Mechanical Properties of Vacancy Tuned Carbon Honeycomb.

Lu Xie,Haojie An,Qin Qin,Qing Peng,Chenwei He

doi:10.3390/nano9020156

Abstract

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.

Highlights

Carbon is one of the most versatile and flexible elements, which can form a variety of carbon allotropes including both 1D carbon nanotubes (CNTs) and 2D graphene with different atomic arrangements
Single atom vacancy defect is reported to reduce the strength of CNT by 19% [17]
molecular dynamics (MD) method has been employed to study the mechanical properties of CHC along different directions

Summary

Introduction

Carbon is one of the most versatile and flexible elements, which can form a variety of carbon allotropes including both 1D carbon nanotubes (CNTs) and 2D graphene with different atomic arrangements. The mechanical properties of CHC studied by Zhang et al [15] show that the Young’s modulus of the structures is determined solely by the density of the hinges, regardless of the structural orientation or regularity and the failure strain of the honeycomb structure is affected significantly by its lattice size and geometrical regularity. Gu et al [16] studied the effects of carbon atoms in the triple junction on the performance of CHC and discussed the mechanical properties of CHC with different chirality and sizes. The mechanical properties of CHC has strong lattice size effect and direction dependence.

Results

Conclusion