Characterization and preparation of Mg-Al-Zn alloys with minor Sc

Mg-9Al-1Zn alloys with 0.3% Sc content (mass fraction) were prepared by ingot metallurgy. The effects of scandium addition on the microstructure and mechanical properties of the alloys have been investigated using optical microscope, scanning electron microscopy and tensile testing. It has been shown that the microstructure is mainly composed of α-Mg matrix, β-Mg17Al12 phase and Mg5Al4Sc intermetallic compound when 0.3% Sc was added. The scandium addition improves the morphology and distribution of Mg17Al12 phase, which substantially improves the mechanical properties of the alloy at both room temperature and high temperature.