Grain size Dependency, Plasticity and Dynamic Property Evaluation for Nano-crystalline BCC-Fe using Molecular Dynamic Simulations

P Dungriyal and SP Singh and R Prasad, PLASTICITY AND IMPACT MECHANICS, 173, 1975-1982 (2017).

DOI: 10.1016/j.proeng.2017.02.458

A recently held study on molecular dynamic simulation resulted in a breakdown in the Hall-Petch relation of nanocrystalline (NC) body- centered cubic Fe under the deformation behavior. A decrease in the average flow stress of Fe nanocrystalline was found due to the decrease with grain refinement below 13.22 nm. The refinement of grain size increases the fraction of grain boundaries in model, which leads to grain boundary movement along the grains, and becomes the main reason behind the breakdown in the Hall-Petch relation detected in the current nanocrystalline pure Fe. This paper also investigates and observes detailed failure mechanism for BCC iron, such as dislocation migration, twin boundary formation, grain boundary sliding and final failure due to intergranular fracture during the MD simulation under tensile deformation. This behavior is different from FCC metals. We also investigated the behavior of material under the dynamic loading and found its loss factor and dependency with different frequencies. (C) 2016 The Authors. Published by Elsevier Ltd.

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