Studies of defects at thermal equilibrium and melting in Cu and Ni by positron annihilation

摘要: Peak counting rates in the angular correlation were measured as a function of temperature above room solid and liquid phases Cu phase Ni. The peak increased about 17% upon melting. Temperature dependence shows hump at 1150 degrees C. Two possible explanations proposed for this anomaly. data numerically analysed by trapping model which it was assumed that only single vacancies divacancies are effective. lower temperatures, where effect is sufficiently small, conventional vacancies. results both analyses consistent. characteristic Tc defined. It demonstrated proportional to E1VF. experimental values plotted against E1VF various FCC metals linear relationship between also experimentally found.