Spontaneous athermal cross-slip nucleation at screw dislocation intersections in FCC metals and L1(2) intermetallics investigated via atomistic simulations
SI Rao and DM Dimiduk and JA El-Awady and TA Parthasarathy and MD Uchic and C Woodward, PHILOSOPHICAL MAGAZINE, 93, 3012-3028 (2013).
In this manuscript, we extend on our prior work to show that under certain conditions cross-slip nucleation is athermal and spontaneous with zero activation energy in FCC elemental metals such as Ni and Cu, and L1(2) intermetallic compounds such as Ni3Al. Using atomistic simulations (molecular statics), we show that spontaneous cross-slip occurs at mildly repulsive intersections. Further, the local Shockley partial dislocation interactions at such repulsive intersections are found to be attractive leading to junction formation. The line orientation of the intersecting dislocation determines whether the spontaneous cross-slip nucleation occurs from either the glide plane to the cross-slip plane or vice versa. Collectively, these results suggest that cross-slip should be preferentially observed at selected screw dislocation intersections in FCC-derviative metals and alloys.
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