TDPAC and Positron Lifetime Studies in Cold-Worked TiHf

Abstract

Well annealed reference TiHf hcp samples are characterized by Time differential perturbed angular correlation (TDPAC) of 133–482 keV γ–γ cascade of 181 Ta and positron lifetime measurements to be free from lattice defects of detectable concentrations. TDPAC measurement on the 50% cold-worked sample shows that a fraction 0.16 of probe nuclei is associated with a cold-working induced defect which is interpreted to be faulted dislocation loop. The complete dissociation of these defects from Hf atoms is observed following the annealing treatment of the sample at 723 K. Predominant annihilation of positrons at dislocation kind of defects is observed by positron lifetime measurements in the cold-worked sample. Complete defect recovery of the sample is seen following the annealing step at 873 K, by positron lifetime measurements. XRD measurement of the cold-worked sample shows the predominant orientation of microcrystallites along [Formula: see text] direction.