| 학회 | 한국재료학회 |
| 학술대회 | 2016년 가을 (11/16 ~ 11/18, 경주 현대호텔) |
| 권호 | 22권 2호 |
| 발표분야 | H. 한-일 재료공학 워크샵 |
| 제목 | Annealing-induced hardening in Al/nano-C composites |
| 초록 | ABSTRACT The desire for the development of crystalline metals with a high performance has inspired researchers to design optimal nano-structures through nano-scale boundaries, solute atoms, and second-phase particles. Furthermore, amorphous or quasi-crystalline phases have occasionally been employed for exotic mechanical properties. However, these structures are obtained only under the specific thermal-dynamic conditions and hence the stability of the structures is extremely low. In this context, composites incorporating nano-scale non-metallic materials have captured a great deal of attention due to their stable and easily formable nano-structures [1]. In particular, carbon-based nano-materials, including fullerenes, carbon nanotubes and graphene, have been considered as a key material for the development of nano-structured composites, due to their exceptional properties and stable molecular structures induced by the strong sp2 C-C bonds. They can also effectively impede diffusion of metal atoms at high temperatures, suppressing changes in the nano-structures of the metal matrix (e.g. grain growth) during hot working processes. However, these materials also suffer from unexpected reaction between metallic matrix and carbon, which generally leads to significant softening of metals at high temperatures. Herein, we propose a new idea for the development of Al-based composites containing supersaturated C atoms, which are dissembled from the individually dispersed C60-fullerenes and are then intercalated into the interstitials of aluminum. It shows annealing-induced hardening behaviors because 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 during annealing. The novel nano-structures, extremely stable at high temperatures, offer significant potential for the development of thermally-stable high-strength structural aluminum. With the self-assembled network nano-structures, the composite with an incorporation of just 2 vol% (i.e. ~3 wt. %) fullerenes exhibits a yield strength of ~500 MPa, which is very stable even at 500 oC. The controlled lattice provides a new paradigm for atomic level design of crystalline materials. REFERENCES [1] H. J. Choi, G. B. Kwon, G. Y. Lee, D. H. Bae, “Reinforcement with carbon nanotubes in aluminum matrix composites,” Script. Mater., vol.59, pp. 360-363, 2008 ACKNOWLEDGEMENT This work was supported by Basic Science Research Program (2009-0093814) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology. |
| 저자 | Hyunjoo Choi |
| 소속 | School of Advanced Materials Engineering |
| 키워드 | Aluminum; Fullerene; Composites; Carbon; Supersaturation |
