Rare earth titanium materials are moving towards industrialization
Titanium metal-a new battlefield for competition among nations
As we all know, titanium and titanium alloys have many excellent characteristics such as low density, high strength, corrosion resistance, and good high and low-temperature characteristics. They also have unique functions such as shape memory, superconductivity, hydrogen storage, and biocompatibility, as small as glasses frames and blood vessels. Brackets, as large as aero-engine blades, all have titanium.
According to Lu Weijie, a professor and doctoral supervisor at the School of Materials Science and Engineering of Shanghai Jiaotong University, titanium is known as "cosmic metal", "aviation metal" and "space metal", and is also known as the "third metal" after iron and aluminum. , Is a key support material in engineering technology and high-tech fields and an extremely important national defense strategy metal material. At present, the amount of titanium material and the development level of the titanium industry have become an important indicator of a country's comprehensive national strength and development.
"Looking at the world, about 80% of titanium products in the United States are used in the aviation field; Europe is planning to invest in the development of new power stations around the world, of which the Asia and Pacific regions account for the main share; in the United Kingdom, the application of titanium in the civil industry accounts for about 40%-45%; Japan is also seeking the application of titanium in equipment such as ocean temperature difference power generation and tidal power generation; seawater desalination technology has also been fully developed in Japan and the Arab region." Tong Botao said.
Tong Botao said frankly that global titanium production companies are striving to explore new application areas for metallic titanium. The amount of titanium used in these new areas has accounted for 10% of the world's total titanium materials. The application fields and consumption structure of titanium products in China are different from those of the United States, Europe, Japan, Russia, and other titanium industry powers. China uses very little in important strategic fields such as aerospace, marine engineering, nuclear power, and medical care, which is very different from developed countries. Far, there is a big gap.
In recent years, with the rapid increase in the amount of titanium used in the fields of China’s chemical industry and seawater desalination, as well as China’s large aircraft plan, the Change moon landing plan, aero-engine research and development plans, nuclear power construction plans, and marine engineering, major projects such as high-quality Titanium has generated huge demand. These projects urgently need large-scale titanium and titanium alloy profiles, pipes (pieces), forgings, plates, and strips, as well as titanium alloy near-net-shape parts, new titanium alloys, and other products.
"China's titanium industry is currently unable to meet the above needs. Many products cannot be mass-produced or even blank, and still need to be imported in large quantities." Lu Weijie said, facing the country's need to implement major projects and the upgrading of product demand in the development of related industries, To strengthen the research and development and industrialization of domestic titanium and titanium alloy materials, to improve the quality of titanium industrial products and the level of deep processing of titanium products, and to promote the upgrading and transformation of China’s titanium industry is the top priority of the entire industry, which has become the development and development of the national economy. The major issue of national defense construction has a major strategic position and role.
Break the bottleneck-composite strengthening into a new direction
"Strengthening independent innovation, vigorously developing high-end products, controlling core technologies, and entering the military industry and aerospace applications; integrating downstream end industrial chain clusters and developing subsequent applications of civilian products are the main directions for the development of titanium manufacturing." Tong Botao said.
According to Lu Weijie, traditional titanium alloys have been developed to the extreme through alloying and structural optimization to improve their performance. Only through composite strengthening can the technical barriers of traditional titanium alloys be broken, allowing titanium alloys to "play their fists" in more fields.
The scientific research team led by Lu Weijie innovatively proposed a technical route to improve the performance of titanium alloys by using multiple and multi-scale reinforcements, designed a new in-situ process, and prepared high-performance rare-earth modified titanium-based composite materials in a simple and low-cost manner. The composition and performance are optimized, and the key forming technical problems of isothermal forging and precision casting of high-performance rare earth modified titanium alloy components are solved.
"Using the in-situ patented technology of independent intellectual property rights, the performance of titanium-based composite precision casting products produced by the production of titanium-based composite materials has been improved by 15-20%, and the performance of rare-earth modified titanium-based composite materials has been achieved in aerospace, aviation, nuclear power, ships, high-end The large-scale application of equipment and other fields has met the national strategic needs." Lu Weijie said.
In addition, Lu Weijie's team also developed and designed a new in-situ processing technology. "Especially using the theory of multiphase fluid mechanics to analyze the melt stopping mechanism of different types of reinforcements on rare earth-reinforced titanium alloy materials. Based on similar physical simulation theory and generalized Darcy's law, a physical simulation of titanium alloy melt seepage feeding is given. The conditions that need to be met during flow, combined with the solidification shrinkage theory, give the shrinkage cavity formation conditions and volume criteria during the solidification and forming process of the rare-earth modified titanium alloy material." Lu Weijie said.
The related research results of titanium alloy preparation by Lu Weijie’s team have been published in well-known journals at home and abroad. In total, more than 200 academic papers have been published, more than 150 articles are included in SCI, more than 1,000 articles are cited by SCI, and more than 100 articles are included in EI. And won the 2015 National Natural Science Second Prize, China International Industry Fair Innovation Award, and the 12th China International High-tech Achievement Fair Excellent Product Award.
Industrialization-the nationalization of titanium applications
According to Lu Weijie, due to the high difficulty of titanium metal smelting and processing technology and the complex process flow, the production process design needs to overcome many technical difficulties, and many special smelting and processing technologies and special equipment are required for the smelting and processing of titanium and titanium alloys. Preparation.
Aiming at the development of isothermal forging technology for rare earth modified alloy materials to ensure the realization of the industrialization goal of isothermal forging technology for rare earth modified titanium alloy materials, the project team adopted high-temperature thermal compression plastic deformation to closely surround the material matrix alloy and ceramic particle reinforcement in the plastic deformation process Research on the high-temperature deformation behavior of particle-reinforced rare-earth-reinforced titanium alloy materials, explore the coordination mechanism of high-temperature deformation process and organization of particle-reinforced rare-earth-reinforced titanium alloy materials, and determine a suitable isothermal forging processing window.
In addition, for the development of precision casting technology for rare-earth-modified titanium alloy materials, the project team used graphite spirals to study the fluidity of composite melts in a vacuum induction furnace and analyzed temperature, reinforcement types, and content. Rare-earth modified titanium alloy materials The influence of fluidity and the mechanism of melt stagnation of rare-earth-modified titanium alloy materials, physical simulation of the filling capacity of wedge-shaped specimens of rare-earth-modified titanium alloy materials, and analysis of the role of reinforcement in the filling process of rare-earth-modified titanium alloy materials mechanism.
Using new computer simulation techniques such as finite element analysis to realize the simulation of isothermal forging process control, effectively design isothermal forging dies and forging process parameters, and efficiently and cost-effectively prepare high-performance rare earth-enhanced titanium alloy material forgings to meet high demands The design requirements of high performance, high reliability, and low-cost aviation parts provide components that can be industrially produced.
At present, the project team has provided 16 batches of particle-reinforced titanium alloy forgings to aerospace units in batches, and has been applied in batches on key national models, and has established corporate standards for high-strength, high-modulus titanium-based composites with user units.
“In terms of precision casting, through cooperation with a domestic aerospace precision casting company, using industrial casting equipment, precision castings such as particle-reinforced titanium alloy impellers and DD shells have been prepared.” Lu Weijie said that the components have been verified by users, especially The heat-resistant particle-reinforced titanium alloy impeller has passed the test in the high-temperature and complex environment, significantly improving the performance of high-end equipment. The complete set of equipment saves 10 million kilowatt-hours of electricity annually, which has produced significant social benefits.
At present, the transformation of this technological achievement has achieved good economic benefits, with an output value of 4.37 million in 2020.
