Effect of Sr/Al Ratio on Microstructure and Properties of Mg-Al-Sr Alloy

The effect of the Sr/Al mass ratio on the microstructure and properties of Mg-Al-Sr alloys was studied using optical microscopy, scanning electron microscopy and energy dispersive spectroscopy, transmission electron microscopy, and a universal tensile testing machine. The results show that the constituents of the alloys vary with the Sr/Al mass ratio. The major second phase includes Al4Sr and Al2Sr, but the amount and morphology of these compounds are different in the alloys. Moreover, the mechanical properties of the alloys at 175 °C vary with the ratio. The tensile strength of the alloys reaches a maximum when the ratio is 0.25.