The study of defect structure in tungsten: Rotation and migration property for the self-interstitial atoms

Irradiation damage research is one of the basic issues to solve the application of first-wall materials in fusion engineering. The diffusion and recovery of the defects can greatly affect the performance of the materials in fusion. The rotation stability, complex migration processes and the uniaxial strain modulus M-[ijk] of the self-interstitial atoms (SIAs) in defect structures of tungsten were investigated by the first-principle method. It was found that the <11h>dumbbell had a lower formation energy than <111>dumbbell. Further confirmation has been done from the uniaxial strain that the uniaxial modulus M-[11h] has a minimum value of 518Gpa in crystal tungsten. It demonstrated that the stress field played an important role to the SIA dumbbells. Nevertheless, the calculation indicated that the <11 h> SIA would be the key subject in finishing the complex migration in evolution of irradiation defects. (C) 2017 Elsevier B.V. All rights reserved.