Aluminum is the national economic construction and national security an important engineering material.But so far no breakthroughs in key technology for preparation of aluminum alloy with high performance, high performance aluminum alloy material for many key models still rely on imports, high performance aluminum alloys research and development also has a lot of work to wait for the people to do it.
Aluminum alloy with high performance in several ways, alloying and toughening of which are nearly 20 years research on high performance aluminum fronts.So-called micro-alloyed and toughening usually refers to mass percentage is less than 0.5% of trace elements, or compound added to aluminum in order to significantly improve alloy strength and toughness of a technology.Among them, adds a particularly notable scandium.
Scandium as a transition element and rare-earth elements added to aluminum and aluminum alloy, can not only significantly refined grain, raising recrystallization temperature of cast alloys to improve strength and toughness of the alloy, and can significantly improve the weldability of aluminum alloys, heat resistance, corrosion resistance, thermal stability and resistance to neutron irradiation damage effects.
Therefore, metal is considered to be a new generation of high-performance aluminum alloys for aerospace, ships, weapons material.Nearly 20 years, the international materials community, particularly the former Soviet Union, due to the military strategic needs, done a lot of research and development of Al-SC alloy.Scandium aluminum alloy started late in China, there are only a few in the mid 90 several review articles.However, this new alloys in Aerospace's outstanding performance has aroused keen interest in the defense industry sector, and the Department expects domestic was immediately carried out research in this area.“The State needs is our goal! ”Subject leader Professor Yin zhimin is keenly feel that this information is of great value.The 1987 Canada University of Toronto scholar of returned overseas Chinese, and has long been engaged in research on high performance aluminum, led a group of young students in the research room immediately began the arduous explorations and practice in this area.
Second, trace SC and zirconium main to Al3 (Sc,Zr) I and Al3 (Sc,Zr) II two species aluminum of property forms exists, aluminum of property of crystal structure for surface heart cubic, lattice constants for 0.410nm, former is alpha (Al) substrate most effective of grain refinement agent, which and substrate total lattice, strongly nail tied bit wrong and Asia Crystal community, it can strongly inhibition alloy hot deformation process and cold plates annealing process of again Crystal;Third, strengthening mechanisms of trace SC and ZR in aluminum alloys for fine-grain strengthening and substructure strengthening aluminum and scandium zirconium compounds caused by particle precipitation hardening.Paper trace Sc and Zr effect on microstructure and properties of Al-mg alloy and the effect of trace Sc and Zr on properties of Al-Zn-Mg alloy, respectively, in the field of materials United Kingdom well-known publications of the materials science and engineering, and Russia renowned publications published in the non-ferrous metals, SCI him dozens of times.From Korea, and France, and Germany, and Japan, researchers wrote, or through E-mail requests for information.Professor Yin zhimin during his trip to Moscow, many times with metal researcher Professor Zacharov and Professor feiladuofu carried out academic exchanges.
Research where to start?Research Group of comrades agreed that "research should first start from the Foundation, based in prison can do great things. ”Add trace scandium to aluminium in can dramatically improve the performance of alloy, what is this magic?Research Group supported by the National Natural Science Foundation of China, the trace amount of scandium in aluminum-magnesium alloy and mechanism study on existent form.They designed a series of contrasting alloy, study of trace scandium to target alloy grain size, recrystallization behavior and to alloy strength and impact toughness.Found a number of significant findings:First, add trace scandium and zirconia add good results than individual, scandium, zirconium compound micro-alloying is effective means of Al-mg alloy toughness;
After significant breakthroughs in basic research on metal followed by research and development is an issue of Al-SC alloys.Because trace scandium joined only by Al-SC alloy to aluminum alloy, the "can't make bricks without straw".Research found that SC is rich in resources.Early 90, China also is the world's leading supplier of scandium oxide primary products on the market, the key question is how to convert the scandium oxide aluminium-scandium alloys."Scandium oxide thermal basic research on new technology for preparation of Al-SC alloys", supported by national Natural Science Foundation, the team of different reaction Thermodynamics of systems-thermal reduction calculated on the basis of, screened the two routes to experiment.Ultimate scandium oxide as raw materials to industry, the use of scandium oxide-thermal reduction method was successfully fabricated aluminium-scandium alloys, subsequent development of preparation and properties of Al-SC alloy plate shows that preparation of Al-SC alloys is well positioned to meet the needs of development of industrial metal.On this basis, research group declared a national invention patent, 2002 authorized a patent for invention.
As China's national strength grows, has included the study of Al-mg-SC alloy state key research projects, scientific research and seize the opportunity.In Technology Department 973 project "improve aluminum material quality of based research" and "XV" research project of support Xia, in trace SC, and zirconium in aluminum magnesium Department and the aluminum zinc magnesium Department alloy in the of micro-alloy of research results of guide Xia, topics group in domestic lead development success has Al-Mg-Sc-Zr and Al-Zn-Mg-Sc-Zr two a alloy prototype, and not added SC and zirconium of similar alloy compared to, alloy tensile strength and yield strength improve has 25%, and plastic still respectively keep in 13% and 10% High standard.Meanwhile, the composite micro-alloyed with scandium, zirconium and toughening research has been extended to 2 863 projects and one "plan key item.
After 8 years of hard work, relying on the national key disciplines of school of material physics and chemistry, formed a team from Canada, and Japan, and Russia, such as academic team composed of returned overseas Chinese young scholars.Who has undertaken several metal-related national natural science Fund, the 973 Program, 863 Program, "ten five" national key scientific research projects such as research and military facilities, organized the international seminar on metal, near dozens of high level papers published, has had a positive impact at home and abroad.
In order to adapt to the new situation of development, innovation team headed by Professor Yin zhimin increase the intensity of research and development of aluminium-scandium alloys, on the one hand, they use precipitation of scientific research funds, Centre for materials engineering within the school has invested more than 200,000 yuan to build a pilot production line in Al-SC alloys, for domestic users supplied "badge" Al-SC alloys;The other hand, cooperation with the aluminum backbone enterprise in the country, shared national research development tasks, and strive to scandium, zirconium compound micro-alloying toughening theory applied to engineering practice, and over the next 10 years, and aluminum backbone enterprise in the country to establish a new system of our own high-performance metal.
At present, the Central South University and Northeast light alloy processing limited liability company and the Southwest Aluminum Company Ltd, to assume Al-SC alloys "ten five" key State projects began commercial test.They had captured the compound plate and its welding wire design and control technology of micro-alloying elements, scandium alloy preparation zirconium and add technology, Al-mg-SC alloy plate rolling technology, extrusion technology for zirconium alloy Al-mg-SC and forging technology, successfully developed strength and high-toughness welded Al-Mg-Mn-Sc-Zr alloy sheets, extruded products, forgings and equipped with wire.
Can be anticipated in the near future, with independent intellectual property right in China's large-size metal forgings, plates, extruded products, will be put into the field of aerospace, aviation, weapon, ship.