Microstructure and Elevated Temperature Mechanical Properties of As-cast Mg-4Al-2Si Magnesium Alloy

The Microstructure and elevated temperature mechanical properties of the as-cast Mg-4Al-2Si(AS42) Magnesium Alloy were investigated by optical microscope,scanning electron microscope,XRD analysis and tensile test.The results show that the as-cast AS42 alloy are composed of α-Mg matrix,β-Mg17Al12 and Mg2Si phase.The reticular divorced eutectic β-Mg17Al12 distribution along the grain boundaries,the massive primary Mg2Si phase distribution in the matrix random,and the coarse 'Chinese script' eutectic Mg2Si phase distribution along the grain boundaries or transcrystalline.According to the results of the elevated temperature transient tensile properties of alloy at 150 ℃,it is found that the ultimate tensile strength,yield strength,and rate of elongation is 97 MPa,58 MPa and 18% respectively.The fracture forms of the as-cast alloy is quasi-cleavage brittle fracture.