A sample which contained 1wt%Hf, and HfC precipitates, was prepared by arc melting and was characterized by transmission electron microscopy and micro-diffraction analysis. The HfC precipitates in the Cu matrix strongly bound vacancies and divacancies in quenched samples; as deduced by time differential perturbed angular correlation data. Isochronal annealing, using time differential perturbed angular correlation and positron lifetime measurements, indicated the stability of these vacancy complexes in quenched samples during annealing at up to 1200K. Beyond this temperature, de-trapping of vacancies from HfC precipitates occurred. This showed that the HfC precipitates inhibited the formation of voids by strongly binding quenched vacancies.

Interaction between HfC Precipitates and Vacancies in Quenched Cu:Hf as Studied by TDPAC and Positron Lifetime Measurements. R.Govindaraj, R.Rajaraman: Journal of Physics - Condensed Matter, 2004, 16[36], 6579-88