High-performance molybdenum-rhenium alloy and bar preparation method thereof

Abstract

The invention provides a high-performance molybdenum-rhenium alloy and a bar preparation method thereof, the alloy is composed of 16%-27% of rhenium, 0.2%-1.2% of aluminum oxide, 0.5%-1.9% of rare earth oxide, 0.1%-0.6% of zirconium oxide and the balance molybdenum, and the mechanical performance of the molybdenum-rhenium alloy is remarkably improved by optimizing the molybdenum-rhenium alloy ratio and the molybdenum-rhenium alloy bar rolling technology. The rare earth oxide is used for refining grains and inhibiting rhenium segregation, and aluminum oxide and zirconium oxide are introduced for synergistic dispersion strengthening, so that the grain size of the molybdenum-rhenium alloy is uniform and fine, and the conditions that the grains in the molybdenum-rhenium alloy are locally coarsened and the stress of a molybdenum-rhenium alloy bar is easily concentrated are avoided; hydrogen sintering at the temperature of 2120-2350 DEG C is adopted to avoid rhenium element segregation, by further optimizing the annealing parameters of the molybdenum-rhenium alloy bar, the internal stress of the molybdenum-rhenium alloy can be effectively eliminated, the crystal structure uniformity is improved, and the method has the advantages that the mechanical performance of the alloy is remarkably improved, the service life of the alloy is prolonged, the equipment maintenance cost is reduced, and popularization and implementation are convenient.

Description

Technical Field

[0001] This application belongs to the field of powder metallurgy technology, specifically relating to a high-performance molybdenum-rhenium alloy and its rod preparation method. Background Technology

[0002] In existing technologies, molybdenum-rhenium alloys, as important high-temperature refractory metal alloys, play an irreplaceable role in aerospace, nuclear energy, and electronics. They possess the high melting point and high hardness of molybdenum, while the addition of rhenium significantly improves room-temperature brittleness, enhances strength, creep resistance, and weldability, and exhibits good stability and corrosion resistance at high temperatures. They are widely used in the manufacture of high-temperature components for aero-engines, structural materials for nuclear reactors, and electrodes for electronic devices. However, current molybdenum-rhenium alloy preparation technologies still face some pressing problems that need to be addressed.

[0003] In existing technologies, molybdenum-rhenium alloys are prone to grain coarsening during processing, leading to a decline in the material's mechanical properties and affecting its long-term stability and reliability at high temperatures. During the preparation of molybdenum-rhenium alloys, limitations in heat treatment and processing techniques can cause uneven grain size within the alloy. Coarse grains become stress concentration points, making the alloy susceptible to cracking under stress, thus reducing its strength and toughness. Furthermore, uneven element distribution within the molybdenum-rhenium alloy significantly reduces its overall mechanical properties. In addition, insufficient mixing of alloy raw materials or improper sintering process control can cause segregation or enrichment of rhenium and other alloying elements in localized areas, disrupting the alloy's microstructure uniformity and affecting its overall performance, such as resulting in uneven microhardness and reduced creep resistance.

[0004] Therefore, in order to fully utilize the excellent properties of molybdenum-rhenium alloys and expand their application fields, it is urgent to develop a high-performance molybdenum-rhenium alloy rod preparation method that can effectively refine grains and promote uniform distribution of alloying elements, so as to improve the performance and service life of molybdenum-rhenium alloys under extreme working conditions such as high temperature and high stress. Summary of the Invention

[0005] In order to solve the technical problems in the prior art, such as the easy occurrence of grain coarsening during the processing of molybdenum-rhenium alloys leading to a decrease in mechanical properties, stress concentration and cracks caused by uneven grain size, inconsistent microhardness and reduced creep resistance due to uneven distribution of alloying elements, and rhenium segregation and destruction of microstructure due to improper control of existing heat treatment and sintering processes, this application proposes a high-performance molybdenum-rhenium alloy. To address the technical problems raised in this application, this application also provides a method for preparing high-performance molybdenum-rhenium alloy rods.

[0006] This application adopts the following scheme: a high-performance molybdenum-rhenium alloy, which, by mass fraction, is composed of the following components: rhenium 16%-27%, alumina 0.2%-1.2%, rare earth oxides 0.5%-1.9%, zirconium oxide 0.1%-0.6%, and the balance molybdenum; The rare earth oxide is selected from any one of lanthanum oxide, yttrium oxide, cerium oxide, neodymium oxide, gadolinium oxide, and samarium oxide; Among them, the rhenium source is any one or more of rhenium powder and ammonium perrhenate; the molybdenum source is any one or more of molybdenum powder, ammonium heptamolybdate, and ammonium tetramolybdate; the alumina source is any one or more of alumina powder and aluminum nitrate; and the zirconium source is zirconium powder.

[0007] In some feasible embodiments, the rare earth oxide is selected as lanthanum oxide, and the lanthanum oxide source is lanthanum oxide powder or lanthanum nitrate.

[0008] To address the technical problems raised in this application, this application also provides a method for preparing high-performance molybdenum-rhenium alloy rods. The rods are prepared from the aforementioned high-performance molybdenum-rhenium alloy, and the rod preparation method includes the following steps: Step 101. Prepare coarse alloy powder according to the preset target alloy ratio, and then transfer the coarse alloy powder to a high-energy ball mill. Under the conditions of ball-to-material ratio of (8-10):1, ball milling speed of 350rpm-400rpm, and argon atmosphere, ball mill for 1h-2h. After separation and drying, the finished alloy powder product is obtained. For example, the ball-to-material ratio is 8:1, 9:1, or 10:1; Step 102. The alloy powder product prepared in step 101 is uniformly loaded into the mold and pressed under the conditions of 150MPa-200MPa and holding pressure for 2min to obtain the alloy blank. Step 103. Transfer the alloy billet prepared in step 102 to a high-frequency induction sintering furnace and sinter it at 2120℃-2350℃ for 4h-6h under a helium atmosphere to obtain the billet to be rolled. Step 104. Transfer the billet to be rolled obtained in step 103 to the rolling mill, and roll it into a bar-shaped billet under the conditions of rolling temperature of 1350℃, rolling times of 4-8 times, and total rolling deformation of 81%-85%. Then, anneal the bar-shaped billet at 1000℃-1500℃ for 2.5h-4h to obtain high-performance molybdenum-rhenium alloy rods.

[0009] In some feasible embodiments, step 101, the method for preparing the crude alloy powder includes the following steps: Step 201. Prepare molybdenum-containing suspension, aluminum-containing suspension, molybdenum-rhenium-lanthanum alloy precursor suspension, and weigh zirconium oxide powder in sequence according to the preset target alloy ratio; Step 202. The molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum oxide alloy precursor suspension prepared in step 201 are sequentially filtered, dried, and then mixed to obtain powder A. Step 203. Mix the zirconium oxide powder weighed in step 201 with powder A prepared in step 202 and transfer it to a reduction furnace. Reduce the powder at 680℃-750℃ for 5-8 hours with continuous hydrogen flow to obtain crude alloy powder.

[0010] In some feasible embodiments, in step 201, the average particle size of the zirconium oxide powder is 40nm-55nm.

[0011] In some feasible embodiments, step 201, the preparation method of molybdenum-containing suspension includes the following steps: weighing ammonium tetramolybdate according to the preset target alloy ratio, then adding ammonium tetramolybdate and nitric acid solution to a high-pressure reactor in sequence, and reacting for 4-8 hours under the conditions of nitric acid solution filling degree of 88%, 500 rpm, 8 MPa, and water bath temperature of 50℃-60℃, to obtain molybdenum-containing suspension. In step 201, the preparation method of aluminum-containing suspension includes the following steps: after weighing aluminum nitrate according to the preset target alloy ratio, aluminum nitrate, urea and deionized water are added to a high-pressure reactor in sequence. After reacting for 6-9 hours under the conditions of 90% deionized water filling degree, 1200 rpm, 15 MPa and 180℃-185℃, aluminum-containing suspension is obtained.

[0012] In some feasible embodiments, step 201, the preparation method of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension includes the following steps: weighing ammonium heptamolybdate, ammonium perrhenate, and lanthanum nitrate according to the preset target alloy ratio, and then adding ammonium heptamolybdate, ammonium perrhenate, lanthanum nitrate, and oxalic acid solution sequentially into a high-pressure reactor. After reacting for 2-4 hours under the conditions of oxalic acid solution filling degree of 85%, 1600rpm-2100rpm, 11MPa, and 90℃-125℃, the molybdenum-rhenium-lanthanum oxide alloy precursor is obtained.

[0013] In some feasible embodiments, in step 104, the annealing treatment of the rod-shaped billet includes an initial cooling stage, an initial heating stage, a second heating stage, and a second cooling stage performed sequentially in time. The initial cooling stage involves cooling the rod-shaped billet from the rolling temperature to 1000℃ and holding it at 1000℃ for 0.5 hours, with a corresponding cooling rate of 5.5℃ / min-7.5℃ / min. The initial heating stage involves heating the rod-shaped billet from 1000℃ to 1300℃ and holding it at 1300℃ for 1 hour, with a corresponding heating rate of 8.5℃ / min-10℃ / min. The secondary heating stage involves heating the rod-shaped billet from 1300℃ to 1500℃ and holding it at 1500℃ for 1 hour, with a corresponding heating rate of 5.5℃ / min-6.5℃ / min. The secondary cooling stage involves cooling the rod-shaped billet from 1500°C to room temperature in the furnace.

[0014] In actual implementation, molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum alloy precursor suspension are prepared separately. The suspensions are then filtered, dried, and mixed to obtain powder A. Powder A is then mixed with zirconium oxide powder and reduced to obtain crude alloy powder. The preparation of crude alloy powder by hydration reduction method can effectively reduce metal impurities in the powder and significantly reduce the particle size of each alloy component, so as to refine the grain of the molybdenum-rhenium alloy product and improve the density of the molybdenum-rhenium alloy rod.

[0015] Compared with the prior art, this application has the following beneficial effects: This application provides a high-performance molybdenum-rhenium alloy and its rod preparation method. The alloy is composed of 16%-27% rhenium, 0.2%-1.2% alumina, 0.5%-1.9% rare earth oxides, 0.1%-0.6% zirconium oxide, and the balance molybdenum. By optimizing the molybdenum-rhenium alloy ratio and the rolling process of the molybdenum-rhenium alloy rod, the mechanical properties of the molybdenum-rhenium alloy are significantly improved. This application refines the grain size and suppresses rhenium segregation using rare earth oxides, while introducing alumina and zirconium oxide for synergistic dispersion strengthening, resulting in uniform and fine grain size in the molybdenum-rhenium alloy. This avoids localized grain coarsening and stress concentration in the molybdenum-rhenium alloy rods. Hydrogen sintering at 2120℃-2350℃ is used to prevent rhenium segregation. By further optimizing the annealing parameters of the molybdenum-rhenium alloy rods, internal stress in the molybdenum-rhenium alloy can be effectively eliminated, and the uniformity of the crystal structure can be improved. This application has the advantages of significantly improving the mechanical properties of the alloy, extending its service life, reducing equipment maintenance costs, and facilitating widespread implementation. Detailed Implementation

[0016] The technical solutions provided in this application are further explained in conjunction with the contents shown in Examples 1-3 and Comparative Examples 1-6.

[0017] Example 1 (1) The preparation of crude alloy powder includes the following steps: The preparation of the molybdenum-containing suspension includes the following steps: after weighing ammonium tetramolybdate according to the alloy composition table shown in Table 1, ammonium tetramolybdate and nitric acid solution (5wt%) are added sequentially to a high-pressure reactor. After reacting for 4 hours under the conditions of nitric acid solution filling degree of 88%, 500 rpm, 8 MPa, and water bath temperature of 50℃, the molybdenum-containing suspension is obtained.

[0018] The preparation of aluminum-containing suspension includes the following steps: Weigh aluminum nitrate according to the alloy composition table shown in Table 1, and then add aluminum nitrate, urea and deionized water to a high-pressure reactor in sequence. After reacting for 6-9 hours under the conditions of 90% deionized water filling degree, 1200 rpm, 15 MPa and 180℃, aluminum-containing suspension is obtained, wherein the mass ratio of aluminum nitrate to urea is 1:4.

[0019] The preparation of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension includes the following steps: according to the alloy composition table shown in Table 1, weigh ammonium heptamolybdate, ammonium perrhenate, and lanthanum nitrate respectively, and then add ammonium heptamolybdate, ammonium perrhenate, lanthanum nitrate, and oxalic acid solution (8.5 wt%) sequentially into a high-pressure reactor. After reacting for 2 hours at a filling degree of 85% of oxalic acid solution, 1600 rpm, 11 MPa, and 90℃, the molybdenum-rhenium-lanthanum oxide alloy precursor suspension is obtained.

[0020] (2) The preparation of crude alloy powder includes the following steps: Step 201. After preparing the molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum alloy precursor suspension according to the alloy composition table shown in Table 1, weigh zirconium oxide powder with an average particle size of 49 nm and a median particle size of 51 nm. Step 202. The molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum oxide alloy precursor suspension prepared in step 201 are sequentially filtered, dried, and then mixed to obtain powder A. Step 203. Mix the zirconium oxide powder weighed in step 201 with powder A prepared in step 202 and transfer it to a reduction furnace. Reduce it at 680°C for 5 hours under continuous hydrogen gas supply to obtain crude alloy powder.

[0021] (3) The preparation of high-performance molybdenum-rhenium alloy rods includes the following steps: Step 101. Prepare coarse alloy powder according to the preset target alloy ratio, then transfer the coarse alloy powder to a high-energy ball mill and ball mill for 1 hour under the conditions of ball-to-material ratio of 8:1, ball milling speed of 350 rpm and argon atmosphere. After separation and drying, the finished alloy powder product is obtained. Step 102. The alloy powder product prepared in step 101 is uniformly loaded into the mold and pressed under the condition of 150MPa and holding pressure for 2min to obtain the alloy blank. Step 103. Transfer the alloy billet prepared in step 102 to a high-frequency induction sintering furnace and sinter it at 2120℃ for 4-6 hours in a helium atmosphere to obtain the billet to be rolled. Step 104. Transfer the billet to be rolled obtained in step 103 to the rolling mill, and roll it into a bar-shaped billet under the conditions of rolling temperature of 1350℃, rolling times of 5 times, and total rolling deformation of 81%. Then, anneal the bar-shaped billet at 1000℃-1500℃ to obtain high-performance molybdenum-rhenium alloy rods.

[0022] In step 104, the annealing treatment of the rod-shaped billet includes an initial cooling stage, an initial heating stage, a second heating stage, and a second cooling stage performed sequentially in time. The initial cooling stage involves cooling the rod-shaped billet from 1350℃ to 1000℃ and holding it at 1000℃ for 0.5 hours, with a corresponding cooling rate of 5.8℃ / min. The initial heating stage involves heating the rod-shaped billet from 1000℃ to 1300℃ and holding it at 1300℃ for 1 hour, with a corresponding heating rate of 8.5℃ / min. The second heating stage involves heating the rod-shaped billet from 1300℃ to 1500℃ and holding it at 1500℃ for 1 hour, with a corresponding heating rate of 5.5℃ / min. The second cooling stage involves cooling the rod-shaped billet from 1500℃ to room temperature in the furnace.

[0023] Example 2 (1) The preparation of crude alloy powder includes the following steps: The preparation of the molybdenum-containing suspension includes the following steps: after weighing ammonium tetramolybdate according to the alloy composition table shown in Table 1, ammonium tetramolybdate and nitric acid solution (5wt%) are added sequentially to a high-pressure reactor. After reacting for 6 hours under the conditions of nitric acid solution filling degree of 88%, 500 rpm, 8 MPa, and water bath temperature of 55℃, the molybdenum-containing suspension is obtained.

[0024] The preparation of aluminum-containing suspension includes the following steps: Weigh aluminum nitrate according to the alloy composition table shown in Table 1, then add aluminum nitrate, urea and deionized water to a high-pressure reactor in sequence, and react for 6-9 hours under the conditions of 90% deionized water filling degree, 1200 rpm, 15 MPa and 182℃ to obtain aluminum-containing suspension, wherein the mass ratio of aluminum nitrate to urea is 1:5.5.

[0025] The preparation of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension includes the following steps: according to the alloy composition table shown in Table 1, weigh ammonium heptamolybdate, ammonium perrhenate, and lanthanum nitrate respectively, and then add ammonium heptamolybdate, ammonium perrhenate, lanthanum nitrate, and oxalic acid solution (8.5 wt%) sequentially into a high-pressure reactor. After reacting for 3 hours at a filling degree of 85% of oxalic acid solution, 1850 rpm, 11 MPa, and 110 °C, the molybdenum-rhenium-lanthanum oxide alloy precursor suspension is obtained.

[0026] (2) The preparation of crude alloy powder includes the following steps: Step 201. After preparing the molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum alloy precursor suspension according to the alloy composition table shown in Table 1, weigh out zirconium oxide powder with an average particle size of 48 nm and a median particle size of 51 nm. Step 202. The molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum oxide alloy precursor suspension prepared in step 201 are sequentially filtered, dried, and then mixed to obtain powder A. Step 203. Mix the zirconium oxide powder weighed in step 201 with powder A prepared in step 202 and transfer it to a reduction furnace. Reduce the powder at 710°C for 6.5 hours with continuous hydrogen flow to obtain crude alloy powder.

[0027] (3) The preparation of high-performance molybdenum-rhenium alloy rods includes the following steps: Step 101. Prepare coarse alloy powder according to the preset target alloy ratio, then transfer the coarse alloy powder to a high-energy ball mill and ball mill for 1.5 hours under the conditions of ball-to-material ratio of 9:1, ball milling speed of 380 rpm and argon atmosphere. After separation and drying, the finished alloy powder product is obtained. Step 102. The alloy powder product prepared in step 101 is uniformly loaded into the mold and pressed under the condition of 170MPa and holding pressure for 2min to obtain the alloy blank. Step 103. Transfer the alloy billet prepared in step 102 to a high-frequency induction sintering furnace and sinter it at 2200℃ for 4-6 hours in a helium atmosphere to obtain the billet to be rolled. Step 104. Transfer the billet to be rolled obtained in step 103 to the rolling mill, and roll it into a bar-shaped billet under the conditions of rolling temperature of 1350℃, rolling times of 6 times, and total rolling deformation of 82%. Then, anneal the bar-shaped billet at 1000℃-1500℃ to obtain high-performance molybdenum-rhenium alloy rods.

[0028] In step 104, the annealing treatment of the rod-shaped billet includes an initial cooling stage, an initial heating stage, a second heating stage, and a second cooling stage performed sequentially in time. The initial cooling stage involves cooling the rod-shaped billet from 1350℃ to 1000℃ and holding it at 1000℃ for 0.5 hours, with a corresponding cooling rate of 6.5℃ / min. The initial heating stage involves heating the rod-shaped billet from 1000℃ to 1300℃ and holding it at 1300℃ for 1 hour, with a corresponding heating rate of 9℃ / min. The second heating stage involves heating the rod-shaped billet from 1300℃ to 1500℃ and holding it at 1500℃ for 1 hour, with a corresponding heating rate of 6℃ / min. The second cooling stage involves cooling the rod-shaped billet from 1500℃ to room temperature in the furnace.

[0029] Example 3 (1) The preparation of crude alloy powder includes the following steps: The preparation of the molybdenum-containing suspension includes the following steps: after weighing ammonium tetramolybdate according to the alloy composition table shown in Table 1, ammonium tetramolybdate and nitric acid solution (5wt%) are added to a high-pressure reactor in sequence. After reacting for 8 hours under the conditions of nitric acid solution filling degree of 88%, 500 rpm, 8 MPa and water bath temperature of 60℃, the molybdenum-containing suspension is obtained.

[0030] The preparation of aluminum-containing suspension includes the following steps: Weigh aluminum nitrate according to the alloy composition table shown in Table 1, then add aluminum nitrate, urea and deionized water to a high-pressure reactor in sequence, and react for 6-9 hours under the conditions of 90% deionized water filling degree, 1200 rpm, 15 MPa and 185℃ to obtain aluminum-containing suspension, wherein the mass ratio of aluminum nitrate to urea is 1:7.

[0031] The preparation of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension includes the following steps: according to the alloy composition table shown in Table 1, ammonium heptamolybdate, ammonium perrhenate, and lanthanum nitrate are weighed respectively. Then, ammonium heptamolybdate, ammonium perrhenate, lanthanum nitrate, and oxalic acid solution (8.5 wt%) are added sequentially to a high-pressure reactor. After reacting for 4 hours at a filling degree of 85% of the oxalic acid solution, 2100 rpm, 11 MPa, and 125℃, the molybdenum-rhenium-lanthanum oxide alloy precursor suspension is obtained.

[0032] (2) The preparation of crude alloy powder includes the following steps: Step 201. After preparing the molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum alloy precursor suspension according to the alloy composition table shown in Table 1, weigh out zirconium oxide powder with an average particle size of 53 nm and a median particle size of 51 nm. Step 202. The molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum oxide alloy precursor suspension prepared in step 201 are sequentially filtered, dried, and then mixed to obtain powder A. Step 203. Mix the zirconium oxide powder weighed in step 201 with powder A prepared in step 202 and transfer it to a reduction furnace. Reduce it at 750°C for 8 hours under continuous hydrogen gas supply to obtain crude alloy powder.

[0033] (3) The preparation of high-performance molybdenum-rhenium alloy rods includes the following steps: Step 101. Prepare coarse alloy powder according to the preset target alloy ratio, then transfer the coarse alloy powder to a high-energy ball mill and ball mill for 2 hours under the conditions of ball-to-material ratio of 10:1, ball milling speed of 400 rpm and argon atmosphere. After separation and drying, the finished alloy powder product is obtained. Step 102. The alloy powder product prepared in step 101 is uniformly loaded into the mold press and pressed under the condition of 200MPa and holding pressure for 2min to obtain the alloy blank. Step 103. Transfer the alloy billet prepared in step 102 to a high-frequency induction sintering furnace and sinter it at 2350℃ for 6 hours under a helium atmosphere to obtain the billet to be rolled. Step 104. Transfer the billet to be rolled obtained in step 103 to the rolling mill, and roll it into a bar-shaped billet under the conditions of rolling temperature of 1350℃, rolling times of 8 times, and total rolling deformation of 85%. Then, anneal the bar-shaped billet at 1000℃-1500℃ to obtain high-performance molybdenum-rhenium alloy rods.

[0034] In step 104, the annealing treatment of the rod-shaped billet includes an initial cooling stage, an initial heating stage, a second heating stage, and a second cooling stage performed sequentially in time. The initial cooling stage involves cooling the bar billet from the rolling temperature to 1000℃ and holding it at 1000℃ for 0.5h, with a corresponding cooling rate of 7.5℃ / min. The initial heating stage involves heating the rod-shaped billet from 1000℃ to 1300℃ and holding it at 1300℃ for 1 hour, with a corresponding heating rate of 10℃ / min. The second heating stage involves heating the rod-shaped billet from 1300℃ to 1500℃ and holding it at 1500℃ for 1 hour, with a corresponding heating rate of 6.5℃ / min. The second cooling stage involves cooling the rod-shaped billet from 1500℃ to room temperature in the furnace.

[0035] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that aluminum oxide in the alloy composition was removed, i.e., the preparation of aluminum-containing suspension was eliminated, and rhenium powder was used to supplement the alloy composition according to the preset alloy composition table. The remaining components and processes remained unchanged, and the Fisher particle size of the rhenium powder was 4.5 μm.

[0036] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that lanthanum oxide was removed from the alloy composition, that is, the preparation of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension was eliminated, and molybdenum powder and rhenium powder were used to supplement the alloy composition according to the preset alloy composition table. The remaining components and processes remained unchanged. The Fisher particle size of the rhenium powder was 4.5 μm, and the Fisher particle size of the molybdenum powder was 3.5 μm.

[0037] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that zirconium oxide was removed from the alloy composition and rhenium powder was used to supplement it according to the preset alloy composition table. The remaining components and processes remained unchanged, and the Fisher particle size of the rhenium powder was 4.5 μm.

[0038] Comparative Example 4 The difference between Comparative Example 4 and Example 3 is that aluminum oxide, lanthanum oxide and zirconium oxide were removed from the alloy composition, and molybdenum powder and rhenium powder were used to supplement the alloy composition according to the preset alloy composition table. The remaining components and processes remained unchanged. The Fisher particle size of the rhenium powder was 4.5 μm and the Fisher particle size of the molybdenum powder was 3.5 μm.

[0039] Comparative Example 5 The difference between Comparative Example 5 and Example 3 is that the preparation process of the crude alloy powder was changed. According to the preset alloy composition table, molybdenum powder, rhenium powder, lanthanum oxide powder, alumina powder and zirconium oxide powder were directly dispersed and mixed to obtain the crude alloy powder. The rhenium powder had a Fisher particle size of 4.5 μm, the molybdenum powder had a Fisher particle size of 3.5 μm, the lanthanum oxide powder had an average particle size of 40 nm, the alumina powder had an average particle size of 55 nm, and the zirconium oxide powder had an average particle size of 51 nm.

[0040] Comparative Example 6 The difference between Comparative Example 6 and Example 3 is that the annealing process of the rod-shaped billet is changed. A single annealing process is used to directly cool the rod-shaped billet from 1350°C to 1000°C, hold it at that temperature for 1 hour, and then allow the rod-shaped billet to cool with the furnace after the holding time is completed.

[0041] Table 1 Alloy composition table for Examples 1-3 and Comparative Examples 1-6

[0042] Continued from Table 1

[0043] After the molybdenum-rhenium alloy rods prepared in Examples 1-3 and Comparative Examples 1-6 were made into corresponding test pieces, the following tests were performed respectively: Test 1: Referring to GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Test at room temperature", the tensile strength and elongation of the test specimens were tested at room temperature. Test 2: Referring to GB / T 228.2-2015 "Metallic materials - Tensile testing - Part 2: High temperature test method", the tensile strength, yield strength, elongation and shrinkage at break of the test specimens were tested at 1600℃ respectively. Test 3: The Vickers hardness of the test pieces was tested according to GB / T 4340.1-2009 "Metallic Materials - Vickers Hardness Test". Test 4: Referring to GB / T 2039-2012 "Metallic Materials - Tensile Creep and Duration Test Methods", the creep strength of the test pieces was tested respectively. The test results are shown in Table 2 below.

[0044] Table 2 Test Results

[0045] Continued from Table 2

[0046] As shown in Table 2, in Example 3, by simultaneously introducing alumina, lanthanum oxide, and zirconium oxide into the molybdenum-rhenium alloy using both liquid-liquid doping and solid-solid doping methods, lanthanum oxide effectively promotes the dispersed distribution of molybdenum-rhenium alloy grains by pinning grain boundaries, significantly reducing the grain size and thus increasing the grain boundary area. This enhances the resistance to dislocation slip between crystals, significantly improving the tensile strength and elongation of the molybdenum-rhenium alloy rod. Furthermore, lanthanum oxide raises the recrystallization temperature to 1400℃, hindering grain boundary migration at high temperatures, thereby improving the tensile strength and elongation of the molybdenum-rhenium alloy rod at 160℃. The tensile strength at 0℃ is achieved through the following: By doping with a small amount of nano-zirconia, the resistance to intercrystalline dislocation slip is further increased via the Orowan mechanism, requiring dislocations to bypass hard particles, thus significantly improving the deformation resistance, hardness, and ductility of the molybdenum-rhenium alloy rod; by doping with alumina to adsorb oxygen impurities in the molybdenum-rhenium alloy, the brittle phase at grain boundaries in the alloy is reduced, thereby enhancing grain boundary bonding and significantly improving the fracture toughness of the molybdenum-rhenium alloy rod; and by promoting dispersion distribution with lanthanum oxide, adsorbing impurities with alumina, and increasing the resistance to intercrystalline dislocation slip with zirconia, the mechanical properties of the molybdenum-rhenium alloy rod are significantly improved.

[0047] In Comparative Example 1, the removal of alumina resulted in the enrichment of oxygen impurities at grain boundaries in the molybdenum-rhenium alloy, an increase in brittle phases at grain boundaries, a decrease in grain boundary bonding strength, and insufficient resistance to dislocations caused by a small amount of zirconium oxide in the crystal. Consequently, the molybdenum-rhenium alloy was prone to grain boundary slip at high temperatures, significantly reducing the mechanical properties of the molybdenum-rhenium alloy rods.

[0048] In Comparative Example 2, the removal of lanthanum oxide weakened the dispersion distribution in the molybdenum-rhenium alloy, resulting in coarsening of the grains, a decrease in recrystallization temperature, and a greater susceptibility to grain boundary slip. Furthermore, the dislocation slip distance increased significantly, leading to a significant reduction in the strength of the molybdenum-rhenium alloy rod.

[0049] In Comparative Example 3, the removal of zirconium oxide reduced the resistance to dislocation movement in the molybdenum-rhenium alloy, making the molybdenum-rhenium alloy more prone to grain boundary slip and significantly reducing the strength of the molybdenum-rhenium alloy rod.

[0050] In Comparative Example 4, after removing lanthanum oxide, aluminum oxide, and zirconium oxide, the alloy strengthening mechanism completely failed, and the strength of the molybdenum-rhenium alloy rod was significantly reduced.

[0051] In Comparative Example 5, the traditional single solid-solid doping process was used for preparation. Lanthanum oxide, aluminum oxide, and zirconium oxide tend to agglomerate inside the molybdenum-rhenium alloy, forming stress concentration sites, which significantly reduces the strength of the molybdenum-rhenium alloy rod.

[0052] In Comparative Example 6, a single annealing process was used, and the recrystallization temperature was too low. The recrystallization of the molybdenum-rhenium alloy was insufficient, and the internal stress of the molybdenum-rhenium alloy was not fully eliminated. The residual stress induced creep pores, which in turn significantly reduced the strength of the molybdenum-rhenium alloy rod.

[0053] This application refines the grain size and suppresses rhenium segregation using rare earth oxides, while introducing alumina and zirconium oxide for synergistic dispersion strengthening, resulting in uniform and fine grain size in the molybdenum-rhenium alloy. This avoids localized grain coarsening and stress concentration in the molybdenum-rhenium alloy rods. Hydrogen sintering at 2120℃-2350℃ is used to prevent rhenium segregation. By further optimizing the annealing parameters of the molybdenum-rhenium alloy rods, internal stress in the molybdenum-rhenium alloy can be effectively eliminated, and the uniformity of the crystal structure can be improved. This application has the advantages of significantly improving the mechanical properties of the alloy, extending its service life, reducing equipment maintenance costs, and facilitating widespread implementation.

[0054] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A high-performance molybdenum-rhenium alloy, characterized in that, By mass fraction, it consists of the following components: rhenium 16%-27%, alumina 0.2%-1.2%, rare earth oxides 0.5%-1.9%, zirconium oxide 0.1%-0.6%, and the balance molybdenum; The rare earth oxide is selected from any one of lanthanum oxide, yttrium oxide, cerium oxide, neodymium oxide, gadolinium oxide, and samarium oxide; Among them, the rhenium source is any one or more of rhenium powder and ammonium perrhenate; the molybdenum source is any one or more of molybdenum powder, ammonium heptamolybdate, and ammonium tetramolybdate; the alumina source is any one or more of alumina powder and aluminum nitrate; and the zirconium source is zirconium powder.

2. The high-performance molybdenum-rhenium alloy according to claim 1, characterized in that, The rare earth oxide is lanthanum oxide, and the lanthanum oxide source is lanthanum oxide powder or lanthanum nitrate.

3. A method for preparing high-performance molybdenum-rhenium alloy rods, characterized in that, The rod is prepared from a high-performance molybdenum-rhenium alloy according to any one of claims 1-2, and the rod preparation method includes the following steps: Step 101. Prepare coarse alloy powder according to the preset target alloy ratio, then transfer the coarse alloy powder to a high-energy ball mill for ball milling, and then separate and dry it in sequence to obtain the finished alloy powder product. Step 102. The alloy powder product prepared in step 101 is uniformly loaded into the mold and pressed under the conditions of 150MPa-200MPa and holding pressure for 2min to obtain the alloy blank. Step 103. Transfer the alloy billet prepared in step 102 to a high-frequency induction sintering furnace and sinter it at 2120℃-2350℃ for 4h-6h under a helium atmosphere to obtain the billet to be rolled. Step 104. After transferring the billet to be rolled in step 103 to the rolling mill and rolling it into a bar-shaped billet, the bar-shaped billet is then annealed at 1000℃-1500℃ for 2.5h-4h to obtain a high-performance molybdenum-rhenium alloy bar.

4. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 3, characterized in that, In step 101, the ball milling parameters for the crude alloy powder are: ball-to-material ratio of (8-10):1, ball milling speed of 350rpm-400rpm, argon atmosphere, and ball milling time of 1h-2h.

5. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 3, characterized in that, In step 101, the method for preparing the crude alloy powder includes the following steps: Step 201. Prepare molybdenum-containing suspension, aluminum-containing suspension, molybdenum-rhenium-lanthanum alloy precursor suspension, and weigh zirconium oxide powder in sequence according to the preset target alloy ratio; Step 202. The molybdenum-containing suspension, aluminum-containing suspension, and molybdenum-rhenium-lanthanum oxide alloy precursor suspension prepared in step 201 are sequentially filtered, dried, and then mixed to obtain powder A. Step 203. Mix the zirconium oxide powder weighed in step 201 with powder A prepared in step 202 and transfer it to a reduction furnace. Reduce the powder at 680℃-750℃ for 5-8 hours with continuous hydrogen flow to obtain crude alloy powder.

6. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 5, characterized in that, In step 201, the average particle size of the zirconium oxide powder is 40nm-55nm.

7. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 5, characterized in that, In step 201, the preparation method of the molybdenum-containing suspension includes the following steps: after weighing ammonium tetramolybdate according to the preset target alloy ratio, ammonium tetramolybdate and nitric acid solution are added to the high-pressure reactor in sequence. After reacting for 4-8 hours under the conditions of nitric acid solution filling degree of 88%, 500 rpm, 8 MPa, and water bath temperature of 50℃-60℃, the molybdenum-containing suspension is obtained. The preparation method of aluminum-containing suspension includes the following steps: aluminum nitrate is weighed according to the preset target alloy ratio, and then aluminum nitrate, urea and deionized water are added to a high-pressure reactor in sequence. After reacting for 6-9 hours under the conditions of 90% deionized water filling degree, 1200 rpm, 15 MPa and 180℃-185℃, aluminum-containing suspension is obtained.

8. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 5, characterized in that, In step 201, the preparation method of the molybdenum-rhenium-lanthanum oxide alloy precursor suspension includes the following steps: weighing ammonium heptamolybdate, ammonium perrhenate, and lanthanum nitrate according to the preset target alloy ratio, and then adding ammonium heptamolybdate, ammonium perrhenate, lanthanum nitrate, and oxalic acid solution sequentially into a high-pressure reactor. After reacting for 2-4 hours under the conditions of oxalic acid solution filling degree of 85%, 1600rpm-2100rpm, 11MPa, and 90℃-125℃, the molybdenum-rhenium-lanthanum oxide alloy precursor is obtained.

9. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 3, characterized in that, In step 104, the rolling temperature of the billet to be rolled is 1350℃, the number of rolling cycles is 4-8, and the total rolling deformation is 81%-85%.

10. The method for preparing a high-performance molybdenum-rhenium alloy rod according to claim 3, characterized in that, In step 104, the annealing treatment of the rod-shaped billet includes an initial cooling stage, an initial heating stage, a second heating stage, and a second cooling stage performed sequentially in time. The initial cooling stage involves cooling the rod-shaped billet from the rolling temperature to 1000℃ and holding it at 1000℃ for 0.5 hours, with a corresponding cooling rate of 5.5℃ / min-7.5℃ / min. The initial heating stage involves heating the rod-shaped billet from 1000℃ to 1300℃ and holding it at 1300℃ for 1 hour, with a corresponding heating rate of 8.5℃ / min-10℃ / min. The secondary heating stage involves heating the rod-shaped billet from 1300℃ to 1500℃ and holding it at 1500℃ for 1 hour, with a corresponding heating rate of 5.5℃ / min-6.5℃ / min. The secondary cooling stage involves cooling the rod-shaped billet from 1500°C to room temperature in the furnace.

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