Characterization of Atomic Motions Governing Grain Boundary Migration

Published

September 24, 2006

Author(s)

Hao Zhang, David J. Srolovitz, Jack F. Douglas, James A. Warren

Abstract

Molecular dynamics simulations were employed to study atomic motion within stationary and migrating asymmetric tilt grain boundaries. We employ several measures of the complexity of the atomic trajectories, including the van Hove correlation function, the non-Gaussian parameter and dynamic entropy. There are two key types of dynamical events within the grain boundaries i) a string-like cooperative motions parallel to the tilt axis and occurring on a characteristic time scale of 25 ps and ii) atomic motion across the grain boundary plane occurring on a characteristic time scale of 150 ps. The characteristic times associated with each type of event decreases with increasing driving force for boundary migration. We present evidence as to how the driving force biases these types of events, leading to boundary migration. While the string-like atomic motion is an intrinsic feature of grain boundary dynamics and is important for grain boundary migration, it is the second type of event that controls grain boundary migration rates.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

74

Issue

11

Pub Type

Journals

Keywords

cooperative motion, grain boundaries, molecular dynamics

Citation

Zhang, H. , Srolovitz, D. , Douglas, J. and Warren, J. (2006), Characterization of Atomic Motions Governing Grain Boundary Migration, Physical Review B (Condensed Matter and Materials Physics) (Accessed December 10, 2024)