A molybdenum-copper alloy plate resistant to molten salt corrosion and preparation method thereof

Abstract

The invention discloses a molybdenum-copper alloy plate resistant to molten salt corrosion, which is composed of the following elements in mass percentage: Cu 15%-40%, C≤0.003%, O≤0.006%, N≤0.003%, and the remainder is Mo and inevitable impurities; its preparation method is: 1. weighing high-purity raw materials according to the required ratio; 2. ball milling the raw materials to mix powder; 3. cold isostatic press pressing into blocks; 4. hydrogen sintering to obtain ingots; 5. low-temperature rolling into slabs; 6. annealing to obtain plates. The present invention uses molybdenum as the matrix and copper as the main alloying element, and adopts powder metallurgy combined with low-temperature rolling and annealing treatment to ensure the accuracy and uniformity of the molybdenum-copper alloy composition, so that the molybdenum-copper alloy plate has good mechanical properties and processing properties, and at the same time has excellent molten salt corrosion resistance, meeting the use conditions of molten salt pile structural materials.

Description

Technical Field

[0001] The invention belongs to the technical field of molybdenum alloys, and in particular relates to a molybdenum-copper alloy plate resistant to molten salt corrosion and a preparation method thereof. Background Art

[0002] As a type of reactor in the fourth generation of new nuclear power reactors, the development of molten salt reactors has attracted much attention. Its characteristics are that molten salt can be used as both fuel and coolant, so there is no need to make fuel assemblies, and online charging and online post-processing can be achieved. Fluoride molten salt is selected as the fuel carrier and coolant of molten salt reactors because of its good heat transfer performance, high operating temperature and no decomposition under high irradiation. Fluoride molten salt has a melting point of 550℃ and a boiling point of 1400℃. It can work under normal pressure and high temperature (700℃). Therefore, the development of materials resistant to high temperature fluoride molten salt corrosion is an urgent problem to be solved. Molybdenum has the characteristics of high melting point, excellent high temperature mechanical properties and good compatibility with alkali metals, so molybdenum has become the best candidate material in the fluoride salt system. However, when pure molybdenum is used as a nuclear-grade material, there are problems such as room temperature brittleness that need to be solved. Therefore, without affecting the high temperature fluoride molten salt corrosion performance, the performance of pure molybdenum is improved by adding alloying elements.

[0003] Copper has stronger resistance to fluoride molten salt corrosion than molybdenum, and can be considered as a second phase added to molybdenum. At present, molybdenum-copper alloys have been widely used as electronic packaging materials and heat sink materials. The preparation methods are divided into powder metallurgy and smelting. Considering the large difference in the melting points of molybdenum and copper, it is difficult to prepare molybdenum-copper alloys with excellent performance by smelting. Therefore, powder metallurgy is the main method for producing molybdenum-copper alloys. Considering that molybdenum-copper alloys themselves are two "pseudo-alloys" that do not dissolve in each other, the mechanical properties of sintered molybdenum-copper alloys are poor, with a tensile strength of only 150MPa~200MPa and an elongation of only 1%~2%. This is because the ingots obtained by sintering have problems with uneven distribution of components and poor density, which makes it unable to meet the use requirements of structural parts. It needs to be heat-treated later to achieve the purpose of improving mechanical properties. At present, there are few reports on the processing of molybdenum-copper alloys.

[0004] The invention patent with the patent authorization number CN115418517B discloses a method for preparing a molybdenum-copper alloy for electronic packaging. The method is simple to operate. Molybdenum powder and copper powder are mixed and then cold isostatically pressed into a compact, which is then hydrogen sintered to obtain the molybdenum-copper alloy. However, no subsequent heat processing and microstructure control are performed, and the mechanical properties are difficult to guarantee.

[0005] The invention patent with the patent authorization number CN108165789B discloses a static pressure infiltration preparation method for molybdenum-copper alloy plates. This method first mixes the raw materials and then puts them into a mold for heating and directly presses them into a slab, which is then sintered to obtain a molybdenum-copper alloy plate. Although this method can effectively improve the density of the finished product, it also does not pay attention to its mechanical properties. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a molybdenum-copper alloy plate resistant to molten salt corrosion in view of the above-mentioned deficiencies in the prior art. The molybdenum-copper alloy plate uses molybdenum as a matrix and copper as a main alloying element. The ratio of molybdenum and copper elements is determined from the perspective of thermodynamics and mechanical properties to ensure that the molybdenum-copper alloy plate has excellent molten salt corrosion resistance and good mechanical properties, thus solving the problem of poor mechanical properties of the existing molybdenum-copper alloy.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a molybdenum-copper alloy plate resistant to molten salt corrosion, characterized in that it is composed of the following elements in mass percentage: Cu 15%~40%, C≤0.003%, O≤0.006%, N≤0.003%, and the remainder is Mo and unavoidable impurities; the mechanical properties of the molybdenum-copper alloy plate meet the following requirements: tensile strength 600MPa~700MPa, and elongation 5%~10%.

[0008] The present invention uses molybdenum as the matrix and copper as the main alloying element to obtain a molybdenum-copper alloy. During the research process of the present invention, it was first found through thermodynamic calculation that compared with the currently commonly used Ni-based alloy, Re, Mo, W and each mole of F 2 The Gibbs free energy of forming salts and metal fluorides under these conditions is higher, and they are less likely to react, that is, they are more corrosion-resistant; taking into account the material cost and processability, Mo is the best candidate material in the fluoride molten salt system. Through the same calculation method, it was found that Cu's resistance to molten salt corrosion is comparable to that of Mo, so Cu was selected as an alloying element to be added to Mo to improve the room temperature brittleness of pure molybdenum while ensuring that the material has excellent resistance to molten salt corrosion.

[0009] The above-mentioned molybdenum-copper alloy plate resistant to molten salt corrosion is characterized in that it is composed of the following elements in percentage by mass: Cu 20%~25%, C≤0.003%, O≤0.003%, N≤0.003%, and the remainder is Mo and unavoidable impurities.

[0010] At the same time, the present invention also discloses a method for preparing the above-mentioned molybdenum-copper alloy plate resistant to molten salt corrosion, characterized in that the method comprises the following steps:

[0011] Step 1: Prepare materials: Select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate;

[0012] Step 2, ball milling and powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powders are ball milled and mixed on a powder mixer to obtain a mixed powder;

[0013] Step 3, cold isostatic pressing: putting the mixed powder obtained in step 2 into a rubber mold and pressing it into a block by a cold isostatic press;

[0014] Step 4, hydrogen sintering: putting the block obtained by pressing in step 3 into a sintering furnace, and then filling it with hydrogen, and hydrogen sintering is performed by segmented heating. After the insulation is completed, the furnace is cooled to room temperature to obtain a molybdenum-copper alloy ingot;

[0015] Step 5, low temperature rolling: warm rolling the molybdenum-copper alloy ingot obtained in step 4, and polishing the surface after rolling to obtain a molybdenum-copper alloy slab;

[0016] Step 6: Annealing: Place the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, then fill it with argon gas for annealing. After the insulation is completed, cool the furnace to room temperature to obtain a molybdenum-copper alloy plate.

[0017] The present invention strictly controls the impurity elements in the molybdenum-copper alloy raw materials and the preparation process, on the one hand, to ensure the accuracy and uniformity of the composition of the molybdenum-copper alloy after hydrogen sintering, to ensure that the added copper element does not segregate; on the other hand, to ensure that the structure of the final molybdenum-copper alloy product is completely recrystallized, the grains are refined, and the comprehensive mechanical properties of the molybdenum-copper alloy are improved.

[0018] The above method is characterized in that the mass purity of the high-purity molybdenum powder in step 1 is above 99.95%, the Fisher particle size is 2μm~8μm, and the mass purity of the high-purity copper powder is above 99.8%, and the particle size is 300 mesh. The present invention strictly controls the purity and particle size of the raw material powder. On the one hand, it ensures that the impurity content of the metal element is extremely low after sintering into an ingot, and will not have a negative impact on the mechanical properties and corrosion properties of the alloy; on the other hand, it ensures that the powder is mixed more evenly to avoid the occurrence of component segregation after sintering.

[0019] The above method is characterized in that the ball milling powder mixing in step 2 adopts a horizontal powder mixer, the speed of the ball milling powder mixing is 150rpm~200rpm, the powder mixing time is 20h~24h, and 3mm diameter zirconia balls and 5mm diameter zirconia balls are added in a mass ratio of 4:3 during the ball milling powder mixing. The present invention adopts a horizontal powder mixer and adds grinding balls to ensure that the matrix raw material and the alloy raw material can be more fully mixed, ensuring the uniformity of the ingot composition after sintering.

[0020] The above method is characterized in that the loading force of the cold isostatic press in step 3 is 250MPa-300MPa, and the holding time is 10min-15min. The present invention uses cold isostatic pressing to press the powder into a block, and the density of the block is ensured by controlling the pressure and the holding time, thereby ensuring the smooth progress of subsequent pressureless sintering.

[0021] The above method is characterized in that the process of hydrogen sintering in step 4 is: first heating to 800℃~900℃ and keeping warm for 1h~3h, then continuing to heat to 1200℃~1300℃ and keeping warm for 1h~3h, and then cooling the furnace to room temperature. The present invention adopts segmented heating, first keeping warm at 800~900℃, on the one hand, to remove the internal gas of the sintered blank, on the other hand, to eliminate the internal stress in the compression deformation, and to give it a certain strength through pre-burning to avoid cracking; then keeping warm at 1200℃~1300℃ to complete high-temperature copper infiltration, making it easier to metallize.

[0022] The above method is characterized in that the temperature of the warm rolling treatment in step 5 is 300°C to 450°C, the total deformation is 60% to 75%, and the furnace is returned to heat preservation after 2 to 4 passes of rolling, and graphite high-temperature grease is applied to the surface of the treated object before heating. The present invention uses warm rolling deformation to make molybdenum and copper more closely combined on the one hand, and improve the composition uniformity of the molybdenum-copper alloy on the other hand, thereby achieving the purpose of improving mechanical properties.

[0023] The above method is characterized in that the temperature of the annealing treatment in step 6 is 700°C to 900°C and the holding time is 1h to 3h. The present invention ensures that the deformed molybdenum-copper alloy sheet structure undergoes recrystallization through annealing, and the obtained structure is more uniform, thereby improving the plasticity of the rolled molybdenum-copper alloy.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The molybdenum-copper alloy plate of the present invention uses molybdenum as a matrix and copper as a main alloying element. The ratio of molybdenum to copper elements is determined from the perspective of thermodynamics and mechanical properties to ensure that the molybdenum-copper alloy plate has excellent resistance to molten salt corrosion and good mechanical properties.

[0026] 2. The present invention adopts powder metallurgy to prepare an ingot with good chemical composition uniformity, and then improves the bonding effect and organizational morphology of molybdenum and copper in the ingot through low-temperature rolling and annealing heat processing, thereby obtaining a molybdenum-copper alloy plate with good comprehensive mechanical properties and resistance to fluoride molten salt corrosion.

[0027] 3. The present invention improves the density and composition uniformity of the molybdenum-copper alloy ingot prepared by powder metallurgy through low-temperature rolling, thereby solving the problem of poor mechanical properties of the molybdenum-copper alloy ingot caused by the above-mentioned problems.

[0028] 4. The present invention obtains a recrystallized molybdenum-copper alloy plate by annealing the molybdenum-copper alloy slab obtained after warm rolling deformation, thereby improving the problem of insufficient plasticity of the rolled slab and making the molybdenum-copper alloy plate have better processing performance.

[0029] 5. The tensile strength of the molybdenum-copper alloy sheet prepared by the present invention can reach 600MPa~700MPa, the elongation is 5%~10%, and the weight loss per unit area after immersion in FLiNaK molten salt at 700℃ for 600h is 1.37mg / cm 2 It has good mechanical properties and resistance to molten salt corrosion, meets the use conditions of molten salt reactor structural materials, and provides a new idea for the selection of molten salt reactors.

[0030] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the metallographic diagram of the molybdenum-copper alloy plate prepared in Example 1 of the present invention.

[0032] Figure 2 This is a graph showing the corrosion weight loss of the molybdenum-copper alloy plates prepared in Examples 1 to 4 of the present invention in a FLiNaK molten salt environment at 700°C. DETAILED DESCRIPTION

[0033] Example 1

[0034] The molybdenum-copper alloy plate resistant to molten salt corrosion in this embodiment is composed of the following elements in percentage by mass: Cu 15%, C 0.002%, O 0.005%, N 0.003%, and the remainder is Mo and unavoidable impurities.

[0035] The molybdenum-copper alloy plate material resistant to molten salt corrosion in this embodiment comprises the following steps:

[0036] Step 1, prepare materials: select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate; the mass purity of the high-purity molybdenum powder is more than 99.95%, and the Fisher particle size is 2μm~8μm, and the mass purity of the high-purity copper powder is more than 99.8%, and the particle size is 300 mesh;

[0037] Step 2, ball milling powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powder is ball milled on a powder mixer to obtain a mixed powder; the ball milling powder mixing adopts a horizontal powder mixer, the speed of the ball milling powder mixing is 150rpm, the powder mixing time is 24h, and when the ball milling powder is mixed, 3mm diameter zirconium oxide balls and 5mm diameter zirconium oxide balls are added in a mass ratio of 4:3;

[0038] Step 3, cold isostatic pressing: the mixed powder obtained in step 2 is placed in a rubber mold and pressed into a block by a cold isostatic press. The loading force of the cold isostatic press is 250 MPa and the holding time is 15 min.

[0039] Step 4, hydrogen sintering: put the block obtained by pressing in step 3 into a sintering furnace, and then fill it with hydrogen, first heat it to 800°C at a heating rate of 10°C / min and keep it for 3 hours, then continue to heat it to 1200°C at a heating rate of 5°C / min and keep it for 3 hours, then cool the furnace to room temperature to obtain a molybdenum-copper alloy ingot;

[0040] Step 5, low temperature rolling: smear graphite high temperature grease on the surface of the molybdenum-copper alloy ingot obtained in step 4, then put it into a muffle furnace and heat it to 300°C for 30 minutes, and then perform warm rolling deformation, with a total deformation of 60%. During rolling, put it into the furnace for 5 minutes after each 3 passes, and polish the surface after rolling to obtain a molybdenum-copper alloy slab;

[0041] Step 6: Annealing: Place the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, then fill it with argon, heat it to 700°C at a heating rate of 10°C / min and keep it for 3 hours for annealing. After the insulation is completed, cool the furnace to room temperature to obtain a molybdenum-copper alloy plate.

[0042] The mechanical properties of the molybdenum-copper alloy plate prepared in this embodiment were tested, and the results are shown in Table 1 below:

[0043] Table 1

[0044]

[0045] It can be seen from Table 1 that the molybdenum-copper alloy plate prepared in this embodiment has good mechanical properties.

[0046] Figure 1 This is the metallographic diagram of the molybdenum-copper alloy plate prepared in this embodiment. Figure 1 It can be seen that the molybdenum-copper alloy plate obtains a recrystallized structure after annealing, and the grain size is uniform, so it has good plasticity.

[0047] The molybdenum-copper alloy plate prepared in this embodiment was cut into hanging samples, and then subjected to a molten salt corrosion resistance test in a LiF-NaF-KF (46.5:11.5:42, molar percentage) mixed molten salt at 700°C. After testing, the molybdenum-copper alloy prepared in this embodiment had a unit area weight loss of 1.67 mg / cm after being immersed in the above molten salt for 600 hours. 2 (like Figure 2 The alloy has excellent resistance to molten salt corrosion.

[0048] Example 2

[0049] The molybdenum-copper alloy plate resistant to molten salt corrosion in this embodiment is composed of the following elements in percentage by mass: Cu 20%, C 0.002%, O 0.003%, N 0.003%, and the remainder is Mo and unavoidable impurities.

[0050] The molybdenum-copper alloy plate material resistant to molten salt corrosion in this embodiment comprises the following steps:

[0051] Step 1, prepare materials: select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate; the mass purity of the high-purity molybdenum powder is more than 99.95%, and the Fisher particle size is 2μm~8μm, and the mass purity of the high-purity copper powder is more than 99.8%, and the particle size is 300 mesh;

[0052] Step 2, ball milling powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powder is mixed by ball milling on a powder mixer to obtain a mixed powder; the ball milling powder mixing adopts a horizontal powder mixer, the speed of the ball milling powder mixing is 180rpm, the powder mixing time is 22h, and when the ball milling powder is mixed, 3mm diameter zirconium oxide balls and 5mm diameter zirconium oxide balls are added in a mass ratio of 4:3;

[0053] Step 3, cold isostatic pressing: the mixed powder obtained in step 2 is placed in a rubber mold and pressed into a block by a cold isostatic press. The loading force of the cold isostatic press is 280 MPa and the holding time is 10 min.

[0054] Step 4, hydrogen sintering: put the block obtained by pressing in step 3 into a sintering furnace, and then fill it with hydrogen, first heat it to 850°C at a heating rate of 10°C / min and keep it for 2h, then continue to heat it to 1250°C at a heating rate of 5°C / min and keep it for 2h, then cool the furnace to room temperature to obtain a molybdenum-copper alloy ingot;

[0055] Step 5, low temperature rolling: smear graphite high temperature grease on the surface of the molybdenum-copper alloy ingot obtained in step 4, then put it into a muffle furnace and heat it to 350°C for 30 minutes, and then perform warm rolling deformation, with a total deformation of 70%. During rolling, put it into the furnace for 5 minutes after each 3 passes, and polish the surface after rolling to obtain a molybdenum-copper alloy slab;

[0056] Step 6: Annealing: Place the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, then fill it with argon, heat it to 800°C at a heating rate of 10°C / min and keep it for 2 hours for annealing. After the insulation is completed, cool the furnace to room temperature to obtain a molybdenum-copper alloy plate.

[0057] The mechanical properties of the molybdenum-copper alloy plate prepared in this embodiment were tested, and the results are shown in Table 2 below:

[0058] Table 2

[0059]

[0060] It can be seen from Table 2 that the molybdenum-copper alloy plate prepared in this embodiment has good mechanical properties.

[0061] The molybdenum-copper alloy plate prepared in this embodiment was cut into hanging samples, and then subjected to a molten salt corrosion resistance test in a LiF-NaF-KF (46.5:11.5:42, molar percentage) mixed molten salt at 700°C. After testing, the molybdenum-copper alloy prepared in this embodiment had a unit area weight loss of 1.59 mg / cm after being immersed in the above molten salt for 600 hours. 2 (like Figure 2 The alloy has excellent resistance to molten salt corrosion.

[0062] Example 3

[0063] The molybdenum-copper alloy plate resistant to molten salt corrosion in this embodiment is composed of the following elements in percentage by mass: Cu 25%, C 0.002%, O 0.003%, N 0.003%, and the remainder is Mo and unavoidable impurities.

[0064] The molybdenum-copper alloy plate material resistant to molten salt corrosion in this embodiment comprises the following steps:

[0065] Step 1, prepare materials: select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate; the mass purity of the high-purity molybdenum powder is more than 99.95%, and the Fisher particle size is 2μm~8μm, and the mass purity of the high-purity copper powder is more than 99.8%, and the particle size is 300 mesh;

[0066] Step 2, ball milling powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powder is mixed by ball milling on a powder mixer to obtain a mixed powder; the ball milling powder mixing adopts a horizontal powder mixer, the speed of the ball milling powder mixing is 180rpm, the powder mixing time is 22h, and when the ball milling powder is mixed, 3mm diameter zirconium oxide balls and 5mm diameter zirconium oxide balls are added in a mass ratio of 4:3;

[0067] Step 3, cold isostatic pressing: the mixed powder obtained in step 2 is placed in a rubber mold and pressed into a block by a cold isostatic press. The loading force of the cold isostatic press is 280 MPa and the holding time is 10 min.

[0068] Step 4, hydrogen sintering: put the block obtained by pressing in step 3 into a sintering furnace, and then fill it with hydrogen, first heat it to 850°C at a heating rate of 10°C / min and keep it for 2h, then continue to heat it to 1250°C at a heating rate of 5°C / min and keep it for 2h, then cool the furnace to room temperature to obtain a molybdenum-copper alloy ingot;

[0069] Step 5, low temperature rolling: smear graphite high temperature grease on the surface of the molybdenum-copper alloy ingot obtained in step 4, then put it into a muffle furnace and heat it to 350°C for 30 minutes, and then perform warm rolling deformation, with a total deformation of 70%. During rolling, put it into the furnace for 5 minutes after each 3 passes, and polish the surface after rolling to obtain a molybdenum-copper alloy slab;

[0070] Step 6: Annealing: Place the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, then fill it with argon, heat it to 800°C at a heating rate of 10°C / min and keep it for 2 hours for annealing. After the insulation is completed, cool the furnace to room temperature to obtain a molybdenum-copper alloy plate.

[0071] The mechanical properties of the molybdenum-copper alloy plate prepared in this embodiment were tested, and the results are shown in Table 3 below:

[0072] Table 3

[0073]

[0074] It can be seen from Table 3 that the molybdenum-copper alloy plate prepared in this embodiment has good mechanical properties.

[0075] The molybdenum-copper alloy plate prepared in this embodiment was cut into hanging samples, and then subjected to a molten salt corrosion resistance test in a LiF-NaF-KF (46.5:11.5:42, molar percentage) mixed molten salt at 700°C. After testing, the molybdenum-copper alloy prepared in this embodiment had a unit area weight loss of 1.44 mg / cm after being immersed in the above molten salt for 600 hours. 2 (like Figure 2 The alloy has excellent resistance to molten salt corrosion.

[0076] Example 4

[0077] The molybdenum-copper alloy plate resistant to molten salt corrosion in this embodiment is composed of the following elements in percentage by mass: Cu 40%, C 0.002%, O 0.003%, N 0.003%, and the remainder is Mo and unavoidable impurities.

[0078] The molybdenum-copper alloy plate material resistant to molten salt corrosion in this embodiment comprises the following steps:

[0079] Step 1, prepare materials: select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate; the mass purity of the high-purity molybdenum powder is more than 99.95%, and the Fisher particle size is 2μm~8μm, and the mass purity of the high-purity copper powder is more than 99.8%, and the particle size is 300 mesh;

[0080] Step 2, ball milling powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powder is mixed by ball milling on a powder mixer to obtain a mixed powder; the ball milling powder mixing adopts a horizontal powder mixer, the speed of the ball milling powder mixing is 200rpm, the powder mixing time is 20h, and when the ball milling powder is mixed, 3mm diameter zirconium oxide balls and 5mm diameter zirconium oxide balls are added in a mass ratio of 4:3;

[0081] Step 3, cold isostatic pressing: the mixed powder obtained in step 2 is placed in a rubber mold and pressed into a block by a cold isostatic press. The loading force of the cold isostatic press is 300 MPa and the holding time is 10 min.

[0082] Step 4, hydrogen sintering: put the block obtained by pressing in step 3 into a sintering furnace, and then fill it with hydrogen, first heat it to 900°C at a heating rate of 10°C / min and keep it warm for 1h, then continue to heat it to 1300°C at a heating rate of 5°C / min and keep it warm for 1h, then cool the furnace to room temperature to obtain a molybdenum-copper alloy ingot;

[0083] Step 5, low temperature rolling: smear graphite high temperature grease on the surface of the molybdenum-copper alloy ingot obtained in step 4, then put it into a muffle furnace and heat it to 400°C for 30 minutes, and then perform warm rolling deformation, with a total deformation of 75%. During rolling, put it into the furnace for 5 minutes after each 3 passes, and polish the surface after rolling to obtain a molybdenum-copper alloy slab;

[0084] Step 6: Annealing: Place the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, then fill it with argon, heat it to 900°C at a heating rate of 10°C / min and keep it for 1 hour for annealing. After the insulation is completed, cool the furnace to room temperature to obtain a molybdenum-copper alloy plate.

[0085] The mechanical properties of the molybdenum-copper alloy plate prepared in this embodiment were tested, and the results are shown in Table 4 below:

[0086] Table 4

[0087]

[0088] It can be seen from Table 4 that the molybdenum-copper alloy plate prepared in this embodiment has good mechanical properties.

[0089] The molybdenum-copper alloy plate prepared in this embodiment was cut into hanging samples, and then subjected to a molten salt corrosion resistance test in a LiF-NaF-KF (46.5:11.5:42, molar percentage) mixed molten salt at 700°C. After testing, the molybdenum-copper alloy prepared in this embodiment had a unit area weight loss of 1.37 mg / cm after being immersed in the above molten salt for 600 hours. 2 (like Figure 2 The alloy has excellent resistance to molten salt corrosion.

[0090] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A molybdenum-copper alloy plate resistant to molten salt corrosion, characterized in that: The molybdenum-copper alloy sheet is composed of the following elements in percentage by mass: Cu 15% to 40%, C ≤ 0.003%, O ≤ 0.006%, N ≤ 0.003%, and the remainder is Mo and unavoidable impurities; the mechanical properties of the molybdenum-copper alloy sheet meet the following requirements: tensile strength 600MPa to 700MPa, elongation 5% to 10%; The preparation method of the molybdenum-copper alloy plate resistant to molten salt corrosion comprises the following steps: Step 1: Prepare materials: Select high-purity molybdenum powder and high-purity copper powder as raw materials, and weigh high-purity molybdenum powder and high-purity copper powder according to the composition requirements of the target product molybdenum-copper alloy plate; Step 2, ball milling and powder mixing: the high-purity molybdenum powder and high-purity copper powder weighed in step 1 are evenly loaded into a powder mixing tank, and zirconium oxide balls are added, and the powders are ball milled and mixed on a powder mixer to obtain a mixed powder; Step 3, cold isostatic pressing: putting the mixed powder obtained in step 2 into a rubber mold and pressing it into a block by a cold isostatic press; Step 4, hydrogen sintering: putting the block obtained by pressing in step 3 into a sintering furnace, then filling it with hydrogen, and performing hydrogen sintering by segmented heating. After the insulation is completed, the furnace is cooled to room temperature to obtain a molybdenum-copper alloy ingot; the hydrogen sintering process is: first heating to 800°C~900°C for 1h~3h, then continuing to heat to 1200°C~1300°C for 1h~3h, and then cooling the furnace to room temperature; Step 5, low temperature rolling: the molybdenum-copper alloy ingot obtained in step 4 is subjected to warm rolling treatment, and the surface is polished clean after rolling to obtain a molybdenum-copper alloy slab; the temperature of the warm rolling treatment is 300°C to 450°C, the total deformation is 60% to 75%, and the ingot is returned to the furnace for heat preservation after 2 to 4 passes of rolling, and graphite high temperature grease is applied to the surface of the treated object before heating; Step 6, annealing: put the molybdenum-copper alloy slab obtained in step 5 into an annealing furnace, and then fill it with argon gas for annealing. After the insulation is completed, the furnace is cooled to room temperature to obtain a molybdenum-copper alloy plate; the annealing temperature is 700°C~900°C, and the insulation time is 1h~3h.

2. The molybdenum-copper alloy plate resistant to molten salt corrosion according to claim 1, characterized in that: The following elements are present in percentage by mass Composition: Cu 20%~25%, C≤0.003%, O≤0.003%, N≤0.003%, the balance is Mo and unavoidable impurities.

3. The molybdenum-copper alloy plate resistant to molten salt corrosion according to claim 1, characterized in that: The mass purity of the high-purity molybdenum powder in step 1 is above 99.95%, and the Fisher particle size is 2 μm to 8 μm. The mass purity of the high-purity copper powder is above 99.8%, and the particle size is 300 mesh.

4. The molybdenum-copper alloy plate resistant to molten salt corrosion according to claim 1, characterized in that: The ball milling powder mixing in step 2 adopts a horizontal powder mixer, the rotation speed of the ball milling powder mixing is 150rpm~200rpm, the mixing time is 20h~24h, and 3mm diameter zirconia balls and 5mm diameter zirconia balls are added in a mass ratio of 4:3 during the ball milling powder mixing.

5. The molybdenum-copper alloy plate resistant to molten salt corrosion according to claim 1, characterized in that: The loading force of the cold isostatic press in step 3 is 250MPa~300MPa, and the holding time is 10min~15min.

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