Modal analysis of dislocation vibration and reaction attempt frequency

作者：Sobie Cameron; Capolungo Laurent^*; McDowell David L; Martinez Enrique

来源：Acta Materialia, 2017, 134: 203-210.

DOI：10.1016/j.actamat.2017.02.005

• Dislocation
• Thermal activation
• Attempt frequency
• Modal analysis

Transition state theory is a fundamental approach for temporal coarse-graining. It estimates the reaction rate for a transition processes by quantifying the activation free energy and attempt frequency for the unit process. To calculate the transition rate of a gliding dislocation, the attempt frequency is often obtained from line tension estimates of dislocation vibrations, a highly simplified model of dislocation behavior. This work revisits the calculation of attempt frequency for a dislocation bypassing an obstacle, in this case a self-interstitial atom (SIA) loop. First, a direct calculation of the vibrational characteristics of a finite pinned dislocation segment is compared to line tension estimates before moving to the more complex case of dislocation-obstacle bypass. The entropic factor associated with the attempt frequency is calculated for a finite dislocation segment and for an infinite glide dislocation interacting with an SIA loop. It is found to be dislocation length independent for three cases of dislocation-self interstitial atom (SIA) loop interactions. Published by Elsevier Ltd on behalf of Acta Materialia Inc.

• 出版日期2017-8-1