Theoretical Simulations of Irradiation-Induced Sputtering at Tungsten Surface

Abstract

The irradiation-induced sputtering and the structural damage at tungsten surface are investigated by using molecular dynamics simulations at the level of quantum mechanics. Our simulations indicate that the sputtered atoms appear when the energy of incident primary knock-on atom (PKA) is more than 200 eV and the incident angle of the PKA is larger than 65 •. Meanwhile, the irradiation-induced vacancies are less when the incident angle of PKA is in the range of 45 • −65 •. So, the optimum incident angles of PKA are suggested to reduce the irradiation-induced damage of the W surface. Furthermore, we find that the interstitials contained in the systems accelerate the sputtering whereas the intrinsic vacancies suppress the sputtering when the PKA is near the defects.

Free-surface effect on displacement cascades in BCC W: molecular dynamics study

“…Researchers have investigated the effect of free surface, where an extensive amount of neutron bombardment takes place, via both simulation [31][32][33][34][35][36][37][38] and experimental [23,[39][40][41] approaches. According to these literatures, free surface influences the formation of primary damage.…”

“…There are also recent MD studies of irradiation on W free surface. Hua et al investigated irradiationinduced sputtering and point defects at W {110} surface [35], and Wei et al studied on He bubble evolution below W {100}, {110} and {111} surfaces [36]. These works enlarged our knowledge on how sputtering interplays with point defects and how He bubble evolves and stabilizes near W free surface, but there are still more to be investigated on free surface effect on displacement cascade and subsequent defect formation in W. For example, Stoller et al [29] addressed two mechanisms to explain preference of vacancy-type defects near surface in BCC Fe: one is massive material removal due to sputtering and the other is surface adsorption of mobile interstitials, but which one is major mechanism was still unclear.…”

Распыление Вольфрама Ионами Бериллия И Неона

“…В ряде работ рассчитывается распыление вольфрама и различных химических соединений с вольфрамом [7][8][9] и моделируются потоки бериллия в плазме [2,10]. Получение данных о коэффициентах распыления вольфрама и их угловых зависимостях также является предметом интенсивных теоретических и экспериментальных исследований [6,[11][12][13]. В задачу настоящей работы входило провести расчеты распыления вольфрама ионами Be и Ne.…”