Accumulation of dislocation loops in the α phase of Zr Excel alloy under heavy ion irradiation

JOURNAL OF NUCLEAR MATERIALS

卷:491

Article

Yu, Hongbing¹  Yao, Zhongwen¹  Idrees, Yasir¹  Zhang, He K.¹  Kirk, Mark A.²  Daymond, Mark R.¹ 

[1] Queens Univ, Dept Mech & Mat Engn, Kingston, ON K7L 3N6, Canada

[2] Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA

关键词: In-situ;    Irradiation damage;    Zr-Excel alloy;    Dislocation loop;   

DOI  :  10.1016/j.jnucmat.2017.04.038

来源: Elsevier

【 摘 要 】

In-situ heavy ion irradiations were performed on the high Sn content Zr alloy 'Excel', measuring type dislocation loop accumulation up to irradiation damage doses of 10 dpa at a range of temperatures. The high content of Sn, which diffuses slowly, and the thin foil geometry of the sample provide a unique opportunity to study an extreme case where displacement cascades dominate the loop formation and evolution. The dynamic observation of dislocation loop evolution under irradiation at 200 degrees C reveals that type dislocation loops can form at very low dose (0.0025 dpa). The size of the dislocation loops increases slightly with irradiation damage dose. The mechanism controlling loop growth in this study is different from that in neutron irradiation; in this study, larger dislocation loops can condense directly from the interaction of displacement cascades and the high concentration of point defects in the matrix. The size of the dislocation loop is dependent on the point defect concentration in the matrix. A negative correlation between the irradiation temperature and the dislocation loop size was observed. A comparison between cascade dominated loop evolution (this study), diffusion dominated loop evolution (electron irradiation) and neutron irradiation suggests that heavy ion irradiation alone may not be enough to accurately reproduce neutron irradiation induced loop structures. An alternative method is proposed in this paper. The effects of Sn on the displacement cascades, defect yield, and the diffusion behavior of point defects are established. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free