AGE-PRRCIPITATION PHASE IN RAPIDLY SOLIDI FIED Al-Li ALLOY MADE BY SPRAY DEPOSITION PROCESS

A new type of spray depostition technology has been adopted to manufacture Al-3.8Li-0.8Mg-0.4Cu-0.13Zr(No.1) and Al-2.15Li-1.28Cu-1.26Mg-0.1Zr(No.2) alloys and comparison andanalysis of precipitation phase of the alloys have been made during its aging process. The experimentalresults have shown that there is a comparatively different in δ' phase particle between the rapidly solidified Al-Li alloy by spray precipitation and IM alloy. The volume fraction of the No. 1 alloy δ' phasewith high Li and low Cu contents is obviously higher than that of the No. 2 alloy with low Li and highCu contents. The former has faster coarsening rate than the latter, but it is still in conformity withOstwarld coarsening law. The long duration of aging treatment makes the equilibrium phase such as δphase precipitate in the grains or at grain boundaries,so as to cause precipitation free zone (PFZ) toform and widen the grain boundaries.