The behaviors of dislocation loops punched by helium interstitials accumulation under the temperature gradient field in tungsten

Abstract

ABSTRACT Enormous amounts of investigations have been made to understand the helium interstitials accumulation processes in tungsten, which is a promising candidate of plasma-facing materials in fusion reactors. However, the temperature gradient, which almost certainly exists in plasma-facing materials, was often neglected in previous studies. In view of this, the molecular dynamics method is employed to simulate the helium interstitials accumulation processes in tungsten at temperature gradient field in this study. The results show that in the temperature gradient field, the helium bubble formed by helium interstitials accumulation processes also grows via punching out 1/2<111> dislocation loops, which is similar to that at constant temperature. However, under the temperature gradient field, 1/2<111> dislocation loops always were emitted to the higher-temperature region. Combined with the first principle calculation, the formation energy of self-interstitial atom at high temperature should be responsible for this phenomenon.