  Strong room-temperature grain coarsening in gold films on polyimide induced
by cyclic uniaxial mechanical strain is demonstrated. Detailed electron
backscatter diffraction analysis revealed that, in contrast to the predictions
of shear-coupled grain boundary migration model, the grain coarsening is
isotropic and coarsened grains do not exhibit any specific crystallographic
orientations or misorientations to the neighboring grains. It is shown that a
thermodynamic model where the driving force appears due to the difference in
yield stresses between the grains with different sizes provides an adequate
explanation of the experimental data.
