Helium implantedAlHf as studied by181Ta TDPAC

Time differential perturbed angular correlation (TDPAC) measurement onAlHf reference sample has shown that a fraction 0.88 of probe nuclei are defect free and are occupying the substitutional sites in fcc Al matrix, and the remaining are associated with Hf solute clusters. Measurements on helium implanted sample indicate the binding of helium associated defects by Hf solute clusters. Isochronal annealing measurements indicate the dissociation of the helium implantation induced defects from Hf solute clusters for annealing treatments beyond 650 K. On comparison of the present results with that reported inCuHf subjected to identical helium implantation, it is inferred that the Hf solute clusters inAlHf bind less strongly the helium associated defects than inCuHf.