Superior tensile properties of in situ nano-sized TiCp/Al-Cu composites fabricated by reaction in melt method

The nano-sized TiCp/Al-Cu composites were fabricated using the self-propagating high-temperature synthesis (SHS) reaction of Al-Ti-CNT master alloys in molten aluminum alloys. The tensile strength and ductility of the alloys were simultaneously improved by the addition of nano-sized TiC particles. The yield strength, ultimate tensile strength and fracture strain of the 0.3 wt% nano-sized TiC particles reinforced Al-Cu matrix composite increased to 350 MPa, 554 MPa and 14.75%, improved by 15.5%, 14.2% and 123.5%, respectively, compared with the unreinforced Al-Cu alloy (303 MPa, 485 MPa and 6.6%). The enhanced mechanical properties are attributed to the refined α-Al dendrites, a larger amount of smaller θ′ precipitates and the dispersed nano-sized TiC particulates. This study provides a feasible method to fabricate the nano-sized TiCp/Al-Cu composites with superior strength and ductility.