SEARCH FOR DAMAGE AND OR DISORDERING EFFECTS DUE TO INTENSE ELECTRONIC EXCITATION IN CRYSTALLINE METALLIC ALLOYS IRRADIATED BY HIGH-ENERGY HEAVY-IONS

The effects of intense electronic excitation produced during high-energy heavy-ion irradiation on the damage creation processes in crystalline metallic alloys are studied by in situ liquid-helium electrical resistance experiments. Targets consist of stacks of austenitic Fe-Cr-Ni and both ordered and disordered Cu3Au and Ni3Fe piled up along the 3.4 GeV Xe beam direction in order to vary the amount of electronic energy loss inside the samples. Additional dimensional measurements performed in the case of austenitic Fe-Cr-Ni indicate no change in the sample length within the experimental uncertainty ( Delta l/l=10-3). It is shown that inelastic collisions have no measurable effects on damage production in ordered or disordered Cu 3Au, while they induce a decrease in the defect production efficiency in the case of Ni3Fe and austenitic Fe-Cr-Ni. The latter effect can be attributed to partial recombination of close Frenkel pairs induced in nuclear collisions, as already observed in pure Fe and Ni.