Date of Award
Program or Major
Master of Science
We used micro- and nanoindentation, macroscopic strain gage methods and FE studies to correlate the indentation modulus and the macroscopic in- and out-of-plane Young's moduli of transversely isotropic pyrolytic carbon. The out-of-plane indentation modulus of bulk PyroC was comparable with predicted values and more than a factor of two higher than the out-of-plane Young's modulus. The in-plane indentation modulus was significantly lower than predicted values which we attribute to nanobuckling of graphite-like planes. Polarized light microscopy studies on carbon-carbon composite samples infiltrated at 10, 20, 30 kPa demonstrated that the increase in pressure leads to lower texture of the PyroC and higher in-plane indentation modulus due to a decreased tendency toward nanobuckling for more isotropic structures. We observed damage of PyroC layers at critical loads when indenting normal to the plane of isotropy and attribute the damage to a combination of crack propagation and delamination types of deformation mechanisms.
Timoshchuk, Nikolay, "On the ability of indentation to capture the anisotropic elastic properties of the pyrolytic carbon" (2011). Master's Theses and Capstones. 671.