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Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation

Professor Lv zhaoping's team in the state key laboratory of new metal materials of our university innovated the alloy design concept and developed a kind of ultra-high strength and toughness martensitic aging steel with high-density nano reinforcement by using different strengthening mechanisms. Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation, a breakthrough research progress of materials scientists from mainland China, was published online by the top international academic journal Nature on April 102017.

Steel material is to modern society what bone is to human body, it is the backbone that supports national economy. In aerospace, new energy, advanced equipment manufacturing, national defense security and high-speed trains and other advanced transportation industries, ultra-high strength and toughness steel is one of the key materials for realizing lightweight design, energy conservation and emission reduction. Strength of steel material is martensitic steel, and its reinforcement mainly depends on the steel material contains a lot of expensive cobalt, molybdenum and titanium alloy elements, pass complex and demanding strict smelting and heat treatment process, so the price does not poor, become a high-end star of iron and steel industry, generally limited to important structures in the aerospace and Marine technology, such as rocket engine shell, landing gear, such as pieces of important mould and key link.

How can the strength of steel materials be further improved? And at the same time reduce the cost and simplify the process? Professor lu zhaoping's team innovated the alloy design concept, significantly reduced the content of precious elements such as molybdenum, completely free of expensive alloy elements such as cobalt and titanium, and replaced with common civilian elements such as aluminum and carbon, using different strengthening mechanisms, developed a high-density nano-strengthened ultra-high strength and toughness maraging steel. The new super high strength and toughness steel not only reduces the cost and the production process is simple, but also the tensile strength reaches 2200MPa and the plasticity is not less than 8%.

Steel as a kind of traditional structural material, is widely believed that further improve the strength and toughness is very difficult, the original results at the same time of breakthrough steel material limit strength 2000 mpa, can still maintain good toughness and plasticity, not only effectively expand the high-end practical engineering applications of steel material, its design concept also is expected to be applied to other alloy, for a kind of ultra-high strength to open a new research idea of design and development. As a steel superpower, China as the country with the largest emissions of greenhouse gases at the same time, in the face of tremendous environmental pressure, the development of high-end, iron and steel industry to achieve industrial upgrading is very urgent, from Beijing university of science and technology, decades of accumulation of original traditional metal materials research has important significance in the development of China's iron and steel industry, the leading shall be realized effectively boost steel power "China dream".