An approach for homogeneous carbon nanotube dispersion in Al matrix composites

•A novel approach was developed on the hot topic of carbon nanotube dispersion in composites.•Homogeneous carbon nanotube dispersion with a large aspect ratio and small damage was obtained.•Strength enhancement by carbon nanotube addition was examined by load transfer mechanism in Al matrix composites.•Al4C3 nano-rods were detected and helpful for load transfer in carbon nanotube/Al composites.

Good dispersion of carbon nanotubes (CNTs) was the bottleneck to convert their attractive properties to CNT reinforced composites. In this study, a solution ball milling (SBM) approach was developed to homogeneously disperse CNTs in Al matrix composites (AMCs). The process integrated strategies of solution coating, mechanical ball milling and Al-flake producing into a simple organic unity. The dispersion quality, crystal-structure and strengthening effect of CNTs in AMCs processed by SBM were investigated through scanning electron microscopy, transmission electron microscopy, Raman analysis and tensile tests. Compared with previous methods, the SBM process was simple and effective to obtain a homogeneous CNT dispersion with a large aspect ratio and small CNT damages. Resultantly, the tensile strength of Al matrix was noticeably enhanced by CNT additions agreeing with the potential strengthening effect predicted by the load transfer mechanism.

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