Shock-induced amorphization in silicon carbide

While silicon carbide (SiC) has been predicted to undergo pressure-induced amorphization, the microstructural evidence of such a drastic phase change is absent as its brittleness usually prevents its successful recovery from high-pressure experiments. Here we report on the observation of amorphous S...

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Bibliographic Details
Published in:Acta materialia 2018-10, Vol.158, p.206-213
Main Authors: Zhao, S., Flanagan, R., Hahn, E.N., Kad, B., Remington, B.A., Wehrenberg, C.E., Cauble, R., More, K., Meyers, M.A.
Format: Article
Language:English
Subjects:
Amorphization
Laser shock compression
Lasers
MATERIALS SCIENCE
Silicon carbide
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Summary:While silicon carbide (SiC) has been predicted to undergo pressure-induced amorphization, the microstructural evidence of such a drastic phase change is absent as its brittleness usually prevents its successful recovery from high-pressure experiments. Here we report on the observation of amorphous SiC recovered from laser-ablation-driven shock compression with a peak stress of approximately 50 GPa. Transmission electron microscopy reveals that the amorphous regions are extremely localized, forming bands as narrow as a few nanometers. In addition to these amorphous bands, planar stacking faults are observed. Large-scale non-equilibrium molecular dynamic simulations elucidate the process and suggest that the planar stacking faults serve as the precursors to amorphization. Our results suggest that the amorphous phase produced is a high-density form, which enhances its thermodynamical stability under the high pressures combined with the shear stresses generated by the uniaxial strain state in shock compression. [Display omitted]
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2018.07.047