Shear Transformation Zones: State determined or protocol dependent?
1 Faculty of Mechanical Engineering - Technion, Haifa 32000, Israel
2 Department of Chemical Physics, Weizmann Institute of Science - Rehovot 76100, Israel
Received: 24 August 2014
Accepted: 17 December 2014
The concept of a Shear Transformation Zone (STZ) refers to a region in an amorphous solid that undergoes a plastic event when the material is put under an external mechanical load. An important question that had accompanied the development of the theory of plasticity in amorphous solids for many years now is whether an STZ is a region existing in the material (which can be predicted by analyzing the unloaded material), or it is an event that depends on the loading protocol (i.e., the event cannot be predicted without following the protocol itself). In this letter we present strong evidence that the latter is the case. Infinitesimal changes of protocol result in macroscopically big jumps in the positions of plastic events, meaning that these can never be predicted from considering the unloaded material.
PACS: 62.20.F- – Deformation and plasticity / 61.43.Dq – Amorphous semiconductors, metals, and alloys
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