An aluminum alloy comprising Al, Sc, Gd, Zr, and optionally Mg. The
aluminum alloy is strengthened by an aluminum solid solution matrix and a
dispersion of Al.sub.3X precipitate having an L1.sub.2 structure where X
comprises Sc, Gd and Zr. Mg is a preferred addition to the alloy
containing Gd and Zr. The alloying additions control strengthening and
coarsening kinetics of the alloy through control of diffusivity in the
aluminum matrix and coherency strain of the Al.sub.3X precipitate.