Effect of Mg Content on Microstructure and Mechanical Properties of Al-20Si Alloy

The microstructure and mechanical properties of Al-20Si alloys were investigated by optical microscope(OM),mechanical apparatus,X-Ray diffraction(XRD) and scanning electron microscope(SEM).The results indicate that the microstructure of the alloy mainly contains α-Al,eutectic silicon,primary silicon and Mg2Si.With the increase of Mg content,the primary silicon gradually decreases and refines;the tensile strength gradually increases;the elongation increases initially and then decreases,while the hardness has the contrary trend of the elongation.