Grain boundary roughening transitions

Bartol Research Institute and Deptartment of Physics and Astronomy, University of Delaware Newark, DE 19716, USA

Corresponding author: chui@udel.edu

Received: 4 August 2009
Accepted: 3 September 2009

Abstract

We consider the roughening of small-angle grain boundaries consisting of arrays of dislocations and found two transitions, corresponding to fluctuations of the dislocations along and perpendicular to the boundaries. The latter contributes to a large-scale fluctuation of the orientation of the crystal but the former does not. The transition temperatures of these transitions are very different, with the latter occuring at a much higher temperature. Order-of-magnitude estimates of these temperatures are consistent with recent experimental results from elasticity and X-ray measurements in solid ⁴He.