Microstructural analysis of high-pressure compressed C₆₀

The structure and hardness of C₆₀ bulk specimens compressed under 5.5 GPa at room temperature to 600 °C are investigated by high-resolution transmission electron microscopy, x-ray diffraction, and micro-Vickers hardness tests. A strong accumulation of the [1 1 0]_tr orientation of high-pressure-treated C₆₀ specimens was developed along the compression axis, and stacking faults and nano-sized deformation twins were introduced into the C₆₀ specimens compressed at 450–600 °C. Curved lattice planes indicating a polymerization of C₆₀ were observed by high resolution transmission electron microscopy (HRTEM). The polymerization of the high-pressure-compressed C₆₀ is also supported by the computer simulation of HRTEM images.