Coarsening kinetics and strengthening mechanisms of core-shell nanoscale precipitates in Al-Li-Yb-Er-Sc-Zr alloy

The tailored nanoparticles with a complex core/shell structure can satisfy a variety of demands, such as lattice misfit, shearability and coarsening resistance. In this research, core-shell nanoscale Al-3(Yb, Er, Sc, Zr, Li) composite particles were precipitated in Al-2Li-0.1Yb-0.1Er-0.1Sc-0.1 Zr (wt%) alloy through the double-aging treatment, in which the core was (Yb, Er, Sc, Zr)-rich formed at 300 degrees C and the shell was Li-rich formed at 150 degrees C. The coarsening kinetics and precipitate size distributions (PSDs) of Al-3(Yb, Er, Sc, Zr, Li) particles aged at 150 degrees C previously aged at 300 degrees C for 24 h showed a better fit to the relation of (2) proportional to kt and normal distribution, indicating that the coarsening of precipitates was controlled by interface reaction, not diffusion. The Orowan bypass strengthening was operative mechanism at 150 degrees C. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

Core-shell nanoparticles in Al-Li alloy were formed through double-aging treatment, controlling the precipitation and coarsening process at different temperatures. The coarsening was found to be controlled by interface reactions, with Orowan bypass strengthening as the operative mechanism at lower temperatures.