Crystallite formation and the enhancement and inhibition of blistering in D+ irradiated Cu: Effects of irradiation induced stresses

A striking feature of the blistering of Cu at 300 K following D+ (120-600 keV) or H+ (100-200 keV) irradiation at 120 K is a ring of blisters around the periphery of the beam spot. The ring is separated from the central blistered region by a wide zone free from blisters. Outside the ring, for D+ energies in the range 120-300 keV, is a band decorated by crystallites. The dose dependence of this pattern of blistering has been investigated and the onset temperatures for the various artifacts determined. The lack of blistering in the zone is attributed to an inhibition of bubble growth by high levels of compressional stress. At the periphery bubble growth and blister formation is enhanced. This is attributed to the following, acting either individually or in concert: the absence of high levels of compressive stress; tensile stresses normal to the surface; and the lateral gradients of the tensile and compressive stresses. (orig.)