Enhanced tensile properties in a high-pressure synthesized Al–Si–Cu-Ge-Mg alloy with nano-sized Al particles in eutectic Si

Abstract

The microstructure and tensile properties of Al–7Si–3Cu-0.5Ge-(0.4Mg) alloys solidified under high pressure were investigated. Dense nano-sized particles formed in the Al matrix owing to the high solid solubility of alloying elements in both alloys. Adding Mg could provide beneficial strengthening effects through forming Mg2Si(Ge) particles and assisting the precipitation of nano-sized Al particles in eutectic Si. The Al particles could not only accommodate lattice strain but also inhibit crack propagation in eutectic Si. Accordingly, the Al–7Si–3Cu-0.5Ge-0.4Mg alloy solidified under high pressure exhibited higher strength and better ductility. The strain distribution and the corresponding strengthening effect of nanoscale particles were discussed by the GPA analysis.