TY - JOUR
T1 - Strong, ductile, and thermally conductive carbon nanotube-reinforced aluminum matrix composites fabricated by ball-milling and hot extrusion of powders encapsulated in aluminum containers
AU - Ogawa, Fumio
AU - Yamamoto, Shuji
AU - Masuda, Chitoshi
N1 - Funding Information:
This work was partly supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology , Japan (Nos. 18560668 and 22560685 ). Fumio Ogawa would like to express his sincere gratitude to the Mitsubishi Material Corporation for their financial support. Financial supports from the Light Metals Educational Foundation Inc. and the Japan Aluminium Association are also greatly acknowledged. Authors are indebted to Hodogaya Co. Ltd for the supply of one of CNTs (MWNT-7) used in this study. Dr. Toshiyuki Nishimura of National Institute for Materials Science is acknowledged for his support in the measurement of thermal conductivity of composites.
PY - 2018/1/10
Y1 - 2018/1/10
N2 - Aluminum matrix composites reinforced by carbon nanotubes (CNTs) were fabricated by ball-milling (with aluminum powder; average diameter 30 µm), followed by hot extrusion of the powders encapsulated in aluminum containers (at 550° with an extrusion ratio of 9). The CNTs were intended to improve the mechanical properties and thermal conductivity of the aluminum composites formed by powder metallurgy. The CNTs were of two types—vapor-grown carbon fibers (VGCFs) with a diameter of 150 nm and multiwalled CNTs (MWCNTs) with a diameter of 65 nm. The composites were evaluated by their Vickers microhardness, tensile strength, and thermal conductivity. The microhardness exceeded 100 HV and increased with increasing volume fraction of reinforcement. The MWCNT-reinforced composites were harder than the VGCF-reinforced composites and exhibited higher ultimate tensile strength (over 450 MPa). The maximum fracture strain (37.2%, observed at a volume fraction of 0.5%) is the highest reported in the literature. Conversely, the VGCF-reinforced composites exhibited higher thermal conductivity than the MWCNT-reinforced composites. The thermal conductivity of the 0.5% VGCF-reinforced composites (203.7 W/m K) also exceeds any previously reported value. In summary, composites with unprecedentedly high ultimate tensile strength, fracture strain, and thermal conductivity were fabricated by a simple process that minimized damage to the CNTs during mixing, protected them from oxidation and excessive reaction with the aluminum matrix and effectively densified composites by hot extrusion.
AB - Aluminum matrix composites reinforced by carbon nanotubes (CNTs) were fabricated by ball-milling (with aluminum powder; average diameter 30 µm), followed by hot extrusion of the powders encapsulated in aluminum containers (at 550° with an extrusion ratio of 9). The CNTs were intended to improve the mechanical properties and thermal conductivity of the aluminum composites formed by powder metallurgy. The CNTs were of two types—vapor-grown carbon fibers (VGCFs) with a diameter of 150 nm and multiwalled CNTs (MWCNTs) with a diameter of 65 nm. The composites were evaluated by their Vickers microhardness, tensile strength, and thermal conductivity. The microhardness exceeded 100 HV and increased with increasing volume fraction of reinforcement. The MWCNT-reinforced composites were harder than the VGCF-reinforced composites and exhibited higher ultimate tensile strength (over 450 MPa). The maximum fracture strain (37.2%, observed at a volume fraction of 0.5%) is the highest reported in the literature. Conversely, the VGCF-reinforced composites exhibited higher thermal conductivity than the MWCNT-reinforced composites. The thermal conductivity of the 0.5% VGCF-reinforced composites (203.7 W/m K) also exceeds any previously reported value. In summary, composites with unprecedentedly high ultimate tensile strength, fracture strain, and thermal conductivity were fabricated by a simple process that minimized damage to the CNTs during mixing, protected them from oxidation and excessive reaction with the aluminum matrix and effectively densified composites by hot extrusion.
KW - Aluminum matrix composite
KW - Ball-milling
KW - CNTs
KW - Hot extrusion
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U2 - 10.1016/j.msea.2017.11.077
DO - 10.1016/j.msea.2017.11.077
M3 - Article
AN - SCOPUS:85034751671
VL - 711
SP - 460
EP - 469
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
ER -