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Glassy carbon (GC) is usually considered the prototypical super-elastic material, which can almost fully recover its shape after compression of several gigapascals (GPa). In this work, nanoindentation is used to study the mechanical response of GC, which was subjected to a range of high pressures using a diamond anvil cell (DAC). We show that GC starts to lose its elasticity after compression to 6 GPa and becomes clearly mechanically anisotropic after being compressed beyond ∼30 GPa. Molecular dynamics (MD) simulations are used to calculate Young's modulus before and after compression. Through our experimental results and MD simulations, we show that the elasticity of GC is at a minimum around 30 GPa but recovers after compression to higher pressures along the DAC compression axis.

The mechanical properties of carbide-derived carbons (CDCs) are computed using molecular dynamics simulations, spanning the experimental density range and synthesis temperatures. The structures consist of nanoporous networks with continuous graphene walls enclosing the pores. Calculation of elastic constants and simulation of tensile strain reveal a direct relationship between the microstructure and elasticity, with the density and temperature inducing significant changes in the pore topology and medium-range order. CDCs have a high elastic moduli and high ultimate tensile strengths while showing resistance to brittle fracture. This suggests that CDCs are a promising route to achieve dense 3D graphene networks with tunable mechanical properties.The mechanical properties of carbide-derived carbons (CDCs) are computed using molecular dynamics simulations, spanning the experimental density range and synthesis temperatures. The structures consist of nanoporous networks with continuous graphene walls enclosing the pores. Calculation of elastic constants and simulation of tensile strain reveal a direct relationship between the microstructure and elasticity, with the density and temperature inducing significant changes in the pore topology and medium-range order. CDCs have a high elastic moduli and high ultimate tensile strengths while showing resistance to brittle fracture. This suggests that CDCs are a promising route to achieve dense 3D graphene networks with tunable mechanical properties.

Computational methods are used to control the degree of structural order in a variety of carbon materials containing primarily sp2 bonding. Room-temperature thermal conductivities are computed using non-equilibrium molecular dynamics. Our results reproduce experimental data for amorphous and glassy carbons and confirm previously proposed structural models for vitreous carbons. An atomistic model is developed for highly oriented thin films seen experimentally, with a maximum computed thermal conductivity of 35 W m−1 K−1. This value is much higher than that of the amorphous and glassy structures, demonstrating that the microstructure influences the thermal conductivity more strongly than the density.