Time-Resolved Laue Diffraction of Deforming Micropillars

We demonstrate real-time resolved white beam Laue diffraction during compression of micron-sized focused ion beam milled single crystals Au pillars, revealing the dynamical correlation between microstructure and plasticity. The evolution of the Laue patterns of the Au pillars demonstrates the occurrence of crystal rotation and strengthening is explained by plasticity starting on a slip system that is geometrically not predicted but selected because of the character of the preexisting strain gradient.

Figure 1

The engineering stress-strain curves shown are the curves for a $2\mu \mathrm{m}$ and a $10\mu \mathrm{m}$ pillar. The arrows indicate the corresponding Laue patterns taken during compression.

Figure 2

Scanning electron microscopy images of (a) the $2\mu \mathrm{m}$ pillar evidencing three active slip planes and (b) the $10\mu \mathrm{m}$ pillar evidencing two active slip systems.

Figure 3

Results obtained from the Laue patterns taken during deformation of the $2\mu \mathrm{m}$ pillar. (a) Inverse pole figure showing crystal rotation via the evolution of the compression axis in the reciprocal space of the pillar. The orientation before deformation is indicated in red (gray) and the red (gray) arrow indicates the classical rotation direction. The actual path direction is given by the arrow in the inset. (b) Satellite peak path emerging from the $(\overline{2}00)$ peak during deformation with vectors showing the different directions associated with classical rotation. The indicated numbers correspond with those on the stress-strain curve in Fig. 1. Intensity distribution of the $(\overline{2}2\overline{2})$ reflection prior to deformation (c), loaded to 40 MPa (d) and loaded to 77 MPa (e). White lines represent the streaking directions and black lines the peak path associated with crystal rotation.