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Molecular dynamics study on radiation hardening and fracture processes
in FCC metals
Molecular dynamics study on radiation hardening and fracture processes
in FCC metals
Hideo Kaburaki (JAERI)
DOE Workshop on Advanced Computational Materials Science, 31 Mar.-2 Apr.,2004
6.39-7.15×10-6Å/step
(3.20-3.58×10-2Å/10ps)
For 80ps (40,000steps)・(111)
Effect of external shear stress for unfaulting
[111]
x
Z
]110[Y
[112]Shear strain
nearly 380,000 atoms
pure alminium
Interatomic potential : Embedded-atom method (EAM) potential [Y. Mishin et al., PRB (2001).]
Unfaulting process of H721 vacancy loop
Partial dislocation loop
Coordination number representation
Central symmetry parameter representation
Stacking fault
Results of unfaulting critical shear stress
for vacancy loops
Intrinsic stacking fault
[111]
Number of atoms 3.8×105
170Å
120Å
200Å
x
Z
]110[
Y
10Å
mixed free
periodic
Hardening process Hardening process ------ the interaction of an edge the interaction of an edge dislocation with a hexagonal interstitial dislocation loopdislocation with a hexagonal interstitial dislocation loop
Simulation SystemSimulation System[112]
Interatomic potential : Embedded-atom method (EAM) potential Cu, Al [Y. Mishin et al., PRB (2001).]
( )iiij
ijtot ρFrVE ∑∑ += )(21 V: Pair potential
F: Embedding energy
Pinning structure formed due to the interaction of an edge dislocation and an interstitial cluster in Cu
H007 H037 H169 H721
Pinning structure formed due to the interaction of an edge dislocation and an interstitial cluster in Al
H007 H037 H169 H721
A molecular dynamics study on displacement cascades in the strain field of an edge dislocation in Cu
Movie1Movie2Movie3
40Å
[110]1kev
Movieat 300K
205×177×125Å
FractureFracture process process ------ developmentdevelopment of crackof crack--tiptipmicrostructuresmicrostructures
ModeⅠcrack in asingle fcc crystal
ModeⅠcrack in asingle fcc crystal
# of atoms: 1,036,960
291.5 Å
291.
5 Å
144.6Å
xy
]110[]011[
z ]001[
CoordinateCoordinatesystemsystem
Simulation CellSimulation Cell
Slip plane = {111}The slip planes and the (110) crack plane intersect obliquely
at 70.5°x ½
Temperature dependence on the crack-tip dislocation nanostructures (Cu)
24 ps
150 K0 K 50 K 300 K
16 ps
Initial crack length
DislDisl. motion on the slip plane (Cu, 50K). motion on the slip plane (Cu, 50K)
16 16 psps 18 18 psps 20 20 psps 22 22 psps
24 24 psps 26 26 psps 28 28 psps 30 30 psps
]121[
]112[0]1[1
AlCu
Expansion and emission process ofExpansion and emission process ofstackingstacking--fault loopsfault loops
fcc
hcp
fcc
hcp
fcc
Shockley partial
11261
C.N. = 10 : Green11 : Red12 : omitted (f.c.c.) 13 : Blue
18.4 ps
21.6 ps
10.0 ps