Positron annihilation line-shape measurements were carried out on pure Al, Al-1.9Li and Al-(12.0 to 12.5)at%Li. The recovery of the samples following quenching and cold-working was explained in terms of vacancy migration and clustering, dislocation annealing and precipitation. The results indicated the occurrence of precipitation, but no positron trapping at dislocations. All of the cold-worked alloys exhibited marked vacancy clustering effects and provided strong evidence for vacancy agglomeration at precipitates.

H.M.Fretwell, J.A.Duffy, M.A.Alam, H.P.Leighly, J.Walmsley: Journal of Physics - Condensed Matter, 1995, 7[23], 4573-81