Strain-induced formation of carbon and boron clusters in boron carbide during dynamic indentation

The authors found that the level of amorphization or structural disorder in boron carbide is higher when induced by dynamic indentation compared to static indentation. Visible and uv Raman spectroscopies indicate that sp(2)-bonded aromatic carbon clusters were formed, consistent with the detected photoluminescence spectra. Infrared absorption shows that amorphous boron clusters were created by dynamic indentation which has strain rates similar to 10(8) order higher than that introduced by static indentation. The decreased intensity of infrared stretching mode of carbon-boron-carbon (CBC) chains also suggests that amorphization is due to the collapse of B11C(CBC) unit cells, which reorganize into the energetically favorite carbon and boron clusters.