Open AccessDefect production and formation of helium-vacancy clusters in cascades of α-iron with different concentration of helium
Author(s) -
Li Yang,
Xihong Zu,
Xiao Hai-Yan,
Sijia Yang,
Kezhao Liu,
Fei Gao
Publication year - 2005
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.54.4857
Subject(s) - helium , nucleation , vacancy defect , materials science , atom (system on chip) , atomic physics , molecular dynamics , displacement (psychology) , chemical physics , physics , thermodynamics , condensed matter physics , psychology , computer science , psychotherapist , embedded system , quantum mechanics
The low-temperature displacement cascades in α-Fe with different concentrations of substitutional He atoms are simulated by molecular dynamics (MD) methods. Primary knock-on atom (PKA) energy, Ep , from 500eV to 5keV is cons idered for irradiation temperature of 100K. The concentration of He in Fe varies from 1% to 5%. The results are compared with those obtained in pure α-Fe. We f ind the number of Frenkel pairs (NF) in Fe with low concentration of He atoms is nearly equal to those in pure Fe, but increases with increasing He c oncentration. The present study demonstrates for the first time that He-vacancy bubbles can be nucleated directly from displacement cascades, even at low tempe rature at which the vacancies are not mobile. However, the efficiency of He-vaca ncy clusters increases with increasing the concentration of He for the same ener gy recoils, and increases with increasing Ep for the same concentrati on of He. The mechanisms of He bubble nucleation in displacement cascades are di scussed in detail.