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“Factors to Control Strength and Plasticity of High Entropy Alloys”学术报告

 

国家重点实验室学术讲座

SKL-AMM Seminar

 

题目/TitleFactors to Control Strength and Plasticity of High Entropy Alloys

报告人/SpeakerKi Buem Kim

报告人工作单位/AffiliationDepartment of Advanced Materials Engineering, Sejong University, Seoul, Korea

日期/Date2010929 周三 September 29 , 2010Wednesday

时间/Time10:00 ? 11:00 am

联系人/Contact张勇 教授, Prof. Yong Zhang

报告地点/Location:北京科技大学主楼 353,  353 Main Building, USTB

 

作者简介/Speaker’s short biography

Ki Buem Kim, Associate Professor, Department of Advanced Materials Engineering, Sejong University, Seoul, Korea. He got his PhD at Material Science, St. Catherine’s College, University of Oxford, Oxford, U.K. in 2004, MS degree at Metallurgical Engineering, Yonsei University, Seoul, Korea in 2000, and BS degree at Metallurgical & Material Science and Engineering, Hong-Ik University, Seoul, korea in 1998. His research interests include Formation and characterization of bulk metallic glasses, Development of ultrafine eutectic structure, Understanding of microscopic deformation mechanisms and Development of porous alloys. Since 2004, more than 100 SCI papers have been published in core journals including PRL, APL, Acta Mater, and so on.

报告内容/Abstract

Advanced alloys including bulk metallic glasses (BMGs) and hetero-duplex alloys often undergo inhomogeneous plastic flows at room temperature. In order to overcome such critical disadvantage of the advanced alloys, it is necessary to design novel microstructure containing both structural and chemical heterogeneities as a source to cause homogeneous plastic flows. Based on this, we have designed novel hetero-duplex structure containing both structural i.e. phase selection and spatial i.e. length-scale heterogeneities as a source to cause homogeneous plastic flows. Along the line to design the heterogeneous microstructure, we have fabricated a series of ultrafine hetero-duplex alloys in Ti-Fe-Sn and Mg-Cu-Zn alloys. Furthermore, the Ti-Fe-Sn alloys reveal an excellent combination of strength and plasticity i.e. yield strength, σy of ~ 1.25 GPa and plastic strain, εp of ~ 18% at room temperature compression. The formation of the hetero-duplex structure in a series of Mg-Cu-Zn alloys also reveals a strong enhancement of the strength with decent plasticity εp of ~ 5%. Based on these results, it is feasible to interpret roles of the structural and spatial heterogeneities to control the strength and plasticity of the Ti- and Mg-based hetero-duplex alloys and it is possible to elucidate role of the heterogeneities from atomic- to micro-scale on the advanced alloys to enhance the mechanical properties.