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Title: Direct Measurement of Microstructural Avalanches during the Martensitic Transition of Cobalt Using Coherent X-Ray Scattering

Journal Article · · Phys. Rev. Lett.

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 10{mu}m, 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.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Organization:
NSFDOE - BASIC ENERGY SCIENCES
OSTI ID:
1024042
Journal Information:
Phys. Rev. Lett., Vol. 107, Issue (1) ; 07, 2011; ISSN 0031-9007
Country of Publication:
United States
Language:
ENGLISH