Effect of strain field on displacement cascade in tungsten studied by molecular dynamics simulation
D Wang and N Gao and ZG Wang and X Gao and WH He and MH Cui and LL Pang and YB Zhu, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 384, 68-75 (2016).
Using atomistic methods, the coupling effect of strain field and displacement cascade in body-centered cubic (BCC) tungsten is directly simulated by molecular dynamics (MD) simulations at different temperatures. The values of the hydrostatic and uniaxial (parallel or perpendicular to primary knock-on atom (PICA) direction) strains are from 2% to 2% and the temperature is from 100 to 1000 K. Because of the annealing effect, the influence of strain on radiation damage at low temperature has been proved to be more significant than that at high temperature. When the cascade proceeds under the hydrostatic strain, the Frenkel Pair (FP) production, the fraction of defect in cluster and the average size of the defect cluster, all increase at tensile state and decrease at compressive state. When the cascade is under uniaxial strain, the effect of strain parallel to PICA direction is less than the effect of hydrostatic strain, while the effect of strain perpendicular to PICA direction can be negligible. Under the uniaxial strain along (1 1 1) direction, the SIA and SIA cluster is observed to orientate along the strain direction at tensile state and the uniaxial compressive strain with direction perpendicular to (1 I 1) has led to the similar preferred nucleation. All these results indicate that under irradiation, the tensile state should be avoided for materials used in nuclear power plants. (C) 2016 Elsevier B.V. All rights reserved.
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