation movement and enhance strength, while also serving as uniformly dispersed hydrogen capture centers to effectively adsorb hydrogen atoms and inhibit their enrichment. This fundamentally endows nickel-based single-crystal superalloys with excellent resistance to hydrogen embrittlement.

[0032] In S1, the mass ratio of elemental Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C is 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. This ratio ensures the formation of a high volume fraction of ordered compounds. This structure provides excellent high-temperature strength and effectively slows down the migration and aggregation of hydrogen atoms by introducing an appropriate amount of slow-diffusion elements. The specific ratio of refractory elements and solid-solution elements synergistically optimizes the crystal structure, which not only enhances the solid solution strengthening of the matrix but also significantly improves the interatomic bonding force, thereby effectively suppressing the initiation and propagation of hydrogen-induced cracks.

[0033] The raw materials in S2 are smelted at temperatures ranging from 1400 to 1600°C, with each smelting session lasting 10 to 15 minutes. Smelting within this temperature range ensures the complete melting and uniform diffusion of all high-melting-point metallic elements while preventing excessive volatilization of low-melting-point elements or melt contamination due to excessively high temperatures. After each smelting process, the raw materials are cooled to room temperature and turned over before the next smelting. This repeated remelting and solidification process greatly promotes the full diffusion and mixing of alloying elements, effectively eliminating potential component segregation and metallurgical defects from the initial smelting. This lays a foundation for high-purity materials with uniform composition and complete structure, which are then prepared by directional solidification.

[0034] The method for heating the S3 melt to a preset temperature and holding it at that temperature for a preset time is as follows: The temperature is increased to 1600℃ at a rate of 20℃ / min, and then held at 1600℃ for 60-80 minutes. This heating rate effectively avoids thermal stress cracks caused by excessively rapid heating, while also preventing abnormal grain growth or raw material oxidation caused by excessively slow heating. Heating the melt to 1600℃, a temperature far above the alloy's liquidus line, and holding it for 60-80 minutes ensures complete homogenization and sufficient overheating of the alloy melt, thereby thoroughly dissolving all primary phases and solidification segregation products.

[0035] The gradient solution heat treatment method in S4 is as follows: The temperature is increased from room temperature to 1000-1100℃ at a heating rate of 8-10℃ / min, and held at 1000-1100℃ for 10-15 min; then increased to 1280-1290℃ at a heating rate of 3-5℃ / min, and held at 1280-1290℃ for 1-1.5 h; then increased to 1295-1300℃ at a heating rate of 1-2℃ / min, and held at 1295-1300℃ for 2-2.5 h; finally, increased to 1315℃ at a heating rate of 1-2℃ / min, and held at 1315℃ for 4-5 h. This phased approach to the final solution temperature effectively avoids the risk of localized overheating of low-melting-point phases in the highly alloyed melt due to rapid heating, ensuring the integrity of the material structure. Precise temperature control at each specific temperature step provides the necessary kinetic conditions for the full diffusion of refractory elements (such as Re and W), gradually dissolving initial dendrite segregation and coarse grains. Phase. Finally, prolonged holding at 1315℃ completely eliminated microscopic segregation, resulting in a highly saturated and homogeneous single phase. The solid solution matrix is ​​used for subsequent aging treatment. The uniform and dispersed precipitation of the strengthening phase lays the ideal structural foundation, thereby fundamentally optimizing the alloy's microstructure against hydrogen embrittlement.

[0036] The first-stage aging heat treatment method is as follows: The temperature is increased from room temperature to 1000-1050℃ at a heating rate of 8-10℃ / min, held at 1000-1050℃ for 5-10 min, then increased to 1120℃ at a heating rate of 3-5℃ / min, and held at 1120℃ for 4-5 h. After the holding period, the temperature is cooled to room temperature. The rapid heating and medium-temperature holding in the initial stage effectively eliminate residual thermal stress that may exist after solution treatment, providing a stable microstructure for subsequent phase transformation. Subsequently, a slow heating to a high-temperature platform of 1120℃ and a long holding period are used to... The nucleation and growth of the phase created optimal thermodynamic conditions. This high-temperature aging process promoted... The phase precipitates uniformly at a moderate rate, forming a fine-sized, diffusely distributed, and well-coherent strengthening phase structure with the matrix. This optimized microstructure not only effectively hinders dislocation movement and improves strength, but also significantly enhances the alloy's ability to trap and fix hydrogen atoms by forming uniformly distributed interfacial hydrogen traps, thus endowing the alloy with excellent resistance to hydrogen embrittlement.

[0037] The cooling method is air cooling, which relies on the object to dissipate heat naturally in still or flowing air. Its cooling rate falls between slow furnace cooling and rapid water cooling, effectively suppressing the precipitation of coarse, brittle phases at high temperatures and avoiding the risk of workpiece deformation or cracking due to excessive quenching stress. During the air cooling process... The phase precipitates at a moderate rate, forming a uniformly sized and diffusely distributed array of reinforced phases. This structure can stably trap hydrogen atoms and effectively hinder their diffusion. Compared to more expensive processes such as controlled atmosphere cooling or oil quenching, air cooling is simple to operate, low in cost, and easy to scale up. While ensuring that the alloy obtains excellent resistance to hydrogen embrittlement and a stable microstructure, it significantly improves production efficiency and process reliability.

[0038] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0039] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0040] Example 1 Step 1: Weigh the raw materials containing elemental elements Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C in a mass ratio of 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. Clean the surface of the raw materials, then perform ultrasonic cleaning and dry them for later use.

[0041] Step 2: The cleaned and dried nickel-based single crystal high-temperature alloying raw material is put into a non-consumable vacuum arc melting furnace (vacuum degree 5×10). -3 The process involves several cleaning and vacuuming operations of the electric arc melting furnace (Pa); after the vacuuming is completed, the arc is ignited, the current is increased to raise the arc temperature, and melting begins; the melting temperature of the raw materials is 1400-1600℃, and each melting time is 10-15 minutes. After the raw materials cool down, they are turned over, and the above process is repeated to continue melting; the raw materials in the crucible are repeatedly melted multiple times to finally obtain the master alloy ingot of nickel-based single crystal high-temperature alloy.

[0042] Step 3: Based on the actual situation, the nickel-based single-crystal high-temperature alloy master alloy ingot is processed into rod-shaped samples by wire electrical discharge machining. The sample (10mm × 100mm) was ultrasonically cleaned, then cleaned with alcohol and dried. The cleaned and dried rod-shaped sample was then placed in a vacuum induction directional solidification furnace, which was evacuated. After the evacuation process, high-purity argon gas was introduced into the furnace for protection. The furnace equipment uses high-frequency electromagnetic induction heating; the induction coil generates an induced current that heats the graphite body, achieving the temperature rise through radiation. The furnace body is filled with Ga-25wt%In-13wt%Sn metal coolant, which rapidly cools the immersed sample. Heating was specifically performed using an induction coil. The initial voltage was 60V, and heating lasted 20 minutes. Afterward, the voltage was increased by 20V every 15 minutes, gradually increasing to 160V, raising the furnace body to 1600℃ at a rate of 20℃ / min. The sample was held at 1600℃ for 60 minutes, and then uniformly pulled out at a speed of 80μm / s, ultimately obtaining a nickel-based single-crystal high-temperature alloy sample rod. Step 4: Perform solution heat treatment on the nickel-based single-crystal superalloy test rod, specifically: heat from room temperature to 1000℃ at a heating rate of 10℃ / min and hold at 1000℃ for 10 min; then heat to 1290℃ at a heating rate of 5℃ / min and hold at 1290℃ for 1 h; then heat to 1300℃ at a heating rate of 2℃ / min and hold at 1300℃ for 2 h; finally heat to 1315℃ at a heating rate of 2℃ / min and hold at 1315℃ for 4 h. After cooling, a solution-treated nickel-based single-crystal superalloy test rod is obtained. Step 5: Place the solution-treated nickel-based single-crystal superalloy test bar into a vacuum heat treatment furnace and perform a first-stage aging heat treatment and a second-stage aging heat treatment in sequence. Specifically, the first-stage aging heat treatment involves heating from room temperature to 1000℃ at a heating rate of 10℃ / min, holding at 1000℃ for 5 min, then heating to 1120℃ at a heating rate of 5℃ / min, holding at 1120℃ for 4 h, and then air-cooling to room temperature after the holding period. The second-stage aging heat treatment involves heating from room temperature to 870℃ at a heating rate of 10℃ / min, holding at 870℃ for 32 h, and then air-cooling to room temperature after the holding period, to obtain a nickel-based single-crystal superalloy with precipitated phase dispersion strengthening and resistance to hydrogen embrittlement.

[0043] Example 2 Step 1: Weigh the raw materials containing elemental elements Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C in a mass ratio of 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. Clean the surface of the raw materials, then perform ultrasonic cleaning and dry them for later use.

[0044] Step 2: The cleaned and dried nickel-based single crystal high-temperature alloying raw material is put into a non-consumable vacuum arc melting furnace (vacuum degree 5×10). -3 The process involves several cleaning and vacuuming operations of the electric arc melting furnace (Pa); after the vacuuming is completed, the arc is ignited, the current is increased to raise the arc temperature, and melting begins; the melting temperature of the raw materials is 1400-1600℃, and each melting time is 10-15 minutes. After the raw materials cool down, they are turned over, and the above process is repeated to continue melting; the raw materials in the crucible are repeatedly melted multiple times to finally obtain the master alloy ingot of nickel-based single crystal high-temperature alloy.

[0045] Step 3: Based on the actual situation, the nickel-based single-crystal high-temperature alloy master alloy ingot is processed into rod-shaped samples by wire electrical discharge machining. The sample (10mm × 100mm) was ultrasonically cleaned, then cleaned with alcohol and dried. The cleaned and dried rod-shaped sample was then placed in a vacuum induction directional solidification furnace, which was evacuated. After the evacuation process, high-purity argon gas was introduced into the furnace for protection. The furnace equipment used high-frequency electromagnetic induction heating; the induction coil generated an induced current to heat the graphite body, achieving the temperature rise through radiation. The furnace body was filled with Ga-25wt%In-13wt%Sn metal coolant, which could rapidly cool the immersed sample. Heating was specifically performed through the induction coil, with an initial voltage of 60V for 20 minutes. The voltage was then increased by 20V every 15 minutes thereafter, gradually increasing to 160V, raising the furnace body to 1600℃ at a rate of 20℃ / min. This temperature was then held at 1600℃ for 65 minutes, and then uniformly pulled out at a speed of 80μm / s, ultimately obtaining a nickel-based single-crystal high-temperature alloy sample rod. Step 4: Perform solution heat treatment on the nickel-based single-crystal superalloy test rod, specifically: heat from room temperature to 1020℃ at a heating rate of 8℃ / min and hold at 1020℃ for 11 min; then heat to 1290℃ at a heating rate of 5℃ / min and hold at 1290℃ for 1 h; then heat to 1300℃ at a heating rate of 2℃ / min and hold at 1300℃ for 2 h; finally heat to 1315℃ at a heating rate of 2℃ / min and hold at 1315℃ for 4 h. After cooling, a solution-treated nickel-based single-crystal superalloy test rod is obtained. Step 5: Place the solution-treated nickel-based single-crystal superalloy test bar into a vacuum heat treatment furnace and perform a first-stage aging heat treatment and a second-stage aging heat treatment in sequence. Specifically, the first-stage aging heat treatment involves heating from room temperature to 1010℃ at a heating rate of 9℃ / min, holding at 1010℃ for 6 min, then heating to 1120℃ at a heating rate of 5℃ / min, holding at 1120℃ for 4 h, and then air-cooling to room temperature after the holding period. The second-stage aging heat treatment involves heating from room temperature to 870℃ at a heating rate of 10℃ / min, holding at 870℃ for 32 h, and then air-cooling to room temperature after the holding period, to obtain a nickel-based single-crystal superalloy with precipitated phase dispersion strengthening and resistance to hydrogen embrittlement.

[0046] Example 3 Step 1: Weigh the raw materials containing elemental elements Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C in a mass ratio of 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. Clean the surface of the raw materials, then perform ultrasonic cleaning and dry them for later use.

[0047] Step 2: The cleaned and dried nickel-based single crystal high-temperature alloying raw material is put into a non-consumable vacuum arc melting furnace (vacuum degree 5×10). -3The process involves several cleaning and vacuuming operations of the electric arc melting furnace (Pa); after the vacuuming is completed, the arc is ignited, the current is increased to raise the arc temperature, and melting begins; the melting temperature of the raw materials is 1400-1600℃, and each melting time is 10-15 minutes. After the raw materials cool down, they are turned over, and the above process is repeated to continue melting; the raw materials in the crucible are repeatedly melted multiple times to finally obtain the master alloy ingot of nickel-based single crystal high-temperature alloy.

[0048] Step 3: Based on the actual situation, the nickel-based single-crystal high-temperature alloy master alloy ingot is processed into rod-shaped samples by wire electrical discharge machining. The sample (10mm × 100mm) was ultrasonically cleaned, then cleaned with alcohol and dried. The cleaned and dried rod-shaped sample was then placed in a vacuum induction directional solidification furnace, which was evacuated. After the evacuation process, high-purity argon gas was introduced into the furnace for protection. The furnace equipment used high-frequency electromagnetic induction heating; the induction coil generated an induced current to heat the graphite body, achieving the temperature rise through radiation. The furnace body was filled with Ga-25wt%In-13wt%Sn metal coolant, which could rapidly cool the immersed sample. Heating was specifically performed through the induction coil, with an initial voltage of 60V for 20 minutes. The voltage was then increased by 20V every 15 minutes thereafter, gradually increasing to 160V, raising the furnace body to 1600℃ at a rate of 20℃ / min. This temperature was then held at 1600℃ for 70 minutes, and then uniformly pulled out at a speed of 80μm / s, ultimately obtaining a nickel-based single-crystal high-temperature alloy sample rod. Step 4: Perform solution heat treatment on the nickel-based single-crystal superalloy test rod, specifically: heat from room temperature to 1050℃ at a heating rate of 8.5℃ / min and hold at 1050℃ for 12 min; then heat to 1290℃ at a heating rate of 5℃ / min and hold at 1290℃ for 1 h; then heat to 1300℃ at a heating rate of 2℃ / min and hold at 1300℃ for 2 h; finally heat to 1315℃ at a heating rate of 2℃ / min and hold at 1315℃ for 4 h. After cooling, a solution-treated nickel-based single-crystal superalloy test rod is obtained. Step 5: Place the solution-treated nickel-based single-crystal superalloy test bar into a vacuum heat treatment furnace and perform a first-stage aging heat treatment and a second-stage aging heat treatment in sequence. Specifically, the first-stage aging heat treatment involves heating from room temperature to 1020℃ at a heating rate of 9℃ / min, holding at 1020℃ for 8 min, then heating to 1120℃ at a heating rate of 4℃ / min, holding at 1120℃ for 4.5 h, and then air-cooling to room temperature after the holding period. The second-stage aging heat treatment involves heating from room temperature to 880℃ at a heating rate of 9℃ / min, holding at 880℃ for 34 h, and then air-cooling to room temperature after the holding period, to obtain a nickel-based single-crystal superalloy with precipitated phase dispersion strengthening and resistance to hydrogen embrittlement.

[0049] Example 4 Step 1: Weigh the raw materials containing elemental elements Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C in a mass ratio of 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. Clean the surface of the raw materials, then perform ultrasonic cleaning and dry them for later use.

[0050] Step 2: The cleaned and dried nickel-based single crystal high-temperature alloying raw material is put into a non-consumable vacuum arc melting furnace (vacuum degree 5×10). -3 The process involves several cleaning and vacuuming operations of the electric arc melting furnace (Pa); after the vacuuming is completed, the arc is ignited, the current is increased to raise the arc temperature, and melting begins; the melting temperature of the raw materials is 1400-1600℃, and each melting time is 10-15 minutes. After the raw materials cool down, they are turned over, and the above process is repeated to continue melting; the raw materials in the crucible are repeatedly melted multiple times to finally obtain the master alloy ingot of nickel-based single crystal high-temperature alloy.

[0051] Step 3: Based on the actual situation, the nickel-based single-crystal high-temperature alloy master alloy ingot is processed into rod-shaped samples by wire electrical discharge machining. The sample (10mm × 100mm) was ultrasonically cleaned, then cleaned with alcohol and dried. The cleaned and dried rod-shaped sample was then placed in a vacuum induction directional solidification furnace, which was evacuated. After the evacuation process, high-purity argon gas was introduced into the furnace for protection. The furnace equipment used high-frequency electromagnetic induction heating; the induction coil generated an induced current to heat the graphite body, achieving the temperature rise through radiation. The furnace body was filled with Ga-25wt%In-13wt%Sn metal coolant, which could rapidly cool the immersed sample. Heating was specifically performed through the induction coil, with an initial voltage of 60V for 20 minutes. The voltage was then increased by 20V every 15 minutes thereafter, gradually increasing to 160V, raising the furnace body to 1600℃ at a rate of 20℃ / min. This temperature was then held at 1600℃ for 75 minutes, and then uniformly pulled out at a speed of 80μm / s, ultimately obtaining a nickel-based single-crystal high-temperature alloy sample rod. Step 4: Perform solution heat treatment on the nickel-based single-crystal superalloy test rod, specifically: heat from room temperature to 1080℃ at a heating rate of 9℃ / min and hold at 1080℃ for 14 min; then heat to 1285℃ at a heating rate of 4℃ / min and hold at 1285℃ for 1.5 h; then heat to 1295℃ at a heating rate of 1℃ / min and hold at 1295℃ for 2.5 h; finally heat to 1315℃ at a heating rate of 1.5℃ / min and hold at 1315℃ for 4.5 h. After cooling, a solution-treated nickel-based single-crystal superalloy test rod is obtained. Step 5: Place the solution-treated nickel-based single-crystal superalloy test bar into a vacuum heat treatment furnace and perform a first-stage aging heat treatment and a second-stage aging heat treatment in sequence. Specifically, the first-stage aging heat treatment involves heating from room temperature to 1040℃ at a heating rate of 10℃ / min, holding at 1040℃ for 8 min, then heating to 1120℃ at a heating rate of 4℃ / min, holding at 1120℃ for 4.5 h, and then air-cooling to room temperature after the holding period. The second-stage aging heat treatment involves heating from room temperature to 890℃ at a heating rate of 8℃ / min, holding at 890℃ for 36 h, and then air-cooling to room temperature after the holding period, to obtain a nickel-based single-crystal superalloy with precipitated phase dispersion strengthening and resistance to hydrogen embrittlement.

[0052] Example 5 Step 1: Weigh the raw materials containing elemental elements Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf, and C in a mass ratio of 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.1. Clean the surface of the raw materials, then perform ultrasonic cleaning and dry them for later use.

[0053] Step 2: The cleaned and dried nickel-based single crystal high-temperature alloying raw material is put into a non-consumable vacuum arc melting furnace (vacuum degree 5×10). -3 The process involves several cleaning and vacuuming operations of the electric arc melting furnace (Pa); after the vacuuming is completed, the arc is ignited, the current is increased to raise the arc temperature, and melting begins; the melting temperature of the raw materials is 1400-1600℃, and each melting time is 10-15 minutes. After the raw materials cool down, they are turned over, and the above process is repeated to continue melting; the raw materials in the crucible are repeatedly melted multiple times to finally obtain the master alloy ingot of nickel-based single crystal high-temperature alloy.

[0054] Step 3: Based on the actual situation, the nickel-based single-crystal high-temperature alloy master alloy ingot is processed into rod-shaped samples by wire electrical discharge machining. The sample (10mm × 100mm) was ultrasonically cleaned, then cleaned with alcohol and dried. The cleaned and dried rod-shaped sample was then placed in a vacuum induction directional solidification furnace, which was evacuated. After the evacuation process, high-purity argon gas was introduced into the furnace for protection. The furnace equipment uses high-frequency electromagnetic induction heating; the induction coil generates an induced current that heats the graphite body, achieving the temperature rise through radiation. The furnace body is filled with Ga-25wt%In-13wt%Sn metal coolant, which rapidly cools the immersed sample. Heating was specifically performed via induction coil heating. The initial voltage was 60V, and heating lasted 20 minutes. The voltage was then increased by 20V every 15 minutes until reaching 160V, allowing the furnace body to heat to 1600℃ at a rate of 20℃ / min. This temperature was maintained at 1600℃ for 80 minutes, and then the sample was uniformly pulled out at a speed of 80μm / s, ultimately yielding a nickel-based single-crystal high-temperature alloy rod. Step 4: Perform solution heat treatment on the nickel-based single-crystal superalloy test rod, specifically: heat from room temperature to 1100℃ at a heating rate of 9.5℃ / min and hold at 1100℃ for 15 min; then heat to 1280℃ at a heating rate of 3℃ / min and hold at 1280℃ for 1.5 h; then heat to 1295℃ at a heating rate of 1℃ / min and hold at 1295℃ for 2.5 h; finally heat to 1315℃ at a heating rate of 1℃ / min and hold at 1315℃ for 5 h. After cooling, a solution-treated nickel-based single-crystal superalloy test rod is obtained. Step 5: Place the solution-treated nickel-based single-crystal superalloy test bar into a vacuum heat treatment furnace and perform a first-stage aging heat treatment and a second-stage aging heat treatment in sequence. Specifically, the first-stage aging heat treatment involves heating from room temperature to 1050℃ at a heating rate of 8℃ / min, holding at 1050℃ for 10 min, then heating to 1120℃ at a heating rate of 3℃ / min, holding at 1120℃ for 5 h, and then air-cooling to room temperature after the holding period. The second-stage aging heat treatment involves heating from room temperature to 890℃ at a heating rate of 8℃ / min, holding at 890℃ for 36 h, and then air-cooling to room temperature after the holding period, to obtain a nickel-based single-crystal superalloy with precipitated phase dispersion strengthening and resistance to hydrogen embrittlement.

[0055] The performance of the nickel-based single-crystal superalloy prepared in Example 1 was tested, and the results are as follows: The microstructure of the nickel-based single-crystal superalloy test bar after surface treatment is as follows: Figure 1 As shown, a distinct dendritic structure is observed, with clear distinction between dendrite trunks and dendrites, indicating severe elemental segregation. The microstructure of the solid-solution nickel-based single-crystal superalloy specimen is shown below. Figure 2 As shown, you can see a butterfly-shaped... Phase, accounting for 49.45%, with the remaining light-colored base being... Mutually.

[0056] For rod-shaped samples obtained by wire electrical discharge machining, hydrogen was charged using an electrochemical workstation. The solutions used included 0.5 mol / L H₂SO₄ and 2 g / L CH₄N₂S solution. A three-electrode hydrogen charging method was employed, with the stretched sample connected to the negative terminal of the power supply, a saturated calomel electrode as the reference electrode, and a 99.99% pure platinum sheet connected to the positive terminal. The current density selected during the experiment was 20 mA / cm². 2 The samples without hydrogen charging and those charged with hydrogen for 72 hours were subjected to slow strain rate tensile tests at room temperature, with a strain rate of 1×10⁻⁶. -4 The obtained stress-strain curve is as follows: Figure 5 As shown, the following data were obtained: elongation after fracture was 15.42% and 6.31%; reduction of area was 23.90% and 16.28%. Combined with the experimental data, it was found that the elongation after fracture of the alloy decreased by 9.11% after hydrogen charging, a decrease of 59.08%. The fracture surface images of the tensile specimens after hydrogen charging are shown below. Figure 8 , Figure 9 As shown, the fracture sample exhibits a large number of planar and step-like morphologies, with numerous dislocation slip lines distributed on the planar surfaces, and multiple cracks can be observed at the step transition points. and Numerous dislocation tangles were observed at the phase interface, indicating high stress and potential defect sites. Overall, the alloy exhibits a significant decrease in plasticity after hydrogen charging, and severe hydrogen embrittlement is observed in the solution-treated specimens. The microstructure of the specimen after first-stage aging heat treatment is shown below. Figure 3 As shown, The phase is irregular in shape and accounts for 63.64% of the total. After 72 hours of electrochemical hydrogen charging and a room temperature slow strain rate tensile test, the stress-strain curve is as follows. Figure 6 As shown, the elongation after fracture was 14.75% and 12.51%, respectively, and the reduction of area was 24.67% and 22.22%, respectively. Under this process, the elongation after fracture of the alloy decreased by 2.24%, accounting for 15.19%. The microstructure of the test bar after secondary aging heat treatment is as follows... Figure 4 As shown, it is cubic in shape. Phase organization, The phase ratio was 79.97%, and after 72 hours of electrochemical hydrogen charging, tensile tests were performed on the two types of samples before and after hydrogen charging. The stress-strain curves are as follows. Figure 7 As shown, its elongation after fracture is 19.59% and 14.40%, and its reduction of area is 35.38% and 28.57%. Under this treatment process, the elongation after fracture of the alloy decreased by 5.19%, with a ratio of 26.49%. Its resistance to hydrogen embrittlement is slightly better than that of solid solution nickel-based single crystal superalloys, but weaker than that of nickel-based single crystal superalloys in the first-stage aging state.

[0057] In summary, the specimens after first-stage aging heat treatment showed the smallest decrease in elongation and reduction of area, indicating that their resistance to hydrogen embrittlement was the best among the three microstructures. The specimens after second-stage aging heat treatment were the second best, while the solution-treated nickel-based single-crystal superalloy exhibited the worst resistance to hydrogen embrittlement. This invention discloses... The proportion and morphology of the phases, once they reach a certain level, will weaken the alloy's resistance to hydrogen embrittlement. The alloy's resistance to hydrogen embrittlement decreases as the proportion and morphology of the phases change. The proportional increase showed a phenomenon of first rising and then falling.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nickel-based single-crystal superalloy resistant to hydrogen embrittlement, characterized in that, The hydrogen-resistant nickel-based single-crystal superalloy comprises, by weight percentage: 4.4wt% Cr, 8.9wt% Co, 2.0wt% Mo, 7.2wt% W, 6.8wt% Ta, 5.7wt% Al, 2.0wt% Re, 1.0wt% Nb, 0.1wt% Hf, 0.1wt% C, with the balance being Ni.

2. A method for preparing a nickel-based single-crystal superalloy resistant to hydrogen embrittlement, characterized in that, Includes the following steps: S1. Weigh out the elemental raw materials Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C, and clean and dry the raw materials. S2. After the dried raw materials are smelted multiple times, a nickel-based single crystal high-temperature alloy master alloy ingot is obtained. S3. The nickel-based single crystal high-temperature alloy master alloy ingot is processed into a rod shape, and after cleaning and drying, it is heated to a preset temperature under an argon atmosphere and held at the preset temperature for a preset time. After cooling, a nickel-based single crystal high-temperature alloy test rod is obtained. S4. The nickel-based single crystal high-temperature alloy test rod is subjected to gradient solution heat treatment, and after cooling, a nickel-based single crystal high-temperature alloy test rod in solid solution state is obtained. S5. Perform a first-stage aging heat treatment on the solid solution-state nickel-based single-crystal superalloy test bar to obtain the hydrogen-resistant nickel-based single-crystal superalloy.

3. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, The mass ratio of Ni, Cr, Co, Mo, W, Ta, Al, Re, Nb, Hf and C in S1 is 61.8:4.4:8.9:2:7.2:6.8:5.7:2:1:0.1:0.

1.

4. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, The melting temperature of the raw materials mentioned in S2 is 1400~1600℃; the melting time for each melting is 10~15min.

5. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, After each melting process in S2, the raw materials are cooled to room temperature and turned over before the next melting process.

6. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, The method described in S3 for heating to a preset temperature and holding at that temperature for a preset time is as follows: heating to 1600℃ at a heating rate of 20℃ / min and holding at 1600℃ for 60~80min.

7. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, The gradient solution heat treatment method described in S4 is as follows: the temperature is increased from room temperature to 1000-1100℃ at a heating rate of 8-10℃ / min, and held at 1000-1100℃ for 10-15 min; then the temperature is increased to 1280-1290℃ at a heating rate of 3-5℃ / min, and held at 1280-1290℃ for 1-1.5 h; then the temperature is increased to 1295-1300℃ at a heating rate of 1-2℃ / min, and held at 1295-1300℃ for 2-2.5 h; finally, the temperature is increased to 1315℃ at a heating rate of 1-2℃ / min, and held at 1315℃ for 4-5 h.

8. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 2, characterized in that, The method for the first-stage aging heat treatment is as follows: the temperature is increased from room temperature to 1000-1050℃ at a heating rate of 8-10℃ / min, and held at 1000-1050℃ for 5-10 min. Then, the temperature is increased to 1120℃ at a heating rate of 3-5℃ / min, and held at 1120℃ for 4-5 h. After the holding period, the temperature is cooled to room temperature.

9. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 8, characterized in that, The method for the first-stage aging heat treatment is as follows: the temperature is increased from room temperature to 1000℃ at a heating rate of 10℃ / min, and held at 1000℃ for 10 min. Then, the temperature is increased to 1120℃ at a heating rate of 5℃ / min, and held at 1120℃ for 4 h. After the holding period, the temperature is cooled to room temperature.

10. The method for preparing a hydrogen-embrittled nickel-based single-crystal superalloy according to claim 8, characterized in that, The cooling method is air cooling.

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