On May 5, China's Long March 5B carrier rocket successfully flew for the first time, and its near-Earth orbit carrying capacity is greater than 22 tons. It is currently China's rocket with the highest near-earth orbit carrying capacity. There is a core component in its strong heart: the hydrogen pump titanium alloy turbine is manufactured by China ZKJS Metal Research Institute to overcome the near-net forming technology of titanium alloy powder. This achievement has been applied to the first launch of Long March 5 since 2016, and it has been used to this day.
The role of the hydrogen pump titanium alloy turbine is to transport a large amount of liquid hydrogen fuel in the arrow body to the engine combustion chamber at high speed, and to mix with liquid oxygen to generate thrust. If there is a problem with the hydrogen pump turbine, the rocket will momentarily fall due to loss of power.
From 2000 to 2005, with the support of relevant state departments, the Titanium Alloy Research Department of the China ZKJS Metal Research Institute imported from abroad the construction of the first titanium alloy clean atomization powdering equipment in China. This idea is too advanced, there is no domestic demand and funding support channels. Yang Rui, the project leader and director of the titanium alloy research department, had to seek financial support from international cooperation. However, in 2006, he and European research institutions jointly applied for the Sino-European aviation cooperation project "Near-Net Forming of Titanium Alloy Powder" under the EU Sixth Framework Program. Although the cooperation project was not approved, academic exchanges continued. On May 6-9, 2008, the Sixth International Conference on Hot Isostatic Pressing was held in Long Beach, California. The European collaborators who participated in the organization of the conference hoped that Yang Rui would attend. Yang Rui was one of the four chairmen of the high-temperature structural intermetallic compound conference held in San Diego, USA in February 2008, but he could not participate because he did not get his visa in time. He did not get it until March after the meeting. He just used this Visa went to the meeting in May. At the meeting, two reports on the hot isostatic pressing of titanium alloy powder attracted the attention of Yang Rui. They were all about the preparation of hydrogen pump turbines for rocket oxyhydrogen engines: an article from the Moscow Institute of Chemical Processing, Russia, to study how to improve Powder titanium alloy performance; another article from Japan Metal Technology Co., Ltd. is to simulate the hot isostatic pressing process of powder. Hearing these two reports, Yang Rui believes that this is the application field of titanium alloy powder products.
Coincidentally, three months later, the hydrogen pump turbine of the Changzheng No. 5 hydrogen-oxygen engine was officially released as a supporting project. At that time, two units had been studying for some time, but the progress was not satisfactory.
After ZKJS has the scientific research conditions, people are the most critical factor. During the construction of the powder equipment, Yang Rui recruited Xu Lei as a doctoral student in 2002 to carry out research on titanium alloy clean powder metallurgy and reserve talents.
The hydrogen pump turbine rotates at a high speed of minus 253 degrees and bears a huge load. Whether the performance of the titanium alloy material prepared by powder metallurgy can meet the application requirements is the first challenge facing the project. The team worked overtime and overtime, and completed the entire process of master alloy, electrode, milling, cladding, hot isostatic pressing, sample processing, and performance testing in a short period of time, and optimized the parameters through trial and error. Researchers such as Lei Jiafeng and other emergency arrangements have played an important role in ensuring that the work is completed as planned.
The test environment for low-temperature mechanical properties is demanding and demanding. At that time, only the low-temperature center of the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences had the relevant conditions and qualifications. , Which provides great help for the team to obtain performance data in a timely manner.
The test results show that the performance of the prepared powder alloy is steadily higher than the technical index requirements, and a good start has greatly encouraged the team. At that time, four teams participated in the project competition. In the end, the ZKJS Metals Institute team won with a solid work foundation and detailed and detailed research programs.
The hydrogen pump turbine is a closed cavity structure, which cannot be machined inside. It requires high dimensional accuracy after forming, and the volume shrinkage of up to 30% when the powder is densified. It is extremely difficult to control the contour size of complex shapes. This is a project encounter. To the biggest technical obstacle.
At the time, Yang Rui, as the chief scientist, was undertaking a 973 project in material calculation design. The team had a good accumulation in material calculation simulation. Before embarking on the component forming test, Xu Lei carried out a large number of simulation calculations, which played an important role in optimizing the design of the package and quickly approaching the theoretical size, effectively reducing the number of necessary experimental verification rounds, and enabling large-scale compression development. The cycle becomes possible.
The cavity of the turbine is realized by placing an internal core. If a hard core is used, although it is beneficial to control the size during high-temperature forming, it is easy to crack the internal structure of the component when cooling. The use of soft cores can avoid cracks, but size control is more difficult. Because the team has mastered the key technology of the computational simulation forming process, their ability to control the size has been significantly enhanced. The so-called "YiGao people are bold". They adopted a soft core solution and successfully resolved the contradiction between dimensional accuracy and forming cracks.
Turbine removal cores require selective corrosion technology. The corrosion science and technical strength of metals are well-known in the world. Thanks to this multidisciplinary comprehensive strength, the team quickly solved this problem and optimized it with the help of Dong Junhua and others. The solution shortens the component manufacturing cycle.
On the basis of overcoming the above technical difficulties, the Metal Institute team produced qualified hydrogen pump turbine prototypes within a year and a half, providing strong support for the development of hydrogen-oxygen engines.
Comrade Zhou Guangzhao, the leader of the advisory expert group of the National 973 Program at that time, after listening to the report on the progress and results of the project, believed that the project played a guiding role in calculation and simulation on the basis of strengthening the principled research, and overcome the major technical difficulties. After being personally recommended by Comrade Zhou Guangzhao, the team leader Yang Rui won the 2010 Zhou Guangzhao Foundation Applied Science Award.
After the first flight of the Long March V rocket, the research team in April 2017 won the team award of the "Outstanding Contribution to the First Flight Mission of the Long March V Carrier Rocket" by five ministries and commissions (the only one in the Chinese Academy of Sciences), and Xu Lei received the "Outstanding Contribution to the First Flight Mission of the Long March V Carrier Rocket "Individual award.