First-principles Investigation of Vacancy and Self-interstitial Atom Segregations at Grain Boundaries in Tungsten

摘要

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].As recombination center of Vs and SIAs,grain boundaries(GBs)are able to enhance the radiation resistance of materials[2].However,experimental investigation show that point defects sink strengths might depend on GB structures.The vacancy sink efficiency of the twin boundaryΣ3(110)[111]is significantly lower than that of other GBs[3−5].