Microstructure and tensile properties of Mg–Li–Al–Zn based alloys with Ce addition

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.