Effect of Mixed Addition of Ce,Sr and Ba on Microstructure and Mechanical Properties of AZ91 Magnesium Alloy

The effect of mixed addition of Ce,Sr and Ba elements on microstructure and mechanical properties of the AZ91 magnesium alloy by means of optical microscope,X-ray diffraction analyzer,scanning electron microscope and energy dispersive spectroscopy was investigated.The results show that the as-cast microstructure as well as room temperature mechanical properties could be greatly refined and improved by mixed addition of Ce,Sr and Ba.In the case of simultaneous addition of 0.5wt%Ce,0.2wt%Sr and 0.2wt%Ba,the grain-refining effect of the alloy was the best,the grain size was the smallest,and the quantity of the small bulk β-Mg17Al12 phase which distributed dispersively in the matrix was the most.The tensile strength as well as the elongation of the alloy increased by 25.0% and 24.0% than the alloy without alloy element addition,up to 195 MPa and 1.86% respectively.