On January 30, 2019, the latest research results of the research team on the preparation of high-strength plastic ultrafine-grain eutectic high-entropy alloys by the research team of Professor Yang Yunbo, a Yangtze River scholar, School of Materials, Shanghai University, based on Enhanced strength–ductility synergy in ultrafine-grained eutectic high-entropy alloys by titled inheriting microstructural lamellae, published in the internationally renowned journal Nature Communications
As we all know, the realization of ultra-high strength plasticity of metal materials is of great significance for the safety, long life, energy saving and emission reduction of metal materials. How to improve the strong plasticity of metal materials at the same time has always been a major scientific problem in the field of structural materials. Eutectic high-entropy alloy is a newly developed alloy system in recent years. Its rich composition and structural changes have brought more extensive possibilities for the preparation of in-situ composite new materials, which can be used for the microstructure design and final performance control of metal materials. Provides great potential. Professor Zhong Yunbo's research team based on the as-cast AlCoCrFeNi2.1 eutectic high-entropy alloy, using a simple and industrializable melting-rolling-heat-treatment process, for the first time, prepared a genetically cast eutectic layer with ultrafine crystal structure-double The heterogeneous lamellar structure is the first to achieve super-strong plasticity (yield strength can reach ~ 1.5 Gpa while maintaining plasticity at ~ 16%) that eutectic high-entropy alloys could not have achieved at the same time. Based on the phase decomposition effect, the prepared samples exhibited a new type of multi-level structural heterogeneity. The analysis shows that the improvement of mechanical properties can mainly be attributed to (1) the two-stage restraint deformation effect on the structure and (2) the autogenous microcrack capture mechanism. The two-phase heterogeneous lamellar structure strengthening mechanism proposed for the first time in this paper provides strength and plasticity enhancement for high-performance structural materials such as high-entropy alloys, bearing steels, tool steels, high-temperature alloys, aluminum alloys, copper alloys, and titanium alloys. New ideas.
Editor's Summary: Producing in situ composite materials with superior strength and ductility has long been a challenge. Here, the authors use lamellar microstructure inherited from casting, rolling, and annealing to produce an ultrafine duplex eutectic high entropy alloy with outstanding properties.
The achievement was completed by the cooperation between Shanghai University and the University of Tennessee in the United States. Shanghai University is the first signature unit. Professor Zhong Yunbo and Ren Weili of Shanghai University and Professor Peter K. Liaw of the University of Tennessee are co-corresponding authors. Dr. Zhong Yunbo under the supervision of Shanghai University 18 Shi Peijian, a first-year doctoral student, is the first author. Dr. Zheng Tianxiang, Professor Ren Zhongming, Professor Hou Xueling, School of Materials Science and Engineering, Shanghai University, Professor Gao Yanfei from the University of Tennessee, Peng Jianchao, an experimenter at Shanghai University Microstructure Center, and Hu Pengfei, a senior experimenter are the co-authors. . This is also the first time that the State Key Laboratory of High Quality Special Steel Metallurgy and Preparation of Shanghai University ’s School of Materials Science and Technology and the Shanghai Key Laboratory of New Technology Development and Application of Steel Metallurgy have published their papers in Nature Communications. This is also another progress made by the metallurgical scholars of Shanghai University under the guidance of the academic thought of “focusing on the key scientific issues facing the industry in the next 10-20 years” proposed by Academician Xu Kuangdi.
This work was supported by the key project of the 13th Five-Year Key R & D Plan of the Ministry of Science and Technology (2016YFB0300401), the key project of the National Natural Science Foundation of China Large Science Device Joint Fund (U1732276), the key project of the Joint Fund for Iron and Steel (U1860202), and key basic research of the Shanghai Science and Technology Commission Funding of the project (No. 15520711000).