摘要
As promising candidates for plasma-facing materials,tungsten-based materials suffer the irradiation of high-energy neutrons in addition to the hydrogen isotopes and helium irradiation and the high-thermal flux.Radiation-produced defects,e.g.self-interstitial atoms(SIAs)and vacancies(Vs),can induce the hardening and embrittlement of tungsten,meanwhile enhancing the retention of hydrogen isotopes and helium in tungsten.Reducing the grain size of materials to introduce a high density of defect sinks,e.g.,grain boundaries(GBs)prevalent in nano-/ultrafine-crystalline materials,was demonstrated to be an effective approach for mitigating irradiation damage in tungsten.In this paper,we reviewed the theoretical advances in exploring radiation-resistance of nano-structured tungsten at across scales.It was concentrated on the results of molecular dynamics,molecular statics,and the object kinetic Monte Carlo simulations on the fundamental interaction of the radiation-created Vs and SIAs with the GB.These mechanisms include GB-promoted V/SIA migration and SIA-V recombination,interstitial-emission induced annihilation,coupling of the V migration close to the GB with the SIA motion within the GB,and interstitial reflection by the locally dense GB structure.We proposed the remaining scientific issues on the defect-GB interactions at across scales and their relation to experimental observations.We prospected the possible trends for simulating the radiation damage accumulation and healing processes in nano-structured tungsten in terms of the development of the across-scale computational techniques and efficiency of the GB-enhanced tolerance of tungsten to irradiation under complex in-service conditions.
基金
This work was financially supported by the National Key Research and Development Program of China(Grant Nos.2017YFE0302400,2017YFA0402800,and 2018YFE0308102)
the National Natural Science Foundation of China(Grant Nos.11735015,51871207,51671185,U1832206,51771181,U1967211 and 51971212)
the Center for Computation Science,Hefei Institutes of Physical Sciences.
