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Title:
Dynamic fracture of tantalum under extreme tensile stress
Affiliation(s):
XFEL.EU staff, Other
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Abstract:
The understanding of fracture phenomena of a material at extremely high strain rates is a key issue for a wide variety of scientific research ranging from applied science and technological developments to fundamental science such as laser-matter interaction and geology. Despite its interest, its study relies on a fine multiscale description, in between the atomic scale and macroscopic processes, so far only achievable by large-scale atomic simulations. Direct ultrafast real-time monitoring of dynamic fracture (spallation) at the atomic lattice scale with picosecond time resolution was beyond the reach of experimental techniques. We show that the coupling between a high-power optical laser pump pulse and a femtosecond x-ray probe pulse generated by an x-ray free electron laser allows detection of the lattice dynamics in a tantalum foil at an ultrahigh strain rate of $\dot{\varepsilon}$ $\sim$ 2 × $10{^8}$ to 3.5 × $10{^8} s{^−}{^1}$. A maximal density drop of 8 to 10%, associated with the onset of spallation at a spall strength of $\sim$ 17 GPa, was directly measured using x-ray diffraction. The experimental results of density evolution agree well with large-scale atomistic simulations of shock wave propagation and fracture of the sample. Our experimental technique opens a new pathway to the investigation of ultrahigh strain-rate phenomena in materials at the atomic scale, including high-speed crack dynamics and stress-induced solid-solid phase transitions.
Imprint:
USA, AAAS, 2017
Journal Information:
Science Advances, Vol. 3, no.6 (3.6), e1602705 (2017)
External related publications:
Language(s):
English


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 Record created 2018-06-22, last modified 2018-06-22

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