[en] An Al-2.34Li-1.07Zr (weight percent) alloy was produced using rapid solidification processing in an attempt to modify the δ' (Al/sub 3/Li) precipitate found in the Al-Li binary system to a complex Al/sub 3/(Li,Zr) phase. Such a modification is expected to increase fracture toughness and ductility by decreasing shear localization, which is a major drawback in Al-Li alloys. A novel microstructure is presented in which a zirconium-rich phase present as fine spheres or discontinuously precipitated rods (with diameters of 6 to 20 nm) is subsequently enveloped by δ' during aging at 190⁰C. Electron diffraction effects, energy-dispersive X-ray analysis in scanning transmission electron microscopy, and preliminary electron energy loss spectroscopy results indicate that the precipitate phase stable at 500⁰C is Al/sub 3/(Li/sub x/,Zr/sub 1-x/), where x appears to be 0.45 to 0.8. This is in contrast to the Al-Li and AL-Zr binary systems, in which the equilibrium phases at 500⁰C for these solute levels are aluminum solid solution and Al/sub 3/Zr in an aluminum matrix, respectively. The alloy shows longitudinal strength-ductility combinations which are significantly better than those of a low-zirconium control alloy and which compare quite favorably with those of other Al-Li alloys