Helium bubble evolution in F82H-mod – correlation between SANS and TEM

The growth of He-bubbles after low temperature He-implantation and subsequent high temperature tempering in F82H-mod steel has been studied by using transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). The results obtained by both techniques show that after implantation the bubbles are homogeneously distributed around an average size of 11 A, while after subsequent tempering He-bubbles one order of magnitude larger grow in size and volume fraction. Additionally, the SANS data show a consistent population of bubbles smaller than 10 A, which is discussed with reference to the possible migration and coalescence mechanisms during high temperature tempering.