Radiation-induced segregation in model alloys

The dependence of the size factor of solutes on radiation-induced segregation (RIS) was studied. Ni–Si, Ni–Co, Ni–Cu, Ni–Mn, Ni–Pd, and Ni–Nb binary solid solution alloys were irradiated with electrons in a high voltage electron microscope at the same irradiation conditions. A focused beam and a grain boundary were utilized to generate a flow of point defects to cause RIS. From the concentration profile obtained by an energy dispersive X-ray analysis, the amount of RIS was calculated. The amount of RIS decreased as the size of the solute increased up to about 10%. However, as the size increased further, the amount of RIS increased. This result shows that RIS is not simply determined by the size effect rule.