Abstract: In this paper, the effet of minor cerium on the properties of Al-Li-Cu alloy was investigated. The materials used in this investigation are rolled sheets of 2 or 3mm in thickness. They were solution heat treated at 540℃, then aged at 140℃, 165℃, 190℃ C(TA) or 4% stretched prior to aging(TB).The experiments show that minor cerium can retard the aging procoss and take against softening upon aging. The alloys containing cerium passess superior strengthening effect after thermomechanical treatment(TB).The test at 200℃ under a stress of 147 Mpa were performed on thermo-mcchanical treated(TB) specimens. The endurance life(rupture time) of Ce-containing alloys is longer than that of alloys free from Co. It indicates that minor Ce can effectively increase the endurance life of Al-Li-Cu alloy at 200℃ .The tensile properties were also measured before or after the specimens were soaked in 3.5% NaCl water solution for 50 hours.The results demonstrate that the corrosion resistacc of alloy is significantly improved by the addition of minor Ce.

Key words: alumium-lithium alloy, aging process, thermomechanical treatment, strengthening phase, endurance life