Preparation method of nanometer rare earth oxide-doped molybdenum alloy plate

Abstract

The invention provides a preparation method of a nanometer rare earth oxide-doped molybdenum alloy plate, and relates to a production processing method of a molybdenum alloy sheet. The method is characterized by comprising the following steps: taking rare earth ammonium dimolybdate as a raw material, and carrying out hydrogen reduction on the rare earth ammonium dimolybdate; pressing molybdenum alloy powder into a molybdenum plate blank under cold isostatic pressing; sintering the molybdenum alloy plate blank; forging and cogging the molybdenum alloy plate blank; alternately rolling for multiple passes; annealing followed by cold rolling into the molybdenum plate; alkali-cleaning the molybdenum plate; and annealing the molybdenum plate after alkali-cleaning. The molybdenum alloy plate prepared by the method has higher strength and higher ductility; and a molybdenum alloy pontoon formed by punching the molybdenum alloy plate has fewer defects and longer service life. The preparation method proposed in the invention has simple process, a small quantity of working procedures and easy realization of industrial production.

Description

technical field [0001] The invention discloses a preparation method of a molybdenum alloy plate doped with a nanometer rare earth oxide, and relates to a production and processing method of a molybdenum alloy plate. Background technique [0002] In the mid-to-late 1980s, countries such as Japan, Germany, Austria, and China began research on rare earth oxide-doped molybdenum alloys. The research results show that the doping of lanthanum oxide in the molybdenum alloy is beneficial to refine the grain, purify the grain boundary, improve the bending resistance and room temperature toughness; compared with pure molybdenum, the rare earth oxide doped molybdenum alloy has higher recrystallization temperature and room temperature strength, and has better high-temperature anti-sag performance; within a certain range of addition, with the increase of rare earth oxide content, the strength of the prepared molybdenum alloy material increases, and the recrystallization temperature also i...

AI Technical Summary

Problems solved by technology

[0003] 1) The size of the second phase particles is not easy to control

At present, the dispersion strengthened molybdenum alloy is mainly prepared by the liquid-solid doping method. The unavoidable droplet agglomeration phenomenon in the rare earth nitrate spraying process causes the particle size of the rare earth oxide in the alloy to be large, and it is difficult to form in the molybdenum alloy matrix. Homogenized and refined second phase particles, so the strengthening and toughening effect on molybdenum alloys is limited; if this preparation method is used, increasing the volume fraction of the second phase will inevitably cause the agglomeration of second phase particles, resulting in the molybdenum alloy material The toughness is reduced, and the deep processing performance is obviously reduced;

[0004] 2) The refinement effect on molybdenum alloy grains is not obvious

In the case of doping rare earth oxides with the same mass fraction, relative to the second phase with a small size, if the size of the doped second phase is larger, the distribution spacing in the molybdenum alloy is also larger, preventing the crystallization of the molybdenum alloy. Therefore, the effect of molybdenum grain refinement in molybdenum alloy doped with large-size second phase particles is not obvious, and the potential of fine grain strengthening and toughening of molybdenum metal cannot be fully exploited;

[0005] 3) The processing quality and service life of molybdenum alloy are low

Since the micron-sized second phase particles will form initial structural defects during processing, it will have serious adverse effects on the rolling, bending, and deep drawing of molybdenum plates, and it is also difficult to prepare high-quality, high-precision molybdenum alloys. product;

[0006] 4) The structure stability of molybdenum alloy is poor at high temperature

For some molybdenum metal products used at high temperatures, such as molybdenum boats and molybdenum heat shields, the grain structure coarsening and strength decrease caused by high-temperature recrystallization and high-temperature service are the root causes of early deformation and failure, and the micron-sized second phase Particles are difficult to effectively prevent the grain growth of molybdenum alloys during service, so they can't make a difference in improving the service life of molybdenum high-temperature parts such as molybdenum boats and molybdenum heat shields;

[0007] 5) It is difficult to avoid the introduction of interstitial impurities

However, in the process of spray doping of rare earth oxides, there is inevitably the phenomenon of polydroplets of the solution, which will make it difficult to control the size of rare earth oxides in molybdenum alloys, which may reach the order of several microns or even tens of microns, and the degree of dispersion uniformity is not ideal. , it is also difficult to avoid the introduction of interstitial impurity elements

[0009] It can be seen that the preparation process of rare earth oxide doped molybdenum alloy plate obtained by liquid-solid mixing method is complicated at present, and the size of rare earth oxide particles in the obtained molybdenum alloy plate is not easy to control, and it is difficult to obtain evenly distributed fine rare earth oxide particles, etc. Problems restrict the development and application of high-quality molybdenum alloy sheets and products

[0010] In order to effectively solve the above problems, it is necessary to develop a preparation technology with simple process and few procedures, which can ensure the formation of evenly distributed and nano-scale rare earth oxides in molybdenum alloys, so as to avoid the excessive size of rare earth oxides and the lack of Uniform distribution will lead to crack propagation and damage of molybdenum alloy plates and products due to defects in the process of processing and application, improve the yield and service life of molybdenum alloy plates and products, and improve the surface quality and processing accuracy of the processed workpieces