Abstract:Serrated flour of Al-Li single crystals was investigated under different aging conditions, temperatures(T)and strain rates(ē).The results show that dynamic strain aging(DSA) of solute Li atoms alone is not strong enough to make the serrated flow at solid solution state. The occurrence ofthe serrated flow is related to the shearing of 8` particles. Critical strain of serration can change normal-ly or inversely with 1' and￡，which indicates the serration in Al-Li alloys is a thermally activated pro-cess.  A proposed mechanism for the occurrence of the serration is that mobile dislocations are pinned   when they cross the sheared E` particles that might be dissolved during deformation，thus induce the ser-rated flow in the  Al-Li  single crystal.

Key words: Al-Li single crystal  serrated flow(PLC effect)   aging conditions