Abstract
Heterogeneous microscale dynamics in the martensitic phase transition of cobalt is investigated with real-time x-ray scattering. During the transformation of the high-temperature face-centered cubic phase to the low-temperature hexagonal close-packed phase, the structure factor evolution suggests that an initial rapid local transformation is followed by a slower period during which strain relaxes. Coherent x-ray scattering measurements performed during the latter part of the transformation show that the kinetics is dominated by discontinuous sudden changes—avalanches. The spatial size of observed avalanches varies widely, from 100 nm to , the size of the x-ray beam. An empirical avalanche amplitude quantifies this behavior, exhibiting a power-law distribution. The avalanche rate decreases with inverse time since the onset of the transformation.
- Received 5 April 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.015702
© 2011 American Physical Society
Synopsis
Atomic avalanches show up in x rays
Published 30 June 2011
State-of-the-art x-ray scattering demonstrates sudden avalanche-like structural changes in cobalt.
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