Effect of solute atom concentration on vacancy cluster formation in neutron-irradiated Ni alloys

Koichi Sato, Daiki Itoh, Toshimasa Yoshiie, Qiu Xu, Akihiro Taniguchi, Takeshi Toyama

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The dependence of microstructural evolution on solute atom concentration in Ni alloys was investigated by positron annihilation lifetime measurements. The positron annihilation lifetimes in pure Ni, Ni-0.05 at.%Si, Ni-0.05 at.%Sn, Ni-Cu, and Ni-Ge alloys were about 400 ps even at a low irradiation dose of 3 × 10-4 dpa, indicating the presence of microvoids in these alloys. The size of vacancy clusters in Ni-Si and Ni-Sn alloys decreased with an increase in the solute atom concentration at irradiation doses less than 0.1 dpa; vacancy clusters started to grow at an irradiation dose of about 0.1 dpa. In Ni-2 at.%Si, irradiation-induced segregation was detected by positron annihilation coincidence Doppler broadening measurements. This segregation suppressed one-dimensional (1-D) motion of the interstitial clusters and promoted mutual annihilation of point defects. The frequency and mean free path of the 1-D motion depended on the solute atom concentration and the amount of segregation.

Original languageEnglish
Pages (from-to)963-967
Number of pages5
JournalJournal of Nuclear Materials
Issue number1-3
Publication statusPublished - 2011 Oct 1

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Materials Science(all)
  • Nuclear Energy and Engineering


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