High-temperature deformation behavior of carbon nanotube (CNT)-reinforced aluminum composites and prediction of their high-temperature strength

The high-temperature deformation behavior of aluminum matrix composites reinforced by carbon nanotubes (CNTs), in which the CNTs broken during the ball milling process were randomly dispersed in the interiors of the grains, were studied at elevated temperatures. The addition of 1 vol.% of CNTs simultaneously improved the strength and ductility of aluminum over a wide strain rate range between 10(-4) and 10(-1) s(-1) at 523 K. The tensile ductility of the composite increased as the strain rate increased, which was attributed to the higher strain rate sensitivity at higher strain rates. The deformation mechanisms of the CNT/Al composites and the matrix materials at high temperatures were analyzed and, based on the results of the analysis, the constitutive equations capable of predicting the strength of the CNT/Al composite at elevated temperatures was proposed. (C) 2014 Elsevier Ltd. All rights reserved.