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Adding various amounts of nano-sized TiC p (0.1–0.7 wt%) made a simultaneous improvement in high-temperature strength and ductility of the Al-Cu matrix alloy. The influences of temperature and strain rate on the high-temperature tensile properties and θ′ precipitate sizes in the Al-Cu matrix alloy and the nano-sized TiC p /Al-Cu composites were investigated. Theoretical calculations suggest that the yield strength increment of the composites at 453 K was primarily attributed to the strengthening effect of both the refined θ′ precipitates and TiC p , while at 493 K only the strengthening effect of TiC p was predominant due to the significant coarsening of θ′ precipitates at this temperature. [ABSTRACT FROM AUTHOR]

Abstract: Many experimental and theoretical studies indicated that the decrease of the size of the reinforcing particles can lead to substantial improvements in the mechanical performance of the composites. However, the investigations on the addition of the nano particles into conventional metal materials are still rare, especially the nano-TiC p into the Al–Cu alloys. In this study, the Ni coated nano-TiC p reinforced Al–Cu matrix composites were successfully fabricated by a casting route. It was found that the nano-TiC p was in the α-Al grains. The α-Al dendrites became finer and more developed. Moreover, the θ′ precipitates in the Al–Cu matrix were finer and uniformly distributed. The tensile strength and elongation of the composites increased simultaneously. After T6 heat treatment, compared with the unreinforced Al–Cu alloy, the tensile strength and elongation of the 0.8wt.% nano-sized TiC p /Al–Cu composite increased from 485MPa and 6.6% to 573MPa and 12.4%, respectively. [Copyright &y& Elsevier]