Shock-induced amorphization in silicon carbide

While 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 observatio of amorphous SiC recovered from laser-ablation-driven shock compression with a peak stress of about 50GPa. TEM 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 MD 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

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Recommended citation: S. Zhao, R. Flanagan, E.N. Hahn, B. Kad, B.A.Remington, C.E. Wehrenberg, R. Cauble, K. More, M.A. Meyers. (2016). “Shock-induced amorphization in silicon carbide.” Acta Materialia. 158(206-213).