Regensburg 2004 – wissenschaftliches Programm
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M: Metallphysik
M 18: Postersitzung
M 18.22: Poster
Dienstag, 9. März 2004, 14:30–16:30, Saal C
Monte Carlo Simulation of Binary Alloys Including Elastic Relaxations — •Rolf Anders1, Gururajan Mogadalai Pandurangan1,2, and Ferdinand Haider1 — 1Univ. Augsburg, Institut f. Physik — 2Indian Institute of Science, Dept. f. Metallurgy
We developped a real space technique which includes local atomic relaxation during each atomic jump, allowing thus to study phase transformations with strong elastic contributions. For each atomic jump, the activation energy is computed using phenomenological interaction potentials. After a succesful jump the atomic coordinates of the vicinity of the jumping atom are relaxed in order to minimise the total energy.
This technique was applied to a binary alloy with vacancy diffusion using the Lennard-Jones potential. The influence of temperature T, misfit σB/σA and chemical interaction εAB/εA on precipitate size and precipitation kinetics was studied. Precipitation was only observed at medium temperatures. At low T diffusion is too slow while at high T the thermal energy is greater than the energy loss per atom through precipitation. A similar behaviour was found with respect to chemical interaction. A value of εAB/εA considerably smaller than 1 slows down precipitation and at εAB/εA≈ 1 no precipitates are formed due to the low energy difference. Increasing σB/σA also causes a slowing down of precipitation.