Effect of carbon nanotubes on the mechanical properties of cast Al–Si–Cu alloys

To enhance the mechanical properties of cast Al–Si–Cu alloys (ADC12), 0.3% of carbon nanotubes (CNTs) was added. The cast ADC12–0.3%CNT samples were synthesised via heated mould continuous casting for the creation of fine grains, and the artificial aging process was conducted at 173°C for 13 h to obtain precipitation hardening. The reinforcement and refinement of eutectic Si and precipitates (Al₂Cu and Mg₂Si) were achieved by adding CNTs, which leads to a high tensile strength of about 450 MPa and a relatively high ductility of about 10%. The obtained tensile strength and 0.2% proof stress are more than twice as high as those of the conventional cast ADC12 alloy. The refinement of the microstructures could be due to the interruption of their growth caused by the CNTs.