Effect of Sn alloying and cold rolling on microstructure and mechanical properties of Mg-14Li alloy

Mg-14Li-(0, 2, 4, 6)Sn alloys were prepared. Effect of Sn alloying and cold rolling on microstructure and me-chanical properties of Mg-14Li alloy have been studied. It is found that the introduction of Sn into Mg-14Li alloy effectively promotes the grain refinement and columnar-to-equiaxed grain transition (CET). The alloys contain three kinds of compounds, Mg2Sn, MgLi2Sn and Li13Sn5. Mg2Sn is mainly distributed at the grain boundaries, MgLi2Sn is mainly distributed on the stacking faults inside Mg2Sn, and Li13Sn5 is distributed inside the grains. With the increase of Sn content from 2 wt% to 6 wt%, the grain size gradually decreases. Both the strength and ductility increase. However, when the Sn content reaches 6 wt%, the ductility decreases. After 50% cold rolling, due to the work hardening effect, the strength of Mg-14Li-(0, 2, 4) Sn alloys increases and their ductility decreases. As for Mg-14Li-6Sn alloy, due to the dynamic recrystallization, both the strength and ductility after 50% cold rolling are improved.

Automated summary

The addition of Sn element can promote grain refinement in the Mg-14Li alloy, enhancing both strength and ductility. As the Sn content increases, the grain size gradually decreases, but too high of a content can lead to a decrease in ductility.