Core-shell structures and precipitation kinetics of Al3 (Sc, Zr) Li2 intermetallic phase in Al-rich alloy

While binary Al-Sc alloys form Al3Sc intermetallic precipitates, ternary Al-Sc-Zr alloys develop precipitates that contain both Sc and Zr. Electron microscopy characterization using Z-contrast imaging indicates rapid initial formation of Al3(Sc, Zr) precipitates with a Sc-rich core followed by the slower development of a Zr-rich Al3(Zr, Sc) shell. The shell acts as a diffusion barrier, slowing down the rate of precipitate coarsening.clos