A high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy and preparation method thereof

Abstract

The invention discloses a high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy and a preparation method thereof, belonging to the field of advanced nonferrous metal materials. The main elements of the tungsten-based alloy are tungsten and rhenium, and the specific components are calculated by mass percentage: 5-23% rhenium, 0.02-4% molybdenum, 0.05-3% tantalum, 0.04-3% niobium, 0.03-2% vanadium, 0.02-0.5% nickel, 0.02-0.9% cobalt, 0.02-0.6% iridium, and the balance is tungsten. The preparation process adopts a high-pressure and rapid temperature rise and fall method to induce the alloy to produce more obvious lattice distortion, promote the rapid solid solution of multiple alloy elements, and realize the non-equilibrium sintering of the target component. The present invention synergistically reduces the intrinsic hydrogen solubility, hydrogen diffusion coefficient and brittle hydride formation tendency of the tungsten-based alloy by regulating the alloy composition and structure and designing the sintering process, and realizes the high-temperature hydrogen embrittlement resistance of the tungsten-based alloy by single-phase solid solution strengthening. At the same time, there is no second phase in the alloy, which effectively avoids the enrichment of hydrogen atoms at the interface between the second phase particles and the matrix, greatly reduces the crack source of hydrogen embrittlement failure of the material at high temperature, and can meet the service requirements of hydrogen metallurgical nozzles under high temperature and hydrogen-rich conditions.

Description

Technical Field

[0001] The invention relates to the field of advanced nonferrous metal materials, and in particular to a high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy and a preparation method thereof. Background Art

[0002] Hydrogen metallurgy technology is a new technology that uses hydrogen to replace carbon as a reducing agent in the process of steel smelting. Hydrogen metallurgy mainly produces water during the reduction process, which can reduce carbon dioxide emissions from long-process steelmaking. At present, hydrogen metallurgy technology still faces some challenges in its application. The nozzle is the most critical component of hydrogen metallurgy. It needs to work for a long time in high temperature, high tensile stress and hydrogen-rich atmosphere, and will face serious hydrogen embrittlement problems. In a hydrogen-rich environment, hydrogen atoms will be adsorbed and diffused into the metal, and will gather at the phase interface, grain boundary, dislocation and pores, microcracks and other locations, which will reduce the strength of the metal lattice and fracture energy, accelerate the movement of local dislocations, and promote the formation of vacancies and nanopores, which greatly reduces the ductility and strength of the metal material and makes the metal material embrittled. At present, there is no high-temperature hydrogen embrittlement-resistant alloy material suitable for the production of hydrogen metallurgical nozzles, and the current mainstream method to improve the hydrogen embrittlement resistance of metal materials is to introduce dispersed nano-precipitated phases in the material as irreversible hydrogen traps to adsorb hydrogen atoms and inhibit hydrogen diffusion. However, the interface between the dispersed precipitate phase and the matrix provides more reversible and irreversible hydrogen traps. When faced with harsh working conditions such as high temperature, high tensile stress and hydrogen-rich atmosphere, hydrogen atoms will quickly accumulate at the interface between the dispersed particles and the matrix, thus becoming the crack source of hydrogen embrittlement failure. Therefore, it is urgent to develop a single-phase solid solution-strengthened high-temperature hydrogen embrittlement-resistant alloy material without a second phase.

[0003] Tungsten has an intrinsic hydrogen diffusion coefficient far lower than that of other high-temperature alloys, and has an extremely high melting point (3410°C), hardness and excellent high-temperature strength. It is the most promising high-temperature hydrogen embrittlement-resistant material. However, tungsten is brittle at room temperature and is prone to cracks and defects, which limits its application in wide temperature ranges and hydrogen environments. Through alloying design, adding some solid solution alloying elements, such as rhenium, molybdenum, tantalum, niobium, etc., can improve the toughness and ductility of tungsten and reduce its brittleness problem while maintaining a single-phase structure. At the same time, it can further improve the high-temperature mechanical properties of tungsten, enhance its intrinsic hydrogen embrittlement resistance, and extend its service life in high-temperature hydrogen-rich environments. Chinese patent document No. CN117004857A discloses a high-strength and toughness tungsten alloy and a preparation method thereof. The tungsten alloy contains solid solution elements such as tungsten, rhenium, and molybdenum, and has high strength and toughness. However, the tungsten alloy contains a dispersed second phase of titanium oxide, which is prone to hydrogen embrittlement failure in high-temperature, hydrogen-rich environments. Chinese patent document No. CN117778858A discloses a high entropy alloy containing tungsten, molybdenum and tantalum and a preparation method thereof. The alloy has a single phase structure and has excellent radiation resistance. However, the alloy is an equimolar high entropy alloy and has not been optimized for high-temperature hydrogen embrittlement resistance. The tantalum content is too high (20-50%) and it does not contain rhenium, so it is prone to embrittlement in a high-temperature hydrogen environment. Summary of the invention

[0004] The purpose of the present invention is to provide a high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, solve the problem of insufficient high-temperature hydrogen embrittlement resistance of existing dispersed second-phase alloy materials, and meet the service requirements of hydrogen metallurgical nozzles. The specific technical solution is as follows:

[0005] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy. The alloy components are as follows by mass percentage: 5-23% rhenium, 0.02-4% molybdenum, 0.05-3% tantalum, 0.04-3% niobium, 0.03-2% vanadium, 0.02-0.5% nickel, 0.02-0.9% cobalt, 0.02-0.6% iridium, and the balance is tungsten.

[0006] Furthermore, the alloy composition is calculated by mass percentage as follows: 8-19% rhenium, 0.5-3% molybdenum, 0.1-2% tantalum, 0.1-3% niobium, 0.07-1.5% vanadium, 0.1-0.4% nickel, 0.1-0.5% cobalt, 0.04-0.6% iridium, and the balance is tungsten.

[0007] Furthermore, the alloy composition is calculated by mass percentage as follows: 10-17% rhenium, 0.8-2.6% molybdenum, 0.15-1.7% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.1-0.6% iridium, and the balance is tungsten.

[0008] Furthermore, the preparation method of the above-mentioned high temperature hydrogen embrittlement resistant tungsten-based alloy for hydrogen metallurgy comprises the following steps:

[0009] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0010] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering or vacuum induction sintering. The sintering pressure is 500MPa-1500MPa, the heating rate is 230-500℃ / min, the temperature is increased to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling, and the cooling rate is 80-140℃ / min, and finally a high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy is obtained.

[0011] Furthermore, the aforementioned alloy is used in hydrogen metallurgical nozzles.

[0012] The high-temperature hydrogen embrittlement-resistant tungsten-based alloy of the present invention is a single-phase solid solution alloy with a room temperature tensile strength of not less than 600MPa and an elongation of not less than 10.0%, a tensile strength of not less than 300MPa and an elongation of not less than 10.0% at 800°C, and a tensile strength of not less than 280MPa and an elongation of not less than 6.0% at 800°C of the sample after high-temperature gas-phase hydrogenation, and a hydrogen embrittlement sensitivity index (HEI) of not more than 39% at 800°C.

[0013] The tungsten content in the alloy of the present invention is not less than 63%. The hydrogen diffusion coefficient of tungsten in the hydrogen metallurgical process temperature range of 600-1000°C is several orders of magnitude lower than that of high-temperature metals such as molybdenum, tantalum, niobium, vanadium, and nickel. As the matrix of the alloy, the diffusion of hydrogen into the alloy under high temperature of hydrogen metallurgy is greatly reduced, and the intrinsic hydrogen diffusion coefficient of the alloy is reduced to the greatest extent.

[0014] The present invention uses rhenium as the second highest element, and together with tungsten, it forms the main element of the alloy. Rhenium and tungsten have similar physical and chemical properties and atomic structures. The two can form a single-phase solid solution alloy with a body-centered cubic structure within a certain composition range. Due to the existence of the "rhenium effect", the tungsten-rhenium alloy overcomes the problem of tungsten brittleness at room temperature and low temperature, and has high melting point, high strength, high plasticity, low plastic brittle transition temperature and more excellent high-temperature mechanical properties. More importantly, the present invention uses rhenium as the main additive element, which can effectively improve the hydrogen solution energy (H solution energies) of the tungsten-based alloy. With the increase of rhenium content, the hydrogen solution energy of the alloy is further improved, making it difficult for hydrogen to enter the face-centered cubic alloy, thereby reducing the concentration of hydrogen in the alloy, which is beneficial to inhibiting hydrogen embrittlement and meeting the performance requirements of hydrogen metallurgical nozzles; for this reason, the rhenium content of the present invention is 5-23%, not more than 23%, which can effectively maintain the single-phase body-centered cubic structure of the alloy and the phase stability after multi-element alloying, ensuring that the alloy has good hydrogen resistance and hydrogen resistance while maintaining a single-phase structure.

[0015] On the other hand, the addition of rhenium will reduce the hydrogen migration barrier (H migration barrier) of tungsten-based alloys and increase the hydrogen diffusion coefficient of the alloy. In order to further optimize the high-temperature hydrogen embrittlement resistance of tungsten-based alloys, the present invention controls the crystal structure by controlling the multi-component alloy components, thereby reducing the hydrogen diffusion coefficient of the alloy after multi-component solid solution. To this end, the present invention adds tantalum, niobium, vanadium, and cobalt as solid solution elements to diversify the single-phase alloy, and further determines their contents to be 0.05~3%, 0.04~3%, 0.03~2%, and 0.02-0.9%, respectively, to construct a diversified chemical environment inside the alloy crystal, causing lattice distortion of the alloy, destroying the lattice symmetry, hindering the hydrogen migration channel, and increasing the hydrogen migration barrier, and ultimately reducing the hydrogen diffusion coefficient of the alloy. In addition, in order to inhibit the formation of brittle hydrides in the alloy, the present invention adds alloying elements of 0.02-4% molybdenum, 0.02-0.5% nickel, and 0.02-0.6% iridium to reduce the hydride formation enthalpy of the multi-component alloy at high temperature, making it difficult for brittle hydrides to form in the alloy, thereby further improving the high-temperature hydrogen embrittlement resistance of the alloy.

[0016] The preparation process of the present invention adopts a high sintering pressure of 500MPa to 1500MPa. By increasing the sintering pressure, the strain in the sintered body is increased, and the aforementioned alloy diversification strategy is coordinated to induce a more obvious lattice distortion, thereby increasing the hydrogen migration barrier and further reducing the hydrogen diffusion coefficient of the alloy. At the same time, the sintering adopts rapid heating and cooling, with a heating rate of 230 to 500°C / min and a cooling rate of 80 to 140°C / min, which shortens the sintering time, promotes the rapid solid solution of multiple alloy elements, realizes the non-equilibrium sintering of the target composition, and obtains a multi-element single-phase tungsten-based alloy with excellent intrinsic high-temperature hydrogen embrittlement resistance.

[0017] The technical solution of the present invention has the following advantages:

[0018] 1. The high-temperature hydrogen embrittlement-resistant tungsten-based alloy of the present invention is a single-phase solid solution alloy without a second phase in the alloy, which can avoid the enrichment of hydrogen atoms at the interface between the second phase particles and the matrix under hydrogen metallurgical conditions, which greatly reduces the crack source of hydrogen embrittlement failure of the material at high temperature, thereby reducing the hydrogen embrittlement failure tendency of the alloy at high temperature, and can meet the service requirements of hydrogen metallurgical nozzles;

[0019] 2. The high-temperature hydrogen embrittlement-resistant tungsten-based alloy of the present invention has tungsten and rhenium as the main elements, and contains a certain amount of high-temperature metal elements such as molybdenum, tantalum, niobium, vanadium, nickel, cobalt, iridium, etc., which improves the toughness and ductility of the tungsten matrix and alleviates its brittleness problem. At the same time, the alloy has a high temperature resistance grade and excellent high-temperature mechanical properties, and can serve for a long time in hydrogen metallurgical conditions;

[0020] 3. The high-temperature hydrogen embrittlement-resistant tungsten-based alloy of the present invention comprehensively improves the alloy's intrinsic resistance to hydrogen diffusion, hydrogen dissolution and inhibition of brittle hydride formation by means of multi-element alloy solid solution strengthening. It does not rely on the complex microstructure in the alloy. All alloy elements have strong single-phase forming ability and can adapt to a variety of preparation processes, including powder metallurgy, smelting, additive manufacturing, etc., and can prepare single-phase tungsten-based alloys with good intrinsic high-temperature hydrogen embrittlement resistance.

[0021] 4. The high-temperature hydrogen embrittlement-resistant tungsten-based alloy of the present invention adopts high-pressure sintering and rapid temperature rise and fall sintering, which can induce more obvious lattice distortion in the alloy during the preparation process, promote rapid solid solution of multiple alloy elements, achieve non-equilibrium sintering of the target composition, and obtain a multi-component single-phase tungsten-based alloy with excellent intrinsic high-temperature hydrogen embrittlement resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XRD pattern of the tungsten-based alloy prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0024] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is as follows by mass percentage: 10-17% rhenium, 0.8-2.6% molybdenum, 0.15-1.7% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6% iridium, and the balance is tungsten;

[0025] The preparation method comprises the following steps:

[0026] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0027] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 100MPa-1500MPa. The heating rate is 400-500℃ / min. The temperature is raised to 2200-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling. The cooling rate is 100-140℃ / min to finally obtain a tungsten-based alloy.

[0028] X-ray diffraction (XRD) analysis was performed on it, such as Figure 1 As shown, it can be seen that the alloy is a body-centered cubic (bcc) solid solution;

[0029] The tensile properties of the tungsten-based alloy of Example 1 were tested, and the room temperature tensile strength was 660 MPa, and the elongation after fracture was 15.4%. The tensile strength at 800°C was 360 MPa, and the elongation after fracture was 11.2%.

[0030] The tungsten-based alloy of Example 1 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 310 MPa, the elongation after fracture was 7.1%, and the hydrogen embrittlement sensitivity index (HEI) was 36.6%. Example 2

[0031] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is calculated by mass percentage: 6-12% rhenium, 0.8-2.6% molybdenum, 0.15-1.7% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6% iridium, and the balance is tungsten;

[0032] The preparation method comprises the following steps:

[0033] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0034] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 500MPa-1000MPa. The heating rate is 230-400℃ / min. The temperature is raised to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling. The cooling rate is 80-140℃ / min to finally obtain a tungsten-based alloy.

[0035] The tensile properties of the tungsten-based alloy of Example 2 were tested, and the room temperature tensile strength was 640 MPa, and the elongation after fracture was 15.2%. The tensile strength at 800°C was 350 MPa, and the elongation after fracture was 10.2%.

[0036] The tungsten-based alloy of Example 2 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 295 MPa, the elongation after fracture was 6.2%, and the hydrogen embrittlement sensitivity index (HEI) was 39%. Example 3

[0037] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is as follows by mass percentage: 20-23% rhenium, 0.8-2.6% molybdenum, 0.5-2% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6% iridium, and the balance is tungsten;

[0038] The preparation method comprises the following steps:

[0039] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0040] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum induction sintering. The sintering pressure is 500MPa-1200MPa, the heating rate is 230-500℃ / min, the temperature is raised to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling, and the cooling rate is 80-120℃ / min to finally obtain a tungsten-based alloy.

[0041] The tensile properties of the tungsten-based alloy of Example 3 were tested, and the room temperature tensile strength was 604 MPa, and the elongation after fracture was 13.3%. The tensile strength at 800°C was 300 MPa, and the elongation after fracture was 10.1%.

[0042] The tungsten-based alloy of Example 3 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 260 MPa, the elongation after fracture was 6.3%, and the hydrogen embrittlement sensitivity index (HEI) was 38%.

[0043] Comparative Example 1

[0044] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is as follows by mass percentage: 1-2% rhenium, 0.8-2.6% molybdenum, 0.5-2% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6% iridium, and the balance is tungsten;

[0045] The preparation method comprises the following steps:

[0046] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0047] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 500MPa-1500MPa. The heating rate is 230-500℃ / min. The temperature is raised to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling. The cooling rate is 80-140℃ / min to finally obtain a tungsten-based alloy.

[0048] The tensile properties of the tungsten-based alloy of Comparative Example 1 were tested, and the room temperature tensile strength was 592 MPa, and the elongation after fracture was 11.7%. The tensile strength at 800°C was 302 MPa, and the elongation after fracture was 9.5%.

[0049] The tungsten-based alloy of Comparative Example 1 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 217 MPa, the elongation after fracture was 3.6%, and the hydrogen embrittlement sensitivity index (HEI) was 62%.

[0050] In Comparative Example 1, since the rhenium content is too low, it cannot play the role of preventing hydrogen dissolution and diffusion at high temperature, so the hydrogen embrittlement sensitivity is greatly increased and the hydrogen embrittlement resistance is significantly deteriorated.

[0051] Comparative Example 2

[0052] A high-temperature hydrogen embrittlement-resistant tungsten-based alloy for hydrogen metallurgy, the composition of which is calculated by mass percentage: 5-10% rhenium, 0.8-2.6% molybdenum, 0.5-2% tantalum, 1-2% manganese, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6 iridium, and the balance is tungsten;

[0053] The preparation method comprises the following steps:

[0054] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0055] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 500MPa-1500MPa. The heating rate is 230-500℃ / min. The temperature is raised to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling. The cooling rate is 80-140℃ / min to finally obtain a tungsten-based alloy.

[0056] The tensile properties of the tungsten-based alloy of Comparative Example 2 were tested, and the room temperature tensile strength was 588 MPa, and the elongation after fracture was 12.3%. The tensile strength at 800°C was 289 MPa, and the elongation after fracture was 9.7%.

[0057] The tungsten-based alloy of Comparative Example 2 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 188 MPa, the elongation after fracture was 2.7%, and the hydrogen embrittlement sensitivity index (HEI) was 72%.

[0058] Due to the presence of a small amount of second phase, a large number of hydrogen atoms are enriched at the phase interface of the tungsten-based alloy prepared in Comparative Example 2 during the high-temperature gas-phase hydrogen charging process, so the hydrogen embrittlement sensitivity is greatly increased and the hydrogen embrittlement resistance is significantly deteriorated.

[0059] Comparative Example 3

[0060] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is calculated by mass percentage: 5-23% chromium, 0.02-4% titanium, 0.05-3% aluminum, 0.04-3% iron, 0.03-2% hafnium, 0.02-0.5% zirconium, 0.02-0.9% copper, 0.02-0.07% silicon, and the balance is tungsten;

[0061] The preparation method comprises the following steps:

[0062] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0063] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 500MPa-1500MPa. The heating rate is 230-500℃ / min. The temperature is raised to 2000-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling. The cooling rate is 80-140℃ / min, and finally a single-phase tungsten-based alloy is obtained.

[0064] The tensile properties of the tungsten-based alloy of Comparative Example 3 were tested, and the room temperature tensile strength was 601 MPa, and the elongation after fracture was 10.5%. The tensile strength at 800°C was 278 MPa, and the elongation after fracture was 9.7%.

[0065] The tungsten-based alloy of Comparative Example 3 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 203 MPa, the elongation after fracture was 2.8%, and the hydrogen embrittlement sensitivity index (HEI) was 71%.

[0066] The tungsten-based alloy prepared in Comparative Example 3 does not contain rhenium elements that can reduce the hydrogen solubility of the alloy, tantalum, niobium, vanadium, and cobalt elements that can reduce the hydrogen diffusion coefficient, and molybdenum, nickel, and iridium elements that can inhibit the formation of brittle hydrides. Therefore, the tungsten-based alloy has a high sensitivity to hydrogen embrittlement and poor high-temperature hydrogen embrittlement resistance.

[0067] Comparative Example 4

[0068] A high-temperature hydrogen embrittlement-resistant single-phase tungsten-based alloy for hydrogen metallurgy, the composition of which is as follows by mass percentage: 10-17% rhenium, 0.8-2.6% molybdenum, 0.15-1.7% tantalum, 0.3-2.5% niobium, 0.1-1.0% vanadium, 0.15-0.35% nickel, 0.15-0.45% cobalt, 0.05-0.6% iridium, and the balance is tungsten;

[0069] The preparation method comprises the following steps:

[0070] Step 1: According to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, the raw material powders of each element are accurately weighed, and mechanical alloying is performed under the protection of argon atmosphere. The high-energy ball milling speed is 350rpm-450rpm, the ball-to-material ratio is 10-15:1, the ball milling medium is anhydrous ethanol, the ball milling time is 35h-45h, and the tungsten-based alloy powder is obtained after vacuum drying;

[0071] Step 2: The tungsten-based alloy powder obtained in step 1 is loaded into a graphite mold for sintering. The sintering method is vacuum discharge plasma sintering. The sintering pressure is 50MPa-100MPa, the heating rate is 50-80℃ / min, the temperature is raised to 2200-2300℃ and kept warm for 20min-30min. After sintering, argon gas is used for rapid cooling, and the cooling rate is 30-40℃ / min to finally obtain a tungsten-based alloy.

[0072] The tensile properties of the tungsten-based alloy of Comparative Example 4 were tested, and the room temperature tensile strength was 635 MPa, and the elongation after fracture was 14.6%. The tensile strength at 800°C was 348 MPa, and the elongation after fracture was 10.7%.

[0073] The tungsten-based alloy of Comparative Example 4 was subjected to high-temperature gas-phase hydrogen charging and then to high-temperature mechanical testing. After hydrogen charging, the tensile strength of the sample at 800°C was 218 MPa, the elongation after fracture was 3.5%, and the hydrogen embrittlement sensitivity index (HEI) was 67.2%.

[0074] In the sintering process of Comparative Example 4, more conventional sintering pressures and heating and cooling rates are used. The resulting tungsten-based alloy contains trace amounts of second phases enriched in tantalum, niobium, vanadium, etc., and the degree of lattice distortion of the main body of the alloy is lower, resulting in a significant decrease in its resistance to hydrogen diffusion and high-temperature hydrogen embrittlement resistance.

[0075] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy, characterized in that: The alloy composition is calculated by mass percentage as follows: 5~23% rhenium, 0.02~4% molybdenum, 0.05~3% tantalum, 0.04~3% niobium, 0.03~2% vanadium, 0.02~0.5% nickel, 0.02-0.9% cobalt, 0.02-0.6% iridium, and the balance is tungsten.

2. The high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy according to claim 1, characterized in that: The alloy composition is calculated by mass percentage as follows: 8~19% rhenium, 0.5~3% molybdenum, 0.1~2% tantalum, 0.1~3% niobium, 0.07~1.5% vanadium, 0.1~0.4% nickel, 0.1-0.5% cobalt, 0.04-0.6% iridium, and the balance is tungsten.

3. A high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy according to claim 1, characterized in that The alloy composition is calculated by mass percentage as follows: 10~17% rhenium, 0.8~2.6% molybdenum, 0.15~1.7% tantalum, 0.3~2.5% niobium, 0.1~1.0% vanadium, 0.15~0.35% nickel, 0.15-0.45% cobalt, 0.1-0.6% iridium, and the balance is tungsten.

4. A method for preparing a high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy according to any one of claims 1 to 3, characterized in that: Step 1: Accurately weigh the raw material powder of each element according to the mass percentage of each element in the high-temperature hydrogen embrittlement resistant tungsten-based alloy, perform mechanical alloying under the protection of argon atmosphere, and obtain tungsten-based alloy powder after high-energy ball milling and vacuum drying; Step 2: Put the tungsten-based alloy powder obtained in step 1 into a graphite mold for sintering, using vacuum discharge plasma sintering or vacuum induction sintering, the sintering pressure is 500MPa~1500MPa, the heating rate is 230~500℃ / min, the temperature is increased to 2000~2300℃ and kept warm for 20min~30min, and after sintering, argon is used for rapid cooling, and the cooling rate is 80~140℃ / min, and finally a high-temperature hydrogen embrittlement resistant single-phase tungsten-based alloy is obtained.

5. The method for preparing a high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy according to claim 4, characterized in that: In step 1, the high-energy ball milling speed is 350 rpm to 450 rpm, the ball-to-material ratio is 10 to 15:1, the ball milling medium is anhydrous ethanol, and the ball milling time is 35 h to 45 h.

6. Application of a high temperature hydrogen embrittlement resistant single-phase tungsten-based alloy for hydrogen metallurgy according to any one of claims 1 to 3, characterized in that: It is used to make hydrogen metallurgical nozzles.

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