수성 알루미나/탄화규소 슬러리의 동결주조와 층상복합체의 제조: (II) 층상 복합체의 미세구조와 기계적 성질 |
양태영, 조용기, 김영우1, 윤석영, 박홍채 |
부산대학교 재료공학부 1포항산업과학연구원 기능성재료연구팀 |
Freeze Casting of Aqueous Alumina/Silicon Carbide Slurries and Fabrication of Layered Composites: (II) Microstructure and Mechanical Properties of Layered Composites |
Tae-Young Yang, Yong-Ki Cho, Young-Woo Kim1, Seog-Young Yoon, Hong-Chae Park |
School of Materials Science and Engineering, Pusan National University 1Functional Materials Research Team, Research Institute of Industrial Science and Technology |
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ABSTRACT |
Symmetric three layer composites have been prepared by freeze casting and then pressureless sintered at $l700-1800^{circ}C$ in $N_2$ gas atmosphere. The relative sintered density of multilayer composites having microstructural characteristics of later intermediate-stage densification increased with sintering temperature and reached about 95% theoretical value at $1800^{circ}C$. Although the indentation strength of the multilayer composites was generally reduced with increasing Vickers indentation load up to 294N, the damage resistance of multilayer composites was superior compared to monolithic layer 95AL/5SN material. The three-point bend strength of the layered materials remained at the values 266-298 MPa after indentation with a load of 49N, while that of the monolithic 95AL/5SN material was 219 MPa. The fracture toughness of the multilayer material was $5.4-6.6;MPa;m^{1/2}$. |
Key words:
Symmetric three layer composites, Freeze casting, Indentation strength, Fracture tougness |
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