**Simulations of dislocation mobility in magnesium from first principles**

I Shin and EA Carter, INTERNATIONAL JOURNAL OF PLASTICITY, 60, 58-70 (2014).

DOI: 10.1016/j.ijplas.2014.04.002

The strength and ductility of metals are governed by the motion of
dislocations, which is quantified by the Peierls stress (sigma(p)). We
use orbital-free density functional theory (OFDFT) to characterize the
motion of 1/3 < 11 (2) over bar0 > dislocations on the basal *0001* and
prismatic *1 (1) over bar 00* planes in hexagonal-close-packed magnesium
(Mg) in order to understand its deformation mechanisms. We predict
sigma(p) values of edge dislocations on the basal and prismatic planes
to be 0.6 and 35.4 MPa, respectively. The presence of stable stacking
faults only on the basal plane produces partial dislocation splitting,
which significantly lowers sigma(p) for basal dislocations. Our atomic
scale simulations reveal that dislocation mobility is strongly
correlated with the number of core atoms moving collectively. OFDFT
sigma(p) results are in excellent agreement with experiments (similar to
0.5 and 39.2 MPa), further validating OFDFT as an independent and
predictive tool for simulating plastic behavior in main group metals at
the mesoscale with first principles' accuracy. (C) 2014 Elsevier Ltd.
All rights reserved.

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