Shear banding leads to accelerated aging dynamics in a metallic glass

Article

关键词: STRETCHED-EXPONENTIAL RELAXATION;    PHOTON-CORRELATION SPECTROSCOPY;    HETEROGENEOUS DYNAMICS;    SUPERCOOLED LIQUIDS;    TEMPERATURE;    DEFORMATION;    STRESS;    CAVITATION;    TRANSITION;    DEPENDENCE;   

DOI  :  10.1103/PhysRevB.97.014204

来源: SCIE

【 摘 要 】

Traditionally, strain localization in metallic glasses is related to the thickness of the shear defect, which is confined to the nanometer scale. Using site-specific x-ray photon correlation spectroscopy, we reveal significantly accelerated relaxation dynamics around a shear band in a metallic glass at a length scale that is orders of magnitude larger than the defect itself. The relaxation time in the shear-band vicinity is up to ten times smaller compared to the as-castmatrix, and the relaxation dynamics occurs in a characteristic three-stage aging response that manifests itself in the temperature-dependent shape parameter known from classical stretched exponential relaxation dynamics of disordered materials. We demonstrate that the time-dependent correlation functions describing the aging at different temperatures can be captured and collapsed using simple scaling functions. These insights highlight how a ubiquitous nanoscale strain-localization mechanism in metallic glasses leads to a fundamental change of the relaxation dynamics at the mesoscale.

【 授权许可】

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