A new loop-punching mechanism for helium bubble growth in tungsten

作者:Xie, Hongxian*; Gao, Ning; Xu, Ke; Lu, Guang-Hong*; Yu, Tao; Yin, Fuxing
来源:Acta Materialia, 2017, 141: 10-17.
DOI:10.1016/j.actamat.2017.09.005

摘要

Growth of helium (He) bubbles with different initial sizes in tungsten (W) has been investigated by performing molecular dynamics simulations. Based on the simulation results a new loop punching mechanism for the large helium bubble growth is proposed. Different from the growth of small-size He bubbles by pushing out self-interstitial atoms and then rearranging into a prismatic dislocation loop, a large-size bubble grows by pushing out a dislocation, subsequently cross-slipping of its screw components and finally evolving into a prismatic dislocation loop. Such dislocations may react with each other to form a dislocation net around the bubble rather than to convert to prismatic dislocation loops.