Simulation of Uniaxial Deformation of Magnesium Nanocrystals of “Rigid” and “Soft” Orientations

• Published in: Physics of the solid state 2020, Vol.62 (1), p.174-184
• Main Author: Vlasova, A. M.
• Format: Article
• Language: English
• Subjects: Dislocation density; Force and energy; Free surfaces; Hydrogen; Hydrogen atoms; Magnesium; Mechanical Properties; Nanocrystals; Physics; Physics and Astronomy; Physics of Strength; Plastic flow; Plasticity; Potential energy; Solid State Physics; Strain rate; Stress-strain curves; Twinning (Crystallography); Vacancies
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783420010369

Atomistic simulation of high-rate deformation ( = 3 × 10 8 s –1 ) by compressing perfect and defect (5% of vacancies and 5% of hydrogen impurity atoms) magnesium nanocrystals of “rigid” [0001] and “soft” [ ] orientations is performed at T = 300–375 K using three different interatomic interaction potentials. The free surface microrelief evolution of magnesium nanocrystals during plastic flow is shown. Stress σ–strain ε diagrams are constructed. The strain dependences of the scalar dislocation density are determined; the dependences of the strain rate on the strain measure ε are constructed. The potential energy variation during deformation is considered. The formation of barriers causing the anomalous behavior of the strain rate is discussed. The effect of vacancies and hydrogen atoms on the shape of stress–strain curves, dislocation structure, and scalar dislocation density is shown. Conclusions about the effect of the type of the interatomic interaction potential on calculated characteristics are made.