Effect of Ce Inoculation on Microstructure and Mechanical Properties of in situ Al–20%Mg 2 Si Composite

In this study, an in situ Al–20%Mg2Si composite fabricated with varying levels of cerium (Ce) as an inoculation was investigated. Microstructural examinations were carried out via scanning electron microscope and X-ray diffraction. The results showed that Ce inoculation changed the morphology of primary Mg2Si from coarse lotus-type particles to fine polyhedral shape. Furthermore, the average size of primary Mg2Si particles decreased obviously. When the Ce addition reached to 0.6%, the refinement of Al–20%Mg2Si composite was the best. Similarly, the superior ultimate tensile stress, elongation at fracture (%El), and Vicker’s hardness (Hv) of Al–20%Mg2Si composite were obtained. However, excess Ce inoculation addition reduced refinement and mechanical properties because of Al11Ce3 phase aggregating.