Effect of (Pr+Ce) Additions on Microstructure and Mechanical Properties of AlSi5Cu1Mg Alloy

Abstract

The microstructure and mechanical properties of AlSi5Cu1Mg alloy with (Pr+Ce) addition were investigated by optical microscopy (OM), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The results demonstrated that the rare earth (Pr+Ce) addition refined the grain. The long needle-like eutectic Si phases turned to granual. The secondary dendrite arm spacing (SADS) of the primary α-Al phase with the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached the minimum value, which decreased by 50.2%. The mean length and the aspect ratio of the eutectic Si decreased by 78.8% and 67.4%. The ultimate tensile strength (UTS), the microhardness, and the breaking elongation of the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached a maximum, and increased by 21.5%, 21.7%, and 8.0% compared to the AlSi5Cu1Mg alloy. The fracture examinations manifested in cleaved surfaces and brittle fracture areas, which were seen from the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy. The number of dimples slightly increased.