Mechanical Properties of Vacancy Tuned Carbon Honeycomb

Carbon honeycomb (CHC) has great application potential in many aspects for the outstanding mechanical properties. However, the effect of both defects and temperature on the mechanical properties are far from reasonable understanding, which might be a huge obstacle for its promising applications as engineering materials. In this work, we investigate the effect of vacancy-type defect, which is inevitably exists in material, on the mechanical properties of CHC via reactive molecular dynamics simulations. The mechanical strength is anisotropic and decreases with the increasing temperature. CHC yield in cell axis direction since the break of C⁻C bonds on the junction. Vacancies weaken CHC by reducing the strength and failure strain. The effect of single vacancy on strength of CHC becomes more obvious with reducing temperature and is sensitive to the location and bonding of the vacancies. The maximum reduction of strength in cell axis direction is with vacancy on the middle of the wall of CHC where sp² bonds are removed. The strength is reduced by 8.1% at 500 K, 11.5% at 300 K and 12.8% at 100 K. With 0.77% defect concentration, the strength reduces 40.3% in cell axis direction but only 18.7% in zigzag direction and 24.4% in armchair direction.