Microstructure evolution and mechanical properties of carbon nanotubes reinforced Al matrix composites
Liu, Xiaoqing; Li, Caiju; Eckert, Jürgen; Konda Gokuldoss, Prashanth; Renk, Oliver; Teng, Long; Liu, Yichun; Bao, Rui; Tao, Jingmei; Tao, Shen; Yi, Jianhong
Journal article, Peer reviewed
Published version
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http://hdl.handle.net/11250/2467651Utgivelsesdato
2017Metadata
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Carbon nanotubes reinforced pure aluminum (CNT/Al) composites were fabricated by combined ball milling and powder metallurgy (PM) techniques. The distribution of CNTs, the evolution of the average Al grain size of the powder mixtures and as-prepared composite bulks were investigated, and the mechanical properties of the composites were also tested. With increasing ball milling time, the entangled CNTs were broken, gradually achieving a uniform dispersion within the Al matrix. The microstructure became denser and the Al grains in the powder mixture and extruded composites got significantly refined. Some small-sized Al4C3 needles along the Al grain boundaries were observed using transmission electron microscopy (TEM). The in-situ formed Al4C3 rods have an orientation relation with the Al matrix as Al4C3 [110]//Al [1¯12], which strongly improved the Al-CNT interface bonding. The yield and the ultimate tensile strength of the composites significantly increased, when the ball milling time increased from 2 to 12 h, finally reaching about 210 ± 4.2 MPa and 253 ± 3.7 MPa, respectively, for the composite milled for 12 h. The enhancement of mechanical properties mainly stems from the uniform distribution of CNTs, the grain refinement of the Al matrix and the in-situ formed Al4C3.