Atomistic simulations of the effect of embedded hydrogen and helium on the tensile properties of monocrystalline and nanocrystalline tungsten

JOURNAL OF NUCLEAR MATERIALS

卷:481

Article

Chen, Zhe^1,3  Kecskes, Laszlo J.²  Zhu, Kaigui^1,4  Wei, Qiuming³ 

[1] Beihang Univ, Dept Phys, Beijing 100191, Peoples R China

[2] US Army Res Lab, Aberdeen, MD 21005 USA

[3] Univ North Carolina Charlotte, Dept Mech Engn, Charlotte, NC 28223 USA

[4] Beihang Univ, Beijing Key Lab Adv Nucl Energy Mat & Phys, Beijing 100191, Peoples R China

关键词: Molecular dynamics;    Tungsten;    Plasma facing materials;    Irradiation;    Tension;   

DOI  :  10.1016/j.jnucmat.2016.09.024

来源: Elsevier

【 摘 要 】

Uniaxial tensile properties of monocrystalline tungsten (MC-W) and nanocrystalline tungsten (NC-W) with embedded hydrogen and helium atoms have been investigated using molecular dynamics (MD) simulations in the context of radiation damage evolution. Different strain rates have been imposed to investigate the strain rate sensitivity (SRS) of the samples. Results show that the plastic deformation processes of MC-W and NC-W are dominated by different mechanisms, namely dislocation-based for MC-W and grain boundary-based activities for NC-W, respectively. For MC-W, the SRS increases and a transition appears in the deformation mechanism with increasing embedded atom concentration. However, no obvious embedded atom concentration dependence of the SRS has been observed for NC-W. Instead, in the latter case, the embedded atoms facilitate GB sliding and intergranular fracture. Additionally, a strong strain enhanced He cluster growth has been observed. The corresponding underlying mechanisms are discussed. (C) 2016 Elsevier B.V. All rights reserved.

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