|About this Abstract
||2010 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||Twinning Nucleation Mechanisms in Hexagonal-Close-Packed Crystals
||Jian Wang, John Hirth, Carlos N Tome
|On-Site Speaker (Planned)
We have studied mechanisms for (-1012) twinning in hexagonal-close-packed crystals at an atomic scale using topological analysis and atomistic simulations. Two twinning mechanisms were found: a normal-twinning mechanism in which a stable twin nucleus is created by simultaneous nucleation of multiple twinning dislocations, and a zonal-twinning mechanism in which a stable twin nucleus is created by simultaneous nucleation of a partial dislocation and multiple twinning dislocations. Atomistic simulations, using density-function-theory for Mg, Zr and Zn and an empirical potential for Mg, were performed to study the kinetics and energetics associated with the two twinning mechanisms. The results show that the zonal-twinning mechanism is energetically favorable relative to the normal-twinning mechanism because the zonal dislocation has a smaller Burgers vector.
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