Microstructures and tensile properties of nano-sized SiCp/Al-Cu composites fabricated by semisolid stirring assisted with hot extrusion.

Al-Cu matrix composites containing nano-sized SiC p were successfully prepared by dispersing nano-sized SiC p /Al master alloy into the molten Al-Cu alloy with combined semi-solid stir casting and hot extrusion processes. Microstructures of nano-sized SiC p /Al-Cu composites and their tensile properties were investigated. Results show that the α-Al dendrites became finer and better formed and nano-sized SiC p was formed in the α-Al grains. With nano-sized SiC p adding to the Al-Cu matrix, the tensile strength of the described composites increased remarkably especially under the temperature of 453 K, while their plasticity were still high. Nano-sized SiC p particles had been uniformly dispersed in the Al alloy, yielding composites with high strength at elevated temperatures. The strengthening mechanisms of nano-sized SiC p were also discussed. This will raise the probability of using Al matrix composites as lightweight materials for structural applications at elevated temperatures. [ABSTRACT FROM AUTHOR]