Addition of solutes such as
lithium enhances ducti
lity of hexagonal-close-packed (hcp)
magnesium (Mg). However, the atomistic underpinning of Li addition on individual defor
mation mechanisms re
main unclear and is the focus of the present work. We compared the defor
mation mechanisms in nanocrystal
line (NC) and single crystal simulation systems of pure Mg and Mg-Li hcp alloys. Five defor
mation modes are observed in the pure NC Mg with randomly oriented grains – one basal
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lineImage" height="19" width="56" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0927025616304402-si15.gif">pan class="mathContainer hidden">pan class="mathCode"><math altimg="si15.gif" overflow="scroll">〈101¯2〉math>pan>pan>pan>. Distributing 10 at.% Li randomly to this NC Mg decreased its compressive yield strength by 14.5%. This also increases the ducti
lity by activating non-basal defor
mation modes and by reducing the plastic anisotropy. We bench
marked these results by comparing the effect of Li addition on these defor
mation modes in Mg single crystals. Finally, we present a for
mabi
lity parameter (
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pan id="mmlsi59" class="mathmlsrc">pan class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0927025616304402&_mathId=si59.gif&_user=111111111&_pii=S0927025616304402&_rdoc=1&_issn=09270256&md5=9e02c885d91b04f5f729b27477fd71a4" title="Click to view the MathML source">Fppan>pan class="mathContainer hidden">pan class="mathCode"><math altimg="si59.gif" overflow="scroll">Fpmath>pan>pan>pan> values for the Mg-Li alloys with respect to pure Mg in single crystal simulations explain the decrease in compressive yield strength and change in defor
mation mechanisms with Li additions. A sensitivity analysis study, comparing our CD-EAM results with a MEAM potential, shows that the effects of Li on the single defor
mation mechanisms are potential independent. Lastly, while results for Mg-10 at.% Li random alloy are presented here, similar conclusions can be drawn for other compositions of this hcp Mg-Li alloy.