The microstructure and mechanical characterization of Al-30%Mg2Si composite with Y inoculation addition

In this study, an in situ Al–30%Mg2Si composite fabricated with the different addition of yttrium (Y) inoculation was investigated. Microstructural examinations were carried out via scanning electron microscope (SEM) and x-ray diffraction (XRD). The results showed that Y 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 Y addition reached to 0.6%, the refinement of Al–30%Mg2Si composite was the best. Similarly, the superior ultimate tensile stress (UTS), elongation at fracture (El), and Vicker's hardness (Hv) of Al–30%Mg2Si composite were obtained. However, excess Y inoculation addition reduced refinement and mechanical properties because of Al3Y phase aggregating.