Abstract:Mg−5Li−3Al−2Zn−xCe (x=0−2.5; mass fraction, %) alloys were prepared by casting, and heat treatments of homogenization at 300 °C and solid solution at 370 °C were carried out. The microstructure and tensile properties of as-cast alloys and their evolutions after solid solution were investigated. The results show that with the increase of Ce content, Al₂Ce/Al₃Ce precipitates are formed and the alloys mainly consist of α−Mg, Al₂Ce, Al₃Ce and AlLi phases, and the amount of AlLi and Al−Ce intermetallics decreases after solid solution. The content and morphology of the second phases have important effects on the mechanical properties of the alloys; the alloy with 1.0%Ce content exhibits excellent tensile strength. The tensile strength and elongation of Mg−5Li−3Al−2Zn−0.5Ce alloy is remarkably improved by the solution strengthening effect because of the addition of Ce.

Key words: Mg−Li alloy; Ce; heat treatments; solution strengthening; tensile properties