Microstructures and mechanical properties of CNT/Al composites fabricated by high energy ball-milling method

Abstract

The mixture powders of carbon nanotubes (CNTs) and aluminum were high-energy ball-milled, and then the CNT/Al composites with different CNT contents were fabricated using a power metallurgy method. Microstructure examinations show that a certain volume of CNTs can be uniformly dispersed in the Al matrix by ball-milling and the CNTs have a close bonding with the Al matrix. By using an appropriate ball-milling process flow, the CNTs suffer no serious damage. Tensile tests indicate that the composite reinforced by 1.5% (volume fraction) CNTs exhibits the best mechanical performance, and the yield strength is improved by 53.6% compared with the Al matrix. When the CNT volume fraction reaches 3%, lots of clusters are formed in the composite, and therefore the tensile properties are significantly reduced. Both grain refinement and load transfer are proved to be the strengthening mechanisms of the CNT/Al composites. © right.