Orientation dependence of shock-induced change of habit plane for the 1/2<111> dislocation loop and plasticity in tungsten

Tungsten (W) is a promising candidate material for future fusion reactors. The shock waves generated under high-energy neutron radiation can lead to the formation of prismatic interstitial dislocation loops (PIDLs). To understand the details of the mechanisms, the interaction between the shock waves and PIDL with Burgers vector of 1/2 < 111 > was studied by using nonequilibrium molecular dynamics (NEMD) simulation. The shock-induced change of habit plane for the 1/2 < 111 > PIDL and plasticity in W depend strongly on the crystallographic orientations. The driving force for changing the loop's habit plane is derived from the resolved shear stress (RSS). A new rotation mechanism is proposed, which can be used to predict the changing trend of PIDL's habit plane. The rotation angle of the habit plane for the 1/2 < 111 > dislocation loop is proportional to the RSS of the activated slip system. In this work, we also predict a source to induce the plasticity (e.g., deformation twin and dislocation network) observed in the experiment and discuss the nucleation, propagation and interaction of these deformations with different crystallographic orientation. The current results provide significant insights into the evolution of 1/ 2 < 111 > PIDL depending on the crystallographic orientation under shock loading.

Automated summary

Tungsten is a promising candidate material for future fusion reactors. The study finds that the habit plane and plasticity of tungsten with a 1/2 < 111 > crystallographic orientation are strongly influenced by shock waves. A new rotation mechanism is proposed to predict the changing trend of the habit plane of dislocation loops.