Study of variation of activation energy barrier with grain boundary misorientations associated with dislocation nucleation from different grain boundaries in Ni

S Chandra and MK Samal and NN Kumar and VM Chavan, PHILOSOPHICAL MAGAZINE, 102, 413-439 (2022).

DOI: 10.1080/14786435.2021.2002456

The present work is an attempt to reveal the relationship between grain boundary crystallography and properties with focus on dislocation nucleation under uniaxial tensile loading in face centred cubic Ni. Using atomistic simulations and nudged elastic band method, this work reports the kinetic activation parameters associated with dislocation nucleation from 388 grain boundaries in Ni. The results reveal that energy barrier at zero stress is relatively higher for grain boundaries with small misorientations. The misorientation axis of grain boundaries also influences the activation energy values. In addition, the incapability of static grain boundary energy and sigma value to predict the low/high energy barrier is revealed. Further statistical analysis is performed to identify general trends in the magnitudes of activation energy barrier. The ramifications of this study in accentuating the development of reliable interface related constitutive relationships are discussed.

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