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Preparation method of high-performance ultra-fine grain molybdenum and lanthanum alloy

A molybdenum-lanthanum alloy and ultra-fine-grained technology, which is applied in the field of molybdenum alloy materials, can solve the problems of low yield strength, tensile strength, reducing the bonding force between grain boundaries, and reducing the performance of molybdenum alloys, so as to reduce the sintering temperature and Effects of sintering time, grain refinement, and improvement of sintering efficiency

Active Publication Date: 2020-05-29
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] When preparing molybdenum alloy, because molybdenum alloy powder is very sensitive to temperature, it will grow rapidly when encountering high temperature during sintering, so the grain size of rare earth oxide doped molybdenum alloy prepared by traditional method is always large (usually 5-17μm), this kind of large-grain alloy will show greater brittleness, and has no problems such as high yield strength and tensile strength; secondly, the aggregation of the coarse second phase at the grain boundary will reduce the grain boundary. binding force, which further degrades the performance of molybdenum alloys

Method used

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  • Preparation method of high-performance ultra-fine grain molybdenum and lanthanum alloy
  • Preparation method of high-performance ultra-fine grain molybdenum and lanthanum alloy
  • Preparation method of high-performance ultra-fine grain molybdenum and lanthanum alloy

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Effect test

Embodiment 1

[0029] Weigh 0.325g of lanthanum nitrate with a particle size of 0.8-1.2μm and 18g of urea, dissolve them in 150mL of water and stir them evenly with a magnetic force. The temperature of the water bath is 85°C and keep warm for 1h. After filtering and washing, a white powder is obtained. Put the white powder into a tube furnace, heat up to 950°C at 10°C / min for calcination, keep it warm for 2 hours, and take out the sample to form a spherical La 2 o 3 , the spherical La in this example 2 o 3 Microscopic appearance such as figure 1 As shown, it can be seen from the figure that it is a regular spherical shape, and its average particle diameter is measured to be 85nm.

[0030] Grind industrial ammonium paramolybdate to an average particle size of 0.8 μm, then place it in a muffle furnace, raise the temperature to 550°C under a hydrogen atmosphere, and perform the first reduction for 1 hour; the first reduction is completed Afterwards, the temperature is raised to 900° C. for ...

Embodiment 2

[0034] All the process parameters in the preparation process are basically the same as in Example 1, only the SPS sintering temperature is 1500°C.

Embodiment 3

[0056] Weigh 0.2g of lanthanum nitrate with a particle size of 0.8-1.2μm and 16g of urea, dissolve them in 400mL of water and stir evenly with a magnetic force. The temperature of the water bath is 80°C, keep warm for 1.5h, filter and wash to obtain a white powder. Put the white powder into a tube furnace, heat it up to 900°C at 11°C / min for calcination, keep it warm for 1.5 hours, take out the sample and it will be a spherical La 2 o 3 , The average particle size was measured to be 70nm.

[0057] Grind industrial ammonium paramolybdate to an average particle size of 0.8 μm, then place it in a muffle furnace, raise the temperature to 500°C under a hydrogen atmosphere, and perform the first step of reduction, the reduction time is 1.2h; the first step of reduction After the end, the temperature is raised to 850°C for the second step of reduction, and the reduction time is 1.2 hours; after the end of the reaction, molybdenum powder with a thickness of about 560nm is obtained, a...

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Abstract

The invention discloses a preparation method of a high-performance ultra-fine grain molybdenum and lanthanum alloy. The preparation method comprises the following steps that 1) spherical nano La2O3 isprepared; 2) molybdenum powder is prepared; 3) mixed powder is prepared; and 4) a molybdenum alloy is prepared, and namely, after the mixed powder is subjected to weight balancing, SPS rapid sintering is performed to obtain the La2O3-Mo molybdenum alloy. According to the preparation method, a La2O3 second phase is prepared by using a water bath method, the purpose of controlling the size and theappearance of the second phase can be achieved by controlling the time length of the water bath and the size of the cooling speed, so that the very fine spherical La2O3 is obtained, particles of the second phase are smaller, so that the distribution is more uniform, and the particles are easier to enter the interiors of the Mo alloy grains, and more obvious strengthening effect is achieved. The strengthening effect of the spherical La2O3 is best, the possibility of micro-cracks is small due to the fact that the tendency of the stress concentration is small, the breaking strength can be furtherimproved, the cracks will deviate from the original main expansion direction, dislocation loops are formed, and therefore, the yield strength and tensile strength are improved.

Description

technical field [0001] The invention belongs to the technical field of molybdenum alloy materials, and in particular relates to a preparation method of a high-performance ultrafine-grained molybdenum-lanthanum alloy. Background technique [0002] Molybdenum alloy is a commonly used superalloy with many excellent properties, including high melting point, high strength, high creep and corrosion resistance, low coefficient of thermal expansion, and excellent thermal and electronic conductivity. It has a very wide range of applications in aerospace, electronic appliances, machining, military, metallurgy and other fields. With the rapid development of economy and industry, high-tech and high-performance molybdenum alloys will inevitably occupy an important position in the development of high-tech weapons and equipment, cutting-edge science and technology, and nuclear energy in the future, which obviously further increases the requirements for the performance of molybdenum alloy m...

Claims

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Application Information

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IPC IPC(8): C22C1/05C22C27/04C22C32/00B22F3/105B22F9/22C01F17/229B82Y40/00
CPCB22F3/105B22F9/22B22F2003/1051B82Y40/00C01P2004/03C01P2004/32C01P2004/64C22C1/05C22C27/04C22C32/0031Y02P10/25
Inventor 吴壮志王德志卢瑶
Owner CENT SOUTH UNIV
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