Molecular dynamics study of the effect of lithium on the tensile behaviors of bcc iron

W Wei and XG Yu, MATERIALS TODAY COMMUNICATIONS, 24, 101217 (2020).

DOI: 10.1016/j.mtcomm.2020.101217

Due to the issues that the solid plasma facing materials of fusion devices present, the concept of liquid lithium first wall becomes more and more popular. However, experiments show that exposure to liquid lithium may cause serious corrosion to the stainless steel, which is the most common structural material, and therefore leads to the degradation of the mechanical properties. To reveal the underlying relationship between lithium corrosion and the change of the mechanical properties, molecular dynamics simulations of the uniaxial tensile tests of the single crystal bcc iron were performed. Three lattice orientations, i.e. < 100>,< 110> and< 111>, were considered. The stress-strain curves of the iron crystal with different lithium concentrations were obtained. The plastic deformation processes were discussed in detail. Results show that the yield stress declined monotonically for all the three orientations as the amount of lithium atoms increased. Besides, the plastic deformation mechanisms were significantly influenced by the lithium atoms as well. The phase transition from bcc to hcp inside < 110> orientated crystal was suppressed and the ductility of < 111> orientated crystal was enhanced.

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