Effects of Al and Y Addition on Microstructures and Mechanical Properties of As‐Cast Mg–14Li Based Alloy

In this study, effects of Al and Y contents on microstructural evolutions and mechanical properties of the as‐cast Mg–14Li alloy are investigated. The results show that Mg–14Li–xAl (x = 1, 2, 3 wt%) alloys are characterized by predominantly single β–Li and MgLiAl₂ phases. Slight refinement of β–Li grains is obtained with the increasing of Al content. The increased Al addition greatly improves the hardness, ultimate tensile strength, and yield strength of the Mg‐14 base alloy, accompanied by a significant reduction in ductility. Meanwhile, with addition of minor Y (0.5 wt%) addition leads to the introduction of homogeneous distribution of Al₂Y particles in the Mg–14Li–3Al alloy, which plays a positive role in the strength enhancement. However, the uneven distribution of apparently coarsed Al₂Y particles contributes to a significant reduction in tensile strength as the Y content is increased up to 1 wt%.