Atomistic assessment of structural evolution for magnesium during hypervelocity nanoprojectile penetration

Abstract

In the present study, the effect of ballistic penetration of a spherical projectile on a monocrystalline magnesium specimen is performed using Embedded Atom Method (EAM) potential in Molecular Dynamics (MD) simulation. The dynamic investigation of structural evolution based on common neighbor analyses and Wigner-Seitz defect analysis are carried out for the varying depth of penetration and velocities of the projectile ( v = 2 km/s, 6 km/s, and 10 km/s). It is found that the extent of amorphization in the specimen is more in the case of higher depth and lower projectile velocity. Voronoi cluster analyses are also done to identify cluster distribution and their transformation during ballistic penetration, which is accompanied by atomic strain and displacement vector evaluation to give light to the effect of shear strain and displacement of atoms respectively. According to Voronoi cluster analysis, Voronoi Polyhedra having <0,4,4,6> and <0,6,0,8> exhibits a higher population during hypervelocity projectile penetration. The findings have potential applications in hypervelocity applications such as defense and space technologies.

Molecular dynamics simulation of effects of loading parameters on fatigue crack growth behavior in titanium single crystal

“…Fatigue loading was applied using a strain-controlled approach, 19,21 as depicted in Figure 1B. The simulation results were imported into OVITO 33 for analysis using the common neighbor analysis (CNA), 34 dislocation analysis (DXA), 35,36 Wigner-Seitz defect analysis (W-S), [37][38][39] polyhedral template matching (PTM), 40 and grain segmentation (GS) methods. 41 3 | RESULTS AND DISCUSSION…”

“…The microanalysis of the crack model above reveals the presence of crystal defects, such as vacancies and prismatic dislocations, emerging within the structure under various loading conditions. To gain a deeper understanding of how these dislocations and vacancy structures are influenced by the loading conditions, dynamic statistics of the percentage of prismatic <a> dislocation density and vacancies are conducted using the DXA method 35,36 and W-S method, [37][38][39] respectively. As shown in Figure 8A1-A3, the number of vacancies under different loading conditions exhibits a continuous increase with cyclic strains.…”