In situ visualization of long-range defect interactions at the edge of melting

Connecting a bulk material's microscopic defects to its macroscopic properties is an age-old problem in materials science. Long-range interactions between dislocations (line defects) are known to play a key role in how materials deform or melt, but we lack the tools to connect these dynamics to the macroscopic properties. We introduce time-resolved dark-field x-ray microscopy to directly visualize how dislocations move and interact over hundreds of micrometers deep inside bulk aluminum. With real-time movies, we reveal the thermally activated motion and interactions of dislocations that comprise a boundary and show how weakened binding forces destabilize the structure at 99% of the melting temperature. Connecting dynamics of the microstructure to its stability, we provide important opportunities to guide and validate multiscale models that are yet untested.

Automated summary

This study utilized time-resolved dark-field x-ray microscopy to directly observe the movement and interactions of dislocations in bulk aluminum. Real-time movies revealed the thermally activated motion and interactions of dislocations, as well as the structural instability near the melting temperature.