adesh.zip
:Click HERE to Download a DEMO version of ADESH(ADESH works on PC-DOS. You will need the pkunzip.exe utility for this zipped file.)
adesh.zip
:Click HERE to Download a DEMO version of ADESH
(ADESH works on PC-DOS. You will need the pkunzip.exe utility for this zipped file.)
Answer
ADESH produced following results in thirty minutes (on a PC with a 486
micro-processor).
(a) Figure 1 shows the atomisitc configuration
of a dislocation in aluminum cell. Red circles mark positions
of aluminum atoms and green circles represent copper atoms.
Copper (as alloying elements or impurities) are randomely
dispersed in aluminum cell. A dislocation is located
at the center of the aluminum cell. The dislocation is viewed edge on
with the dislocation line perpendicular to the screen.
After using swap technique with ADESH, the copper atoms were
segregated near the dislocation. The driving force for
this segregation is the energy reduction of the configuration.
Please see Figure 3.
The energy of the configuration was calculated using Lennard-Jones
function. The average energy of atoms in vertical slices was caluclated
and plotted from left to right of the aluminum cells.
(1)The cell with the dislocation (yellow),
(2) with the dislocation and random copper atoms (green), and,
(3) with the dislocation and segregated copper atoms (red).
The dislocation is at the center of the cell and hence the strain energy
of atoms is higher in that region. The segregation of
copper near the dislocations reduced the energy of the configuration.
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