Effect of Zn on Microstructure and Mechanical Properties of Mg-6Al Alloy

The microstructure and mechanical properties of Mg-6Al-xZn alloys were investigated by means of optical microscope,universal tester,X-ray diffractometer,electron probe microanalyzer and scanning electron microscope.The results indicate that the microstructure of Mg-6Al-xZn alloys with different Zn contents was mainly composed ofα-Mg,β-Mg_(17) Al_(12) phase andτ-Mg_(32)(Al,Zn)_(49) phase.With the increasing of Zn content,the amount of the second phase in the alloys gradually increased and the grains were refined.The Mg-6Al-6Zn alloy had the highest tensile strength at room temperature and the highest toughness.When the content of Zn was more than 6wt%,the universal mechanical properties of the alloy decreased with the grain size increasing.