scholarly journals Formation of Interstitial Dislocation Loops by Irradiation in Alpha-Iron under Strain: A Molecular Dynamics Study

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 317
Author(s):  
Mohammad Bany Salman ◽  
Mehmet Emin Kilic ◽  
Mosab Jaser Banisalman
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dislocation Loop ◽  
Dynamics Simulation ◽  
Peak Time ◽  
Dislocation Loops ◽  
Alpha Iron ◽  
Static Strain ◽  
Hydrostatic Strain ◽  
Threshold Displacement

The present work reports the formation of an interstitial dislocation loop with a lower primary knock-on atom (PKA) energy in alpha-iron under strain conditions by the use of molecular dynamics simulation. The study was conducted using a PKA energy of 1~10 keV and hydro-static strain from −1.4 to 1.6%. The application of 1.6% hydrostatic strain results in the formation of ½<111> dislocation loop with a low PKA of 3 keV. This result was associated with a threshold displacement energy decrement when moving from compression to tension strain, which resulted in more Frenkel pairs initiated at peak time. Furthermore, many of the initiated defects were energetically favorable by 2 eV in the form of the interstitial dislocation loop rather than a mono defect.

Molecular Dynamics Simulation of Neutron Damage in β-SIC

1998 ◽  
Vol 540 ◽  
Author(s):  
J.M. Perlado ◽  
L. Malerba ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Point Defects ◽  
Damage Accumulation ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Temperature Sensitive ◽  
Neutron Damage ◽  
Preliminary Study ◽  
Threshold Displacement

AbstractMolecular Dynamics (MD) simulations of neutron damage in β-SiC have been performed using a modified version of the Tersoff potential. The Threshold Displacement Energy (TDE) for Si and C atoms at 300 K has been determined along directions [001], [110], [111] and [ 1 1 1 ]. The existence of recombination barriers, which allow the formation of metastable, temperature-sensitive defects even below the threshold, has been observed. Displacement cascades produced by both C- and Si-recoils of energies spanning from 0.5 keV up to, respectively, 5 keV and 8 keV have also been simulated at 300 K and 1300 K. Their analysis, together with the analysis of damage accumulation (∼3.4×10-3 DPA) at 1300 K, reveals that the two sub-lattices exhibit opposite responses to irradiation: whereas only a little damage is produced on the “ductile” Si sub-lattice, many point-defects accumulate on the much more “fragile” C sub-lattice. A preliminary study of the nature and clustering tendency of these defects is performed. The possibility of disorder-induced amorphization is considered and the preliminary result is that no amorphization takes place at the dose and temperature simulated.

Atomistic Simulations of Dislocation-Loop Glidings in Al(111) Nanoindentation

2004 ◽  
Vol 261-263 ◽  
pp. 735-740
Author(s):  
Sukky Jun ◽  
Young Min Lee ◽  
Sung Youb Kim ◽  
Se Young Im
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Film Thickness ◽  
Dislocation Loop ◽  
Dislocation Motion ◽  
Dynamics Simulation ◽  
Atomistic Simulations ◽  
Dislocation Loops ◽  
Simulation Results ◽  
Film Nucleation

Molecular dynamics simulation of nanoindentation on Al(111) surface is presented. The simulation is performed using the Ercolessi-Adams glue potential and the Berendsen thermostat. Boundary conditions of 'pseudo' thin film are imposed in order to focus on the dislocation motion in ultra-thin film. Nucleation and development of defects underneath the indenter tip are visualized, and the gliding patterns of dislocation loops are investigated with particular emphasis on the effect of film thickness. Simulation results show that the early emission of dislocation loop is highly dependent on the film thickness.

scholarly journals Effect of Cutting Crystal Directions on Micro-Defect Evolution of Single Crystal γ-TiAl Alloy with Molecular Dynamics Simulation

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1278
Author(s):  
Jianhua Li ◽  
Ruicheng Feng ◽  
Haiyang Qiao ◽  
Haiyan Li ◽  
Maomao Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Dislocation Loop ◽  
Tial Alloy ◽  
Amorphous Layer ◽  
Stacking Fault ◽  
Dynamics Simulation ◽  
Machined Surface ◽  
Stacking Fault Tetrahedron

In this work, the distribution and evolution of micro-defect in single crystal γ-TiAl alloy during nanometer cutting is studied by means of molecular dynamics simulation. Nanometer cutting is performed along two typical crystal directions: [ 1 ¯ 00 ] and [ 1 ¯ 01 ] . A machined surface, system potential energy, amorphous layer, lattice deformation and the formation mechanism of chip are discussed. The results indicate that the intrinsic stacking fault, dislocation loop and atomic cluster are generated below the machined surface along the cutting crystal directions. In particular, the Stacking Fault Tetrahedron (SFT) is generated inside the workpiece when the cutting crystal direction is along [ 1 ¯ 00 ] . However, a “V”-shape dislocation loop is formed in the workpiece along [ 1 ¯ 01 ] . Furthermore, atomic distribution of the machined surface indicates that the surface quality along [ 1 ¯ 00 ] is better than that along [ 1 ¯ 01 ] . In a certain range, the thickness of the amorphous layer increases gradually with the rise of cutting force during nanometric cutting process.

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