Effects of He implantation on radiation induced segregation in Cu-Au and Ni-Si alloys

Effects of He implantation on radiation induced segregation (R1S) in Cu-Au and Ni-Si alloys were investigated using in situ Rutherford backscattering spectrometry during simultaneous irradiation with 1.5-MeV He and low-energy (100 or 400-keV) He ions at elevated temperatures. RIS during single He io n irradiation, and the effects of pre-implantation with low-energy He ions, were also studied. RIS near the specimen surface, which was pronounced dur ing 1.5-MeV He single-ion irradiation, was strongly reduced under low-energ y He single-ion irradiation, and during simultaneous irradiation with 1.5-M eV He and low-energy He ions. A similar RIS reduction was also observed in the specimens pre-implanted with low-energy He ions. The experimental resul ts indicate that the accumulated He atoms cause the formation of small bubb les, which provide additional recombination sites for freely migrating defe cts. (C) 1999 Elsevier Science B.V. All rights reserved.