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Seminar - Alloy Design by Dislocation Engineering by Dr. Mingxin Huang
日期:2017 年 11 月 29 日 ( 星期三)
Time:11:00 am - 12:00 pm
Venue:EF305

Abstract:

Ultrahigh-strength alloys with good ductility are ideal materials for lightweight structural application in various industries. However, improving the strength of alloys frequently results in a reduction in ductility, which is known as the strength-ductility trade-off in metallic materials. Current alloy design strategies for improving the ductility of ultrahigh-strength alloys mainly focus on the selection of alloy composition (atomic length scale) or manipulating ultrafine and nano-grained microstructure (grain length scale). The intermediate length scale between atomic and grain scales is the dislocation length scale. A new alloy design concept based on such dislocation length scale, namely alloy desgin by dislocation engineering, is illustrated in the present work. This dislocation engineering concept has been successfully substantiated by the design and fabrication of a deformed and partitioned (D&P) steel with a yield strength of 2.2 GPa and an uniform elongation of 16% [1]. In the D&P steel, high dislocation density can not only increase strength but also improve ductility. High dislocation density is mainly responsible for the improved yield strength through dislocation forest hardening, whilst the improved ductility is achieved by the glide of intensive mobile dislocations and well-controlled transformation-induced plasticity (TRIP) effect, both of which are governed by the high dislocation density resulting from warm rolling and martensitic transformation during cold rolling. The new alloy design strategy is also proposed for warm-rolled Quenching and Portioning steels [2].

[1] B.B. He, B. Hu, H.W. Yen, G.J. Cheng, Z.K. Wang, H.W. Luo*, M.X. Huang*, High dislocation density induced large ductility in deformed and partitioned steels, Science, 1029-1032, vol357 (2017)

[2] M.X. Huang, B.B. He, Alloy design by dislocation engineering, Journal of Materials Science and Technology, in press, 2017

Bio-sketch:

Dr. Huang is currently an Associate Professor at Department of Mechanical Engineering, University of Hong Kong, Hong Kong. Dr. Huang received his BEng and MSc in Solid Mechanics from Shanghai Jiao Tong University (SJTU) in 2002 and 2004, respectively, and his PhD in Materials Science in 2008 from Delft University of Technology (TU Delft), The Netherlands. Dr. Huang was a Research Engineer at ArcelorMittal in Maizieres-les-Metz, France, from 2008 to 2010. Dr. Huang joined in 2010 University of Hong Kong as an Assistant Professor and was promoted to Associate Professor with tenure in 2016.

Dr. Huang is an Editorial Board Member of Materials Science and Technology and Metallurgical and Materials Transactions A. Dr. Huang’s works have been published in top journals of his field including SCIENCE, Acta Materialia, Journal of Mechanics and Physics of Solids and International Journal of Plasticity. Dr. Huang’s current research interests focus on two areas: (1) fundamentals of microstructure-property relationship and phase transformation of metals and alloys, and (2) development of lightweight high-strength steels for automotive applications. Both experimental and modelling works are involved in his research. Dr. Huang’s research projects include fundamental projects as well as industry-oriented projects and have been well funded by General Research Fund, Innovation and Technology Fund, National Science Foundation of China, and industries from Europe and China (e.g. ArcelorMittal France, General Motors, Ansteel).