An almost unifying theory for grain boundary‐based plasticity
October 1-6, 2017
Revealed in metallic nanocrystals, or thin films (Fig. 1) grain boundary (GB)-based plasticity has been studied for many years under various names: stress-assisted grain growth, grain rotation, grain boundary sliding or shear-coupled grain boundary migration. Based on MD simulations, TEM and in-situ TEM approaches, we will show that a key player in these mechanisms is the disconnection [1, 2]. This defect combines a step and a Burgers vector character, and belongs to GBs, especially real GBs. The motion of these defects can explain most of the above-mentioned mechanisms depending on the amplitude of both its step and dislocation components. But not all of them. Some observations suggest that local atomic shuffling also plays a role as clear non-conservative behaviours are detected, probably postponing the expected happy ending of a complete GB-based plasticity understanding.
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Marc Legros, Armin Rajabzadeh, Sylvie Lartigue-Korinek, and Mayerling Martinez, "An almost unifying theory for grain boundary‐based plasticity" in "Nanomechanical Testing in Materials Research and Development VI", Karsten Durst, Technical University of Darmstadt, Germany Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/nanomechtest_vi/19