title: Energetics of vacancy segregation to [100] symmetric tilt grain boundaries in bcc tungsten.
abstract: The harsh irradiation environment poses serious threat to the structural integrity of leading candidate for plasma-facing materials, tungsten (W), in future nuclear fusion reactors. It is thus essential to understand the radiation-induced segregation of native defects and impurities to defect sinks, such as grain boundaries (GBs), by quantifying the segregation energetics. In this work, molecular statics simulations of a range of equilibrium and metastable [100] symmetric tilt GBs are carried out to explore the energetics of vacancy segregation. We show that the low-angle GBs have larger absorption length scales over their high-angle counterparts. Vacancy sites that are energetically unfavorable for segregation are found in all GBs. The magnitudes of minimum segregation energies for the equilibrium GBs vary from -2.61 eV to -0.76 eV depending on the GB character, while those for the metastable GB states tend to be much lower. The significance of vacancy delocalization in decreasing the vacancy segregation energies and facilitating GB migration has been discussed. Metrics such as GB energy and local stress are used to interpret the simulation results, and correlations between them have been established. This study contributes to the possible application of polycrystalline W under irradiation in advanced nuclear fusion reactors.
authors.affiliation: College of Energy, Xiamen University, Xiamen City, Fujian Province, 361102, China.|Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109 USA.
authors.forename: Nanjun
authors.initials: N
authors.lastname: Chen
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.|Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109 USA.
authors.forename: Liang-Liang
authors.initials: LL
authors.lastname: Niu
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Shu
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Zhou
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Jin
authors.affiliation: College of Energy, Xiamen University, Xiamen City, Fujian Province, 361102, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Ran
authors.affiliation: Department of Physics, Beihang University, Beijing 100191, China.
authors.forename: Guang-Hong
authors.initials: GH
authors.lastname: Lu
authors.affiliation: Department of Nuclear Engineering and Radiological Science, University of Michigan, Ann Arbor, MI 48109 USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Gao