Late stages of δ’ precipitation in an Al-Li alloy by small-angle neutron scattering

The late stage of phase separation in an Al–Li(3 wt. %) alloy aged at 463 K has been studied by small-angle neutron scattering. The time dependence of the distribution of δ’ particle sizes has been obtained from an analysis of the cross-section curves measured in absolute units. The coarsening of the δ’-${\mathrm{Al}}_3$Li precipitates obeys Ostwald ripening kinetics but diffusion interaction effects are needed to account for the width and shape of the size distribution functions. The center-to-center interparticle distances have been estimated from an analysis of the interparticle structure factor describing the interference effects due to the spatial correlation between the precipitates.