Cold-worked and hydrogen chargedNbHf as studied by TDPAC and positron lifetime measurements

Abstract

Time differential perturbed angular correlation (TDPAC) and positron lifetime measurements on cold-worked and hydrogen charged NbHf indicate a strong binding of hydrogen decorated vacancy clusters with Hf impurities. Both TDPAC and positron lifetime results are mutually consistent on this aspect. Transformation of H-vacancy clusters into H-bubbles is indicated by the positron lifetime behaviour at annealing temperatures beyond 900 K. Impurity effects like oxygen pickup and coating of voids cannot be ruled out at elevated temperatures.