Grain boundary phase transition and dislocation networks

October 16, 2011

[1] A grain boundary phase transition in Si-Au

S Ma et al

A grain boundary transition from a bilayer to an intrinsic (nominally clean) boundary is observed in Si-Au. An atomically-abrupt transition between the two complexions (grain boundary stabilized phases) implies the occurrence of a first-order interfacial phase transition associated with a discontinuity in the interfacial excess. This observation supports a grain-boundary complexion theory with broad applications. This transition is atypical in that the monolayer complexion is absent. A model is proposed to explain the bilayer stabilization and the origin of this complexion transition.

[2] Universal Strain – Temperature Dependence of Dislocation Structures at the Nano-Scale

P Landau et al

The universal topology of experimental strain-temperature maps of dislocation structures of fcc metals allows the ordering of dislocation structure forming processes in these metals, which is not consistent with the stacking fault energy or the melting temperature. Using dimensional analysis, it is shown that the metals can be ordered by the activation energy for cross-slip. The experimental maps are scaled by the cross-slip activation energy to form a universal strain temperature map. The implications for dislocation rearrangement mechanisms are discussed.

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