LAUSR

Abstract The typical SiCp/Al–Cu–Mg composites have strong natural aging hardening trend, thus decreasing performance for cold working after quenching. The study developed a SiCp/Al–2Cu-1.2Mg-0.6Si (in wt.%) composite with low natural aging strength and high natural aging ductility. Compared to the typical SiCp/2009Al (Al–4Cu-1.2 Mg, in wt%) composite, the SiCp/Al–2Cu-1.2Mg-0.6Si composite had a 73 MPa decrement in yield strength and an increment in uniform elongation from 8.5% to 10.5% after one-week natural aging due to much fewer Cu, whereas the composite exhibited a 33 MPa increment in yield strength after artificial aging. Due to modification of precipitation by Si, finer and equal quantity (volume fraction) of intragranular precipitates formed after artificial aging in the SiCp/Al–2Cu-1.2Mg-0.6Si composite in comparison with the SiCp/2009Al composite. Therefore, higher yield strength after artificial aging could be achieved although Cu content was much lower. The SiCp/Al–2Cu-1.2Mg-0.6Si composite exhibited great potential for application, thereby enriching the classification of SiCp/Al composites.