The presence of Hf solute clusters in a Cu matrix was identified by means of time differential perturbed angular correlation studies, and was further confirmed by energy-dispersive X-ray analysis. Cold-working of the samples resulted in strain at the Hf solute clusters; as deduced from the time differential perturbed angular correlation data. Annealing of the samples led to the restoration of the strain-free state of the solute clusters. A defect which was associated with 0.06 of the probe nuclei, and which was stable up to 925K, was interpreted as being a faulted dislocation loop. Positron lifetime measurements of cold-worked samples revealed the presence of a single lifetime component which was attributed to the annihilation of positrons; mainly at dislocations, faulted dislocation loops and also at misfit dislocations in the interface between the Hf solute clusters and the matrix.

The Effect of Cold Working on Hf Solute Clusters in CuHf as Studied by Time Differential Perturbed Angular Correlation (TDPAC) and Positron Lifetime Measurements. R.Govindaraj, R.Rajaraman: Journal of Physics - Condensed Matter, 2000, 12[24], 5179-87