Study of He-bubble growth in α-particle implanted F82H-mod martensitic steel

This paper presents the results of a small-angle neutron scattering (SANS) study of He-bubble growth in martensitic steel F82H-mod. The investigated samples had been homogeneously implanted with 400 appm He at 250°C, then submitted to 2 h annealings up to 975°C, together with a non-implanted sample of the same material (one for each temperature) serving as a reference to isolate the SANS signal arising from the He-bubbles. An as-implanted sample was also investigated together with its thermal reference. The He-bubble volume distributions, obtained from the SANS data and discussed with reference to uncertainties arising from background subtraction, show that the uniform distribution of the as-implanted sample, with bubbles approximately 15 إ in size, evolves during high temperature annealing into a bimodal one with a secondary population of bubbles as large as 100 إ approximately.