The following kinds of materials, which are potentially useful for CTR construction, namely: the 12KH18N10T, W-4541, W-4016 and SS-304 steels, Ni, Cu and Mo have been Cyclotron irradiated with 3.0, 4.7 and 6.8 MeV He ions with the aim of investigating the energy and the dose dependence of the induced surface deformation effects (blistering and flaking). We report the experimentally determined values for the blisters average diameter and for the critical fluences inducing blistering. We describe other observed features due to irradiation, as sponge-and wave-like structures, submicronic cracks, multilayer flaking, secondary blisters and microcraters. It is discussed the potential validity of the two main categories of explanations which could describe the reported phenomena: the gas driven (gas bubble coalescence) model and the stress-induced model of blistering.