Three-dimensional imaging of dislocation propagation during crystal growth and dissolution

TL;DR

This paper demonstrates how Bragg Coherent Diffraction Imaging (BCDI) enables in situ 3D visualization of dislocation networks within crystals during growth and dissolution, revealing their role in material behavior.

Contribution

The study introduces the application of BCDI for in situ 3D imaging of dislocation dynamics during crystal growth and dissolution, a capability not available with traditional techniques.

Findings

BCDI can visualize entire dislocation networks in 3D within single crystals.

Dislocation propagation correlates with crystal growth and dissolution mechanisms.

The method offers insights into the material response to external stimuli.

Abstract

Atomic level defects such as dislocations play key roles in determining the macroscopic properties of crystalline materials. Their effects are important and wide-reaching, and range from increased chemical reactivity to enhanced mechanical properties to vastly increased rates of crystal growth. Dislocations have therefore been widely studied using traditional techniques such as X-ray diffraction (XRD) and optical imaging. More recently, advances in microscopy have allowed their direct visualization. Atomic force microscopy (AFM) has enabled the 2D study of single dislocations while transmission electron microscopy (TEM), which was initially limited to 2D projections of thin specimens, can now visualize strain fields in 3D with near atomic resolution. However, these techniques can- not offer in situ, 3D imaging of the formation or movement of dislocations during dynamic processes such as crystal growth and dissolution. Here, we describe how Bragg Coherent Diffraction Imaging (BCDI) can be used to visualize in 3D the entire network of dislocations present within an individual crystal. Using calcite (CaCO3) single crystals, we also use BCDI to monitor the propagation of the dislocation network during repeated growth and dissolution cycles, and show how this is intimately linked to the growth and dissolution mechanisms. These investigations demonstrate the potential of BCDI for studying the mechanisms underlying the response of crystalline materials to external stimuli.