The Hero Behind the Scenes Breaking Through the Key Technologies of MIM for Titanium Alloy Metal Injection Molding

The "Hero Behind the Scenes" Breaking Through the Key Technologies of Titanium Metal Injection Molding

——On Xu Lei, an outstanding Communist Party member of the Chinese Academy of Sciences who "serves the country with science and technology in a new era"

Strict and realistic, conscientious and innovative... This is a true portrayal of Xu Lei, a researcher at the Institute of Metals, Chinese Academy of Sciences.

Xu Lei is not only a front-line scientific researcher, but also an excellent Communist Party member. He led the team to break through a number of technical bottlenecks, presided over and completed a number of scientific research tasks, and made a series of original achievements in the field of titanium alloy powder metallurgy research.

Recently, Xu Lei was awarded the honorary title of Excellent Communist Party Member of the Chinese Academy of Sciences for "Serving the Country with Science and Technology in a New Era".

Strengthen the ideals and beliefs of Party members

As a member of the Communist Party, Xu Lei is always strict with himself according to the standards of a member of the Party. He has played a good role as a pioneer and model of the Communist Party in the study of political theory, tackling key problems in science and technology, contacting the masses and abiding by laws and disciplines. With full work enthusiasm, solid work style and excellent work achievements, he has a good reputation among the staff. Xu Lei told the China Science Daily: "Last year, after I participated in the training class for young cadres organized by the Shenyang Branch of the Chinese Academy of Sciences in the revolutionary holy land of Jinggangshan, I strengthened my ideal and belief of being a qualified Communist Party member." When getting along with colleagues, Xu Lei always treats everyone with the attitude of "being kind to others", and transmits the warmth of the Party organization to each colleague in the team through himself. He always said: "Everyone is a happy family behind him. Only when his personal thoughts are improved and his attitude is positive can the family behind him be stable and happy." When participating in the organization activities, Xu Lei has always been proactive, regardless of gains and losses, so that the glorious title of "Party member" shines on him.

Assisting the First Flight of the "Long Five Year Plan"

Xu Lei has been engaged in the research and development of titanium injection molding alloys and near net shaped products for a long time. In his daily work, he attaches importance to playing the vanguard and exemplary role of Party members, and successfully breaks through the key technologies of powder metallurgy hydrogen pump impellers through unremitting efforts, making important contributions to the successful first flight of the "Long Five Year Plan". The Ti-5Al-2.5Sn ELI hydrogen pump impeller is a key component for fuel pressurization of liquid hydrogen and liquid oxygen engines for high thrust launch vehicles necessary for the second phase of the lunar exploration project and the future space station and lunar landing program under research in China. "The casting impeller contains casting defects, and accidents occur frequently during high-speed operation. As a result, powder metallurgy near net forming technology (also known as powder casting abroad, which is an upgraded version of precision casting) has become a development trend and has been applied in the United States and Europe." Xu Lei told the reporter, "This technology was previously blank in China, which seriously restricted the development of China's aerospace engineering models."

In April 2009, the national major project of titanium metal injection molding impeller was officially established, and Metal Institute won the competition due to its advantages in technical solutions. As the head of near net forming technology, Xu Lei has conquered three key technologies for the development of powder impeller since 2009.

Xu Lei explained that, first of all, we obtained excellent mechanical properties by improving the cleanliness of raw powder and optimizing the matching of powders with different sizes, which laid a solid material performance foundation for ensuring the reliability of impeller performance. Subsequently, by studying the mechanism of hot isostatic pressing densification of titanium metal injection molding, we developed the accurate size prediction and control technology of near net shaped components, which improved the consistency of leaf shape size from a deviation of more than 20% to less than 5%, reaching the technical indicators required by the application for the first time. Finally, in the process of trial production of products, stable process curing and small batch production, we constantly developed, improved and optimized the design, and finally established a complete set of powder pretreatment and near net forming devices, developed relevant technologies, and formed the R&D and small batch production capacity of hydrogen pump impeller manufacturing for the first time.

On November 3, 2016, with the perfect first flight of "Long March 5", the impeller products provided by metal became the first titanium alloy powder metallurgy rotating parts that passed the rocket engine flight assessment in China, marking a comprehensive breakthrough in the key technology of titanium metal injection molding hydrogen pump impeller in China. The technology will also be used for the larger thrust engines required for the subsequent space stations and lunar landing plans, with broad application prospects.

"In the next ten years, we will also have many opportunities to undertake more research and development tasks of key components for large transport, and through experience, we will have more technical advantages in domestic competition." Xu Lei said.

In April 2017, with the approval of the Central Committee, the Ministry of Human Resources and Social Security, the Ministry of Industry and Information Technology, the State Administration of Science, Technology and Industry for National Defense, the State owned Assets Supervision and Administration Commission, and the Political Work Department of the Central Military Commission decided to award the honorary title of "Outstanding Contributors to the First Flight Mission of the Long March 5 Launch Vehicle" to 40 units nationwide, and the honorary title of "Outstanding Contributors to the First Flight Mission of the Long March 5 Launch Vehicle" to 259 comrades nationwide. Among them, the research team of the Institute of Metals for lightweight high-strength alloy parts won the honorary title of "Outstanding Contributor to the First Flight Mission of the Long March 5 Launch Vehicle", becoming the only unit of the Chinese Academy of Sciences to win this honor, and Xu Lei won the honorary title of "Outstanding Contributor to the First Flight Mission of the Long March 5 Launch Vehicle".

As the first titanium injection molded rotating part applied in the aerospace field in China, the successful development of the hydrogen pump impeller in the charge of Xu Lei marks that the Institute of Metals has expanded the direction of titanium alloy powder metallurgy and has an absolute advantage in China, providing good conditions for the promotion and application of this technology in other industries and personnel training.

Popularize powder forming technology

In the scientific research team led by Xu Lei, more than 70% of the members are party members, and the career staff with doctorate degrees in the team are all party members. It is a truly scientific research team led by party members. Xu Lei often educates the party members in the team in his work: "We should have the spirit of" suffering first and enjoying later ". We should do more than ordinary people, and use major achievements to help the national science and technology cause develop better and faster." Under the leadership of Xu Lei, the team has undertaken a number of major research projects of national ministries and commissions. During the "Twelfth Five Year Plan" period, the team had a good foundation for the development of Ti Al intermetallic compounds through continuous technical breakthrough, and broke through a series of key technologies on the powder forming of brittle materials. The team has completed the development of powder metallurgy Ti2AlNb low-pressure turbine guide assembly, overcome the process problems such as accurate size control and performance consistency control, and delivered several sets of low-pressure turbine guide assembly. The team applied this technology to aeroengines for the first time in the world.

In 2015, Xu Lei's team began to develop the key components of the turbine pump unit of China's new generation launch vehicle, including more than a dozen products such as impellers, various supporting models, and materials including titanium alloys and superalloys. In addition, Xu Lei's team has independently researched and developed titanium alloy powder metallurgy near net forming technology, developed relevant special equipment, and built a platform for research and development and small batch production of titanium alloy powder metallurgy complex components. It is one of the first units in China to realize the engineering application of titanium alloy powder metallurgy hot isostatic pressing technology. The research team led by Xu Lei has become the only research team for the complete set of aerospace engine powder metallurgy products in China, which is also conducting new exploration in the civil field.

Xu Lei told the reporter: "Around 2014, our team cooperated with General Motors of the United States on a project - powder metallurgy titanium aluminum alloy automobile coupling rod, and also cooperated with Airbus to complete the lean powder and wire additive manufacturing project."

At present, the development of powder metallurgy technology in China has just started, and users and design units have gradually realized the characteristics and advantages of this new process. Xu Lei also pointed out: "At present, the bottleneck of the development of powder metallurgy near net forming technology is the lack of a systematic and professional mold design and densification simulation and prediction team. The prediction of accurate size often depends on experience, resulting in relatively low efficiency and high cost. On the whole, because the technology has a good prospect of promotion and application, these difficulties and technical bottlenecks are expected to be broken through in the future."