Speaker: Hyunjoo Choi
Affiliation: Kookmin University, Seoul, South Korea
Date: Dec. 25th (Tuesday), 2018
Time: 14: 30-16: 00 PM
Location: 353 Main Building
Contact: Prof. Zhaoping Lu (email@example.com)
Abstract: The relative abundance and high specific strength of aluminum has contributed to its prominence as a structural material for use in the aerospace and automotive industries. However, usages of aluminum as an engineering material has been limited by its low-specific strength compared to other engineering metals such as steel or titanium. One possible way to enhance the mechanical properties of aluminum is to reinforce it with strong materials, producing aluminum-based composites. Herein, we select the nano-carbon materials (e.g., fullerenes, carbon nanotubes, and graphene) as reinforcing agents, try to uniformly disperse them in the aluminum matrix via powder metallurgy, and investigate their strengthening efficiency in the composites. Furthermore, we also propose a new idea for the development of nano-network structures in Al/C60 composites by the self-assembly of Al-C phases. Carbon atoms, dissembled from the individually dispersed C60-fullerenes, are intercalated into the interstitials of aluminum, producing Al-C phases with artificially moderated lattice structures. The isolated Al-C phases grow with a strong anisotropy derived from lattice mismatch, meet neighbor Al-C phases, and then self-assemble into network structures. The novel nano-structures, extremely stable at high temperatures, offer significant potential for the development of thermally-stable high-strength structural aluminum. The controlled lattice provides a new paradigm for atomic level design of crystalline materials. A variety of examples where mechanical and thermal properties of magnesium, steel, and high-entropy alloys are improved by using this design concept and will be introduced.
Speaker’s short biography: School of Advanced Materials Engineering, Kookmin University. PhD in Metallurgical Engineering (Yonsei University, Seoul, 2005-2010), B.S. in Metallurgical Engineering (Yonsei University, Seoul, 2001-2005).