Abstract
-10 J/m, and 4.3 x 10[-11] J/m,are deduced for Nb-0.3%Zr, Nb[-1]%Zr, and Nb-2.07%Zr , respectively, at 1050 °C . A value of 1 x 10[-10] J/m was determined for Nb -1 %Zr at 950 °C. These values are greater than those deduced for Nb because the presence of Zirconium effectively cleanses bubble surfaces of interstitial impurities. Bubbles in Nb-0.3%Zr and Nb-1%Zr at 1050 °C exhibit a breakaway/re-saturation phenomenon which, it is suggested, is caused by Zr-interstitial segregation effects . An ordering phenomenon that significantly influences bubble growth was observed in Nb-1%Zr at 1250 C. Finally, bubbles become overpressurized during annealing, and this has an important bearing on the morphological changes of bubbles with time at temperature.