First-principles Investigation of Vacancy and Self-interstitial Atom Formation Energy at Grain Boundary in Tungsten

钨晶界上空位和自间隙子形成能的第一性原理研究

Materials served in nuclear energy systems usually expose to high irradiation doses of particles.Projectile particles lead to creations of a large numbers of vacancies(Vs)and self-interstitial atoms(SIAs)in materials.The SIAs may gather to form dislocation loops and stacking-fault tetrahedrons,and the Vs usually gather to form voids.These defects contribute to material swelling,hardening,amorphization and embrittlement,and may accelerate material failure under irradiation[1].Extensive experimental results demonstrated that nano-crystalline materials generally showed good radiation resistance than common poly-crystalline materials because there existed a high fraction of grain boundaries(GBs)in nano-crystalline materials[2].