Effects of Al and Sm Addition on Microstructure and Mechanical Properties of Mg-Li Based Alloy

The effects of Al and Sm additions on microstructure and mechanical properties of as-cast and as-extruded Mg-8Li alloys were investigated. The microstructure of as-cast Mg-8Li alloy consists of α-Mg and β-Li phases. On the other hand, the addition of Sm led to significant grain refinement of Mg alloys due to the formation of Mg₄₁Sm₅ particles. Sm addition to Mg-Al resulted in the formation of the MgLi₂Al, AlLi, and Al₂Sm intermetallic compounds. The microstructure and precipitates of Al and Sm addition alloys were refined and elongated in the extrusion direction because of severe deformation during extrusion. The maximum values of the yield strength and ultimate tensile strength were 195.9MPa and 221.4MPa at Mg-8Li-5Al-2Sm alloy content. MgLi₂Al, AlLi, and Al2Sm intermetallic compounds played significant roles in the increase of the mechanical properties