Effects of copper addition on the in-situ synthesis of SiC particles in Al–Si–C–Cu system

•The effect of copper addition on in-situ SiCp in Al–Si–C alloy was investigated.•The synthesis temperature and the size of SiCp decreases with copper addition.•The addition of copper into Al–Si–C alloy decreases its solidus temperature.•The hardness and relative density increases when copper is added into the alloy.

In this research work, SiC particles have been successfully in-situ synthesized in Al–Si–Cu matrix alloy utilizing a novel liquid–solid reaction method. The effect of copper addition on the synthesis of SiC in Al–Si–C–Cu system was investigated. The composites mainly contain spherical SiC particles and θ-Al2Cu eutectic phases, which are embedded in the α-Al matrix. Results indicated that the temperature for forming in-situ SiC particles significantly reduced from 750 °C to 700 °C with the copper addition. The size of in-situ synthesized SiC particles can be as low as 0.2 μm. Further study found that the addition of 10 wt.% copper into Al–Si–C alloy causes its solidus temperature to decrease by about 65 °C. Additionally, the Rockwell hardness value of SiCp/Al–18Si–5Cu composites has an average of 92, which is 50% higher than that of the sample without copper addition.