The effect of microstructural evolution on micromechanical behavior of pyrolytic carbon after heat treatment

In order to investigate the effect of microstructural evolution on the micromechanical behavior of pyrolytic carbon (PyC), the microstructural parameters and evolution of high texture (HT) and medium texture (MT) PyC after heat treatment from 1600 °C to 2450 °C were studied comparatively. The micro-indentation test was also performed to reveal the micromechanics. In terms of microstructure, after heat treatment, the HT matrix was directly delaminated into many nano-layers accompanied by multiple microcracks, while the MT matrix was delaminated into micro-layers including lots of cracks. Meanwhile, numerous nanopores were still observed in the MT matrix after heat treatment at 2450 °C. The interfaces of two textures became smoother and wider, and the width of HT interface was narrower than that of MT at different heat treatment temperatures. Moreover, the increasing tendency of the basal plane length (L_a) and the height of layered stacking (L_c) of HT were greater than those of MT as HT PyC contained more C[dbnd]C bonds than MT PyC. The micro-indentation results showed that the indentation depth of HT was always deeper than that of MT, and the corresponding micro-hardness and elastic modulus of MT were also greater than that of HT after different temperature treatment.